Merge pull request '[s7] S7 — Optimized DB / S7Plus (decision PR)' (#408) from auto/s7/PR-S7-F into auto/driver-gaps

Closes #304

ZB.MOM.WW.OtOpcUa.slnx

@@ -13,12 +13,13 @@
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ZB.MOM.WW.OtOpcUa.Driver.Modbus.csproj"/>
-        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.S7/ZB.MOM.WW.OtOpcUa.Driver.S7.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/ZB.MOM.WW.OtOpcUa.Driver.AbCip.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Shared/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Shared.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Host/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Host.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Client.Shared/ZB.MOM.WW.OtOpcUa.Client.Shared.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Client.CLI/ZB.MOM.WW.OtOpcUa.Client.CLI.csproj"/>
@@ -49,7 +50,6 @@
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy.Tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.E2E/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.E2E.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests.csproj"/>
-        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing.Tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli.Tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli.Tests.csproj"/>
@@ -65,7 +65,8 @@
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests.csproj"/>
-        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Shared.Tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Shared.Tests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Host.Tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Host.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests.csproj"/>

docs/Client.CLI.md

@@ -183,19 +183,46 @@ otopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa \
 | `--start` | Start time, ISO 8601 or date string (default: 24 hours ago) |
 | `--end` | End time, ISO 8601 or date string (default: now) |
 | `--max` | Maximum number of values (default: 1000) |
-| `--aggregate` | Aggregate function: Average, Minimum, Maximum, Count, Start, End |
+| `--aggregate` | Aggregate function name (see catalog below). Case-insensitive. |
 | `--interval` | Processing interval in milliseconds for aggregates (default: 3600000) |
 
 #### Aggregate mapping
 
+The CLI accepts the seven aggregates listed below — these are the
+human-driven set the operator typically asks for from the command line.
+
 | Name | OPC UA Node ID |
 |------|---------------|
-| `Average` | `AggregateFunction_Average` |
+| `Average` (or `avg`) | `AggregateFunction_Average` |
-| `Minimum` | `AggregateFunction_Minimum` |
+| `Minimum` (or `min`) | `AggregateFunction_Minimum` |
-| `Maximum` | `AggregateFunction_Maximum` |
+| `Maximum` (or `max`) | `AggregateFunction_Maximum` |
 | `Count` | `AggregateFunction_Count` |
-| `Start` | `AggregateFunction_Start` |
+| `Start` (or `first`) | `AggregateFunction_Start` |
-| `End` | `AggregateFunction_End` |
+| `End` (or `last`) | `AggregateFunction_End` |
+| `StandardDeviation` (or `stddev` / `stdev`) | `AggregateFunction_StandardDeviationSample` |
+
+The driver-side `IHistoryProvider.ReadProcessedAsync` API (used by the
+OtOpcUa server's HistoryRead facade) supports the full OPC UA Part 13 §5
+catalog — ~30 aggregates including `TimeAverage`, `Interpolative`, `Range`,
+`PercentGood`, `Delta`, etc. See
+[`docs/drivers/OpcUaClient.md`](drivers/OpcUaClient.md#historyread-aggregates-part-13-catalog)
+for the full list. Adding a new CLI shorthand is a one-line change in
+`HistoryReadCommand.ParseAggregateType` — file an issue if you need one
+exposed.
+
+#### Event-mode coverage
+
+Drivers that implement the filter-aware
+`IHistoryProvider.ReadEventsAsync(fullReference, EventHistoryRequest, ct)`
+overload (currently the OPC UA Client gateway driver — Galaxy keeps the
+fixed-field fallback) honour `EventFilter` SelectClauses and a `WhereClause`
+when the server-side history facade forwards them. The CLI does not yet
+expose a dedicated `--events` flag — clients that need filter-aware event
+history call `HistoryReadEvents` through their own SDK; the CLI's
+`historyread` command stays focused on the data-history (Raw / Processed /
+AtTime) path. Adding `--events` is tracked as a follow-up — the wire path
+on the driver side is in place (see
+[`docs/drivers/OpcUaClient.md`](drivers/OpcUaClient.md#historyread-events)).
 
 ### alarms
 

docs/Driver.AbCip.Cli.md

@@ -20,6 +20,8 @@ dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli -- --help
 | `-g` / `--gateway` | **required** | Canonical `ab://host[:port]/cip-path` |
 | `-f` / `--family` | `ControlLogix` | ControlLogix / CompactLogix / Micro800 / GuardLogix |
 | `--timeout-ms` | `5000` | Per-operation timeout |
+| `--addressing-mode` | `Auto` | `Auto` / `Symbolic` / `Logical` — see [AbCip-Performance §Addressing mode](drivers/AbCip-Performance.md#addressing-mode). `Logical` against Micro800 silently falls back to Symbolic with a warning. |
+| `--partner` | _(unset)_ | PR abcip-5.1 — partner gateway URI for a ControlLogix HSBY pair (e.g. `ab://10.0.0.6/1,0`). When set, the driver runs a second role-probe loop against the partner and the [`hsby-status`](#hsby-status--which-chassis-is-active-now) command can surface which chassis is currently Active. See [AbCip-HSBY.md](drivers/AbCip-HSBY.md) for the full guide. |
 | `--verbose` | off | Serilog debug output |
 
 Family ↔ CIP-path cheat sheet:
@@ -55,6 +57,21 @@ otopcua-abcip-cli read -g ab://10.0.0.5/1,0 -t "Recipe[3]" --type Real
 otopcua-abcip-cli read -g ab://10.0.0.5/1,0 -t "Motor01.Speed" --type Real
 ```
 
+#### Diagnostic / system tags
+
+PR abcip-4.3 exposes five read-only diagnostic variables per device under
+`AbCip/<device>/_System/` in the OPC UA address space (see
+[AbCip-Operability §System tags](drivers/AbCip-Operability.md#system-tags--_system-folder)
+for the full table). These are not reachable through the AB CIP CLI — they
+live on the OPC UA server side, not the libplctag wire — so to read one,
+point the **OPC UA client** CLI at the running OtOpcUa server:
+
+```powershell
+# Read _ConnectionStatus for one device through the OPC UA server
+otopcua-client-cli read -u opc.tcp://localhost:4840 \
+    -n "ns=2;s=AbCip/ab://10.0.0.5/1,0/_System/_ConnectionStatus"
+```
+
 ### `write` — single Logix tag
 
 Same shape as `read` plus `-v`. Values parse per `--type` using invariant
@@ -73,6 +90,65 @@ otopcua-abcip-cli write -g ab://10.0.0.5/1,0 -t StartCommand --type Bool -v true
 otopcua-abcip-cli subscribe -g ab://10.0.0.5/1,0 -t Motor01_Speed --type Real -i 500
 ```
 
+### `hsby-status` — which chassis is Active now?
+
+PR abcip-5.1 — read the role tag (`WallClockTime.SyncStatus` by default,
+`S:34` for legacy SLC500 / PLC-5 fronts) on a ControlLogix HSBY pair and
+print which chassis is currently Active. Requires `--partner`.
+
+```powershell
+otopcua-abcip-cli hsby-status -g ab://10.0.0.5/1,0 --partner ab://10.0.0.6/1,0
+
+# Custom role tag (legacy fronts) and more samples
+otopcua-abcip-cli hsby-status -g ab://10.0.0.5/1,0 --partner ab://10.0.0.6/1,0 \
+    --role-tag S:34 --samples 5
+```
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `--role-tag` | `WallClockTime.SyncStatus` | Address of the role tag. Use `S:34` for SLC500 / PLC-5. |
+| `--samples` | `3` | Number of role-probe ticks to wait for before printing. |
+
+The output prints the resolved roles + the address of whichever chassis the
+driver currently considers Active. PR abcip-5.1 only **reports** the role —
+PR abcip-5.2 will land the routing change so reads / writes flow to the
+Active chassis automatically.
+
+See [AbCip-HSBY.md](drivers/AbCip-HSBY.md) for the role-tag detection matrix
++ active-resolution rules + the feature-flag gate.
+
+### `rebrowse` — force a controller-side `@tags` re-walk
+
+PR abcip-2.5 (issue #233) added `RebrowseAsync` to drop the cached UDT
+template shapes and re-run the symbol-table enumerator without restarting
+the driver. The CLI variant builds a transient driver against the supplied
+gateway, runs the rebrowse, and prints the freshly discovered tag names —
+useful after a controller program-download to confirm the new tags are
+visible on the wire before wiring them through the OtOpcUa server.
+
+```powershell
+otopcua-abcip-cli rebrowse -g ab://10.0.0.5/1,0
+```
+
+## Refreshing the tag DB
+
+Two operator-facing surfaces drive the same `RebrowseAsync` plumbing — pick
+the one that matches your context:
+
+| Surface | When to use | Command |
+|---|---|---|
+| **CLI `rebrowse`** | Off-server validation. Spins up a transient driver against the gateway, prints the discovered tag list, no shared state with the live OtOpcUa server. | `otopcua-abcip-cli rebrowse -g ab://10.0.0.5/1,0` |
+| **OPC UA write to `_RefreshTagDb`** | Production / Admin-UI button (PR abcip-4.4). Forces the **live** driver to re-walk + clear its template cache. The `AbCip.RefreshTriggers` driver-diagnostics counter increments per truthy write. | `otopcua-client-cli write -u opc.tcp://localhost:4840 -n "ns=2;s=AbCip/ab://10.0.0.5/1,0/_System/_RefreshTagDb" -v true --type Boolean` |
+
+Read-back semantics: `_RefreshTagDb` always reads back as `false` (Kepware-
+style "latches to idle the moment the dispatch returns") so a subscribed
+client sees a stable shape regardless of how many refreshes have fired.
+Falsy / unparseable writes are no-ops that still report `Good` so a UI
+template that resets the trigger flag after firing it doesn't see a phantom
+error. See
+[AbCip-Operability §System tags](drivers/AbCip-Operability.md#refreshing-the-tag-db-via-opc-ua-write)
+for the full semantics + the diagnostics counter wiring.
+
 ## Typical workflows
 
 - **"Is the PLC reachable?"** → `probe`.
@@ -81,3 +157,36 @@ otopcua-abcip-cli subscribe -g ab://10.0.0.5/1,0 -t Motor01_Speed --type Real -i
 - **"Is this GuardLogix safety tag writable from non-safety?"** → `write` and
   read the status code — safety tags surface `BadNotWritable` / CIP errors,
   non-safety tags surface `Good`.
+- **"Did my program download show up in the address space?"** → `rebrowse`
+  (off-server) or write `true` to the live server's `_RefreshTagDb` system
+  tag (in-server, PR abcip-4.4) — both drop the template cache + force a
+  fresh `@tags` walk.
+
+## Connection Size
+
+PR abcip-3.1 introduced a per-device `ConnectionSize` override on the driver
+side (`AbCipDeviceOptions.ConnectionSize`, range `500..4002`). The CLI does
+not expose a flag for it — every CLI invocation uses the family-default
+Connection Size (4002 / 504 / 488 depending on `--family`). When a Forward
+Open is rejected with a CIP error like `0x01/0x113` ("connection request
+size invalid"), the symptom is almost always a **mismatch between the chosen
+family default and the controller firmware**:
+
+- **v19-and-earlier ControlLogix** caps at 504 — pick `--family CompactLogix`
+  on the CLI to fall back to that narrower default.
+- **5069-L1/L2/L3 CompactLogix** narrow-buffer parts also cap at 504, which
+  is the family default already.
+- **FW20+ ControlLogix** accepts the full 4002.
+
+For the warning *"AbCip device 'X' family 'Y' uses a narrow-buffer profile
+(default ConnectionSize Z); the configured ConnectionSize N exceeds the
+511-byte legacy-firmware cap..."* see
+[`docs/drivers/AbCip-Performance.md`](drivers/AbCip-Performance.md) — that
+warning is fired by the driver host, not the CLI.
+
+## Related operability knobs
+
+- [`docs/drivers/AbCip-Operability.md`](drivers/AbCip-Operability.md) — Phase 4
+  per-tag knobs (per-tag scan rate, deadband, etc). The CLI does not expose
+  these knobs directly; they're set in driver config JSON and consumed by the
+  driver at subscribe time.

docs/Driver.AbLegacy.Cli.md

@@ -19,7 +19,11 @@ dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli -- --help
 |---|---|---|
 | `-g` / `--gateway` | **required** | Canonical `ab://host[:port]/cip-path` |
 | `-P` / `--plc-type` | `Slc500` | Slc500 / MicroLogix / Plc5 / LogixPccc |
-| `--timeout-ms` | `5000` | Per-operation timeout |
+| `--timeout-ms` | `5000` | Per-operation timeout — see precedence note below |
+| `--retries` | `0` | Retry count on transient `BadCommunicationError` (PR 9 / #252) |
+| `--demote-failure-threshold` | `3` | **PR ablegacy-12 / #255** — consecutive comm failures before the device is auto-demoted |
+| `--demote-for-ms` | `30000` | **PR ablegacy-12 / #255** — auto-demote cool-down window in ms |
+| `--no-demote` | off | **PR ablegacy-12 / #255** — disable auto-demote entirely (counters still tick) |
 | `--verbose` | off | Serilog debug output |
 
 Family ↔ CIP-path cheat sheet:
@@ -28,6 +32,52 @@ Family ↔ CIP-path cheat sheet:
   with no backplane
 - **LogixPccc** — `1,0` (Logix controller accessed via the PCCC compatibility
   layer; rare)
+- **PLC-5 via 1756-DHRIO bridge** — `1,<slot>,2,<station-octal>` (PLC-5 only).
+  See [drivers/AbLegacy-DH-Bridging.md](drivers/AbLegacy-DH-Bridging.md) for
+  the full DH+ syntax, octal-station reference (00..77 = 0..63), and manual
+  hardware smoke procedure.
+
+#### DHRIO worked example (PR ablegacy-13 / #256)
+
+PLC-5 on DH+ node 7 (octal 07), DHRIO module in chassis slot 3,
+EtherNet/IP gateway 192.168.1.10:
+
+```powershell
+otopcua-ablegacy-cli read `
+    -g ab://192.168.1.10/1,3,2,07 `
+    -P Plc5 -a N7:10 -t Int
+```
+
+The parser validates `1,<slot>,2,<station>`: port-1 must be the backplane,
+slot must be 0..16, port-3 must be `2` (DH+), station must be octal 0..77 (so
+`80`, `90`, etc. are rejected). Combining a DH+ bridge path with a non-PLC-5
+family at startup throws `InvalidOperationException("DHRIO bridging is
+PLC-5-only")`.
+
+### Per-device timeout / retry tuning (#252, PR 9)
+
+The CLI's `--timeout-ms` is the **driver-wide default** when launched as a
+one-shot test client. In production (server-side, multi-device deployment)
+each `AbLegacyDeviceOptions` row carries its own optional `Timeout` /
+`Retries` that override the driver-wide value.
+
+Precedence (highest → lowest): per-device override → driver-wide default →
+hard-coded fallback (2000 ms / 0 retries).
+
+Tuning cheat sheet — start here, measure, then trim:
+
+| Family | Recommended `Timeout` | Notes |
+|---|---|---|
+| SLC 5/01 (RS-232 / DH+ bridge) | **5000 ms** | Slowest of the bunch; serial round-trip plus DH+ hop |
+| SLC 5/02 / 5/03 (DH+) | 3000 ms | Bridged Ethernet → DH+ adds ~1 s |
+| **SLC 5/04 / 5/05** (Ethernet) | **2000 ms** | Fastest of the SLC family — direct EIP/PCCC |
+| MicroLogix 1100 / 1400 | **3000 ms** | Single-CPU, slow scan; no backplane |
+| PLC-5 (Ethernet I/F) | 2500 ms | Comparable to SLC 5/05 over EIP |
+| LogixPccc compat layer | 2000 ms | Logix CPU is fast; PCCC layer is the floor |
+
+A small `--retries 1` (or `2` for slow chassis) is generally safe — the retry
+loop only fires on transient `BadCommunicationError`; terminal errors
+(`BadNodeIdUnknown`, `BadTypeMismatch`, …) surface on the first attempt.
 
 ## PCCC address primer
 
@@ -58,6 +108,37 @@ otopcua-ablegacy-cli probe -g ab://192.168.1.20/1,0
 otopcua-ablegacy-cli probe -g ab://192.168.1.30/ -P MicroLogix -a S:0
 ```
 
+`probe` output (PR ablegacy-12 / #255) reports both `Health` (driver health
+state) and `Host state`. The latter is sourced from `IHostConnectivityProbe`
+and surfaces `Demoted` when the auto-demote threshold has tripped — a fast
+visual signal that the CLI is short-circuiting future reads against this
+device until the cool-down expires:
+
+```text
+Gateway:      ab://192.168.1.20/1,0
+PLC type:     Slc500
+Health:       Degraded
+Host state:   Demoted
+Last error:   libplctag status -33 reading N7:0
+```
+
+### Auto-demote knobs
+
+```powershell
+# Trip after just one comm failure, hold for 60s.
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a N7:0 -t Int `
+    --demote-failure-threshold 1 --demote-for-ms 60000
+
+# Opt out of auto-demote — stresses the link without short-circuiting.
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a N7:0 -t Int --no-demote
+```
+
+The CLI is a one-shot test client — auto-demote primarily matters in the
+server-side multi-device deployment, where a single demoted PLC can no
+longer block reads against its healthy peers. Use the CLI flags to
+reproduce a flapping-link scenario locally before tuning the server-side
+`appsettings.json` `Demote` block.
+
 ### `read`
 
 ```powershell
@@ -75,8 +156,17 @@ otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a L19:0 -t Long
 
 # Timer ACC
 otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a T4:0.ACC -t TimerElement
+
+# Diagnostic counter (PR ablegacy-10 / #253). The seven _Diagnostics/<name>
+# addresses live alongside user tags — short-circuit serves them straight from
+# the in-process counter store, so no PCCC frame is sent to the PLC.
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 --address _Diagnostics/RequestCount
 ```
 
+The diagnostic surface auto-emits per device — no config required. See
+`docs/drivers/AbLegacy-Diagnostics.md` for the full counter table + reset
+semantics + collision-rejection rules.
+
 ### `write`
 
 ```powershell
@@ -95,6 +185,108 @@ PLC-managed — use with caution.
 otopcua-ablegacy-cli subscribe -g ab://192.168.1.20/1,0 -a N7:10 -t Int -i 500
 ```
 
+#### Deadband
+
+PR 8 — per-tag absolute / percent change filter on top of the polled subscription. The driver
+caches the last *published* value per tag and suppresses `OnDataChange` notifications until the
+new sample crosses the configured threshold.
+
+| Flag | Effect |
+|---|---|
+| `--deadband-absolute <value>` | Suppress until `|new - prev| >= value`. |
+| `--deadband-percent <value>` | Suppress until `|new - prev| >= |prev * value / 100|`. `prev == 0` always publishes (avoids div-by-zero). |
+
+Booleans bypass the filter entirely (every transition publishes); strings + status changes
+always publish; first-seen always publishes; both flags set → either passing triggers a
+publish (Kepware-style logical OR).
+
+```powershell
+# Float — drop sub-0.5 jitter from the noisy load-cell address.
+otopcua-ablegacy-cli subscribe -g ab://192.168.1.20/1,0 -a F8:0 -t Float -i 500 `
+    --deadband-absolute 0.5
+
+# Integer — only fire on >= 5% deviation from the last reported value.
+otopcua-ablegacy-cli subscribe -g ab://192.168.1.20/1,0 -a N7:10 -t Int -i 500 `
+    --deadband-percent 5
+```
+
+## Array reads
+
+PR 7 — one PCCC frame can carry up to ~120 words. Address an array tag with either the
+Rockwell-native `,N` suffix or the libplctag-native `[N]` suffix on the word number; both
+forms canonicalise to `[N]` when the driver hands the tag to libplctag, and the parser
+caps `N` at 120.
+
+```powershell
+# Rockwell `,N` form — "10 consecutive words starting at N7:0"
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "N7:0,10" -t Int
+
+# libplctag `[N]` form — same wire result
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "N7:0[10]" -t Int
+
+# Float / Long arrays — same suffix syntax, narrower frame ceiling on Float (~60 elements)
+# and Long (~60 elements) because each element is 4 bytes vs Int's 2.
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "F8:0,4" -t Float
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "L19:0,4" -t Long
+
+# --array-length override — pin the element count from config rather than the address
+# suffix. Wins over the parsed `,N` / `[N]` value when both are set; useful for keeping the
+# address string compact while bumping the element count from a tags config file.
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "N7:0" --array-length 10 -t Int
+```
+
+Array tags reject sub-element references (`T4:0,5.ACC`) and bit suffixes (`N7:0,10/3`) at
+parse time — both combinations are semantically meaningless against a contiguous block.
+
+For `B`-files the Rockwell convention is "one BOOL per word, not per bit": `B3:0,10`
+returns `bool[10]` (one per word's non-zero state), not `bool[160]`.
+
+### `import-rslogix`
+
+ablegacy-11 / [#254](https://github.com/dohertj2/lmxopcua/issues/254) — bulk-import RSLogix
+500 / 5 CSV symbol exports into an `appsettings.json` tag fragment. Avoids hand-typing every
+`N7:0` / `F8:12` / `B3:0/5` row of a several-hundred-tag PLC. Binary `.RSS` / `.RSP` project
+files are out of scope; export to CSV first.
+
+```powershell
+# Default: emit JSON fragment to stdout
+otopcua-ablegacy-cli import-rslogix `
+    --file C:\plc\plc-export.csv `
+    --device ab://192.168.1.20/1,0
+
+# Write the fragment to a file + print a summary line to stdout
+otopcua-ablegacy-cli import-rslogix `
+    --file C:\plc\plc-export.csv `
+    --device ab://192.168.1.20/1,0 `
+    --output tags.json
+
+# Filter by Scope column — only import Local:1 program-scoped tags
+otopcua-ablegacy-cli import-rslogix `
+    --file C:\plc\plc-export.csv `
+    --device ab://192.168.1.20/1,0 `
+    --scope Local:1
+
+# Summary mode — one-line counter for CI / health checks
+otopcua-ablegacy-cli import-rslogix `
+    --file C:\plc\plc-export.csv `
+    --device ab://192.168.1.20/1,0 `
+    --emit summary
+```
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-f` / `--file` | **required** | RSLogix CSV path |
+| `-d` / `--device` | **required** | `ab://host[:port]/cip-path` every imported tag binds to |
+| `--emit` | `appsettings-fragment` | `appsettings-fragment` (JSON) or `summary` (one-line counter) |
+| `-o` / `--output` | stdout | Optional output file path |
+| `--scope` | none | Scope filter — `Global` / `Local:N` (case-insensitive); empty Scope counts as Global |
+| `--max-rows` | unlimited | Defensive cap on rows imported |
+| `--strict` | off | Fail-fast on first malformed row (default permissive: skip + log) |
+
+See [drivers/AbLegacy-RSLogix-Import.md](drivers/AbLegacy-RSLogix-Import.md) for the full
+column reference, file-letter → `AbLegacyDataType` mapping, and the API surface
+(`IRsLogixImporter`, `AbLegacyDriverOptions.AddRsLogixImport`).
+
 ## Known caveat — ab_server upstream gap
 
 The integration-fixture `ab_server` Docker container accepts TCP but its PCCC

docs/Driver.FOCAS.Cli.md

@@ -5,22 +5,27 @@ protocol. Uses the **same** `FocasDriver` the OtOpcUa server does — PMC R/G/F
 file registers, axis bits, parameters, and macro variables — all through
 `FocasAddressParser` syntax.
 
-Sixth of the driver test-client CLIs.
+Sixth of the driver test-client CLIs, added alongside the Tier-C isolation
+work tracked in task #220.
 
 ## Architecture note
 
-FOCAS is an in-process driver. The pure-managed `WireFocasClient`
+FOCAS is a Tier-C driver: `Fwlib32.dll` is a proprietary 32-bit Fanuc library
-speaks the FOCAS2 binary protocol directly over TCP:8193, removing the
+with a documented habit of crashing its hosting process on network errors.
-Tier-C process-isolation split that the historical P/Invoke + out-of-
+The target runtime deployment splits the driver into an in-process
-process Host arrangement required. The CLI loads `FocasDriver` with
+`FocasProxyDriver` (.NET 10 x64) and an out-of-process `Driver.FOCAS.Host`
-`WireFocasClientFactory` and talks to the CNC without any native
+(.NET 4.8 x86 Windows service) that owns the DLL — see
-components.
+[v2/implementation/focas-isolation-plan.md](v2/implementation/focas-isolation-plan.md)
+and
+[v2/implementation/phase-6-1-resilience-and-observability.md](v2/implementation/phase-6-1-resilience-and-observability.md)
+for topology + supervisor / respawn / back-pressure design.
 
-A dev-friendly mock is available — start
+The CLI skips the proxy and loads `FocasDriver` directly (via
-`tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/docker-compose.yml`
+`FwlibFocasClientFactory`, which P/Invokes `Fwlib32.dll` in the CLI's own
-and point `--cnc-host` at `localhost` for end-to-end CLI exercises
+process). There is **no public simulator** for FOCAS; a meaningful probe
-without a real CNC. See
+requires a real CNC + a licensed `Fwlib32.dll` on `PATH` (or next to the
-[drivers/FOCAS-Test-Fixture.md](drivers/FOCAS-Test-Fixture.md).
+executable). On a dev box without the DLL, every wire call surfaces as
+`BadCommunicationError` — still useful as a "CLI wire-up is correct" signal.
 
 ## Build + run
 
@@ -46,6 +51,7 @@ Every command accepts:
 | `-p` / `--cnc-port` | `8193` | FOCAS TCP port (FOCAS-over-EIP default) |
 | `-s` / `--series` | `Unknown` | CNC series — `Unknown` / `Zero_i_D` / `Zero_i_F` / `Zero_i_MF` / `Zero_i_TF` / `Sixteen_i` / `Thirty_i` / `ThirtyOne_i` / `ThirtyTwo_i` / `PowerMotion_i` |
 | `--timeout-ms` | `2000` | Per-operation timeout |
+| `--cnc-password` | (none) | **F4-d (issue #271)** — optional CNC connection-level password emitted via `cnc_wrunlockparam` on connect. Required only by controllers that gate parameter writes / selected reads behind a password switch (16i + some 30i firmwares with parameter-protect on). **PASSWORD INVARIANT: never logged.** The CLI's Serilog config does not destructure this flag and `FocasDeviceOptions.ToString` redacts the value. See [`v2/focas-deployment.md`](v2/focas-deployment.md) § "FOCAS password handling". |
 | `--verbose` | off | Serilog debug output |
 
 ## Addressing
@@ -105,16 +111,74 @@ Values parse per `--type` with invariant culture. Booleans accept
 ```powershell
 otopcua-focas-cli write -h 192.168.1.50 -a R100 -t Int16 -v 42
 otopcua-focas-cli write -h 192.168.1.50 -a G50.3 -t Bit -v on
-otopcua-focas-cli write -h 192.168.1.50 -a MACRO:500 -t Float64 -v 3.14
+
+# MACRO: write — recipe / setpoint surface (server-side WriteOperate ACL)
+otopcua-focas-cli write -h 192.168.1.50 -a MACRO:500 -t Int32 -v 42
+
+# PARAM: write — commissioning surface (server-side WriteConfigure ACL,
+# CNC must be in MDI mode + parameter-write switch enabled, else EW_PASSWD
+# surfaces as BadUserAccessDenied)
+otopcua-focas-cli write -h 192.168.1.50 -a PARAM:1815 -t Int32 -v 100
 ```
 
+> **WARNING — `write -a G50.3 -t Bit -v on` is a read-modify-write.**
+> The wire call `pmc_wrpmcrng` is byte-addressed; the driver reads the
+> parent byte at `G50` first, sets bit 3, and writes the byte back. Other
+> bits in `G50` that the ladder is concurrently updating may be clobbered
+> by the byte we read a millisecond ago. Coordinate via a ladder-side
+> handshake when this matters. **PMC writes also bypass the ladder's
+> normal MDI-mode protection** — a misdirected bit can move motion or
+> latch a feedhold the moment it lands. Verify e-stop is live and the
+> machine is in JOG mode before issuing the first PMC write of a
+> session. See [`docs/drivers/FOCAS.md`](drivers/FOCAS.md) "PMC bit-write
+> read-modify-write semantics" for the full RMW flow.
+
 PMC G/R writes land on a running machine — be careful which file you hit.
 Parameter writes may require the CNC to be in MDI mode with the
 parameter-write switch enabled.
 
+#### Server-enforced ACL — issue #269, plan PR F4-b
+
+When the same write flows through the OtOpcUa server (rather than the CLI's
+direct-to-CNC path), the server-layer ACL gates by tag kind:
+
+- `PARAM:` writes require **`WriteConfigure`** group membership — heavier
+  ACL because a misdirected parameter write can put the CNC in a bad
+  state.
+- `MACRO:` writes require **`WriteOperate`** — matches the standard HMI
+  recipe / setpoint surface.
+- PMC R/G/F writes require **`WriteOperate`**.
+
+The classification is declared by the FOCAS driver per tag and enforced by
+`DriverNodeManager`; the driver itself never inspects user identity. See
+[`docs/security.md`](security.md) for the full LDAP-group → permission
+mapping, [`docs/v2/acl-design.md`](v2/acl-design.md) for the design, and
+[`docs/v2/focas-deployment.md`](v2/focas-deployment.md) "Write safety" for
+the operator pre-check runbook (MDI mode, parameter-write switch).
+
 **Writes are non-idempotent by default** — a timeout after the CNC already
 applied the write will NOT auto-retry (plan decisions #44 + #45).
 
+#### Server-side `Writes` enforcement (issue #268 F4-a + #269 F4-b + #270 F4-c)
+
+The OtOpcUa server gates every FOCAS write behind multiple independent
+opt-ins: `FocasDriverOptions.Writes.Enabled` (driver-level master switch),
+`Writes.AllowParameter` (PARAM kill switch — F4-b), `Writes.AllowMacro`
+(MACRO kill switch — F4-b), `Writes.AllowPmc` (PMC kill switch — F4-c),
+and `FocasTagDefinition.Writable` (per-tag). All default `false`; any one
+off short-circuits the server-side `WriteAsync` to `BadNotWritable` before
+the wire client is touched. See [`docs/drivers/FOCAS.md`](drivers/FOCAS.md)
+"Writes (opt-in, off by default)" subsection +
+[`docs/v2/decisions.md`](v2/decisions.md) for the decision record.
+
+**The CLI bypasses the server-side flag.** `otopcua-focas-cli write` is a
+per-invocation operator tool — it sets `Writes.Enabled = true` locally for
+the lifetime of one process and creates the synthesised tag with
+`Writable = true`. This is intentional: the CLI is the operator's
+direct-to-CNC fallback, not a long-lived process bound to the central
+config DB. Configuring the server still requires both opt-ins to be set
+explicitly in the DriverInstance JSON.
+
 ### `subscribe` — watch an address until Ctrl+C
 
 FOCAS has no push model; the shared `PollGroupEngine` handles the tick
@@ -147,8 +211,7 @@ fails.
 **"Why did this macro flip?"** → `subscribe` to the macro, let the
 operator reproduce the cycle, watch the HH:mm:ss.fff timeline.
 
-**"Can I reach the CNC on TCP:8193?"** → `probe` against any host. A
+**"Is the Fwlib32 DLL wired up?"** → `probe` against any host. A
-`BadCommunicationError` means the wire client couldn't open a socket
+`DllNotFoundException` surfacing as `BadCommunicationError` with a
-(firewall / wrong host / FOCAS Ethernet option unlicensed on the CNC).
+matching `Last error` line means the driver is loading but the DLL is
-`BadDeviceFailure` after a successful connect means the CNC is rejecting
+missing; anything else means a transport-layer problem.
-the session setup — check the CNC's FOCAS option and password settings.

docs/Driver.Modbus.Cli.md

@@ -119,37 +119,3 @@ address.
 **"What's the right byte order for this family?"** → `read` with
 `--byte-order BigEndian`, then with `--byte-order WordSwap`. The one that
 gives plausible values is the correct one for that device.
-
-## v2 addressing grammar
-
-The driver accepts the industry-standard tag-address grammar so you can
-paste tag spreadsheets from Wonderware / Kepware / Ignition without
-per-row manual translation. Full reference + grammar rules:
-[`docs/v2/modbus-addressing.md`](v2/modbus-addressing.md).
-
-Quick examples:
-
-```
-40001                  HoldingRegisters[0], Int16
-400001                 same, 6-digit form
-40001:F                Float32
-40001:F:CDAB           Float32 word-swapped
-40001:STR20            20-char ASCII string
-40001:S:5              Int16[5] array (3-field shorthand)
-40001:F:CDAB:10        Float32[10] with explicit word-swap (4-field strict)
-40001.5                bit 5 of HR[0]
-HR1:I                  Int32 via mnemonic region prefix (matches Wonderware)
-C100                   Coil 100 (mnemonic, 1-based)
-V2000:F:CDAB           DL205 V-memory at PDU 1024 + Float32 + word-swap (Family=DL205)
-D100:I                 MELSEC D-register 100, Int32 (Family=MELSEC)
-```
-
-**Type-code reminder** (post-#146): `:I` is **Int32** (matches Wonderware
-DASMBTCP + Ignition `HRI`). The explicit Int16 code is `:S`. Bare HR/IR
-with no type still defaults to Int16. Pre-#146 codes `:DI` / `:L` /
-`:UDI` / `:UL` / `:LI` / `:ULI` / `:LBCD` are removed; configs that use
-them get a clear "Unknown type code" diagnostic at parse time.
-
-In `DriverConfig` JSON, set the per-tag `addressString` field instead of
-the structured `region` + `address` + `dataType` fields. Both styles can
-coexist within one driver instance.

docs/Driver.S7.Cli.md

@@ -22,6 +22,11 @@ dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli -- --help
 | `--rack` | `0` | Hardware rack (S7-400 distributed setups only) |
 | `--slot` | `0` | CPU slot (S7-300 = 2, S7-400 = 2 or 3, S7-1200/1500 = 0) |
 | `--timeout-ms` | `5000` | Per-operation timeout |
+| `--tsap-mode` | `Auto` | ISO-on-TCP connection class: `Auto` / `Pg` / `Op` / `S7Basic` / `Other`. Hardened S7-1500 / ET 200SP CPUs may require `Op` or `S7Basic`. See [s7.md TSAP / Connection Type](v2/s7.md#tsap--connection-type). |
+| `--local-tsap` | (unset) | Optional 16-bit local TSAP override (e.g. `0x0200`). Required when `--tsap-mode Other`; wins over class default under Pg/Op/S7Basic. |
+| `--remote-tsap` | (unset) | Optional 16-bit remote TSAP override. Required when `--tsap-mode Other`; wins over class default under Pg/Op/S7Basic. |
+| `--password` | (unset) | Connection-level password sent right after `OpenAsync`. Used by hardened S7-300/400 (protection levels 1-3) and S7-1200/1500 (TIA Portal *Connection Mechanism* gate). Never logged. NB: S7netplus 0.20 doesn't expose `SendPassword`; the CLI prints a one-line warning and continues. See [s7.md "PLC password / protection levels"](v2/s7.md#plc-password--protection-levels). |
+| `--protection-level` | `Auto` | Declarative hint: `Auto` / `None` / `Level1` / `Level2` / `Level3` (S7-300/400) / `ConnectionMechanism` (S7-1200/1500). Diagnostic only — the wire-side unlock is driven by `--password`. |
 | `--verbose` | off | Serilog debug output |
 
 ## PUT/GET must be enabled
@@ -31,6 +36,28 @@ Enable it in TIA Portal: *Device config → Protection & Security → Connection
 mechanisms → "Permit access with PUT/GET communication from remote partner"*.
 Without it the CLI's first read will surface `BadNotSupported`.
 
+### Pre-flight PUT/GET enablement (PR-S7-C5)
+
+The driver issues a tiny 2-byte read against `Probe.ProbeAddress` (default
+`MW0`) immediately after `OpenAsync` and **fails `InitializeAsync` with a
+typed `S7PutGetDisabledException`** when the PLC rejects the read with the
+wire-level "function not allowed" response. The exception message names the
+exact TIA Portal toggle to flip — operators see the configuration fix at
+init time, not after the first per-tag read produces `BadDeviceFailure`.
+
+Two opt-out knobs on the JSON `Probe` block:
+
+- `ProbeAddress` — set to `""` (empty string) to skip the pre-flight read
+  entirely. Useful when no fingerprint address has been wired.
+- `SkipPreflight` — set to `true` to defer the check to runtime while
+  keeping the background liveness loop. Per-tag reads still surface
+  `BadDeviceFailure` until PUT/GET is enabled, but Init succeeds and the
+  driver becomes visible in the Admin UI.
+
+See [s7.md "Pre-flight PUT/GET enablement"](v2/s7.md#pre-flight-putget-enablement)
+for the full rationale, classifier behaviour, and the wire-level
+`ErrorCode` matching.
+
 ## S7 address grammar cheat sheet
 
 | Form | Meaning |
@@ -70,6 +97,17 @@ otopcua-s7-cli read -h 192.168.1.30 -a M0.0 -t Bool
 
 # 80-char S7 string
 otopcua-s7-cli read -h 192.168.1.30 -a DB10.STRING[0] -t String --string-length 80
+
+# CPU diagnostics (SZL) — virtual @System.* addresses (PR-S7-E1).
+# Requires ExposeSystemTags = true on the driver instance; surfaces as
+# BadNotSupported until S7netplus exposes a public ReadSzlAsync (or we ship
+# a raw-PDU helper). See docs/v2/s7.md "CPU diagnostics (SZL)" for the full
+# table and the snap7 / S7netplus 0.20 caveat.
+otopcua-s7-cli read -h 192.168.1.30 -a @System.CpuType   -t String
+otopcua-s7-cli read -h 192.168.1.30 -a @System.Firmware  -t String
+otopcua-s7-cli read -h 192.168.1.30 -a @System.OrderNo   -t String
+otopcua-s7-cli read -h 192.168.1.30 -a @System.CycleMs.Min -t Float64
+otopcua-s7-cli read -h 192.168.1.30 -a "@System.DiagBuffer.Entry[0]" -t String
 ```
 
 ### `write`
@@ -83,6 +121,63 @@ otopcua-s7-cli write -h 192.168.1.30 -a M0.0 -t Bool -v true
 **Writes to M / Q are real** — they drive the PLC program. Be careful what you
 flip on a running machine.
 
+### Hardened CPU — forcing OP-class TSAP
+
+```powershell
+# Probe a hardened S7-1500 that rejects PG class but accepts OP.
+otopcua-s7-cli probe -h 10.50.12.30 --tsap-mode Op
+
+# Read against the same CPU.
+otopcua-s7-cli read -h 10.50.12.30 --tsap-mode Op -a DB1.DBW0 -t Int16
+
+# Manual TSAP override (e.g. site with a fixed proprietary TSAP gateway).
+otopcua-s7-cli probe -h 10.50.12.30 --tsap-mode Other --local-tsap 0x4D57 --remote-tsap 0x4D58
+```
+
+Without `--tsap-mode`, the CLI uses S7netplus's CpuType-derived default (PG
+class for almost everything). The same connection-refused failure shape that a
+wrong `--slot` produces also shows up when the CPU rejects PG class — try
+`--tsap-mode Op` first when the handshake is failing on otherwise-correct
+endpoint config. See [s7.md TSAP / Connection Type](v2/s7.md#tsap--connection-type)
+for the byte table and motivation.
+
+### Hardened CPU — supplying a connection-level password
+
+```powershell
+# S7-300 protection-level 2 — read+write protected without unlock.
+otopcua-s7-cli read -h 192.168.1.31 -c S7300 --slot 2 `
+    --password "tia-portal-set-password" `
+    --protection-level Level2 `
+    -a DB1.DBW0 -t Int16
+
+# S7-1500 ConnectionMechanism — TIA Portal Protection & Security pane gate.
+otopcua-s7-cli probe -h 10.50.12.30 `
+    --tsap-mode Op `
+    --password "tia-portal-set-password" `
+    --protection-level ConnectionMechanism
+```
+
+The password is emitted to the PLC immediately after `OpenAsync` succeeds and
+before the pre-flight PUT/GET probe runs (the same probe that would otherwise
+be the first operation a hardened CPU refuses). Never logged in any form;
+identifier-only success line is `S7 password sent for {Host}`.
+
+**S7netplus 0.20 does not yet expose a public `SendPassword`** — the driver
+discovers the method reflectively, so a future minor release will be picked
+up automatically. Until then, configuring `--password` on a hardened CPU
+emits this warning at Init:
+
+```
+[Warning] S7 password is set on driver '<id>' against host '<host>', but
+the linked S7netplus library does not expose SendPassword; password is
+being ignored at the wire.
+```
+
+Init still completes (the COTP handshake itself doesn't require the
+password) but the first read against a hardened CPU will surface
+`BadDeviceFailure`. See [s7.md "PLC password / protection levels"](v2/s7.md#plc-password--protection-levels)
+for the full motivation, the no-log invariant, and the workaround matrix.
+
 ### `subscribe`
 
 ```powershell
@@ -91,3 +186,42 @@ otopcua-s7-cli subscribe -h 192.168.1.30 -a DB1.DBW0 -t Int16 -i 500
 
 S7comm has no native push — the CLI polls through `PollGroupEngine` just like
 Modbus / AB.
+
+### `import-symbols`
+
+PR-S7-D1 / [#299](https://github.com/dohertj2/lmxopcua/issues/299) — read a TIA
+Portal CSV ("Show all tags" export) or STEP 7 Classic `.AWL` file and emit a
+JSON tag fragment for `appsettings.json`, or a one-line summary. Mirrors the
+AB Legacy `import-rslogix` CLI in shape.
+
+```powershell
+# TIA Portal CSV — emit JSON fragment to stdout
+otopcua-s7-cli import-symbols --file plc-export.csv --format tia
+
+# STEP 7 Classic AWL — emit summary line
+otopcua-s7-cli import-symbols --file classic.awl --format awl --emit summary
+
+# DE-locale CSV — auto-detected; output to file
+otopcua-s7-cli import-symbols `
+    --file plc-de.csv `
+    --format tia `
+    --emit appsettings-fragment `
+    --output tags.json
+
+# Strict mode — fail-fast on the first malformed row (CI lint)
+otopcua-s7-cli import-symbols --file plc.csv --format tia --strict
+```
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-f` / `--file` | **required** | Path to the TIA CSV or `.AWL` file |
+| `--format` | `tia` | `tia` (CSV) or `awl` (STEP 7 Classic) |
+| `-d` / `--device` | none | Optional documentation tag (held for symmetry with `import-rslogix`) |
+| `--emit` | `appsettings-fragment` | `appsettings-fragment` (JSON) or `summary` (one-line counter) |
+| `-o` / `--output` | stdout | Optional path; when set the JSON fragment is written there + summary line goes to stdout |
+| `--max-rows` | unlimited | Defensive cap on rows imported |
+| `--strict` | off | Fail-fast on the first malformed row (default permissive: skip + log) |
+
+UDT-typed rows import as placeholder tags (data type forced to `Byte`); see
+[S7-TIA-Import.md](drivers/S7-TIA-Import.md) for the full format reference,
+locale auto-detection, and AWL position-based addressing rules.

docs/Driver.TwinCAT.Cli.md

@@ -1,9 +1,9 @@
 # `otopcua-twincat-cli` — Beckhoff TwinCAT test client
 
-Ad-hoc probe / read / write / subscribe / browse tool for Beckhoff TwinCAT 2 /
+Ad-hoc probe / read / write / subscribe tool for Beckhoff TwinCAT 2 / TwinCAT 3
-TwinCAT 3 runtimes via ADS. Uses the **same** `TwinCATDriver` the OtOpcUa
+runtimes via ADS. Uses the **same** `TwinCATDriver` the OtOpcUa server does
-server does (`Beckhoff.TwinCAT.Ads` package). Native ADS notifications by
+(`Beckhoff.TwinCAT.Ads` package). Native ADS notifications by default;
-default; `--poll-only` falls back to the shared `PollGroupEngine`.
+`--poll-only` falls back to the shared `PollGroupEngine`.
 
 Fifth (final) of the driver test-client CLIs.
 
@@ -28,6 +28,56 @@ sessions. Pick one:
 The CLI compiles + runs without a router, but every wire call fails with a
 transport error until one is reachable.
 
+## UDT decomposition
+
+PR 4.1 (issue #315) replaces the old "skip non-atomic symbols" behaviour
+of `BrowseSymbolsAsync` with a recursive type walker
+(`TwinCATTypeWalker`). When the OtOpcUa server's TwinCAT driver runs
+discovery with `EnableControllerBrowse=true`, struct / UDT / function-block
+typed symbols flatten into one OPC UA variable per atomic leaf. Browse
+addresses use the same dotted-instance form the PLC exposes:
+
+| PLC declaration | OPC UA browse paths surfaced |
+|---|---|
+| `MAIN.bStart : BOOL` | `MAIN.bStart` |
+| `GVL.stMotor : ST_Motor` | `GVL.stMotor.bRunning`, `GVL.stMotor.nState`, `GVL.stMotor.rTemperature`, … |
+| `GVL.aRecipe : ARRAY[1..10] OF DINT` | `GVL.aRecipe[1]` … `GVL.aRecipe[10]` |
+| `GVL.aPairs : ARRAY[0..2] OF ST_Pair` | `GVL.aPairs[0].nCount`, `GVL.aPairs[0].rValue`, `GVL.aPairs[1].…` |
+| `GVL.aBig : ARRAY[1..5000] OF DINT` | `GVL.aBig` (single whole-array root — over the cap) |
+
+The CLI's `read` / `write` / `subscribe` commands take dotted paths
+directly:
+
+```powershell
+# Read a struct member
+otopcua-twincat-cli read -n 192.168.1.40.1.1 -s GVL.stMotor.rTemperature -t Real
+
+# Read an array element
+otopcua-twincat-cli read -n 192.168.1.40.1.1 -s "GVL.aRecipe[3]" -t DInt
+```
+
+### Array expansion bound
+
+`TwinCATDriverOptions.MaxArrayExpansion` (default `1024`) caps how many
+elements an array contributes to the discovered address space. Arrays
+whose total element count exceeds the cap surface as a single
+whole-array root with `IsArrayRoot=true` instead of one variable per
+element. Raise the bound when operators routinely care about individual
+elements of large recipe / lookup tables; lower it to keep discovery
+cheap for symbol tables that ship multi-thousand-element scratch
+arrays. Pre-declared whole-array tags from the `Tags` config bypass the
+walker entirely — set `ArrayDimensions` on a `TwinCATTagDefinition` to
+keep array reads on the existing PR 1.4 read-array path.
+
+### Cycle / depth guard
+
+The walker tracks the visited-type set + a hard depth cap of 8 levels
+so a self-pointer (`POINTER TO ST_Self`) or pathological alias chain
+terminates rather than spinning. POINTER / REFERENCE members are
+skipped at the type-graph level — surfacing them would require
+dereferencing through the AMS routing layer which has its own access
+patterns.
+
 ## Common flags
 
 | Flag | Default | Purpose |
@@ -50,13 +100,6 @@ caller interpret semantics.
 
 ### `probe`
 
-Per-command flags:
-
-| Flag | Default | Purpose |
-|---|---|---|
-| `-s` / `--symbol` | **required** | Symbol path to probe (e.g. `MAIN.bRunning`) |
-| `--type` | `DInt` | Declared data type — see the [Data types](#data-types) list |
-
 ```powershell
 # Local TwinCAT 3, probe a canonical global
 otopcua-twincat-cli probe -n 127.0.0.1.1.1 -s "TwinCAT_SystemInfoVarList._AppInfo.OnlineChangeCnt"
@@ -65,6 +108,35 @@ otopcua-twincat-cli probe -n 127.0.0.1.1.1 -s "TwinCAT_SystemInfoVarList._AppInf
 otopcua-twincat-cli probe -n 192.168.1.40.1.1 -s MAIN.bRunning --type Bool
 ```
 
+#### Health probe
+
+The OtOpcUa server's TwinCAT driver runs an internal probe loop (PR 3.2, issue #314)
+that — alongside the cheap `ReadStateAsync` reachability check — samples four
+well-known system symbols once per probe interval and surfaces the result through
+the cross-driver `driver-diagnostics` RPC (added for Modbus, task #154). The same
+symbols can be probed directly via the CLI for ad-hoc troubleshooting:
+
+```powershell
+# Cycle time (UDINT, 100 ns ticks → ÷10000 for ms)
+otopcua-twincat-cli probe -n 192.168.1.40.1.1 -s "TwinCAT_SystemInfoVarList._TaskInfo[1].CycleTime" --type UDInt
+
+# Last task execution wall-clock (UDINT, 100 ns ticks → ÷10000 for ms)
+otopcua-twincat-cli probe -n 192.168.1.40.1.1 -s "TwinCAT_SystemInfoVarList._TaskInfo[1].LastExecTime" --type UDInt
+
+# Online-change count — increments on every accepted online change
+otopcua-twincat-cli probe -n 192.168.1.40.1.1 -s "TwinCAT_SystemInfoVarList._AppInfo.OnlineChangeCnt" --type UDInt
+
+# Loaded PLC project name (STRING(80))
+otopcua-twincat-cli probe -n 192.168.1.40.1.1 -s "TwinCAT_SystemInfoVarList._AppInfo.AppName" --type String
+```
+
+Within the running OtOpcUa server these four signals land on
+`DeviceState.LastDiagnostics` as a `TwinCATDeviceDiagnostics` record + are folded
+into `DriverHealth.Diagnostics` keyed `TwinCAT.CycleTimeMs`, `TwinCAT.LastExecTimeMs`,
+`TwinCAT.JitterMs` (computed `LastExecTimeMs - CycleTimeMs`),
+`TwinCAT.OnlineChangeCnt`, and `TwinCAT.OnlineChangeIncrements`. See
+`docs/drivers/TwinCAT-Test-Fixture.md §Diagnostics` for the full mapping.
+
 ### `read`
 
 ```powershell
@@ -84,6 +156,14 @@ otopcua-twincat-cli read -n 192.168.1.40.1.1 -s "Recipe[3]" -t Real
 otopcua-twincat-cli read -n 192.168.1.40.1.1 -s GVL.sMessage -t WString
 ```
 
+ADS variable handles for `read` / `write` symbols are cached transparently
+inside the CLI's underlying `AdsTwinCATClient`. The first read of a symbol
+resolves a handle; repeats reuse the cached handle for smaller AMS payloads
+and skipped name resolution. The cache wipes on reconnect, on
+`DeviceSymbolVersionInvalid` (with a one-shot retry), and on CLI exit. See
+`docs/drivers/TwinCAT-Test-Fixture.md §Handle caching` for the full story
+including the staleness caveat after an online change.
+
 ### `write`
 
 ```powershell
@@ -96,41 +176,78 @@ Structure writes refused — drop to driver config JSON for those.
 
 ### `subscribe`
 
-Per-command flags:
-
-| Flag | Default | Purpose |
-|---|---|---|
-| `-s` / `--symbol` | **required** | Symbol path — same format as `read` |
-| `-t` / `--type` | `DInt` | Declared data type |
-| `-i` / `--interval-ms` | `1000` | Publishing interval in **milliseconds** — native mode passes this as the ADS `NotificationSettings.CycleTime` |
-
 ```powershell
 # Native ADS notifications (default) — PLC pushes on its own cycle
 otopcua-twincat-cli subscribe -n 192.168.1.40.1.1 -s GVL.Counter -t DInt -i 500
 
 # Fall back to polling for runtimes where native notifications are constrained
 otopcua-twincat-cli subscribe -n 192.168.1.40.1.1 -s GVL.Counter -t DInt -i 500 --poll-only
+
+# Coalesce bursty changes — runtime buffers up to 500 ms before dispatch
+otopcua-twincat-cli subscribe -n 192.168.1.40.1.1 -s GVL.Counter -t DInt -i 50 --max-delay-ms 500
 ```
 
-The subscribe banner announces which mechanism is in play — "ADS notification"
-or "polling" — so it's obvious in screen-recorded bug reports.
-
-### `browse`
-
-Walks the controller's symbol table via ADS `SymbolLoaderFactory` (same path
-`TwinCATDriver.DiscoverAsync` takes when `EnableControllerBrowse = true`).
-Output filters to symbols whose type maps onto the driver's atomic surface —
-UDTs / function-block instances don't appear.
-
 | Flag | Default | Purpose |
 |---|---|---|
-| `--prefix` | _(none)_ | Case-sensitive instance-path prefix filter (e.g. `GVL_Fixture`) |
+| `-s` / `--symbol` | **required** | Symbol path — same format as `read` |
-| `--max` | `500` | Max symbols to print. `0` = unbounded |
+| `-t` / `--type` | `DInt` | IEC type (see Data types section) |
+| `-i` / `--interval-ms` | `1000` | **Cycle time** — minimum interval between change checks the PLC runtime applies |
+| `--max-delay-ms` | `0` | **Max coalescing window** — upper bound on how long the runtime buffers change events before dispatch. `0` = fire ASAP, no coalescing |
+| `--poll-only` | off | Disable native notifications, use `PollGroupEngine` instead |
+
+`-i` / `--interval-ms` and `--max-delay-ms` are different things and both flow
+into the Beckhoff `NotificationSettings` ctor:
+
+- **`--interval-ms`** is the *cycle*: the runtime checks for value changes at
+  most this often. Smaller = lower latency, higher CPU.
+- **`--max-delay-ms`** is the *coalescing ceiling*: once a change is detected,
+  the runtime can hold it for up to this long before dispatching, which lets
+  it batch a burst of changes into a single callback. Default `0` means
+  every detected change fires immediately — same as the pre-PR-3.1 behaviour.
+
+For high-frequency signals (a counter incrementing every 10 ms PLC cycle),
+pair a small `-i` (so latency stays bounded) with a non-zero `--max-delay-ms`
+(so the OPC UA queue downstream doesn't flood). For slow signals just leave
+`--max-delay-ms` at `0`.
+
+The subscribe banner announces which mechanism is in play — "ADS notification"
+or "polling" — and includes the `max-delay` value when set, so it's obvious
+in screen-recorded bug reports.
+
+`--poll-only` polls go through the same cached-handle path as `read`, so
+repeated polls of the same symbol carry only a 4-byte handle on the wire
+rather than the full symbolic path.
+
+### `alarms` (PR 5.1 / #316)
+
+Stream TC3 EventLogger alarms via the driver's `IAlarmSource` bridge.
+Subscribes against AMS port 110 (`AMSPORT_EVENTLOG`) on the same target,
+prints each event with timestamp / source / severity / message until
+Ctrl+C.
 
 ```powershell
-# Everything under a single GVL
+# All alarms — every event the EventLogger surfaces
-otopcua-twincat-cli browse -n 192.168.1.40.1.1 --prefix GVL_Fixture
+otopcua-twincat-cli alarms -n 192.168.1.40.1.1
 
-# Full dump (beware: flat-mode walks on a real controller can top 10k symbols)
+# Filter by source — only events whose source name matches (case-insensitive)
-otopcua-twincat-cli browse -n 192.168.1.40.1.1 --max 0
+otopcua-twincat-cli alarms -n 192.168.1.40.1.1 --source Conveyor1.MotorOverload
+
+# Multiple sources — repeat the flag
+otopcua-twincat-cli alarms -n 192.168.1.40.1.1 --source Conveyor1 --source Pump3
 ```
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `--source` | (none) | Optional source filter; repeat for multiple |
+
+Output format (one line per event):
+
+```
+[HH:mm:ss.fff] <source> sev=<Low|Medium|High|Critical> type=<event-class> cond=<condition-id> "<message>"
+```
+
+The verb forces `EnableAlarms=true` on the underlying driver; the
+default driver config keeps it off so deployments without an
+EventLogger configured pay no cost. See
+[`docs/drivers/TwinCAT.md` §Alarms](drivers/TwinCAT.md) for the
+full bridge architecture and decode caveats.

docs/DriverClis.md

@@ -67,6 +67,19 @@ their flag values to the already-shipped driver.
   then the other. The plausible result identifies the correct setting
   for that device family. (Modbus, S7.)
 
+## Family-specific commands
+
+Most drivers ship the four shared verbs and nothing else. AB Legacy adds a
+fifth family-specific verb for bulk symbol-table import:
+
+| Driver | Extra verb | Doc |
+|---|---|---|
+| AB Legacy | `import-rslogix` — read RSLogix 500/5 CSV symbol exports + emit a JSON tag fragment | [drivers/AbLegacy-RSLogix-Import.md](drivers/AbLegacy-RSLogix-Import.md) |
+
+Binary RSLogix project files (`.RSS` / `.RSP`) are out of scope for v1 — the
+format is proprietary and undocumented; no parser ships in libplctag or any
+community library. Export to CSV first.
+
 ## Known gaps
 
 - **AB Legacy cip-path quirk** — libplctag's ab_server requires a

docs/Redundancy.md

@@ -98,6 +98,10 @@ Role swaps, stand-alone promotions, and base-level adjustments all happen throug
 
 The OtOpcUa Client CLI at `src/ZB.MOM.WW.OtOpcUa.Client.CLI` supports `-F` / `--failover-urls` for automatic client-side failover; for long-running subscriptions the CLI monitors session KeepAlive and reconnects to the next available server, recreating the subscription on the new endpoint. See [`Client.CLI.md`](Client.CLI.md) for the command reference.
 
+## vs. upstream-side redundancy
+
+The mechanics on this page describe **OtOpcUa as a redundant server** — two of our instances clustered behind one OPC UA address space, exposing `ServerUriArray` + dynamic `ServiceLevel` to downstream clients. The mirror-image scenario — **the OPC UA Client driver consuming an upstream redundant pair** — is documented separately in [`drivers/OpcUaClient.md` § Upstream redundancy](drivers/OpcUaClient.md#upstream-redundancy-serverarray). Both rely on the same OPC UA Part 4 § 6.6.2 model (non-transparent warm/hot via `RedundancySupport` + `ServerUriArray` + `ServiceLevel`); they sit at opposite ends of the gateway pipeline. A deployment can wire either, both, or neither.
+
 ## Depth reference
 
 For the full decision trail and implementation plan — topology invariants, peer-probe cadence, recovery-dwell policy, compliance-script guard against enum-value drift — see `docs/v2/plan.md` §Phase 6.3.

docs/ServiceHosting.md

@@ -83,7 +83,7 @@ The host spins up `StaPump` (the STA thread with message pump), creates the MXAc
 
 ### Pipe security
 
-`PipeServer` builds a `PipeAcl` from the provided `SecurityIdentifier` + uses `NamedPipeServerStream` with `maxNumberOfServerInstances: 1`. The handshake requires a matching shared secret in the first Hello frame; callers whose SID doesn't match `OTOPCUA_ALLOWED_SID` are rejected before any frame is processed via `NamedPipeServerStream.RunAsClient` + a SID comparison against the configured allow list. The DACL grants `ReadWrite | Synchronize` only to the allowed SID and denies `LocalSystem`. The installed dev host (`OtOpcUaGalaxyHost`) runs as `dohertj2` with the secret at `.local/galaxy-host-secret.txt`.
+`PipeServer` builds a `PipeAcl` from the provided `SecurityIdentifier` + uses `NamedPipeServerStream` with `maxNumberOfServerInstances: 1`. The handshake requires a matching shared secret in the first Hello frame; callers whose SID doesn't match `OTOPCUA_ALLOWED_SID` are rejected before any frame is processed. **By design the pipe ACL denies BUILTIN\Administrators** — live smoke tests must therefore run from a non-elevated shell that matches the allowed principal. The installed dev host (`OtOpcUaGalaxyHost`) runs as `dohertj2` with the secret at `.local/galaxy-host-secret.txt`.
 
 ### Installation
 

docs/drivers/AbCip-HSBY.md

@@ -0,0 +1,332 @@
+# AbCip — ControlLogix HSBY paired-IP support
+
+PR abcip-5.1 + 5.2 ship **non-transparent** HSBY (Hot-Standby) awareness
+to the AB CIP driver. Each device may declare a partner gateway; when both
+gateways are up the driver concurrently probes a role tag on each chassis,
+reports which one is currently Active, and routes reads / writes through
+that chassis automatically.
+
+- **PR abcip-5.1** — gathers + reports the role of each chassis through
+  driver diagnostics. See [Role-tag detection matrix](#role-tag-detection-matrix)
+  + [Active-resolution rules](#active-resolution-rules).
+- **PR abcip-5.2** — wires the resolved active address into
+  `AbCipDriver.ResolveHost` and the runtime-cache lifecycle. See
+  [Failover behaviour](#failover-behaviour-pr-52) +
+  [Failure-mode walkthrough](#failure-mode-walkthrough).
+
+## When to use HSBY paired IPs
+
+You have a redundant **ControlLogix** chassis pair (1756-RM redundancy
+module, two CPUs, one acting + one standby) and the SCADA / OPC UA layer
+needs to keep talking to *whichever chassis is currently Active* without an
+operator manually re-pointing the connection.
+
+Pre-5.1 the driver only knew about a single `HostAddress`. After a
+hot-standby switch-over, the standby (now Active) carried a **different IP**
+and the driver kept probing the dead-but-was-Active address until someone
+edited the config.
+
+PR abcip-5.1 closes the visibility half of that gap by reading the role tag
+on both chassis. PR abcip-5.2 closes the routing half by re-pointing
+`ResolveHost` at the Active address each tick + invalidating the per-tag
+runtime cache + write-coalescer state on every flip.
+
+## Configuration
+
+```jsonc
+{
+    "Devices": [
+        {
+            "HostAddress": "ab://10.0.0.5/1,0",
+            "PartnerHostAddress": "ab://10.0.0.6/1,0",
+            "Hsby": {
+                "Enabled": true,
+                "RoleTagAddress": "WallClockTime.SyncStatus",
+                "ProbeIntervalMs": 2000
+            }
+        }
+    ]
+}
+```
+
+| Field | Default | Notes |
+|---|---|---|
+| `PartnerHostAddress` | `null` | Canonical `ab://gateway[:port]/cip-path` of the partner chassis. `null` = no HSBY pair; the driver behaves exactly like every pre-5.1 build. |
+| `Hsby.Enabled` | `false` | Master switch. When `false` (or `Hsby` omitted) no role probing happens, even if `PartnerHostAddress` is set. |
+| `Hsby.RoleTagAddress` | `WallClockTime.SyncStatus` | Address of the role tag on each chassis. See [role-tag detection matrix](#role-tag-detection-matrix). |
+| `Hsby.ProbeIntervalMs` | `2000` | How often each chassis is sampled. 2 s is a good default — tight enough to detect a switch-over within one Admin-UI refresh, loose enough to leave headroom for the regular probe loop. |
+
+## Feature-flag gate (`Redundancy.Hsby.Enabled`)
+
+`Hsby.Enabled = false` (the default) is the off-switch for the entire
+feature. The role-probe loop never starts, the diagnostics keys are not
+emitted, and the driver behaves identically to a pre-5.1 build. This is the
+gate to flip when an operator wants to roll the feature out cautiously
+across a fleet — set `Hsby.Enabled = true` per-device in driver config (no
+build flag, no env var).
+
+When the gate is on but the partner gateway is unreachable, the role-probe
+loop reports `HsbyRole.Unknown` for the partner each tick. The primary's
+role still drives the active-chassis resolution; the operator sees the
+partner's role as Unknown in the Admin UI / driver diagnostics, which is the
+correct surface for "we can't reach the standby chassis right now."
+
+## Role-tag detection matrix
+
+| Firmware / fronts | Address | Decode |
+|---|---|---|
+| **v20 / v24 / v32+ ControlLogix HSBY** | `WallClockTime.SyncStatus` (DINT) | `0` = Standby, `1` = Synchronized / Active, `2` = Disqualified, anything else = Unknown |
+| **PLC-5 / SLC500 status-byte fallback** | `S:34` Module Status word | bit 0 = "this chassis is Active". Bit set → `Active`; clear → `Standby` |
+| **Custom user role tag** | any DINT-typed CIP path | Same matrix as `WallClockTime.SyncStatus` (0 / 1 / 2). Out-of-range values → Unknown. |
+
+`AbCipHsbyRoleProber.MapValueToRole` is the value-to-role mapper; unit tests
+in `tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Tests/AbCipHsbyTests.cs` pin every
+row of the matrix.
+
+## What gets reported
+
+The driver surfaces three diagnostics counters per HSBY-enabled device
+(visible via `driver-diagnostics` RPC + the Admin UI):
+
+| Counter | Value |
+|---|---|
+| `AbCip.HsbyActive` | `1` if primary is Active, `2` if partner is Active, `0` if neither (or HSBY off) |
+| `AbCip.HsbyPrimaryRole` | `(int)HsbyRole` — `0` = Unknown, `1` = Active, `2` = Standby, `3` = Disqualified |
+| `AbCip.HsbyPartnerRole` | Same encoding as `HsbyPrimaryRole`, observed on the partner chassis |
+| `AbCip.HsbyFailoverCount` (PR 5.2) | Total number of `ActiveAddress` transitions the probe loop has observed across every HSBY-enabled device on this driver. Each increment maps to one runtime-cache invalidation + write-coalescer reset. |
+
+When more than one HSBY pair is configured on the same driver instance the
+flat keys are scoped per primary host: `AbCip.HsbyActive[ab://10.0.0.5/1,0]`,
+etc.
+
+The `DeviceState.ActiveAddress` field (internal; surfaced via
+`HsbyActive` diagnostics) is the address PR 5.2 routes through
+`ResolveHost` + uses to scope the per-host bulkhead / breaker key.
+See [Failover behaviour](#failover-behaviour-pr-52) for the runtime
+implications.
+
+### Active-resolution rules
+
+| Primary role | Partner role | `ActiveAddress` resolution |
+|---|---|---|
+| Active | Standby / Disqualified / Unknown | primary |
+| Standby / Disqualified / Unknown | Active | partner |
+| Active | Active (split-brain) | **primary wins**, warning logged |
+| Standby + Standby | Standby + Standby | `null` — PR 5.2's `ResolveHost` falls back to the configured primary; the existing dial flow surfaces `BadCommunicationError` if the primary is also down. See [Both-stuck](#both-stuck-no-chassis-active). |
+| Unknown + Unknown | Unknown + Unknown | `null` (same fallback as Standby + Standby) |
+
+Split-brain (both chassis claim Active simultaneously) is a real
+production failure mode — typically a redundancy-module misconfiguration or
+a partial network split. The driver picks primary deterministically + emits
+a warning through `AbCipDriverOptions.OnWarning` so operators see it in the
+log.
+
+## CLI flags
+
+The `otopcua-abcip-cli` tool exposes the HSBY plumbing through two surfaces
+(see [Driver.AbCip.Cli.md](../Driver.AbCip.Cli.md) for the full CLI guide):
+
+- `--partner <gateway>` — global flag on every command. Sets
+  `PartnerHostAddress` + auto-enables `Hsby.Enabled = true` so the role
+  probe runs alongside any read / write / subscribe.
+- `hsby-status` — dedicated command that prints which chassis is
+  currently Active. Reads the role tag on both gateways for a few ticks +
+  prints the `(primary, partner, active)` tuple.
+
+```powershell
+# Print which chassis is Active right now
+otopcua-abcip-cli hsby-status -g ab://10.0.0.5/1,0 --partner ab://10.0.0.6/1,0
+
+# Subscribe through the active chassis (PR 5.2 follow-up — today the
+# subscribe stays pointed at the primary; the role probe runs alongside).
+otopcua-abcip-cli subscribe -g ab://10.0.0.5/1,0 --partner ab://10.0.0.6/1,0 \
+    -t Motor01_Speed --type Real -i 500
+```
+
+## Test coverage
+
+- **Unit** (`tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Tests/AbCipHsbyTests.cs`):
+    - Pure `MapValueToRole` matrix (WallClockTime.SyncStatus + S:34 bit
+      mask + Unknown values).
+    - End-to-end driver loop: primary Active / partner Standby resolves to
+      primary; both Active resolves to primary with a warning; both
+      Standby clears `ActiveAddress`; primary read failure routes to
+      partner.
+    - Diagnostics surface (`AbCip.HsbyActive` / `HsbyPrimaryRole` /
+      `HsbyPartnerRole`).
+    - DTO JSON round-trip (`PartnerHostAddress` + `Hsby.{Enabled,
+      RoleTagAddress, ProbeIntervalMs}` survive deserialise → driver →
+      `DeviceState`).
+    - `Hsby.Enabled = false` → no role probing.
+- **Integration** (`tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/`):
+    - `AbCipHsbyRoleProberTests.cs` (PR 5.1) and
+      `AbCipHsbyFailoverTests.cs` (PR 5.2) — both **skipped by default**
+      (`Assert.Skip`). `ab_server` cannot emulate a ControlLogix HSBY
+      pair (no `WallClockTime.SyncStatus`, no second chassis concept).
+      The Docker `paired` profile (PR 5.1) brings up two `ab_server`
+      instances + a stub `hsby-mux` sidecar so the topology is
+      documented, but a patched `ab_server` image that actually serves
+      the role tag is still on the follow-up list.
+    - Trait `Category=Hsby` so `dotnet test --filter Category=Hsby`
+      finds them once they're promoted.
+- **End-to-end** (`scripts/e2e/test-abcip-hsby.ps1`, PR 5.2):
+    - Paired-fixture variant of `test-abcip.ps1`. Subscribes to a tag
+      through the OPC UA server, flips the active chassis mid-stream
+      via the `hsby-mux` sidecar's `POST /flip` endpoint, asserts the
+      stream survives + `AbCip.HsbyFailoverCount` increments. Gated
+      on operator-supplied `BridgeNodeId` + a running paired fixture;
+      ships unwired into `test-all.ps1` until the patched `ab_server`
+      lands.
+
+## Failover behaviour (PR 5.2)
+
+PR 5.2 wires `DeviceState.ActiveAddress` into the read / write hot path
+through `AbCipDriver.ResolveHost` and the runtime-cache lifecycle. After
+the role-probe loop (PR 5.1) detects an active-address transition the
+driver re-points every wire-level operation at the now-Active chassis
+without operator intervention.
+
+### What flips on a failover
+
+| Aspect | Pre-flip | Post-flip |
+|---|---|---|
+| `ResolveHost(tag)` return | primary `HostAddress` | the partner address (when partner is now Active) |
+| Per-tag libplctag handles in `DeviceState.Runtimes` | created against primary gateway | dropped on flip; lazily re-created against the partner gateway on next read / write |
+| Parent-DINT RMW handles in `DeviceState.ParentRuntimes` | primary gateway | dropped on flip; same re-create-on-demand path |
+| `AbCipWriteCoalescer` per-device cache | last-known-written values from the primary | reset; the first write of any value to the partner pays the full round-trip |
+| `LogicalInstanceMap` (Logical-mode `@tags` walk) | populated for primary | cleared; the next read on a Logical-mode device re-walks `@tags` against the partner |
+| Per-host bulkhead key (Polly bulkhead + breaker, plan decision #144) | keyed on primary `HostAddress` | keyed on the new active address — the partner gets its own fresh breaker state instead of inheriting a tripped breaker from the now-standby |
+| `AbCip.HsbyFailoverCount` diagnostic | 0 | incremented by 1 on every transition observed by the probe loop |
+
+### How the invalidation runs
+
+PR 5.2 introduces an internal `OnActiveAddressChanged` event raised by
+`HsbyProbeLoopAsync` on every `DeviceState.ActiveAddress` transition. The
+driver subscribes to it from its own constructor; the handler
+(`HandleActiveAddressChanged`) does the cache invalidation in one place:
+
+1. Disposes every entry in `DeviceState.Runtimes` and
+   `DeviceState.ParentRuntimes`, then clears both dicts. Disposed
+   `IAbCipTagRuntime` instances release their underlying libplctag
+   handles so the native heap doesn't leak.
+2. Clears `DeviceState.LogicalInstanceMap` and resets
+   `LogicalWalkComplete = false` so the next read on a Logical-mode
+   device re-fires the `@tags` symbol walk against the new chassis.
+3. Calls `AbCipWriteCoalescer.Reset(deviceHostAddress)` so cached
+   "we already wrote 42" decisions don't stale-suppress the first
+   partner-side write.
+4. Resets `DeviceState.RuntimesAddress = null` so subsequent
+   diagnostics observers see a fresh stamp on the next runtime
+   creation.
+5. `Interlocked.Increment` on the driver-wide
+   `AbCip.HsbyFailoverCount` counter.
+
+The handler is idempotent — a second event for the same address change
+is harmless because the dicts are already empty + the coalescer reset
+is itself idempotent.
+
+### Bulkhead key semantics
+
+The per-host resilience pipeline (Polly bulkhead + circuit breaker, plan
+decision #144) keys on whatever `IPerCallHostResolver.ResolveHost`
+returns. PR 5.2 changes that resolver so an HSBY-failed-over device
+returns the partner's address, which means:
+
+- The **device-state lookup** (`_devices.TryGetValue`) keeps using the
+  configured primary `HostAddress` as the dictionary key — that key
+  never changes for the lifetime of a device, so multi-device
+  configurations stay routable.
+- The **resilience pipeline** (Polly bulkhead, breaker, retry policies)
+  receives the active address as the host-name dimension. The standby
+  chassis's tripped breaker (if its primary went away) doesn't bleed
+  over to the partner; the partner gets fresh limits + a closed
+  breaker.
+
+When HSBY is disabled (`Hsby.Enabled = false`) `ResolveHost` returns the
+configured primary `HostAddress` exactly as it always has — pre-5.2
+behaviour, no double-key risk.
+
+## Failure-mode walkthrough
+
+PR 5.2 adds three failover surface areas to reason about. The table
+below summarises the behaviour the driver reports + how an operator
+can inspect it.
+
+### Primary-stuck (primary unreachable, partner Active)
+
+The primary chassis goes away (network partition, power loss, a stuck
+Forward Open). The role-probe loop reads `HsbyRole.Unknown` for the
+primary and `HsbyRole.Active` for the partner.
+
+| Surface | Behaviour |
+|---|---|
+| `DeviceState.ActiveAddress` | partner address |
+| `DeviceState.PrimaryRole` | `Unknown` |
+| `DeviceState.PartnerRole` | `Active` |
+| `ResolveHost(tag)` | partner address |
+| Reads / writes | route through partner gateway transparently |
+| `AbCip.HsbyFailoverCount` | incremented when the address transitioned away from the primary |
+| `AbCip.HsbyActive` | `2` (partner is the active chassis) |
+| Operator action | none required for routing; investigate why the primary is unreachable through the connectivity-probe loop's `_System/_ConnectionStatus` for the device |
+
+### Secondary-stuck (partner unreachable, primary Active)
+
+The partner chassis goes away (its OPC UA server is down, its IP is
+unreachable, the redundancy module unhitched it). The probe loop reads
+`HsbyRole.Active` for the primary and `HsbyRole.Unknown` for the partner.
+
+| Surface | Behaviour |
+|---|---|
+| `DeviceState.ActiveAddress` | primary address (no transition; this is the steady state) |
+| `DeviceState.PrimaryRole` | `Active` |
+| `DeviceState.PartnerRole` | `Unknown` |
+| `ResolveHost(tag)` | primary address |
+| Reads / writes | route through primary gateway exactly as in a non-HSBY deployment |
+| `AbCip.HsbyFailoverCount` | unchanged — no flip happened |
+| `AbCip.HsbyActive` | `1` (primary is the active chassis) |
+| Operator action | investigate why the partner is unreachable; the operational risk is that a future primary-side outage has no fall-back |
+
+### Both-stuck (no chassis Active)
+
+Both chassis report `Standby` / `Disqualified` / `Unknown` (a
+redundancy-module misconfiguration, both controllers in Program mode,
+or both unreachable).
+
+| Surface | Behaviour |
+|---|---|
+| `DeviceState.ActiveAddress` | `null` |
+| `ResolveHost(tag)` | falls back to the configured primary `HostAddress` |
+| Reads / writes | dispatched to the configured primary; a stuck primary surfaces `BadCommunicationError` per the existing dial flow |
+| `AbCip.HsbyActive` | `0` (no chassis Active) |
+| `AbCip.HsbyFailoverCount` | incremented when the transition `Active → null` happened |
+| Operator action | investigate the redundancy module / mode keys; the SCADA layer sees stuck-or-bad-quality reads, not incorrect routing |
+
+The "fall back to primary on null Active" choice is deliberate. Routing
+all reads to a deterministic chassis (the configured primary) keeps the
+breaker key + bulkhead state stable while the operator diagnoses the
+double-down outage; the alternative (round-robin / partner) would just
+trip both breakers in turn and obscure which chassis is the real
+problem.
+
+## Follow-ups (beyond PR 5.2)
+
+- **Patched `ab_server` image** — add a writable `WallClockTime.SyncStatus`
+  tag (or a separate Python shim) so the Docker `paired` profile can
+  exercise the wire-level role probe + the
+  `tests/.../IntegrationTests/AbCipHsbyFailoverTests.cs` scaffold can
+  flip its `Assert.Skip` for a real integration assertion.
+- **`hsby-mux` REST endpoint** — `POST /flip {"active": "primary"}` writes
+  `1` to the chosen chassis + `0` to the other so integration tests +
+  `scripts/e2e/test-abcip-hsby.ps1` can drive switch-overs
+  deterministically.
+- **GuardLogix HSBY** — same role-tag plumbing applies; verify against a
+  real 1756-L8xS pair when one is on-site.
+
+## See also
+
+- [`docs/Driver.AbCip.Cli.md`](../Driver.AbCip.Cli.md) — `--partner` flag +
+  `hsby-status` command reference
+- [`docs/drivers/AbServer-Test-Fixture.md`](AbServer-Test-Fixture.md) §"What
+  it does NOT cover" — HSBY entry
+- [`docs/Redundancy.md`](../Redundancy.md) — server-level (OPC UA-stack)
+  redundancy; HSBY is the **driver-level** companion

docs/drivers/AbCip-Operability.md

@@ -0,0 +1,406 @@
+# AB CIP — Operability knobs
+
+Phase 4 of the AB CIP driver plan introduces operator-tunable behaviour that
+changes how the driver schedules per-tag traffic, deduplicates updates, and
+surfaces health — knobs that an operator typically reaches for *after* the
+address space is in place and the deployment is past the green-field phase.
+The Phase 3 doc (`AbCip-Performance.md`) covers connection-shape and
+read-strategy knobs; this doc is the home for the per-tag scheduling and
+operability levers as PRs land.
+
+PR abcip-4.1 ships the first knob: per-tag **Scan Rate** (Kepware-parity scan
+classes).
+
+## Per-tag scan rate
+
+### What it is
+
+A per-tag override of the OPC UA subscription's `publishingInterval`. The AB
+CIP driver mirrors the Galaxy hierarchy as a single OPC UA address space, so
+every tag served from one driver normally ticks at the publishing interval the
+client requested when it created the Subscription. This knob lets specific
+tags publish at a different cadence — fast HMI tags at 100 ms, batch /
+historian tags at 1–10 s — without forcing the operator to split tags into
+separate subscriptions or driver instances.
+
+It is the Kepware "scan classes" model expressed per-tag. The same shape is
+already shipped in the S7 driver (`S7TagDefinition.ScanGroup`) and the AB
+Legacy / TwinCAT drivers; AB CIP adopts a leaner per-tag-only form because the
+CIP single-connection model means the practical knob a deployment reaches for
+is "this one tag, faster", not "every tag in this group".
+
+### How it interacts with OPC UA publishingInterval
+
+OPC UA semantics:
+
+- The Subscription's `publishingInterval` is the *upper bound* on how often
+  the server publishes a NotificationMessage. Each MonitoredItem also has its
+  own `samplingInterval`; that's where this knob lands.
+- A per-tag `samplingInterval` shorter than the Subscription's
+  `publishingInterval` means the server samples faster but only publishes at
+  the next Subscription tick — clients may receive multiple values for one
+  tag in a single Publish response.
+- A per-tag `samplingInterval` longer than the Subscription's
+  `publishingInterval` is legal too — the server simply skips ticks for that
+  tag.
+
+AB CIP-side: the driver's `SubscribeAsync` receives one `publishingInterval`
+plus a list of tag references. With per-tag `ScanRateMs` it buckets the input
+list by resolved interval and registers one `PollGroupEngine` subscription per
+bucket. Each bucket runs an independent timer, so a 100 ms tag never waits
+for a 1000 ms tag's `Task.Delay` to expire.
+
+### Override knob
+
+`AbCipTagDefinition.ScanRateMs` (`int?`, default `null`). `null` = use the
+subscription's default `publishingInterval` (legacy behaviour). Bind via
+driver config JSON:
+
+```json
+{
+  "Tags": [
+    {
+      "Name": "Motor1.Speed",
+      "DeviceHostAddress": "ab://10.0.0.5/1,0",
+      "TagPath": "Motor1.Speed",
+      "DataType": "DInt",
+      "ScanRateMs": 100
+    },
+    {
+      "Name": "Motor1.RunHours",
+      "DeviceHostAddress": "ab://10.0.0.5/1,0",
+      "TagPath": "Motor1.RunHours",
+      "DataType": "DInt",
+      "ScanRateMs": 5000
+    },
+    {
+      "Name": "Motor1.NamePlate",
+      "DeviceHostAddress": "ab://10.0.0.5/1,0",
+      "TagPath": "Motor1.NamePlate",
+      "DataType": "String"
+    }
+  ]
+}
+```
+
+Result: three buckets — 100 ms, 5000 ms, and the subscription default for
+`NamePlate`. UDT members inherit the parent tag's `ScanRateMs` at fan-out
+time, so a UDT declared at 100 ms publishes every member at 100 ms without
+the operator having to repeat the override on each member.
+
+### Floor and degenerate cases
+
+- `PollGroupEngine` floors every bucket at **100 ms** — a `ScanRateMs: 25`
+  is clamped up. The floor matches the Modbus / S7 / TwinCAT floors and
+  protects the wire from sub-mailbox-scan polling.
+- `ScanRateMs: 0` and negative values are treated as unset — the tag falls
+  back to the subscription default. Mis-typed config degrades, doesn't fault.
+- A `ScanRateMs` equal to the subscription default collapses into the same
+  bucket as plain tags. The driver doesn't fragment poll loops when the
+  override is redundant.
+- Tags whose names don't appear in the driver's tag map (typo / discovery
+  miss) fall through to the subscription default — same "config typo
+  degrades" stance as the rest of the driver.
+
+### Wire impact
+
+Per-bucket independent timers do **not** parallelise CIP traffic. The driver
+serializes wire-side reads through its per-device libplctag handles, so a
+fast bucket and a slow bucket trade off against each other on the wire — the
+multi-rate split decouples *cadence* (the 100 ms bucket isn't queued behind
+the 1000 ms bucket's `Task.Delay`), not *throughput*. The wire still moves
+one CIP request at a time per device.
+
+If you're reading a large tag set and the slow bucket starves the fast
+bucket, the lever is `AbCipDeviceOptions.ConnectionSize` (Phase 3) — pack
+more tags into one CIP RTT so the slow bucket finishes faster. Per-tag scan
+rate is a *scheduling* knob, not a *throughput* knob.
+
+### Comparison to Kepware scan classes
+
+| Kepware concept | AB CIP equivalent |
+|---|---|
+| Scan class table (named groups → rate) | implicit: each distinct `ScanRateMs` value is its own bucket |
+| Default scan class | OPC UA Subscription's `publishingInterval` |
+| Per-tag scan class assignment | `AbCipTagDefinition.ScanRateMs` |
+| "Scan mode: Respect client" | always — the OPC UA `publishingInterval` is the default |
+| "Force write" / "Write through cache" | not exposed — AB CIP writes always go to the wire |
+
+The leaner shape (per-tag rate, not named groups) keeps the JSON config flat
+and reflects how operators tend to use the knob in practice — a handful of
+"this specific tag needs to be fast" overrides on top of a sensible default,
+rather than a separate tier of scan-class definitions.
+
+### Verification
+
+- **Unit**: `AbCipPerTagScanRateTests` (`tests/.../AbCip.Tests`). Asserts
+  bucketing math, default-rate collapse, UDT member inheritance, JSON DTO
+  round-trip, and end-to-end cadence against the in-process fake.
+- **Integration**: `AbCipPerTagScanRateTests`
+  (`tests/.../AbCip.IntegrationTests`). Drives two tags at 100 ms / 1000 ms
+  against a live `ab_server` and asserts the bucket count + each tag receives
+  the initial-data push.
+- **E2E**: `scripts/e2e/test-abcip.ps1` — see the *PerTagScanRate* assertion.
+
+### Cross-references
+
+- `docs/Driver.AbCip.Cli.md` — there is no CLI surface change for this knob;
+  scan rate is a config-time concern.
+- `docs/drivers/AbCip-Performance.md` — Phase 3 throughput knobs that pair
+  with per-tag scan rate when a slow bucket starves a fast one.
+- S7 driver `ScanGroup` model in `src/.../S7DriverOptions.cs` — the
+  named-group form of the same idea.
+
+## Write deadband / write-on-change
+
+PR abcip-4.2 ships the second operability knob: per-tag write coalescing,
+the *write-side* companion to the read-side deadband already shipped at the
+OPC UA monitored-item layer. The driver remembers the value last
+successfully written for a tag and can suppress redundant or below-threshold
+follow-up writes — they return `Good` to the OPC UA client without ever
+hitting the wire.
+
+### What it is
+
+- **`AbCipTagDefinition.WriteDeadband`** (`double?`, default `null`) —
+  numeric absolute-difference threshold. When set, a write whose
+  `|new − last|` is below the deadband is suppressed.
+- **`AbCipTagDefinition.WriteOnChange`** (`bool`, default `false`) —
+  equality gate. When set, a write whose value equals the last successfully
+  written value is suppressed.
+
+Both knobs combine on the same tag. For numerics, the deadband path takes
+priority; the equality fallback covers the cases the deadband doesn't (BOOL
+setpoints, STRING constants, `WriteDeadband=0`, etc).
+
+### Worked setpoint-jitter example
+
+A motor speed setpoint published from an HMI tends to wobble by a few
+ticks even when the operator hasn't touched it — UI rounding, Modbus
+gateway re-encoding, RPN script noise. With `WriteDeadband: 0.5`:
+
+```json
+{
+  "Tags": [
+    {
+      "Name": "Motor1.Speed.SP",
+      "DeviceHostAddress": "ab://10.0.0.5/1,0",
+      "TagPath": "Motor1.Speed.SP",
+      "DataType": "Real",
+      "WriteDeadband": 0.5
+    }
+  ]
+}
+```
+
+Sequence of writes from the HMI (one every 100 ms, no operator input):
+
+| Time | Value | `\|new − last\|` | Wire? |
+|---|---|---|---|
+| 0 ms | 50.0 | n/a (first) | yes |
+| 100 ms | 50.2 | 0.2 < 0.5 | suppressed |
+| 200 ms | 50.3 | 0.3 < 0.5 | suppressed |
+| 300 ms | 50.6 | 0.6 ≥ 0.5 | yes |
+| 400 ms | 50.6 | 0.0 < 0.5 | suppressed |
+| 500 ms | 51.5 | 0.9 ≥ 0.5 | yes |
+
+Three writes hit the wire; three are suppressed. The OPC UA client sees
+`Good` on every call. The PLC sees only the values that actually crossed
+the deadband.
+
+### Combining with WriteOnChange
+
+A digital reset bit driven by a UI that pulses it at every cycle:
+
+```json
+{
+  "Name": "Conveyor.Reset",
+  "DeviceHostAddress": "ab://10.0.0.5/1,0",
+  "TagPath": "Conveyor.Reset",
+  "DataType": "Bool",
+  "WriteOnChange": true
+}
+```
+
+Three consecutive `false → false → false` writes from the UI collapse to
+one wire write (`false`, the first). When the operator clicks the reset
+button (`true`), that write passes; subsequent `true → true` repeats
+suppress until the UI clears it back to `false`.
+
+Numeric tags can also opt into both: `WriteDeadband: 0.5` plus
+`WriteOnChange: true` is well-defined — the deadband suppresses jitter, the
+equality gate suppresses exact repeats (which the deadband path also catches
+because `|0| < 0.5`, but having both set documents the operator's intent).
+
+### Special cases
+
+- **First write** always passes through. The coalescer has no prior value
+  to compare against, so the first write of any tag pays the full
+  round-trip and seeds the cache.
+- **NaN / Infinity** bypass deadband suppression. IEEE-754 comparisons
+  against NaN are undefined and a stale `+Inf` shouldn't silently swallow
+  a real reset; the wire decides. `WriteOnChange` equality on NaN still
+  follows .NET semantics (`Equals(NaN, NaN) == true` for `double` boxed in
+  `object`), so a `WriteOnChange` tag stuck on NaN will suppress repeats
+  until something else writes a real value.
+- **Failed writes** do *not* seed the cache. If the wire write fails, the
+  next attempt with the same value still hits the wire because the
+  coalescer never recorded a "last successful value" for it.
+- **Reconnect drops the cache**. The driver's host-state probe transitions
+  `Stopped → Running` after a reconnect; both transitions reset the
+  per-device coalescer cache, so the first post-reconnect write of any
+  value pays the full round-trip. The PLC may have been restarted while
+  the driver was offline and our cached "we already wrote 42" is stale.
+- **Two devices, same tag address**. The cache is keyed on
+  `(deviceHostAddress, tagAddress)` so two PLCs running the same Logix
+  program keep independent caches — writing 42 to A doesn't suppress
+  writing 42 to B.
+- **Bit-in-DINT writes** consult the coalescer too, so a UI that pulses
+  `Flags.3` at every cycle benefits from the same `WriteOnChange`
+  suppression as a plain BOOL tag.
+- **Plain back-compat tags** (no `WriteDeadband`, no `WriteOnChange`)
+  take a fast-path through the coalescer that increments only the
+  `WritesPassedThrough` counter — no dictionary lookup, no allocation. The
+  knobs are zero-overhead opt-in.
+
+### Diagnostics
+
+The driver surfaces two counters through `DriverHealth.Diagnostics` (the
+same path the `driver-diagnostics` RPC + Admin UI render for Modbus / S7 /
+OPC UA Client):
+
+- `AbCip.WritesSuppressed` — total writes the coalescer skipped.
+- `AbCip.WritesPassedThrough` — total writes that hit the wire after
+  consulting the coalescer.
+
+Their ratio is the "wire savings" headline. A deployment with `0`
+suppressions either has no tags opted in or has the deadband too tight /
+the equality threshold too loose; revisit the per-tag config.
+
+### Verification
+
+- **Unit**: `AbCipWriteDeadbandTests` (`tests/.../AbCip.Tests`). Asserts
+  the deadband math, the equality fallback, the first-write pass-through,
+  reset-on-reconnect, two-device cache independence, suppressed-Good
+  status, NaN bypass, the back-compat fast path, and DTO round-trip.
+- **Integration**: `AbCipWriteDeadbandTests`
+  (`tests/.../AbCip.IntegrationTests`). Drives a 5-write jittery sequence
+  with `WriteDeadband: 1.0` against a live `ab_server` and asserts the
+  driver's diagnostics counter matches the expected suppression count.
+- **E2E**: `scripts/e2e/test-abcip.ps1` — see the *WriteCoalesce*
+  assertion.
+
+### Cross-references
+
+- `docs/drivers/AbServer-Test-Fixture.md` §7 — capability surfaces beyond
+  read; mentions write-coalesce coverage.
+- Modbus driver — read-side deadband in `ModbusDriver` predates this
+  write-side equivalent; the config shape is intentionally similar.
+- Kepware "Deadband (write)" knob — this is the AB CIP equivalent.
+
+## System tags / `_System` folder
+
+PR abcip-4.3 surfaces five read-only diagnostic variables under
+`AbCip/<device>/_System/` so SCADA / Admin clients can pivot from "is the
+wire up?" to "what's our scan rate / tag count?" without leaving the OPC UA
+address space. The values come straight from the live
+`IHostConnectivityProbe` + `DriverHealth` surfaces — reads bypass libplctag
+and are served from the in-memory snapshot the probe loop / read loop
+updates. PR abcip-4.4 added `_RefreshTagDb` as a sixth, writeable entry —
+the Kepware-style refresh trigger.
+
+### What it ships
+
+| Variable | Type | Access | Source | Notes |
+|---|---|---|---|---|
+| `_ConnectionStatus` | String | ViewOnly | `HostState` | `Running` / `Stopped` / `Unknown` / `Faulted`. Mirrors what the connectivity probe sees. |
+| `_ScanRate` | Float64 | ViewOnly | `AbCipProbeOptions.Interval` | Configured probe interval in milliseconds — compare against `_LastScanTimeMs` to spot wire stretch. |
+| `_TagCount` | Int32 | ViewOnly | `_tagsByName` | Discovered tag count for this device, excluding `_System/*`. |
+| `_DeviceError` | String | ViewOnly | `DriverHealth.LastError` | Most recent error message; empty when the device is healthy. |
+| `_LastScanTimeMs` | Float64 | ViewOnly | `ReadAsync` wall-clock | Duration of the most-recent `ReadAsync` iteration on this device. |
+| `_RefreshTagDb` | Boolean | **Operate** | n/a (write-only trigger) | PR abcip-4.4 — Kepware-style refresh trigger. Reads always return `false`. Writing any truthy value (`true`, non-zero number, `"true"` / `"1"` strings, case-insensitive) dispatches to `RebrowseAsync` against the device's cached `IAddressSpaceBuilder`. Falsy / unparseable writes are no-ops that report `Good` so a UI that resets the trigger flag doesn't see a phantom error. The `AbCip.RefreshTriggers` diagnostic counter increments per truthy write. |
+
+### When the snapshot updates
+
+- **Probe transitions** — every `Running ↔ Stopped` flip refreshes the
+  device's snapshot inline, so a client subscribed to
+  `_System/_ConnectionStatus` sees the new state on the next OPC UA
+  publish tick.
+- **Read iterations** — `ReadAsync` recomputes `_LastScanTimeMs` per
+  device that owned at least one reference in the batch + writes a fresh
+  snapshot before returning.
+- **Driver init** — every device gets a seeded snapshot
+  (`Unknown` / `0` / `""`) before the probe loop spins up so a read that
+  arrives before the first probe iteration returns a stable shape rather
+  than null.
+
+### Browse + read example
+
+```powershell
+# Browse the synthetic folder
+otopcua-client-cli browse -u opc.tcp://localhost:4840 \
+    -n "ns=2;s=AbCip/ab://10.0.0.5/1,0/_System"
+
+# Read the connection status
+otopcua-client-cli read -u opc.tcp://localhost:4840 \
+    -n "ns=2;s=AbCip/ab://10.0.0.5/1,0/_System/_ConnectionStatus"
+```
+
+The driver-side reference embeds the device host address (the
+`_System/<device>/<name>` form) so the dispatcher can route by device
+without an additional registry. PR abcip-4.4 turned `_RefreshTagDb` into
+a writeable refresh trigger; the rest of the surface remains `ViewOnly`.
+
+### Refreshing the tag DB via OPC UA write
+
+PR abcip-4.4 wires `_RefreshTagDb` to the same `RebrowseAsync` entry point
+the CLI's `rebrowse` command exercises (issue #233). Operators have two
+roughly-equivalent ways to force a controller-side `@tags` re-walk after a
+program download:
+
+```powershell
+# Path A — OPC UA write to the system tag (production / Admin UI path)
+otopcua-client-cli write -u opc.tcp://localhost:4840 \
+    -n "ns=2;s=AbCip/ab://10.0.0.5/1,0/_System/_RefreshTagDb" \
+    -v true --type Boolean
+
+# Path B — direct CLI rebrowse against a transient driver (admin / debug path)
+otopcua-abcip-cli rebrowse -g ab://10.0.0.5/1,0
+```
+
+Both paths drop the UDT template cache + re-run the enumerator walk. Path A
+is the operator-facing surface (the same `IDriverControl.RebrowseAsync`
+contract, just dispatched from the OPC UA write surface instead of an
+in-process call). Path B spins up its own driver instance so it doesn't
+share the live server's cache, which makes it useful for one-off
+controller-side validation.
+
+The `AbCip.RefreshTriggers` driver-diagnostics counter increments per
+successful truthy write, so the Admin UI / driver-diagnostics RPC can show
+a "Refreshes since boot" tile that pairs naturally with the existing
+`WritesSuppressed` / `WritesPassedThrough` write-coalescer counters.
+
+### Verification
+
+- **Unit**: `AbCipSystemTagSourceTests`
+  (`tests/.../AbCip.Tests`) — covers snapshot round-trip, two-device
+  isolation, recognised-name lookup, default-shape on unseeded devices,
+  discovery emits the six canonical nodes, and `ReadAsync` dispatches
+  through the source instead of libplctag.
+- **Unit**: `AbCipRefreshTagDbTests`
+  (`tests/.../AbCip.Tests`) — PR abcip-4.4 — covers discovery emits the
+  trigger as Operate, reads always return `false`, truthy/falsy/null write
+  semantics, the `AbCip.RefreshTriggers` counter, two-device counter
+  independence, defends-in-depth `BadNotWritable` for read-only system
+  variables, no-op-Good when no builder is cached yet, and mixed-batch
+  routing alongside ordinary tag writes.
+- **Integration**: `AbCipSystemTagDiscoveryTests`
+  (`tests/.../AbCip.IntegrationTests`) — `[AbServerFact]` connects to a
+  real `ab_server`, browses `_System/`, reads each variable, asserts
+  every one returns Good with a non-null value.
+- **Integration**: `AbCipRefreshTagDbTests`
+  (`tests/.../AbCip.IntegrationTests`) — PR abcip-4.4 — `[AbServerFact]`
+  drives a `_RefreshTagDb` write, asserts the template cache drops + the
+  per-device counter advances against a live `ab_server`.
+- **E2E**: `scripts/e2e/test-abcip.ps1` — see the *SystemTagBrowse* +
+  *RefreshTagDbWrite* assertions.

docs/drivers/AbCip-Performance.md

@@ -0,0 +1,405 @@
+# AB CIP — Performance knobs
+
+Phase 3 of the AB CIP driver plan introduces a small set of operator-tunable
+performance knobs that change how the driver talks to the controller without
+altering the address space or per-tag semantics. They consolidate decisions
+that Kepware exposes as a slider / advanced page so deployments running into
+high-latency PLCs, narrow-CPU CompactLogix parts, or legacy ControlLogix
+firmware have an explicit lever to pull.
+
+This document is the home for those knobs as PRs land. PR abcip-3.1 ships the
+first knob: per-device **CIP Connection Size**.
+
+## Connection Size
+
+### What it is
+
+CIP Connection Size — the byte ceiling on a single Forward Open response
+fragment, set during the EtherNet/IP Forward Open handshake. Larger
+connection sizes pack more tags into a single CIP RTT (higher request-packing
+density, fewer round-trips for the same scan list); smaller connection sizes
+stay compatible with legacy or narrow-buffer firmware that rejects oversized
+Forward Open requests.
+
+### Family defaults
+
+The driver picks a Connection Size from the per-family profile when the
+device-level override is unset:
+
+| Family | Default | Rationale |
+|---|---:|---|
+| `ControlLogix` | `4002` | Large Forward Open — FW20+ |
+| `GuardLogix` | `4002` | Same wire protocol as ControlLogix |
+| `CompactLogix` | `504` | 5069-L1/L2/L3 narrow-buffer parts (5370 family) |
+| `Micro800` | `488` | Hard cap on Micro800 firmware |
+
+These map straight to libplctag's `connection_size` attribute and match the
+defaults Kepware uses out of the box for the same families.
+
+### Override knob
+
+`AbCipDeviceOptions.ConnectionSize` (`int?`, default `null`) overrides the
+family default for one device. Bind it through driver config JSON:
+
+```json
+{
+  "Devices": [
+    {
+      "HostAddress": "ab://10.0.0.5/1,0",
+      "PlcFamily": "ControlLogix",
+      "ConnectionSize": 504
+    }
+  ]
+}
+```
+
+The override threads through every libplctag handle the driver creates for
+that device — read tags, write tags, probe tags, UDT-template reads, the
+`@tags` walker, and BOOL-in-DINT parent runtimes. There is no per-tag
+override; one Connection Size applies to the whole controller (matches CIP
+session semantics).
+
+### Valid range
+
+`[500..4002]` bytes. This matches the slider Kepware exposes for the same
+family. Values outside the range fail driver `InitializeAsync` with an
+`InvalidOperationException` — there's no silent clamp; misconfigured devices
+fail loudly so operators see the problem at deploy time.
+
+| Value | Behaviour |
+|---|---|
+| `null` | Use family default (4002 / 504 / 488) |
+| `499` or below | Driver init fault — out-of-range |
+| `500..4002` | Threaded through to libplctag |
+| `4003` or above | Driver init fault — out-of-range |
+
+### Legacy-firmware caveat
+
+ControlLogix firmware **v19 and earlier** caps the CIP buffer at **504
+bytes** — Connection Sizes above that cause the controller to reject the
+Forward Open with CIP error 0x01/0x113. The 5069-L1/L2/L3 CompactLogix narrow
+parts are subject to the same cap.
+
+The driver emits a warning via `AbCipDriverOptions.OnWarning` when the
+configured Connection Size **exceeds 511** *and* the device's family profile
+default is also at-or-below the legacy cap (i.e. CompactLogix with default
+504, or Micro800 with default 488). Production hosting should wire
+`OnWarning` to the application logger; the unit tests (`AbCipConnectionSizeTests`)
+collect into a list to assert which warnings fired.
+
+The warning fires once per device at `InitializeAsync`. It does not block
+initialisation — operators may need the override anyway when running newer
+CompactLogix firmware that does support the larger Forward Open. The
+controller will reject the connection at runtime if it can't honour the size,
+and that surfaces through the standard `IHostConnectivityProbe` channel.
+
+### Performance trade-off
+
+| Larger Connection Size | Smaller Connection Size |
+|---|---|
+| More tags per CIP RTT — higher throughput | Compatible with legacy / narrow firmware |
+| Bigger buffers held by libplctag native (RSS impact) | Lower memory footprint |
+| Forward Open rejected on FW19- ControlLogix | Always works (assuming ≥500) |
+| Required for high-density scan lists | Forces more round-trips — higher latency |
+
+For most FW20+ ControlLogix shops, the default `4002` is correct and the
+override is unnecessary. The override is mainly useful when:
+
+1. **Migrating off Kepware** with a controller-specific slider value already
+   tuned in production — set Connection Size to match.
+2. **Mixed-firmware fleets** where some controllers are still on FW19 — set
+   the legacy controllers explicitly to `504`.
+3. **CompactLogix L1/L2/L3** running newer firmware that supports a larger
+   Forward Open than the family-default 504 — bump the override up.
+4. **Micro800** never goes above `488`; the override is for documentation /
+   discoverability rather than capability change.
+
+### libplctag wrapper limitation
+
+The libplctag .NET wrapper (1.5.x) does not expose `connection_size` as a
+public `Tag` property. The driver propagates the value via reflection on the
+wrapper's internal `NativeTagWrapper.SetIntAttribute("connection_size", N)`
+after `InitializeAsync` — equivalent to libplctag's
+`plc_tag_set_int_attribute`. Because libplctag native parses
+`connection_size` only at create time, this is **best-effort** until either:
+
+- the libplctag .NET wrapper exposes `ConnectionSize` directly (planned in
+  the upstream backlog), in which case the reflection no-ops cleanly, or
+- libplctag native gains post-create hot-update for `connection_size`, in
+  which case the call lands as intended.
+
+In the meantime the value is correctly stored on `DeviceState.ConnectionSize`
++ surfaces in every `AbCipTagCreateParams` the driver builds, so the override
+is observable end-to-end through the public driver surface and unit tests
+even if the underlying wrapper isn't yet honouring it on the wire.
+
+Operators who need *guaranteed* Connection Size enforcement against FW19
+controllers today can pin `libplctag` to a wrapper version that exposes
+`ConnectionSize` once one is available, or run a libplctag native build
+patched for runtime updates. Both paths are tracked in the AB CIP plan.
+
+### See also
+
+- [`docs/Driver.AbCip.Cli.md`](../Driver.AbCip.Cli.md) — AB CIP CLI uses the
+  family default ConnectionSize on each invocation; per-device overrides only
+  apply through the driver's device-config JSON, not the CLI's command-line.
+- [`docs/drivers/AbServer-Test-Fixture.md`](AbServer-Test-Fixture.md) §5 —
+  ab_server simulator does not enforce the narrow CompactLogix cap, so
+  Connection Size correctness is verified by unit tests + Emulate-rig live
+  smokes only.
+- [`PlcFamilies/AbCipPlcFamilyProfile.cs`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/PlcFamilies/AbCipPlcFamilyProfile.cs) —
+  per-family default values.
+- [`AbCipConnectionSize`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipConnectionSize.cs) —
+  range bounds + legacy-firmware threshold constants.
+
+## Addressing mode
+
+### What it is
+
+CIP exposes two equivalent ways to address a Logix tag on the wire:
+
+1. **Symbolic** — the request carries the tag's ASCII name and the controller
+   parses + resolves the path on every read. This is the libplctag default
+   and what every previous driver build has used.
+2. **Logical** — the request carries a CIP Symbol Object instance ID (a small
+   integer assigned by the controller when the project was downloaded). The
+   controller skips ASCII parsing entirely; the lookup is a single
+   instance-table dereference.
+
+Logical addressing is faster on the controller side and produces smaller
+request frames. The trade-off is that the driver has to learn the
+name → instance-id mapping once, by reading the `@tags` pseudo-tag at
+startup, and the resolution step has to repeat after a controller program
+download (instance IDs are re-assigned).
+
+### Enum values
+
+`AbCipDeviceOptions.AddressingMode` (`AddressingMode` enum, default
+`Auto`) takes one of three values:
+
+| Value | Behaviour |
+|---|---|
+| `Auto` | Driver picks. **Currently resolves to `Symbolic`** — a future PR will plumb a real auto-detection heuristic (firmware version + symbol-table size). |
+| `Symbolic` | Force ASCII symbolic addressing on the wire. The historical default. |
+| `Logical` | Use CIP logical-segment / instance-ID addressing. Triggers a one-time `@tags` walk at the first read; subsequent reads consult the cached map. |
+
+`Auto` is documented as "Symbolic-for-now" so deployments setting `Auto`
+explicitly today will silently flip to a real heuristic when one ships,
+matching the spirit of the toggle. Operators who want to pin the wire
+behaviour should set `Symbolic` or `Logical` directly.
+
+### Family compatibility
+
+Logical addressing depends on the controller implementing CIP Symbol Object
+class 0x6B with stable instance IDs. Older AB families don't:
+
+| Family | Logical addressing supported? | Why |
+|---|---|---|
+| `ControlLogix` | yes | Native class 0x6B support, FW10+ |
+| `CompactLogix` | yes | Same wire protocol as ControlLogix |
+| `GuardLogix` | yes | Same wire protocol; safety partition is tag-level, not addressing-level |
+| `Micro800` | **no** | Firmware does not implement class 0x6B; instance-ID reads trip CIP "Path Segment Error" 0x04 |
+| `SLC500` / `PLC5` | **no** | Pre-CIP families; PCCC bridging only — no Symbol Object at all |
+
+When `AddressingMode = Logical` is set on an unsupported family, the driver
+**falls back to Symbolic with a warning** (via `OnWarning`) instead of
+faulting. This keeps mixed-firmware deployments working — operators can ship
+a uniform "Logical" config across the fleet and let the driver downgrade
+the families that can't honour it.
+
+The driver-level decision is exposed via
+`PlcFamilies.AbCipPlcFamilyProfile.SupportsLogicalAddressing` and resolved at
+`AbCipDriver.InitializeAsync` time; the resolved mode is stored on
+`DeviceState.AddressingMode` and threaded through every
+`AbCipTagCreateParams` from then on.
+
+### One-time symbol-table walk
+
+The first read on a Logical-mode device triggers a one-time `@tags` walk via
+`LibplctagTagEnumerator` (the same component used for opt-in controller
+browse). The driver caches the resulting name → instance-id map on
+`DeviceState.LogicalInstanceMap`; subsequent reads consult the cache without
+issuing another walk. The walk is gated by a per-device `SemaphoreSlim` so
+parallel first-reads serialise on a single dispatch.
+
+The walk happens in `AbCipDriver.EnsureLogicalMappingsAsync` and runs only
+for devices that have actually resolved to `Logical`. Symbolic-mode devices
+skip the walk entirely. Walk failures are non-fatal: the
+`LogicalWalkComplete` flag still flips to `true` so the driver does not
+re-attempt indefinitely, and per-tag handles fall back to Symbolic addressing
+on the wire (libplctag's default).
+
+A controller program download invalidates the instance IDs. There is no
+auto-invalidation today — operators trigger a fresh walk by either
+restarting the driver or calling `RebrowseAsync` (the same surface that
+clears the UDT template cache) with logic-mode plumbing extended in a
+future PR. For now, restart-on-download is the recommended workflow.
+
+### libplctag wrapper limitation
+
+The libplctag .NET wrapper (1.5.x) does **not** expose a public knob for
+instance-ID addressing. The driver translates Logical-mode params into
+libplctag attributes via reflection on
+`NativeTagWrapper.SetAttributeString("use_connected_msg", "1")` +
+`SetAttributeString("cip_addr", "0x6B,N")` — same best-effort fallback
+pattern as the Connection Size knob.
+
+This means **Logical mode is observable end-to-end through the public
+driver surface and unit tests today**, but the actual wire behaviour
+remains Symbolic until either:
+
+- the upstream libplctag .NET wrapper exposes the
+  `UseConnectedMessaging` + `CipAddr` properties on `Tag` directly
+  (planned in the upstream backlog), in which case the reflection no-ops
+  cleanly, or
+- libplctag native gains post-create hot-update for `cip_addr`, in which
+  case the call lands as intended.
+
+The driver-level bookkeeping (resolved mode, instance-id map, family
+compatibility, fall-back warning) is fully wired so the upgrade path is
+purely a wrapper-version bump.
+
+### Performance trade-off
+
+| Symbolic addressing | Logical addressing |
+|---|---|
+| Works everywhere | Requires Symbol Object class 0x6B |
+| ASCII parse on every read (controller-side cost) | One-time walk; instance-id lookup thereafter |
+| No first-read latency | First read on a device pays the `@tags` walk |
+| Smaller code surface | Stale on program download — restart driver to re-walk |
+| Best for small / sparse tag sets | Best for >500-tag scans with stable controller |
+
+For scan lists in the **single-digit-tag** range, the per-poll ASCII parse
+cost is invisible. For **medium** scan lists (~100 tags) the gain is real
+but small — typically 5–10% per CIP RTT depending on tag-name length. The
+break-even point is where the ASCII-parse overhead starts dominating,
+roughly **>500 tags** in a tight scan loop, which is also where libplctag's
+own request-packing benefits compound. Large MES / batch projects with
+many UDT instances are the canonical case.
+
+### Driver config JSON
+
+Bind the toggle through the driver-config JSON:
+
+```json
+{
+  "Devices": [
+    {
+      "HostAddress": "ab://10.0.0.5/1,0",
+      "PlcFamily": "ControlLogix",
+      "AddressingMode": "Logical"
+    }
+  ]
+}
+```
+
+`"Auto"`, `"Symbolic"`, and `"Logical"` parse case-insensitively. Omitting
+the field defaults to `"Auto"`.
+
+### See also
+
+- [`AbCipDriverOptions.AddressingMode`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriverOptions.cs) —
+  enum definition + per-value docstrings.
+- [`AbCipPlcFamilyProfile.SupportsLogicalAddressing`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/PlcFamilies/AbCipPlcFamilyProfile.cs) —
+  family compatibility table source-of-truth.
+- [`docs/drivers/AbServer-Test-Fixture.md`](AbServer-Test-Fixture.md) §
+  "What it actually covers" — Logical-mode fixture coverage status.
+- [`AbCipAddressingModeBenchTests`](../../tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/AbCipAddressingModeBenchTests.cs) —
+  scaffold for the wall-clock comparison; gated on `[AbServerFact]`.
+
+## Read strategy (PR abcip-3.3)
+
+A per-device toggle that controls how multi-member UDT batches are read.
+The default `Auto` value matches every previous build's behaviour for dense
+reads but switches to per-member bundling when only a handful of members of
+a large UDT are subscribed — the canonical "5 of 50" sparse-subscription
+case where reading the whole UDT buffer just to extract a few fields wastes
+wire bandwidth.
+
+### Three modes
+
+| Mode | When to use |
+|---|---|
+| `WholeUdt` | Most members of every subscribed UDT are read together. One libplctag read per parent UDT, members decoded in-memory at their byte offsets. The task #194 default. |
+| `MultiPacket` | A few members of a large UDT are subscribed at a time. One read per subscribed member, bundled per parent into one CIP Multi-Service Packet. |
+| `Auto` (default) | Planner picks per-batch from the subscribed-member fraction (see *Sparsity threshold*). |
+
+### Sparsity threshold
+
+Auto mode divides `subscribedMembers / totalMembers` for each parent UDT and
+picks `MultiPacket` when the fraction is **strictly less than** the
+threshold, else `WholeUdt`. Default threshold `0.25` — a 1/4 subscription is
+the rough break-even where the wire-cost of one whole-UDT read still beats
+N member reads on a ControlLogix 4002-byte connection-size buffer; above
+1/4, the per-member overhead dominates.
+
+Tune via `AbCipDeviceOptions.MultiPacketSparsityThreshold` (clamped to
+`[0..1]`). Threshold `0.0` = "never MultiPacket"; `1.0` = "always MultiPacket
+when any member is subscribed."
+
+### Family compatibility
+
+`MultiPacket` requires CIP service `0x0A` (Multi-Service Packet) on the
+controller. Source of truth is
+[`AbCipPlcFamilyProfile.SupportsRequestPacking`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/PlcFamilies/AbCipPlcFamilyProfile.cs):
+
+| Family | `SupportsRequestPacking` |
+|---|---|
+| ControlLogix | yes |
+| CompactLogix | yes |
+| GuardLogix | yes (wire identical to ControlLogix) |
+| Micro800 | **no** |
+| SLC500 / PLC5 (when those profiles ship) | **no** |
+
+User-forced `MultiPacket` against a non-packing family logs a warning at
+device init and falls back to `WholeUdt`. `Auto` against a non-packing
+family stays `Auto` at the device level — the per-batch heuristic caps the
+strategy to `WholeUdt` so the wire never sees a Multi-Service-Packet against
+a controller that can't decode it.
+
+### libplctag wrapper limitation
+
+The libplctag .NET wrapper (1.5.x) does not expose the `0x0A` service as a
+public knob — same wrapper-version constraint that gates PR abcip-3.1's
+`connection_size` and PR abcip-3.2's instance-ID addressing. Today's
+MultiPacket runtime therefore issues N libplctag reads sequentially when
+the planner picks the strategy; the wire-level bundling lands cleanly when
+an upstream wrapper release exposes the primitive.
+
+The driver-level bookkeeping (resolved strategy, per-batch heuristic,
+family-compat fall-back, per-device dispatch counters) is fully wired so
+the upgrade path is a wrapper-version bump only — the planner already
+produces the right plan, and `AbCipMultiPacketReadPlanner.Build` is
+covered by unit tests that pin the plan shape rather than wire bytes.
+
+### Driver config JSON
+
+```json
+{
+  "Devices": [
+    {
+      "HostAddress": "ab://10.0.0.5/1,0",
+      "PlcFamily": "ControlLogix",
+      "ReadStrategy": "Auto",
+      "MultiPacketSparsityThreshold": 0.25
+    }
+  ]
+}
+```
+
+`"Auto"`, `"WholeUdt"`, and `"MultiPacket"` parse case-insensitively.
+Omitting the field defaults to `"Auto"`. Omitting
+`MultiPacketSparsityThreshold` defaults to `0.25`.
+
+### See also
+
+- [`AbCipDriverOptions.ReadStrategy`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriverOptions.cs) —
+  enum definition + per-value docstrings.
+- [`AbCipMultiPacketReadPlanner`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipMultiPacketReadPlanner.cs) —
+  plan shape + Auto-mode heuristic.
+- [`AbCipPlcFamilyProfile.SupportsRequestPacking`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/PlcFamilies/AbCipPlcFamilyProfile.cs) —
+  family compatibility table source-of-truth.
+- [`AbCipReadStrategyTests`](../../tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Tests/AbCipReadStrategyTests.cs) —
+  device-init resolution, heuristic edges, dispatch counters, DTO round-trip.
+- [`AbCipEmulateMultiPacketReadTests`](../../tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/Emulate/AbCipEmulateMultiPacketReadTests.cs) —
+  golden-box-tier wire-level coverage scaffold; gated on `AB_SERVER_PROFILE=emulate`.

docs/drivers/AbLegacy-DH-Bridging.md

@@ -0,0 +1,141 @@
+# AB Legacy — DH+ via 1756-DHRIO bridging
+
+PR ablegacy-13 / [#256](https://github.com/dohertj2/lmxopcua/issues/256). The AB
+Legacy driver can address a PLC-5 sitting on a DH+ link by routing CIP requests
+through a 1756-DHRIO module installed in a ControlLogix chassis. This is the
+canonical way to keep an installed-base PLC-5 fleet alive after the chassis-
+level migration to ControlLogix; the DHRIO module exposes a DH+ "side" that
+talks to the legacy PLC-5 / SLC-DH+ peers and a backplane "side" that the
+ControlLogix CPU + Ethernet bridge can route through.
+
+## Wire layout
+
+```
+OtOpcUa server  ──EtherNet/IP──►  1756-EN2T (slot 0)  ──backplane──►  1756-DHRIO (slot N)  ──DH+──►  PLC-5
+```
+
+Two CIP hops:
+
+1. **Backplane** — port `1`, slot `<N>` (the slot the DHRIO module lives in).
+2. **DH+** — port `2`, station `<S>` (the DH+ node address of the target PLC-5,
+   in **octal**).
+
+Resulting CIP path: `1,<N>,2,<S>`.
+
+> The first port `1` is always the backplane; port `2` is the DH+ side of the
+> 1756-DHRIO module. This mirrors the convention Rockwell uses in RSLinx + RSLogix
+> 5.
+
+## Octal station number
+
+The DH+ network was specified with **octal** node addresses. Rockwell tooling
+displays them in octal too (RSLogix 5 → "DH+ Node Address" field on the
+controller properties dialog). The driver follows suit — the station segment
+of the CIP path **must be parsed as octal** (digits 0..7 only; `8`, `9`, and
+multi-byte garbage are rejected).
+
+DH+ addresses run `0..77` octal == `0..63` decimal. Quick reference:
+
+| Octal | Decimal | Octal | Decimal | Octal | Decimal | Octal | Decimal |
+|------:|--------:|------:|--------:|------:|--------:|------:|--------:|
+| 00 | 0  | 20 | 16 | 40 | 32 | 60 | 48 |
+| 01 | 1  | 21 | 17 | 41 | 33 | 61 | 49 |
+| 02 | 2  | 22 | 18 | 42 | 34 | 62 | 50 |
+| 03 | 3  | 23 | 19 | 43 | 35 | 63 | 51 |
+| 04 | 4  | 24 | 20 | 44 | 36 | 64 | 52 |
+| 05 | 5  | 25 | 21 | 45 | 37 | 65 | 53 |
+| 06 | 6  | 26 | 22 | 46 | 38 | 66 | 54 |
+| 07 | 7  | 27 | 23 | 47 | 39 | 67 | 55 |
+| 10 | 8  | 30 | 24 | 50 | 40 | 70 | 56 |
+| 11 | 9  | 31 | 25 | 51 | 41 | 71 | 57 |
+| 12 | 10 | 32 | 26 | 52 | 42 | 72 | 58 |
+| 13 | 11 | 33 | 27 | 53 | 43 | 73 | 59 |
+| 14 | 12 | 34 | 28 | 54 | 44 | 74 | 60 |
+| 15 | 13 | 35 | 29 | 55 | 45 | 75 | 61 |
+| 16 | 14 | 36 | 30 | 56 | 46 | 76 | 62 |
+| 17 | 15 | 37 | 31 | 57 | 47 | 77 | 63 |
+
+Anything past `77` octal (i.e. decimal > 63) is invalid on a real DH+ network
+and rejected by the parser.
+
+## PLC-5 only
+
+DHRIO bridging is **PLC-5-only**. The driver enforces this at
+`AbLegacyDriver.InitializeAsync` time: a DH+ bridge path combined with
+`PlcFamily=Slc500 / MicroLogix / LogixPccc` throws
+`InvalidOperationException("DHRIO bridging is PLC-5-only")` immediately rather
+than letting reads silently fail with `BadCommunicationError` on the wire.
+
+Background: the 1756-DHRIO module only speaks DH+ to PLC-5 / SLC-DH+ peers, and
+libplctag's PCCC stack only exposes the PLC-5 side. SLC 5/04 boxes on DH+
+**can** be physically reached through a DHRIO module, but the protocol stack
+needed to drive them isn't exposed by libplctag — out of scope for this driver.
+
+## CLI worked example
+
+PLC-5 at DH+ node `07` (octal == 7 decimal), DHRIO module in slot 3, gateway
+`192.168.1.10`:
+
+```powershell
+otopcua-ablegacy-cli probe `
+    -g ab://192.168.1.10/1,3,2,07 `
+    -P Plc5 `
+    -a N7:0
+```
+
+```powershell
+# Read N7:10 from the PLC-5 across the DHRIO bridge
+otopcua-ablegacy-cli read `
+    -g ab://192.168.1.10/1,3,2,07 `
+    -P Plc5 `
+    -a N7:10 `
+    -t Int
+```
+
+The driver surfaces the parsed bridge form on the host-address record:
+`BackplaneSlot=3`, `DhPlusPort=2`, `DhPlusStation=7` (decimal-translated). Use
+those values when reading driver-diagnostics output to confirm the bridge was
+recognised — a non-bridge CIP path leaves all three fields null.
+
+## Manual smoke procedure
+
+There is no automated end-to-end coverage for DH+ bridging because the only
+path to wire-level validation is real hardware (libplctag's `ab_server` Docker
+image doesn't simulate the DHRIO + DH+ + PLC-5 stack). The unit-test layer
+covers parser positive / negative cases.
+
+Hardware smoke checklist:
+
+1. Confirm the 1756-DHRIO module is present in the target ControlLogix chassis.
+   RSLinx Classic should show `DH+, 1` under the chassis tree with the PLC-5
+   nodes enumerated underneath.
+2. Note the DHRIO module's slot number (the `<N>` in `1,<N>,2,<S>`).
+3. Note the target PLC-5's DH+ node address — read it off the front-panel switch
+   bank, or the controller properties in RSLogix 5. **Read it as octal**.
+4. From an OtOpcUa box that can reach the EtherNet/IP gateway:
+
+   ```powershell
+   otopcua-ablegacy-cli probe -g ab://<gateway>/1,<slot>,2,<station-octal> -P Plc5 -a S:0
+   ```
+
+   `S:0` (status file word 0) is non-destructive and present on every PLC-5.
+5. If the probe succeeds, exercise an N file read against a known
+   non-zero address. Compare against the value displayed in RSLogix 5 →
+   Online → Data → N7.
+
+If the probe fails with `BadCommunicationError`:
+
+- Wrong slot number — re-check via RSLinx.
+- Wrong octal node — convert from RSLogix 5's display value (already octal); a
+  decimal-thinking conversion mistake is the most common smoke failure.
+- DHRIO module's DH+ baud rate doesn't match the PLC-5's switch setting (57.6k
+  / 115.2k / 230.4k) — driver-side problem this can't paper over.
+- A scanner on the DHRIO is in scheduled-mode and starving unscheduled
+  PCCC traffic — bump the DHRIO's unscheduled-message slice in RSLogix 5000.
+
+## See also
+
+- [`Driver.AbLegacy.Cli.md`](../Driver.AbLegacy.Cli.md) — the family / CIP-path
+  cheat sheet now carries a DHRIO row.
+- [`drivers/AbLegacy-Test-Fixture.md`](AbLegacy-Test-Fixture.md) — DH+ bridging
+  is unit-only; no Docker fixture supports it.

docs/drivers/AbLegacy-Diagnostics.md

@@ -0,0 +1,188 @@
+# AB Legacy diagnostic counters
+
+Per-device diagnostic counters surface as auto-generated read-only OPC UA
+variables under each device's synthetic `_Diagnostics/` folder. HMIs can bind
+directly without going through a separate diagnostics RPC. Mirrors the AB CIP
+`_System/` pattern from PR abcip-4.3.
+
+Closes #253 (PR ablegacy-10).
+
+## The nine counters
+
+Each device managed by the `AbLegacyDriver` exposes nine read-only nodes under
+`AbLegacy/<host>/_Diagnostics/<name>`. The first seven shipped in PR ablegacy-10;
+`DemoteCount` + `LastDemotedUtc` arrived with PR ablegacy-12 / #255 (auto-demote
+on comm failure).
+
+| Name | Type | Semantics |
+|---|---|---|
+| `RequestCount` | Int64 | Total `ReadAsync` requests issued against this device. One increment per non-diagnostic reference per call, success or failure. |
+| `ResponseCount` | Int64 | Successful read responses. |
+| `ErrorCount` | Int64 | Failed read responses (any non-Good status). |
+| `RetryCount` | Int64 | Retry attempts beyond the first per the PR 9 retry loop. A single read with two retries adds two. |
+| `LastErrorCode` | Int32 | Most recent libplctag status code on a failed read; `0` when no error has been seen since the last reset. |
+| `LastErrorMessage` | String | Most recent libplctag error message on a failed read; empty when no error has been seen since the last reset. |
+| `CommFailures` | Int64 | Count of read failures mapped to `BadCommunicationError`. Spans transient libplctag throws + retried-out chains so operators see a single "wire fell off" counter. |
+| `DemoteCount` | Int64 | **PR ablegacy-12** — cumulative auto-demote events for this device. Bumps every time the driver crosses the consecutive-failure threshold and arms a fresh cool-down window. Cumulative across `ReinitializeAsync` (preserved through redeploys) so a flapping link surfaces as a steadily climbing counter. |
+| `LastDemotedUtc` | String | **PR ablegacy-12** — ISO-8601 UTC timestamp of the most recent auto-demotion. Empty string when this device has never been demoted. |
+
+**Address shape**: `_Diagnostics/<deviceHostAddress>/<name>` —
+e.g. `_Diagnostics/ab://10.0.0.5/1,0/RequestCount`.
+
+The `<deviceHostAddress>` segment is the canonical `ab://host[:port]/cip-path`
+string from `AbLegacyDeviceOptions.HostAddress`. The browse path looks like
+`AbLegacy/<deviceHostAddress>/_Diagnostics/<name>` — the same shape as a
+user-config tag node, just under a reserved sibling folder.
+
+## Reset behaviour
+
+| Trigger | Effect |
+|---|---|
+| `ReinitializeAsync` | Every counter for every device resets to zero, plus `LastErrorMessage` clears to empty. **PR ablegacy-12 exception:** `DemoteCount` + `LastDemotedUtc` survive the reinit so an operator redeploying mid-incident doesn't lose the flapping-link history. |
+| `ShutdownAsync` | All counters drop with the device map (including `DemoteCount`). |
+| Driver process restart | Counters start at zero. |
+| Probe transition Stopped→Running | **No automatic reset** — counters are cumulative across reconnect events so operators can spot intermittent links by watching `CommFailures` keep climbing. |
+| Probe transition Demoted→Running | **PR ablegacy-12** — early-clear of the active demote window, but the cumulative `DemoteCount` stays put. |
+
+There is no in-process "reset" RPC at the time of writing. If you need to
+clear counters without a redeploy, kick a `ReinitializeAsync` from the Admin
+RPC surface — the driver re-EnsureDevice's each host so the freshly registered
+counters start at zero.
+
+## What does *not* increment counters
+
+Reads against `_Diagnostics/<host>/<name>` are **driver-local observability**,
+not field traffic — they short-circuit before the libplctag dispatch and do
+NOT increment `RequestCount` or any other counter. Otherwise a 1 Hz HMI poll
+of `RequestCount` would make the counter chase its own tail.
+
+Writes against `_Diagnostics/*` are rejected with `BadNotWritable` because
+every diagnostic node is `SecurityClassification.ViewOnly` — a misbehaving
+SCADA template can't accidentally clobber the diagnostic surface.
+
+## Collision with user tags
+
+User-config tags must not shadow the seven reserved diagnostic names and
+must not live under the synthetic `_Diagnostics/` folder. Both shapes are
+rejected at `InitializeAsync` time with a clear `InvalidOperationException`:
+
+- A tag named `RequestCount` (or any of the other six reserved names) is
+  rejected because it would silently never resolve at read time — the
+  diagnostics short-circuit wins.
+- A tag whose `Address` starts with `_Diagnostics/` is rejected because the
+  whole prefix is owned by the auto-emitted counters.
+
+Pick a different name (`SiteRequestCount`, `MachineRequestCount`) or a
+different address path (real PCCC files like `N7:0`).
+
+## HMI binding examples
+
+### OPC UA Client CLI
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- read `
+  -u opc.tcp://localhost:4840 `
+  -n "ns=2;s=AbLegacy/ab://10.0.0.5/1,0/_Diagnostics/RequestCount"
+```
+
+### AB Legacy CLI (driver-direct, no OPC UA layer)
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli -- read `
+  -g "ab://10.0.0.5/1,0" -P Slc500 `
+  --address "_Diagnostics/RequestCount"
+```
+
+The driver-direct path lets you sanity-check the counter without standing up
+an OPC UA server — useful when triaging a wire-level issue on the bench.
+
+### Subscription pattern
+
+Subscribe to all seven counters at a slow rate (e.g. 5–10 s) on a long-lived
+overview dashboard, plus a faster rate (1 s) on `LastErrorMessage` /
+`LastErrorCode` when actively debugging a flapping link. The diagnostics
+short-circuit makes every read O(1) — there's no penalty for fast polling
+of the counter itself, only the OPC UA subscription bookkeeping.
+
+## Auto-demote on comm failure (PR ablegacy-12 / #255)
+
+When a device fails N consecutive reads or probes the driver marks it
+**Demoted** for a configurable cool-down window. Reads against a demoted
+device short-circuit with `BadCommunicationError` *without invoking
+libplctag* — that's the whole point of the feature: one slow PLC sharing
+the driver thread can't starve faster peers reading from healthy hosts on
+the same `AbLegacyDriver` instance.
+
+### Configuration
+
+Per-device, optional. `null` keeps the documented defaults (auto-demote
+**enabled** with 3 failures / 30 s).
+
+```jsonc
+{
+  "Devices": [
+    {
+      "HostAddress": "ab://10.0.0.5/1,0",
+      "PlcFamily": "Slc500",
+      "Demote": {
+        "FailureThreshold": 3,    // default 3
+        "DemoteForMs": 30000,     // default 30s
+        "Enabled": true           // default true
+      }
+    }
+  ]
+}
+```
+
+| Knob | Default | Notes |
+|---|---|---|
+| `FailureThreshold` | `3` | Consecutive comm failures before the device is demoted. A successful read or probe resets the tally. Terminal failures (`BadNodeIdUnknown`, `BadTypeMismatch`, …) **do not count** — they're config / decoder mismatches, not field outages. |
+| `DemoteForMs` | `30000` (30s) | Cool-down window. Reads while this is active short-circuit; a successful probe clears it early. |
+| `Enabled` | `true` | Set to `false` to keep the diagnostic counters but skip the auto-throttle. The failure tally still ticks but never arms the cool-down. |
+
+### Recovery
+
+Three ways out of Demoted, in order of likelihood:
+
+1. **Probe success** — the per-device probe loop (`Probe.Enabled = true`,
+   default address `S:0`) is the fast path. The next probe iteration after
+   demotion will exercise the wire; on success it clears
+   `DemotedUntilUtc` immediately and transitions the host to `Running`.
+2. **Window expiry** — once `DemoteForMs` elapses the demote marker
+   clears on the next read attempt. The read goes through; if it fails,
+   the failure tally keeps counting from where it left off (so a
+   permanently-down device re-arms the window after one more consecutive
+   failure rather than having to repeat the full threshold).
+3. **`ReinitializeAsync`** — clears `ConsecutiveFailures` +
+   `DemotedUntilUtc` outright. Cumulative `DemoteCount` survives.
+
+### Observability
+
+`DemoteCount` is the headline counter — it bumps once per demotion event,
+not per short-circuited read. A device that flaps every hour for a week
+shows `DemoteCount = ~168` on Friday afternoon, which is the operator
+signal you actually want.
+
+`LastDemotedUtc` is the ISO-8601 UTC timestamp of the most recent
+demotion. Bind it on a per-device tile alongside `DemoteCount` for
+"flapping link" alerting.
+
+### Host-state surface
+
+A demoted device reports `HostState.Demoted` (new in PR ablegacy-12
+on `Core.Abstractions/IHostConnectivityProbe.cs`). Consumers that
+predate the new value (the central `HostStatusPublisher`) safely treat
+it as `Stopped` — no schema migration needed.
+
+## Cross-references
+
+- [`AbLegacyDiagnosticTags.cs`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDiagnosticTags.cs)
+  — counter store + read short-circuit
+- [`AbLegacyDriver.cs`](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDriver.cs)
+  — increment sites in `ReadAsync`, discovery emission in `DiscoverAsync`,
+  auto-demote bookkeeping in `RecordFailureAndMaybeDemote` + `ProbeLoopAsync`
+- [`AbLegacy-Test-Fixture.md`](AbLegacy-Test-Fixture.md) — `AbLegacyDiagnosticsTests`
+  + `AbLegacyAutoDemoteTests` + collision-rejection contract
+- [AB CIP `_System/` parallel](../../src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipSystemTagSource.cs)
+  — same pattern with the CIP-specific six entries (incl. writeable
+  `_RefreshTagDb` trigger)

docs/drivers/AbLegacy-RSLogix-Import.md

@@ -0,0 +1,163 @@
+# AB Legacy — RSLogix symbol & data-table import
+
+ablegacy-11 / [#254](https://github.com/dohertj2/lmxopcua/issues/254) — bulk-import
+RSLogix 500 / 5 symbol exports into the AB Legacy driver. Saves operators from
+hand-typing every `N7:0` / `F8:12` / `B3:0/5` row of a several-hundred-tag PLC
+into `appsettings.json`.
+
+## Supported formats — v1
+
+| Format | Status | Notes |
+|---|---|---|
+| `.CSV` "Database Export" | **supported** | Header columns `Symbol,Address,Description,DataType,Scope`; quoted fields, doubled-quote escapes, comment lines (`;` / `#`) all honoured |
+| `.SLC` text export | **supported** | RSLogix 500's "Save As Text" emits the same column shape — point the importer at the file directly |
+| `.RSS` (RSLogix 500 binary project) | **out of scope** | Proprietary; no parser ships in libplctag or any community project. Export to CSV first |
+| `.RSP` (RSLogix 5 binary project) | **out of scope** | Same as `.RSS` |
+
+The binary `.RSS` / `.RSP` non-goal isn't a "we don't have time" decision —
+Rockwell's binary format is undocumented + tied to RSLogix's internal page
+layout, and the only known parsers are commercial IDE plugins. v1 ships with
+text/CSV only and a clean abstraction (`IRsLogixImporter`) so a binary parser
+can slot in later without reshaping the call sites.
+
+## CSV column reference
+
+| Column | Required | Notes |
+|---|---|---|
+| `Symbol` | yes | OPC UA tag name. RSLogix symbols are already stable; the importer uses them verbatim |
+| `Address` | yes | PCCC address. File letter implies `DataType` (see below); the importer's resolution wins over the CSV's `DataType` column |
+| `Description` | no | Parsed but currently unused — `AbLegacyTagDefinition` has no `Description` field at the v2 schema layer (see [#248](https://github.com/dohertj2/lmxopcua/issues/248)). Held in the column contract for future schema bumps |
+| `DataType` | no | RSLogix-supplied (`INT` / `REAL` / `BOOL` / `TIMER` / …). Ignored at import time; the importer derives the type from the file letter |
+| `Scope` | no | `Global` (default when blank) or `Local:N` for ladder-file-N-scoped tags. Acts as a filter when `--scope` is set on the CLI |
+
+### File-letter → `AbLegacyDataType` mapping
+
+| Letter | Example | Maps to | Notes |
+|---|---|---|---|
+| `N` | `N7:0` | `Int` (signed 16-bit) | |
+| `F` | `F8:0` | `Float` (32-bit IEEE-754) | |
+| `B` | `B3:0/0` | `Bit` | Bit-within-word also forces Bit when `BitIndex` is set |
+| `L` | `L9:0` | `Long` (signed 32-bit) | SLC 5/05+ only |
+| `ST` | `ST10:0` | `String` | 82-byte fixed-length + length word |
+| `T` | `T4:0.ACC` | `TimerElement` | Sub-element implied by `.ACC` / `.PRE` / `.EN` / `.DN` |
+| `C` | `C5:0.ACC` | `CounterElement` | |
+| `R` | `R6:0.LEN` | `ControlElement` | |
+| `A` | `A14:0` | `AnalogInt` | Older hardware |
+| `I` / `O` / `S` | `I:0/0` | `Int` (or `Bit` with bit suffix) | I/O + status files |
+| `PD` / `MG` / `PLS` / `BT` | `PD9:0` | `PidElement` etc. | Family-gated; PD/MG common on SLC500 + PLC-5; PLS/BT PLC-5 only |
+| `RTC` / `HSC` / `DLS` / … | `RTC:0.YR` | `MicroLogixFunctionFile` | MicroLogix 1100 / 1400 only |
+
+A bit suffix (`/N`) on any file letter forces `Bit`, regardless of the file
+letter's normal classification — `N7:0/3` parses as Bit, not Int.
+
+## Scope filter
+
+The `Scope` column distinguishes program-scoped tags (`Local:1`, `Local:2`, …)
+from globals. RSLogix exports usually mix both. The CLI's `--scope` flag (and
+`ImportOptions.ScopeFilter` at the API level) keeps only the rows whose
+`Scope` value matches case-insensitively; rows with no `Scope` column count as
+`Global`.
+
+```powershell
+# Import only the Global symbols
+otopcua-ablegacy-cli import-rslogix `
+    --file plc-export.csv `
+    --device ab://192.168.1.20/1,0 `
+    --scope Global
+
+# Import only the file-2 program-scope tags
+otopcua-ablegacy-cli import-rslogix `
+    --file plc-export.csv `
+    --device ab://192.168.1.20/1,0 `
+    --scope Local:2
+```
+
+## CLI subcommand — `import-rslogix`
+
+```powershell
+otopcua-ablegacy-cli import-rslogix --help
+```
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-f` / `--file` | **required** | Path to the CSV export |
+| `-d` / `--device` | **required** | Canonical AB Legacy gateway URI every imported tag binds to |
+| `--emit` | `appsettings-fragment` | `appsettings-fragment` (JSON) or `summary` (one-line counter) |
+| `-o` / `--output` | stdout | Optional path; when set the JSON fragment is written there + summary line goes to stdout |
+| `--scope` | none | Optional Scope filter (case-insensitive) |
+| `--max-rows` | unlimited | Defensive cap on rows imported |
+| `--strict` | off | Fail-fast on the first malformed row (default permissive: skip + log) |
+
+### `appsettings-fragment` output shape
+
+The default `--emit appsettings-fragment` mode writes a JSON object whose
+`Tags` array is shaped like the `AbLegacyDriverConfigDto.Tags` array — paste
+straight into the driver-instance config under
+`Drivers/<instance>/Config/Tags`.
+
+```json
+{
+  "Tags": [
+    {
+      "Name": "MotorSpeed",
+      "DeviceHostAddress": "ab://192.168.1.20/1,0",
+      "Address": "N7:0",
+      "DataType": "Int",
+      "Writable": true
+    },
+    …
+  ]
+}
+```
+
+### Summary line
+
+`--emit summary` writes a single line:
+
+```
+Imported 142 tag(s), skipped 3, errors 0.
+```
+
+`Skipped` covers Scope-filter rejections + missing-required-field rows; `errors`
+covers rows whose `Address` failed to parse as a PCCC address.
+
+## API surface — `IRsLogixImporter` + `AddRsLogixImport`
+
+For server-side / bootstrap use-cases the importer is also reachable via:
+
+```csharp
+using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy;
+using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Import;
+
+var options = new AbLegacyDriverOptions
+{
+    Devices = [new AbLegacyDeviceOptions("ab://192.168.1.20/1,0")],
+};
+
+// Append imported tags onto an existing options object.
+var updated = options.AddRsLogixImport(
+    path: @"C:\plc\plc-export.csv",
+    deviceHostAddress: "ab://192.168.1.20/1,0",
+    out var result);
+
+// result.ParsedCount / SkippedCount / ErrorCount surface the import telemetry.
+Console.WriteLine($"Imported {result.ParsedCount} tags");
+```
+
+For a hand-managed importer instance (e.g. supplying a custom `ILogger`) call
+`new RsLogixSymbolImport(logger).Parse(stream, deviceHostAddress, opts)`
+directly.
+
+## Operational notes
+
+- The importer is **additive** — `AddRsLogixImport` concatenates onto the
+  existing `Tags` list rather than replacing it. Hand-rolled tags (system-status
+  variables, computed fields the operator added by hand) survive a re-import.
+- Re-imports are not idempotent today — calling `AddRsLogixImport` twice will
+  produce duplicate tag rows. Operators are expected to either start from a
+  clean options object or de-duplicate themselves; a future schema rev may add
+  a `replace=true` switch.
+- Description metadata is dropped on the floor — see the column reference
+  above. When [#248](https://github.com/dohertj2/lmxopcua/issues/248) lands a
+  `Description` field on `AbLegacyTagDefinition` the importer will start
+  populating it without further changes to the CSV contract.

docs/drivers/AbLegacy-Test-Fixture.md

@@ -36,6 +36,12 @@ supplies a `FakeAbLegacyTag`.
 
 - `AbLegacyAddressTests` — PCCC address parsing for SLC / MicroLogix / PLC-5
   / LogixPccc-mode (`N7:0`, `F8:12`, `B3:0/5`, etc.)
+- `AbLegacyArrayTests` — PR 7 array contiguous-block addressing: parser
+  positives + rejects for `,N` / `[N]` suffixes, options-override
+  (`ArrayLength`), driver `IsArray` discovery, and array decoding for N / F /
+  L / B files (Rockwell convention: one BOOL per word for `B3:0,10`). Latency
+  benchmark against the Docker fixture is a perf-flagged integration case in
+  `AbLegacyArrayReadTests` — runs only when ab_server is reachable.
 - `AbLegacyCapabilityTests` — data type mapping, read-only enforcement
 - `AbLegacyReadWriteTests` — read + write happy + error paths against the fake
 - `AbLegacyBitRmwTests` — bit-within-DINT read-modify-write serialization via
@@ -43,6 +49,63 @@ supplies a `FakeAbLegacyTag`.
 - `AbLegacyHostAndStatusTests` — probe + host-status transitions driven by
   fake-returned statuses
 - `AbLegacyDriverTests` — `IDriver` lifecycle
+- `AbLegacyDiagnosticsTests` — PR ablegacy-10 / #253 per-device diagnostic
+  counters: 5 reads (3 ok / 2 fail) → `RequestCount=5`, `ResponseCount=3`,
+  `ErrorCount=2`; `LastErrorCode` reflects the most recent libplctag status;
+  `RetryCount` increments per retry attempt beyond the first; counters reset
+  on `ReinitializeAsync`; discovery emits the canonical diagnostic variables
+  per device under `_Diagnostics/` (now 9 with PR ablegacy-12); collision
+  rejection at `InitializeAsync` for user tags shadowing reserved names or
+  `_Diagnostics/` addresses; the `_Diagnostics/<host>/<name>` short-circuit
+  returns the live snapshot through `ReadAsync` without bumping
+  `RequestCount`; two devices keep counters independent.
+- `AbLegacyAutoDemoteTests` — **PR ablegacy-12 / #255** auto-demote on comm
+  failure: 3 consecutive failures arm the demote window and surface
+  `HostState.Demoted`; subsequent reads short-circuit with
+  `BadCommunicationError` *without invoking libplctag* (verified via
+  `factory.Tags["N7:0"].ReadCount` not advancing); successful read resets
+  the consecutive-failure counter; failure-success-failure pattern doesn't
+  cross the threshold; `DemoteCount` + `LastDemotedUtc` surface via
+  `_Diagnostics/`; `Enabled=false` opts out (failures still count, demotion
+  never fires); `ReinitializeAsync` clears the active window but preserves
+  cumulative `DemoteCount`; cool-down expiry allows the next read through;
+  two devices in one driver — one faulty, one healthy — proves the faulty
+  side's demotion doesn't starve the healthy side; `BadNodeIdUnknown`
+  (terminal) does not count toward the comm-failure tally; DTO JSON
+  round-trip preserves `FailureThreshold` / `DemoteForMs` / `Enabled` at
+  the per-device level; `HostState.Demoted` enum value is wired through
+  `Core.Abstractions`. Companion integration test in
+  `tests/.../IntegrationTests/AbLegacyAutoDemoteTests.cs` runs the
+  two-device-one-unreachable scenario against a live ab_server fixture
+  using `127.0.0.1:1` as the unreachable peer.
+- `RsLogixSymbolImportTests` — ablegacy-11 / #254 RSLogix CSV symbol-import parser:
+  canonical 8-row CSV (one row per N/F/B/L/ST/T/C/R) → 8 typed
+  `AbLegacyTagDefinition`s with the right `DataType`; header + comment-line
+  (`;` / `#`) skipping; malformed-row → log warning + skip (`IgnoreInvalid=true`
+  default) vs. `InvalidDataException` (`IgnoreInvalid=false`); empty stream →
+  empty result; UTF-8 BOM survival; embedded comma in quoted Description;
+  doubled-quote escape; `--scope` filter (Global vs. Local:N); `MaxRowsToImport`
+  cap; missing required header column → `InvalidDataException` regardless of
+  `IgnoreInvalid`; `TryResolveDataType` rejects garbage + bit-suffix overrides
+  the file letter (`N7:0/3` → Bit).
+- `RsLogixSymbolImportGoldenTests` — golden-snapshot integration: loads
+  `Fixtures/rslogix-canonical.csv` (8-row canonical export covering every v1
+  file letter), serialises the resulting tag list, and compares to
+  `Fixtures/rslogix-canonical-expected.json`. On mismatch the actual JSON is
+  dumped to `%TEMP%/rslogix-canonical-actual.json` and the path printed in the
+  failure message so the dev can `cp` the golden after reviewing the diff.
+- `AbLegacyDriverFactoryAddRsLogixImportTests` — covers the
+  `AbLegacyDriverFactoryExtensions.AddRsLogixImport` extension method:
+  appends imported tags onto an existing options object without dropping the
+  hand-rolled tags or the device list; mutates by-copy (immutability
+  guarantee); `AddRsLogixImportWithResult` tuple overload returns both the
+  modified options and the import counters.
+- `AbLegacyDeadbandTests` — PR 8 per-tag deadband / change filter:
+  absolute-only suppression sequence `[10.0, 10.5, 11.5, 11.6] -> [10.0, 11.5]`,
+  percent-only suppression with a zero-prev short-circuit, both-set logical-OR
+  semantics (Kepware), Boolean edge-only publish, string change-only publish,
+  status-change always-publish, first-seen always-publish, ReinitializeAsync
+  cache wipe, JSON DTO round-trip.
 
 Capability surfaces whose contract is verified: `IDriver`, `IReadable`,
 `IWritable`, `ITagDiscovery`, `ISubscribable`, `IHostConnectivityProbe`,
@@ -69,6 +132,17 @@ driver-side correctness depends on libplctag being correct.
 `IPerCallHostResolver` contract is verified; real PCCC wire routing across
 multiple gateways is not.
 
+### 3a. DH+ via 1756-DHRIO bridging (PR ablegacy-13 / #256)
+
+Unit-only — coverage lives in `AbLegacyDhPlusBridgingTests`. The CIP-path
+parser positive / negative cases (octal-station validation, slot bounds, port
+shape) and the PLC-5-only family guard at `InitializeAsync` are exercised
+against fakes. There is no Docker fixture for DH+ because libplctag's
+`ab_server` doesn't simulate the DHRIO + DH+ + PLC-5 stack — wire-level
+validation requires real hardware. See
+[`AbLegacy-DH-Bridging.md`](AbLegacy-DH-Bridging.md) for the manual smoke
+procedure.
+
 ### 4. Alarms / history
 
 PCCC has no alarm object + no history object. Driver doesn't implement
@@ -111,6 +185,33 @@ cover the common ones but uncommon ones (`R` counters, `S` status files,
    network; parts are end-of-life but still available. PLC-5 +
    LogixPccc-mode behaviour + DF1 serial need specific controllers.
 
+## Per-device options (`AbLegacyDeviceOptions`)
+
+Each entry in `AbLegacyDriverOptions.Devices` carries:
+
+| Field | Type | Default | Notes |
+|---|---|---|---|
+| `HostAddress` | string | required | `ab://host[:port]/cip-path` |
+| `PlcFamily` | enum | `Slc500` | Slc500 / MicroLogix / Plc5 / LogixPccc |
+| `DeviceName` | string | null | Friendly label used in browse + diagnostics |
+| `Timeout` | TimeSpan? | null → driver-wide default | **PR 9 / #252** — wins over the driver-wide `Timeout`. Mix-and-match: SLC 5/01 ≈ 5 s, SLC 5/05 ≈ 2 s, MicroLogix 1100 ≈ 3 s |
+| `Retries` | int? | null → driver-wide default → 0 | **PR 9 / #252** — retries on transient `BadCommunicationError`; terminal errors surface on the first attempt |
+
+JSON shape (mirrored on `AbLegacyDeviceDto`):
+
+```json
+{
+  "HostAddress": "ab://192.168.1.10/1,0",
+  "PlcFamily": "Slc500",
+  "DeviceName": "slc-5-01-line-A",
+  "TimeoutMs": 5000,
+  "Retries": 1
+}
+```
+
+Per-device overrides also flow into the probe loop — slow chassis won't be
+falsely marked Stopped just because the driver-wide probe timeout is tight.
+
 ## Key fixture / config files
 
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/AbLegacyServerFixture.cs`
@@ -124,5 +225,10 @@ cover the common ones but uncommon ones (`R` counters, `S` status files,
   — known-limitations write-up + resolution paths
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Tests/FakeAbLegacyTag.cs` —
   in-process fake + factory
+- `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Tests/Fixtures/rslogix-canonical.csv`
+  — ablegacy-11 / #254 8-row canonical RSLogix CSV symbol export, one row per
+  v1 file letter (N/F/B/L/ST/T/C/R)
+- `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Tests/Fixtures/rslogix-canonical-expected.json`
+  — golden snapshot the import tests compare against
 - `src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDriver.cs` — scope remarks
   at the top of the file

docs/drivers/AbServer-Test-Fixture.md

@@ -38,6 +38,16 @@ quirk. UDT / alarm / quirk behavior is verified only by unit tests with
 - `--plc controllogix` and `--plc compactlogix` mode dispatch.
 - The skip-on-missing-binary behavior (`AbServerFactAttribute`) so a fresh
   clone without the simulator stays green.
+- **Symbolic vs Logical addressing wall-clock** (PR abcip-3.2,
+  `AbCipAddressingModeBenchTests`) — both modes complete + emit timing.
+  **Emulate-tier only**: `ab_server` does not currently honour the CIP Symbol
+  Object class 0x6B `cip_addr` attribute that Logical mode sets, so on the
+  fixture the two modes measure the same wire path. The bench scaffold
+  asserts both complete + records timing for human inspection; the actual
+  Symbolic-vs-Logical perf comparison requires a real ControlLogix /
+  CompactLogix on the network. See
+  [`docs/drivers/AbCip-Performance.md`](AbCip-Performance.md) §"Addressing
+  mode" for the full caveat.
 
 ## What it does NOT cover
 
@@ -60,6 +70,19 @@ Unit coverage: `AbCipFetchUdtShapeTests`, `CipTemplateObjectDecoderTests`,
 `AbCipDriverWholeUdtReadTests` — all with golden Template-Object byte buffers
 + offset-keyed `FakeAbCipTag` values.
 
+PR abcip-3.3 layers a per-device **`ReadStrategy`** selector on top
+(`WholeUdt` / `MultiPacket` / `Auto`, see
+[`AbCip-Performance.md`](AbCip-Performance.md) §"Read strategy"). Strategy
+switching is planner-side: the dispatcher picks between
+`AbCipUdtReadPlanner` (whole-UDT) and `AbCipMultiPacketReadPlanner`
+(per-member, bundled per parent) per batch. The selector + per-batch Auto
+heuristic + family-compat fall-back + per-device dispatch counters are
+**unit-tested only** in `AbCipReadStrategyTests` — `ab_server` cannot host
+a 50-member UDT to exercise the sparse case the strategy is designed for,
+and the libplctag .NET wrapper (1.5.x) does not expose explicit
+Multi-Service-Packet bundling, so wire-level coverage stays Emulate-tier
+in `AbCipEmulateMultiPacketReadTests` (gated on `AB_SERVER_PROFILE=emulate`).
+
 ### 2. ALMD / ALMA alarm projection (#177)
 
 Depends on the ALMD UDT shape, which `ab_server` cannot emulate. The
@@ -96,6 +119,15 @@ value per PR 10, but `ab_server` accepts whatever the client asks for — the
 cap's correctness is trusted from its unit test, never stressed against a
 simulator that rejects oversized requests.
 
+PR abcip-3.1 layers the **per-device `ConnectionSize` override** on top
+(`AbCipDeviceOptions.ConnectionSize`, range `[500..4002]`, see
+[`AbCip-Performance.md`](AbCip-Performance.md)). Same gap — `ab_server`
+happily honours an oversized override against the CompactLogix profile, so
+the legacy-firmware warning + Forward Open rejection that real 5069-L1/L2/L3
+parts emit are unit-tested only. Live coverage stays Emulate / rig-only
+(connect against a real CompactLogix L2 with `ConnectionSize=1500` to
+confirm the Forward Open fails with CIP error 0x01/0x113).
+
 ### 6. BOOL-within-DINT read-modify-write (#181)
 
 The `AbCipDriver.WriteBitInDIntAsync` RMW path + its per-parent `SemaphoreSlim`
@@ -107,14 +139,48 @@ the RMW path is not exercised end-to-end.
 
 No smoke test for:
 
-- `IWritable.WriteAsync`
+- `IWritable.WriteAsync` — atomic write coverage; PR abcip-4.2 added a
+  multi-write *suppression* smoke (jittery 5-write sequence with
+  `WriteDeadband: 1.0` against `ab_server`, asserting the driver's
+  diagnostics counter matches the expected suppression count) but pure
+  atomic-write coverage end-to-end is still unit-only.
 - `ITagDiscovery.DiscoverAsync` (`@tags` walker)
 - `ISubscribable.SubscribeAsync` (poll-group engine)
-- `IHostConnectivityProbe` state transitions under wire failure
+- ~~`IHostConnectivityProbe` state transitions under wire failure~~ —
+  covered as of PR abcip-4.3. `AbCipSystemTagDiscoveryTests` connects to
+  `ab_server`, drives the discovery + read path against the synthetic
+  `_System/_ConnectionStatus` variable, and asserts the live snapshot
+  reflects the probe-driven `HostState`. Wire-failure transitions still
+  rely on unit-level `ThrowOnRead` injection rather than a real wire pull,
+  but the end-to-end probe → snapshot → OPC UA address-space link is
+  exercised against `ab_server`.
 - `IPerCallHostResolver` multi-device routing
 
 The driver implements all of these + they have unit coverage, but the only
-end-to-end path `ab_server` validates today is atomic `ReadAsync`.
+end-to-end paths `ab_server` validates today are atomic `ReadAsync` and
+write-deadband / write-on-change suppression.
+
+### 8. ControlLogix HSBY paired-IP role probing (PR abcip-5.1)
+
+`ab_server` has no second-chassis concept and no `WallClockTime.SyncStatus`
+tag. The HSBY paired-IP role-prober (PR abcip-5.1) is unit-tested only —
+`AbCipHsbyTests` drives two fake runtimes (primary + partner), pins each
+chassis's role-tag value, and asserts the active-resolution rules + DTO
+round-trip + diagnostics surface.
+
+The `paired` Docker compose profile spins up two `ab_server` instances +
+a stub `hsby-mux` sidecar so the topology is documented, but PR 5.2 follow-
+up needs a patched `ab_server` image (or a Python shim) that actually
+serves the role tag before the integration test
+(`AbCipHsbyRoleProberTests`) can flip its `Assert.Skip` into a real wire
+assertion. Until then the test is gated on `Category=Hsby` + skipped by
+default.
+
+Lab-rig coverage is the authoritative path — a real 1756-RM redundant
+chassis pair is the only place the live `WallClockTime.SyncStatus` matrix
++ split-brain handling can be exercised end-to-end. See
+[`AbCip-HSBY.md`](AbCip-HSBY.md) for the full configuration + role-tag
+detection matrix.
 
 ## Logix Emulate golden-box tier
 

docs/drivers/FOCAS-Test-Fixture.md

@@ -2,149 +2,168 @@
 
 Coverage map + gap inventory for the FANUC FOCAS2 CNC driver.
 
-**Status:** as of 2026-04-24, OtOpcUa speaks FOCAS2 directly over TCP
+**TL;DR: there is no integration fixture.** Every test uses a
-via the pure-managed [`Focas.Wire`](https://github.com/Ladder99/focas-mock/tree/main/dotnet/Focas.Wire)
+`FakeFocasClient` injected via `IFocasClientFactory`. Fanuc's FOCAS library
-client. Integration tests run the managed driver end-to-end against the
+(`Fwlib32.dll`) is closed-source proprietary with no public simulator;
-vendored `focas-mock` Python server (at
+CNC-side behavior is trusted from field deployments.
-[`tests/.../Docker/focas-mock/`](../../tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/focas-mock/VENDORED.md))
-whose native FOCAS Ethernet responder is verified PDU-by-PDU against the
-real `fwlibe64.dll`.
 
-No shim DLL, no P/Invoke, no licensed binary — any dev box or CI runner
+## What the fixture is
-with Docker can run the full fixture end-to-end.
 
-Hardware validation against a real CNC is still useful to catch
+Nothing at the integration layer.
-series-specific firmware quirks (see [§ Hardware-only gaps](#hardware-only-gaps))
+`tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/` is unit-only. The driver ships
-but the mock's wire responder covers every FOCAS call OtOpcUa issues.
+as Tier C (process-isolated) per `docs/v2/driver-stability.md` because the
+FANUC DLL has known crash modes; tests can't replicate those in-process.
 
-## What the fixture covers
+## What it actually covers (unit only)
 
-### Unit layer (no container required)
+- `FocasCapabilityTests` — data-type mapping (PMC bit / word / float,
-
+  macro variable types, parameter types)
-`tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/` uses `FakeFocasClient`
+- `FocasCapabilityMatrixTests` — per-CNC-series range validation (macro
-injected via `IFocasClientFactory`:
+  / parameter / PMC letter + number) across 16i / 0i-D / 0i-F /
-
+  30i / PowerMotion. See [`docs/v2/focas-version-matrix.md`](../v2/focas-version-matrix.md)
-- `FocasCapabilityTests` — data-type mapping (PMC bit / byte / word /
+  for the authoritative matrix. 46 theory cases lock every documented
-  long / float / double, macro variable types, parameter types)
+  range boundary — widening a range without updating the doc fails a
-- `FocasCapabilityMatrixTests` — per-CNC-series range validation across
+  test.
-  16i / 0i-D / 0i-F / 30i / Power Motion, 46 theory cases locking every
+- `FocasReadWriteTests` — read + write against the fake, FOCAS native status
-  documented range boundary. See
+  → OPC UA StatusCode mapping
-  [`docs/v2/focas-version-matrix.md`](../v2/focas-version-matrix.md).
-- `FocasReadWriteTests` — read / write contract against the fake, FOCAS
-  native status → OPC UA `StatusCode` mapping
 - `FocasScaffoldingTests` — `IDriver` lifecycle + multi-device routing
-- `FocasPmcBitRmwTests` — PMC bit read-modify-write synchronisation
+- `FocasPmcBitRmwTests` — PMC bit read-modify-write synchronization (per-byte
-- `FocasAlarmProjectionTests` — raise / clear diffing, severity mapping
+  `SemaphoreSlim`, mirrors the AB / Modbus pattern from #181)
-- `FocasHandleRecycleTests` — proactive session recycle cadence
+- `FwlibNativeHelperTests` — `Focas32.dll` → `Fwlib32.dll` bridge validation
+  + P/Invoke signature validation
 
 Capability surfaces whose contract is verified: `IDriver`, `IReadable`,
-`ITagDiscovery`, `ISubscribable`, `IHostConnectivityProbe`,
+`IWritable`, `ITagDiscovery`, `ISubscribable`, `IHostConnectivityProbe`,
-`IPerCallHostResolver`, `IAlarmSource`. `IWritable` intentionally
+`IPerCallHostResolver`.
-returns `BadNotWritable` — OtOpcUa is read-only against FOCAS.
 
 Pre-flight validation runs in `FocasDriver.InitializeAsync` — configs
 referencing out-of-range addresses fail at load time with a diagnostic
-message naming the CNC series + documented limit.
+message naming the CNC series + documented limit. This closes the
+cheap half of the hardware-free stability gap; Tier-C process
+isolation (task #220) closes the expensive half — see
+[`docs/v2/implementation/focas-isolation-plan.md`](../v2/implementation/focas-isolation-plan.md).
 
-### Integration layer (mock only, no CNC, no shim)
+## What it does NOT cover
 
-`tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/` drives the
+### 1. FOCAS wire traffic
-managed `FocasDriver` end-to-end. A single gate:
 
-**Docker compose up** — tests skip when the TCP probe to
+No FOCAS TCP frame is sent. `Fwlib32.dll`'s TCP-to-FANUC-gateway exchange is
-`localhost:8193` fails with a pointer to the compose command.
+closed-source; the driver trusts the P/Invoke layer per #193. Real CNC
+correctness is trusted from field deployments.
 
-When the mock is up, `WireFocasClient` dials it over TCP exactly like a
+### 2. Alarm / parameter-change callbacks
-real CNC, and the mock's native FOCAS Ethernet responder replies with
-binary PDUs against the documented command IDs. Covered assertions:
 
-- Session open / close (`cnc_allclibhndl3` + `cnc_freelibhndl`)
+FOCAS has no push model — the driver polls via the shared `PollGroupEngine`.
-- Parameter read-back after `mock_patch` seed → `cnc_rdparam`
+There are no CNC-initiated callbacks to test; the absence is by design.
-- Macro read-back after seed → `cnc_rdmacro` (scaled-decimal
-  translation verified)
-- PMC range read after seed → `pmc_rdpmcrng`
-- `IAlarmSource` raise + clear transitions after `mock_patch`
-  alarm-list changes → `cnc_rdalmmsg2`
-- Fixed-tree bootstrap: identity / axes / spindle / program / timers /
-  servo meters populate via `cnc_sysinfo`, `cnc_rdaxisname`,
-  `cnc_rdspdlname`, `cnc_rddynamic2`, `cnc_exeprgname2`,
-  `cnc_rdblkcount`, `cnc_rdopmode`, `cnc_rdsvmeter`, `cnc_rdspload`,
-  `cnc_rdspmaxrpm`, `cnc_rdtimer`
-- Per-series profile selection via `mock_load_profile` — tests can
-  pin one profile and assert series-gated capability suppression
 
-### E2E script (CLI)
+### 3. Macro / ladder variable types
 
-`scripts/e2e/test-focas.ps1` drives the Client.CLI against a running
+FANUC has CNC-specific extensions (macro variables `#100-#999`, system
-OtOpcUa server. Accepts:
+variables `#1000-#5000`, PMC timers / counters / keep-relays) whose
+per-address semantics differ across 0i-F / 30i / 31i / 32i Series. Driver
+covers the common address shapes; per-model quirks are not stressed.
 
-- `-CncHost` / `-CncPort` for real hardware
+### 4. Model-specific behavior
-- `-ProfileName <compose-profile>` for the Docker mock
-- `-Series <csv>` for per-series matrix mode
-- `-HandleLeakCycles <N>` for handle-leak stress
 
-## Hardware-only gaps
+- Alarm retention across power cycles (model-specific CNC behavior)
+- Parameter range enforcement (CNC rejects out-of-range writes)
+- MTB (machine tool builder) custom screens that expose non-standard data
 
-The mock has parity with the real `fwlibe64.dll` for the calls OtOpcUa
+### 5. Tier-C process isolation — architecture shipped, Fwlib32 integration hardware-gated
-issues, but a real CNC can still surface things a reference
-implementation can't:
 
-1. **Series-specific firmware quirks** — alarm retention across power
+The Tier-C architecture is now in place as of PRs #169–#173 (FOCAS
-   cycles, parameter range enforcement by the CNC (not the driver),
+PR A–E, task #220):
-   MTB custom screens, series-specific option bits. Each series has
-   documented behaviours that only a bench CNC exercises.
-2. **Wire-level stress** — burst reads, concurrent device writes,
-   network-partition recovery under load. The mock handles these
-   correctly but production behaviour is the source of truth.
-3. **Transient operational states** — alarm floods, emergency-stop
-   transitions, power-on resync. These are easy to stub but hard to
-   cover comprehensively in the mock.
 
-Track the close-out under task #54 (live-CNC smoke). When the rig
+- `Driver.FOCAS.Shared` carries MessagePack IPC contracts
-lands, the hardware path runs alongside the mock path; the mock
+- `Driver.FOCAS.Host` (.NET 4.8 x86 Windows service via NSSM) accepts
-stays as the CI quality gate.
+  a connection on a strictly-ACL'd named pipe + dispatches frames to
+  an `IFocasBackend`
+- `Driver.FOCAS.Ipc.IpcFocasClient` implements the `IFocasClient` DI
+  seam by forwarding over IPC — swap the DI registration and the
+  driver runs Tier-C with zero other changes
+- `Driver.FOCAS.Supervisor.FocasHostSupervisor` owns the spawn +
+  heartbeat + respawn + 3-in-5min crash-loop breaker + sticky alert
+- `Driver.FOCAS.Host.Stability.PostMortemMmf` ↔
+  `Driver.FOCAS.Supervisor.PostMortemReader` — ring-buffer of the
+  last ~1000 IPC operations survives a Host crash
 
-## When to trust each layer
+The one remaining gap is the production `FwlibHostedBackend`: an
+`IFocasBackend` implementation that wraps the licensed
+`Fwlib32.dll` P/Invoke. That's hardware-gated on task #222 — we
+need a CNC on the bench (or the licensed FANUC developer kit DLL
+with a test harness) to validate it. Until then, the Host ships
+`FakeFocasBackend` + `UnconfiguredFocasBackend`. Setting
+`OTOPCUA_FOCAS_BACKEND=fake` lets operators smoke-test the whole
+Tier-C pipeline end-to-end without any CNC.
 
-| Question | Unit | Integration (mock) | Real CNC |
+## When to trust FOCAS tests, when to reach for a rig
-| --- | :---: | :---: | :---: |
-| "Does PMC address `R100.3` route to the right bit?" | ✅ | ✅ | ✅ |
-| "Does the Fanuc status → OPC UA StatusCode map cover every documented code?" | ✅ (contract) | ✅ | ✅ |
-| "Does `FocasDriver.ReadAsync` correctly decode a seeded parameter?" | no | ✅ | ✅ |
-| "Does `IAlarmSource` fire raise + clear events?" | ✅ (Fake) | ✅ (wire) | ✅ |
-| "Does a real read against a 30i Series return correct bytes?" | no | ✅ (via profile) | ✅ (required) |
-| "Do series-specific firmware quirks behave as documented?" | no | no | ✅ (required) |
-| "Does the driver survive real network partitions?" | no | partial (socket kill) | ✅ (required) |
 
-## Running the integration fixture
+| Question | Unit tests | Real CNC |
+| --- | --- | --- |
+| "Does PMC address `R100.3` route to the right bit?" | yes | yes |
+| "Does the FANUC status → OPC UA StatusCode map cover every documented code?" | yes (contract) | yes |
+| "Does a real read against a 30i Series return correct bytes?" | no | yes (required) |
+| "Does `Fwlib32.dll` crash on concurrent reads?" | no | yes (stress) |
+| "Do macro variables round-trip across power cycles?" | no | yes (required) |
 
-```powershell
+## Alarm history (`cnc_rdalmhistry`) — issue #267, plan PR F3-a
-# 1) Start the mock on a chosen profile.
-docker compose -f tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/docker-compose.yml up -d
 
-# 2) Run the tests. No shim build, no DLL copy — the driver dials the mock directly.
+`FocasAlarmProjection` ships two modes:
-dotnet test tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/
-```
 
-Or use `scripts/integration/run-focas.ps1` which wraps compose up / test
+- **`ActiveOnly`** (default) — surfaces only currently-active alarms.
-/ compose down and accepts `-Profile <name>` to pin a per-series run.
+  No history poll. Same back-compat shape every prior FOCAS deployment used.
+- **`ActivePlusHistory`** — additionally polls `cnc_rdalmhistry` on connect
+  + on the configured cadence (`HistoryPollInterval`, default 5 min). Each
+  unseen entry fires an `OnAlarmEvent` with `SourceTimestampUtc` set from
+  the CNC's reported timestamp, not Now.
+
+Unit-test coverage in `FocasAlarmProjectionTests`:
+
+- mode `ActiveOnly` — no `ReadAlarmHistoryAsync` call ever issued
+- mode `ActivePlusHistory` — first poll fires on subscribe (== "on connect")
+- dedup — same `(OccurrenceTime, AlarmNumber, AlarmType)` triple across two
+  polls only emits once
+- distinct entries with different timestamps each emit separately
+- same alarm number / different type still emits both (type is part of the
+  dedup key)
+- `OccurrenceTime` is the wire timestamp (round-trips a year-old stamp
+  without bleeding into Now)
+- `HistoryDepth` clamp — user-supplied 500 collapses to 250 on the wire;
+  zero / negative falls back to the 100 default
+- `FocasAlarmHistoryDecoder` — round-trips through `Encode` / `Decode` and
+  pins the simulator command id at `0x0F1A`
+
+Future integration coverage (not yet shipped — no FOCAS integration test
+project exists):
+
+- a focas-mock with a per-profile ring buffer and `mock_patch_alarmhistory`
+  admin endpoint will let `cnc_rdalmhistry` round-trip end-to-end through
+  the wire protocol
+- `FocasSimFixture.SeedAlarmHistoryAsync` will let series tests prime canned
+  history without per-test JSON
+
+## Follow-up candidates
+
+1. **Nothing public** — Fanuc's FOCAS Developer Kit ships an emulator DLL
+   but it's under NDA + tied to licensed dev-kit installations; can't
+   redistribute for CI.
+2. **Lab rig** — used FANUC 0i-F simulator controller (or a retired machine
+   tool) on a dedicated network; only path that covers real CNC behavior.
+3. **Process isolation first** — before trusting FOCAS in production at
+   scale, shipping the Tier-C out-of-process Host architecture (similar to
+   Galaxy) is higher value than a CI simulator.
 
 ## Key fixture / config files
 
-- `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/focas-mock/`
-  — vendored `focas-mock` Python source + Dockerfile
-- `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/docker-compose.yml`
-  — per-series compose profiles
-- `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/FocasSimFixture.cs`
-  — collection fixture + mock admin API client
-- `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Series/FixedTreePopulatesTests.cs`
-  — fixed-tree end-to-end tests
-- `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Series/WireBackendTests.cs`
-  — pure-wire-backend end-to-end tests
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/FakeFocasClient.cs` —
-  in-process unit fake
+  in-process fake implementing `IFocasClient`
-- `src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/Wire/WireFocasClient.cs` — the
+- `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/FocasCapabilityMatrixTests.cs`
-  managed wire client backing production deployments
+  — parameterized theories locking the per-series matrix
+- `src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriver.cs` — ctor takes
+  `IFocasClientFactory`
 - `src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasCapabilityMatrix.cs` —
-  per-series range validator
+  per-CNC-series range validator (the matrix the doc describes)
 - `docs/v2/focas-version-matrix.md` — authoritative range reference
+- `docs/v2/implementation/focas-isolation-plan.md` — Tier-C isolation
+  plan (task #220)
+- `docs/v2/driver-stability.md` — Tier C scope + process-isolation rationale

docs/drivers/FOCAS.md

@@ -1,238 +1,281 @@
-# FOCAS Driver
+# FOCAS driver
 
-Getting-started guide for the FANUC FOCAS2 driver. This is the short path — for
+Fanuc CNC driver for the FS 0i / 16i / 18i / 21i / 30i / 31i / 32i / 35i /
-the exhaustive per-node mapping read [`docs/v2/driver-specs.md §7`](../v2/driver-specs.md),
+Power Mate i families. Talks to the controller via the licensed
-for deployment details read [`docs/v2/focas-deployment.md`](../v2/focas-deployment.md),
+`Fwlib32.dll` (Tier C, process-isolated per
-for the test-harness map read [FOCAS-Test-Fixture.md](FOCAS-Test-Fixture.md).
+[`docs/v2/driver-stability.md`](../v2/driver-stability.md)).
 
-## What it talks to
+For range-validation and per-series capability surface see
+[`docs/v2/focas-version-matrix.md`](../v2/focas-version-matrix.md).
 
-FANUC CNCs (0i-D / 0i-F / 0i-MF / 0i-TF / 16i / 30i / 31i / 32i / Power Motion i)
+## Fixed-tree `Production/` projection — issue #258 (F1-b) + issue #272 (F5-a)
-over the proprietary FOCAS2 protocol on TCP port 8193. The wire is spoken
-directly by the pure-managed [`Focas.Wire`](https://github.com/Ladder99/focas-mock)
-client — no Fwlib64.dll, no P/Invoke, no out-of-process isolation needed.
 
-OtOpcUa is **read-only** against FOCAS; all reads go over the native wire
+Per-device read-only nodes refreshed from the same `cnc_rdparam` /
-protocol using the documented command IDs. Writes return
+cycle-timer poll the probe loop already runs. No additional wire calls
-`BadNotWritable` by design.
+are issued for any of these — they are all cache-or-derive reads.
 
-## Project split
+| Node | DataType | Source | Notes |
+| --- | --- | --- | --- |
+| `Production/PartsProduced` | `Int32` | `cnc_rdparam(6711)` | Active parts-count counter. Wraps to 0 on operator reset. |
+| `Production/PartsRequired` | `Int32` | `cnc_rdparam(6712)` | Operator-set target. |
+| `Production/PartsTotal` | `Int32` | `cnc_rdparam(6713)` | Lifetime parts counter. |
+| `Production/CycleTimeSeconds` | `Int32` | `cnc_rdtimer` (channel 0) | Live cycle-time accumulator. Resets to 0 on next cycle start (CNC-side behaviour). |
+| **`Production/LastCycleSeconds`** | **`Float64`** | **derived** | **Plan PR F5-a — seconds for the most recently completed cycle, computed as `CycleTimeSeconds(now) - CycleTimeSeconds(at previous parts-count increment)`. `null` until the second observed parts-count increment establishes a delta. Pure derivation, no new wire calls. See edge-case rules below.** |
+| **`Production/LastCycleStartUtc`** | **`DateTime`** *(UTC)* | **derived** | **Plan PR F5-a — UTC wall-clock of the most-recent cycle's start, computed as `nowUtc - LastCycleSeconds`. `null` alongside `LastCycleSeconds` until the second observed increment.** |
 
-| Project | Target | Role |
+### F5-a derivation edge-case rules
-|---------|--------|------|
-| `src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/` | net10.0 | In-process driver — hosts `WireFocasClient` which speaks FOCAS2 over TCP directly |
 
-Previous `Driver.FOCAS.Host` / `Driver.FOCAS.Shared` Tier-C split has been
+- **First observation** establishes the baseline; `LastCycleSeconds` /
-retired — the managed wire client removes the native-crash blast radius
+  `LastCycleStartUtc` stay `null` until the second observed parts-count
-that justified the out-of-process service.
+  increment produces the first delta.
+- **Parts-count counter reset** (current value goes backwards, e.g.
+  shift-change zero) **preserves the last published values** so an
+  operator reading the tag mid-shift-change sees the last known cycle
+  duration rather than `null` / Bad. The next positive transition
+  produces a fresh delta from the new baseline.
+- **Cycle-timer rollover** (delta would be negative — e.g. CNC zeroes
+  the cycle timer at part completion) **leaves the previously-published
+  values unchanged for one tick** and re-baselines so the next
+  increment produces a clean delta. The driver does NOT publish a
+  negative `LastCycleSeconds`.
+- **Parts-count jumps `> 1`** (backfill — e.g. counter increments by
+  3 at once) publish the **timer delta over the window** as
+  `LastCycleSeconds`. The plan's "delta over the window between
+  successive parts-count increments" definition does not divide by the
+  count delta; the value reflects the actual elapsed timer between the
+  two observations.
+- **Reconnect / reinit** clears the derivation state — the prior CNC
+  session's cycle-timer + parts-count snapshots may be invalidated by
+  the FWLIB session boundary, so the next post-reconnect probe tick
+  re-establishes the baseline before the next delta publishes.
 
-## Minimum deployment
+## Alarm history (`cnc_rdalmhistry`) — issue #267, plan PR F3-a
 
-Register the driver instance in the main server's `appsettings.json`. No
+`FocasAlarmProjection` exposes two modes via `FocasDriverOptions.AlarmProjection`:
-separate service, no DLL deployment, no shared-secret handshake:
+
+| Mode | Behaviour |
+| --- | --- |
+| `ActiveOnly` *(default)* | Subscribe / unsubscribe / acknowledge wire up so capability negotiation works, but no history poll runs. Back-compat with every pre-F3-a deployment. |
+| `ActivePlusHistory` | On subscribe (== "on connect") and on every `HistoryPollInterval` tick, the projection issues `cnc_rdalmhistry` for the most recent `HistoryDepth` entries. Each previously-unseen entry fires an `OnAlarmEvent` with `SourceTimestampUtc` set from the CNC's reported timestamp — OPC UA dashboards see the real occurrence time, not the moment the projection polled. |
+
+### Config knobs
 
 ```jsonc
-"Drivers": {
+{
-  "focas-cnc-1": {
-    "Type": "FOCAS",
-    "Config": {
-      "Backend": "wire",
-      "Devices": [
-        { "HostAddress": "focas://10.20.30.40:8193", "Series": "ThirtyOne_i" }
-      ],
-      "Tags": [
-        { "Name": "Mode",  "DeviceHostAddress": "focas://10.20.30.40:8193",
-          "Address": "PARAM:3402", "DataType": "Int32", "Writable": false },
-        { "Name": "SpndLoad", "DeviceHostAddress": "focas://10.20.30.40:8193",
-          "Address": "MACRO:500", "DataType": "Float64", "Writable": false }
-      ]
-    }
-  }
-}
-```
-
-The main server opens two TCP sockets per configured device and speaks the
-FOCAS2 binary protocol directly. No local privileged components, no
-platform bitness constraint — the driver runs on every host OtOpcUa runs
-on.
-
-## Address forms
-
-| Form | Example | Meaning |
-|------|---------|---------|
-| `X0.0` / `R100` / `R100.3` | PMC bit or byte | Letter + number; optional `.bit` for bit access |
-| `PARAM:1815` / `PARAM:1815/0` | CNC parameter | Number + optional axis index |
-| `MACRO:500` | Custom macro variable | System / user macro variable number |
-
-Addresses are validated against the per-device `Series` at `InitializeAsync` —
-a config referencing a number outside the documented range for that series
-fails at load time with an error message naming the limit. See
-[`docs/v2/focas-version-matrix.md`](../v2/focas-version-matrix.md) for the
-authoritative range table.
-
-## Backend selection
-
-The driver picks its client from `Config.Backend`:
-
-| Value | Client | Use it for |
-|-------|--------|------------|
-| `wire` (default) | `WireFocasClient` | Production — pure-managed FOCAS2 over TCP |
-| `unimplemented` / `none` / `stub` | `UnimplementedFocasClientFactory` | Scaffolding a DriverInstance row before the CNC endpoint is reachable |
-
-Previous backends (`fwlib`, `fwlib32`, `ipc`) have been retired along
-with `Driver.FOCAS.Host` and the Fwlib P/Invoke path. Configs that still
-reference them will throw at startup with a message pointing here.
-
-## Capability surface
-
-| Capability | Wire path | Notes |
-|------------|-----------|-------|
-| `IReadable` | `ReadAsync` → `cnc_rdpmcrng` / `cnc_rdparam` / `cnc_rdmacro` | One TCP request/response per read; `Focas.Wire` serializes requests on socket 2 internally |
-| `IWritable` | returns `BadNotWritable` | OtOpcUa is read-only against FOCAS by design — no `cnc_wrparam` / `pmc_wrpmcrng` / `cnc_wrmacro` path is implemented |
-| `ITagDiscovery` | `DiscoverAsync` | Emits `FOCAS/{device}/{tag}` folders per configured device |
-| `ISubscribable` | polled via shared `PollGroupEngine` | FOCAS has no push model — subscriptions turn into per-tag polling groups |
-| `IHostConnectivityProbe` | periodic `cnc_rdcncstat` | Probe cadence is `Probe.Interval`; transitions fire `OnHostStatusChanged` |
-| `IPerCallHostResolver` | lookup in `_tagsByName` | Each call routes to the device of the referenced tag |
-| `IAlarmSource` | polled `cnc_rdalmmsg2` via `FocasAlarmProjection` | Opt-in — set `AlarmProjection.Enabled=true`; diffs `(AlarmNumber, Type)` between ticks |
-
-Ack is a no-op — FANUC clears alarms on its own once the underlying condition
-resolves, so `AcknowledgeAsync` swallows the batch rather than surfacing
-`BadNotSupported`.
-
-## Fixed node tree
-
-Enable a pre-defined hierarchy of CNC nodes populated automatically from
-`cnc_sysinfo` + `cnc_rdaxisname` + `cnc_rddynamic2` + related FWLIB calls,
-so operators get an out-of-the-box view of identity / axes / program /
-timers without declaring per-address tags.
-
-```jsonc
-"Config": {
-  "Devices": [ ... ],
-  "Tags":    [ ... ],
-  "FixedTree": {
-    "Enabled": true,
-    "PollInterval": "00:00:00.250",       // fast — per-axis dynamic reads
-    "ProgramPollInterval": "00:00:01",    // medium — program + mode changes
-    "TimerPollInterval": "00:00:30"       // slow — cumulative counters
-  }
-}
-```
-
-What gets populated (all under `FOCAS/{deviceHostAddress}/`):
-
-| Subtree | Nodes | Source call |
-|---------|-------|-------------|
-| `Identity/` | `SeriesNumber`, `Version`, `MaxAxes`, `CncType`, `MtType`, `AxisCount` | `cnc_sysinfo` once at bootstrap |
-| `Axes/{name}/` | `AbsolutePosition`, `MachinePosition`, `RelativePosition`, `DistanceToGo`, `ServoLoad` — one folder per discovered axis | `cnc_rdaxisname` once + `cnc_rddynamic2` + `cnc_rdsvmeter` per tick |
-| `Axes/FeedRate/Actual`, `Axes/SpindleSpeed/Actual` | Current feed + spindle RPM | `cnc_rddynamic2` |
-| `Spindle/{name}/` | `Load` (percentage), `MaxRpm` — one folder per discovered spindle | `cnc_rdspdlname` once + `cnc_rdspload` + `cnc_rdspmaxrpm` |
-| `Program/` | `Name` (filename), `ONumber`, `Number`, `MainNumber`, `Sequence`, `BlockCount` | `cnc_exeprgname2` + `cnc_rdblkcount` + cached `cnc_rddynamic2` |
-| `OperationMode/` | `Mode` (int), `ModeText` ("AUTO", "MDI", "EDIT", …) | `cnc_rdopmode` |
-| `Timers/` | `PowerOnSeconds`, `OperatingSeconds`, `CuttingSeconds`, `CycleSeconds` | `cnc_rdtimer` × 4 |
-
-### Per-series node suppression
-
-The driver probes each optional call once at bootstrap. If the target CNC
-returns `EW_FUNC` / `EW_NOOPT` / `EW_VERSION` on the wire, the
-corresponding subtree is **not emitted** — the operator doesn't see nodes
-that will only ever return `BadDeviceFailure`. Capability suppression
-covers `Spindle/`, `Program/` + `OperationMode/`, `Timers/`, and
-per-axis `ServoLoad` independently. Identity + `Axes/*` position reads
-(which every Fanuc CNC supports) are always emitted.
-
-Position values are scaled integers (matching FOCAS's convention). The
-managed side exposes them as `Float64` OPC UA nodes; a future
-`cnc_getfigure` integration will add per-axis decimal scaling. Until
-then, treat the raw integer as the value the CNC reports and scale on
-the client side if decimal precision matters.
-
-**Still user-authored**: `PARAM:6711`, `MACRO:500`, `R100` etc. — specific
-numbers whose meaning is MTB-specific. Those go under the device folder
-alongside the fixed subtree.
-
-## Alarm projection
-
-Alarm surfacing is **disabled by default** because the polling cost is wasted
-on sites that don't consume CNC alarms. Opt in per driver instance:
-
-```jsonc
-"Config": {
-  "Devices": [ ... ],
-  "Tags":    [ ... ],
   "AlarmProjection": {
-    "Enabled": true,
+    "Mode": "ActivePlusHistory",        // "ActiveOnly" (default) | "ActivePlusHistory"
-    "PollInterval": "00:00:02"
+    "HistoryPollInterval": "00:05:00",  // default 5 min
+    "HistoryDepth": 100                 // default 100, capped at 250
   }
 }
 ```
 
-Every alarm transition fires `OnAlarmEvent` with:
+### Dedup key
 
-- `SourceNodeId` = the device host address (FOCAS has no per-node alarm model;
+`(OccurrenceTime, AlarmNumber, AlarmType)`. The same triple across two
-  the CNC exposes a single flat active-alarm list per session)
+polls only emits once. The dedup set is in-memory and **resets on
-- `ConditionId` = `"{host}#{Type}:{AlarmNumber}"`
+reconnect** — first poll after reconnect re-emits everything in the ring
-- `AlarmType` = projected from FANUC's `ALM_TYPE_*` (e.g. `Overtravel`, `Servo`,
+buffer. OPC UA clients that need exactly-once semantics dedupe client-side
-  `Parameter`, `MacroAlarm`)
+on the same triple (the timestamp + type + number tuple is stable across
-- `Severity` = Overtravel / Servo / PulseCode → `Critical`; Parameter / Macro
+the boundary).
-  → `Medium`; everything else → `High`
 
-Cleared alarms fire a second event with `" (cleared)"` appended to the message
+### `HistoryDepth` cap
-so downstream consumers can ignore the clear if they only care about raises.
 
-## Handle recycling
+Capped at `FocasAlarmProjectionOptions.MaxHistoryDepth = 250` so an
+operator who types `10000` by accident can't blast the wire session with a
+giant request. Typical FANUC ring buffers cap at ~100 entries; the default
+`HistoryDepth = 100` matches the most common ring-buffer size.
 
-FANUC CNCs have a finite FWLIB handle pool (~5–10 concurrent connections) and
+### Wire surface
-certain series have documented handle-leak bugs that manifest after long uptime.
+
-The driver can proactively close + reopen each device's session on a cadence to
+- Wire-protocol command id: `0x0F1A` (see
-release its slot back to the pool:
+  [`docs/v2/implementation/focas-wire-protocol.md`](../v2/implementation/focas-wire-protocol.md)).
+- ODBALMHIS struct decoder: `Wire/FocasAlarmHistoryDecoder.cs`.
+- Tier-C Fwlib32 backend short-circuits the packed-buffer decoder by
+  surfacing the FWLIB struct fields directly into
+  `FocasAlarmHistoryEntry`.
+
+## Writes (opt-in, off by default) — issue #268 (F4-a) + #269 (F4-b) + #270 (F4-c)
+
+Writes ship behind multiple independent opt-ins. All default off so a freshly
+deployed FOCAS driver is read-only until the deployment makes a deliberate
+choice. Decision record: [`docs/v2/decisions.md`](../v2/decisions.md) →
+"FOCAS write-path opt-in".
+
+| Knob | Default | Effect when off |
+| --- | --- | --- |
+| `FocasDriverOptions.Writes.Enabled` *(driver-level master switch)* | `false` | Every entry in a `WriteAsync` batch short-circuits to `BadNotWritable` with status text `writes disabled at driver level`. Wire client never gets touched. |
+| **`FocasDriverOptions.Writes.AllowParameter`** *(F4-b granular kill switch)* | **`false`** | **`PARAM:` writes return `BadNotWritable` with no wire client constructed. Defense in depth — even if `Enabled = true` an operator must explicitly opt into parameter writes per kind because a misdirected `cnc_wrparam` can put the CNC in a bad state.** |
+| **`FocasDriverOptions.Writes.AllowMacro`** *(F4-b granular kill switch)* | **`false`** | **`MACRO:` writes return `BadNotWritable` with no wire client constructed. Macro writes are the normal HMI-driven recipe / setpoint surface; gating them separately from `AllowParameter` lets a deployment open MACRO without exposing the heavier PARAM write surface.** |
+| **`FocasDriverOptions.Writes.AllowPmc`** *(F4-c granular kill switch)* | **`false`** | **PMC writes (R/G/F/D/X/Y/K/A/E/T/C letters, both Bit and Byte) return `BadNotWritable` with no wire client constructed. PMC is ladder working memory — a mistargeted bit can move motion, latch a feedhold, or flip a safety interlock, so PMC writes are gated separately from PARAM/MACRO so an operator team can open PARAM (commissioning) without exposing the much higher-blast-radius PMC surface.** |
+| `FocasTagDefinition.Writable` *(per-tag opt-in)* | `false` | The per-tag check returns `BadNotWritable` for that tag even when the driver-level flags are on. |
+
+> **PMC SAFETY CALLOUT** — PMC is the FANUC ladder's working memory. A
+> mistargeted bit can move motion (a Y-coil writing to a servo enable),
+> latch a feedhold (an internal R-relay the ladder ANDs with cycle-start),
+> or flip a safety interlock (an X-input shadow). **Treat PMC writes the
+> same way you'd treat editing a live ladder:** verify e-stop is live and
+> the machine is in jog mode before issuing the first write of a session.
+> The driver gates these writes behind THREE independent opt-ins
+> (`Writes.Enabled` + `Writes.AllowPmc` + per-tag `Writable`) precisely
+> because the blast radius is higher than parameter writes.
+
+### PMC bit-write read-modify-write semantics — F4-c
+
+The FOCAS wire call `pmc_wrpmcrng` is **byte-addressed** — there is no
+sub-byte write primitive. When the driver receives a write request on a
+`Bit` tag (e.g. `R100.3`), it:
+
+1. Reads the parent byte via `pmc_rdpmcrng` (1 byte at `R100`).
+2. Masks the target bit (set: `current | (1 << bit)`; clear: `current & ~(1 << bit)`).
+3. Writes the modified byte back via `pmc_wrpmcrng` (1 byte at `R100`).
+
+A **per-byte semaphore** serialises concurrent bit writes against the same
+byte so two updates that race never lose one another's bit. RMW means **a
+PMC bit write reads first, then writes back the whole byte** — if the ladder
+is also writing to that byte at the same instant, there is a small window
+where the driver's value can clobber the ladder's. Operators who care about
+this race must coordinate the write through a ladder-side handshake (e.g.
+the operator sets a request bit, the ladder reads + clears it).
+
+### Config shape — F4-c
 
 ```jsonc
-"Config": {
+{
-  "Devices": [ ... ],
+  "Writes": {
-  "HandleRecycle": {
     "Enabled": true,
-    "Interval": "01:00:00"
+    "AllowParameter": true,   // F4-b — opt into cnc_wrparam
-  }
+    "AllowMacro": true,       // F4-b — opt into cnc_wrmacro
+    "AllowPmc": true          // F4-c — opt into pmc_wrpmcrng (incl. RMW bit writes)
+  },
+  "Tags": [
+    { "Name": "RPM", "Address": "PARAM:1815", "DataType": "Int32",
+      "Writable": true, "WriteIdempotent": false },
+    { "Name": "Recipe", "Address": "MACRO:500", "DataType": "Int32",
+      "Writable": true, "WriteIdempotent": false },
+    { "Name": "StartFlag", "Address": "R100.3", "DataType": "Bit",
+      "Writable": true, "WriteIdempotent": true }
+  ]
 }
 ```
 
-Disabled by default — a healthy CNC + driver doesn't need it. Enable when field
+### Server-layer ACL (LDAP groups)
-experience shows handle exhaustion. Typical tuning: 30 min for sites running
-multiple OtOpcUa instances against the same CNC (they share the pool); 6 h for a
-single-client deployment. Reads / writes during recycle simply wait for the
-reconnect rather than failing — worst case, an operator sees a brief read
-latency spike once per cadence.
 
-## Testing
+Per the [`docs/v2/acl-design.md`](../v2/acl-design.md) tier model, the FOCAS
+driver only declares per-tag `SecurityClassification`; `DriverNodeManager`
+applies the gate. The classification post-F4-b is:
 
-- **Unit tests** — `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/` cover the
+| Tag kind | Classification | LDAP group required (default mapping) |
-  driver surface via `FakeFocasClient`. Includes the alarm-projection raise /
+| --- | --- | --- |
-  clear diffing tests.
+| `PARAM:N` writable | `Configure` | **`WriteConfigure`** |
-- **Integration tests** — `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/`
+| `MACRO:N` writable | `Operate` | `WriteOperate` |
-  hold the Docker simulator scaffold (Stream B / C of the simulator plan —
+| Other writable (PMC R/G/F/...) | `Operate` | `WriteOperate` |
-  `docs/v2/implementation/focas-simulator-plan.md`).
+| Non-writable | `ViewOnly` | (no write permission) |
-- **E2E script** — `scripts/e2e/test-focas.ps1` stages Host + Proxy + a real
-  CNC (or the simulator) and exercises connect → read → write → subscribe
-  round-trips. See [`docs/drivers/FOCAS-Test-Fixture.md`](FOCAS-Test-Fixture.md)
-  for the coverage map.
 
-## Troubleshooting
+Parameter writes need the heavier `WriteConfigure` group because they're
+mostly emergency commissioning territory; macro writes use `WriteOperate`
+because they're the normal HMI recipe surface. The driver-level
+`AllowParameter` / `AllowMacro` kill switches sit independently of ACL — an
+operator-team kill switch the deployment can flip without redeploying ACL
+group memberships. See [`docs/security.md`](../security.md) for the full
+group/permission map.
 
-| Symptom | Likely cause | Fix |
+`WriteIdempotent` is plumbed through Polly retry by the server-layer
-|---------|--------------|-----|
+`CapabilityInvoker.ExecuteWriteAsync`. When `false` (default), failed writes
-| `BadCommunicationError` on every read | CNC unreachable on TCP:8193 | Check firewall / LAN reachability; FOCAS Ethernet option must be licensed on the CNC side |
+are NOT auto-retried per plan decisions #44/#45 — a timeout that fires after
-| Every read returns `BadNotWritable` on writes | Expected — OtOpcUa is read-only against FOCAS | If you actually need writes, open a feature request — the driver's managed wire client doesn't expose the write commands |
+the CNC already accepted the write would otherwise risk a duplicate
-| `BadOutOfRange` on reads for a macro/parameter | Config address outside the declared `Series` range | Check `docs/v2/focas-version-matrix.md` — either fix the address or widen the `Series` |
+non-idempotent action (alarm acks, M-code pulses, recipe steps). Flip
-| Alarm events never fire | `AlarmProjection.Enabled` left at default (false) | Set it to `true` in the driver config |
+`WriteIdempotent` on per tag for genuinely-idempotent writes (a parameter
+value that the operator simply wants forced to a target).
 
-## Further reading
+### FOCAS password — issue #271 (F4-d)
 
-- [`docs/v2/driver-specs.md §7`](../v2/driver-specs.md) — full OPC UA node
+Some controllers — notably 16i and certain 30i firmwares with the
-  mapping, pre-defined tag set, per-API notes
+parameter-protect switch on — gate `cnc_wrparam` and a handful of reads
-- [`docs/v2/focas-version-matrix.md`](../v2/focas-version-matrix.md) —
+behind a connection-level password. Without unlocking the session, every
-  per-series macro / parameter / PMC range table
+gated wire call returns `EW_PASSWD`, which the F4-b mapping surfaces as
-- [`docs/v2/implementation/focas-wire-protocol.md`](../v2/implementation/focas-wire-protocol.md)
+`BadUserAccessDenied`.
-  — captured FOCAS2 wire semantics (magic prefix, handshake, command-id table)
+
-- [upstream `Focas.Wire`](https://github.com/Ladder99/focas-mock/tree/main/dotnet/Focas.Wire)
+`FocasDeviceOptions.Password` plumbs the password through the device config:
-  — the managed client implementation OtOpcUa consumes as a NuGet dependency
+
+```jsonc
+{
+  "Devices": [
+    {
+      "HostAddress": "focas://10.0.0.5:8193",
+      "Password": "1234"          // F4-d — optional CNC password
+    }
+  ]
+}
+```
+
+When set, the driver:
+
+1. **On connect**, calls `IFocasClient.UnlockAsync(password, ct)` after
+   the FWLIB handle opens but before any read/write fires. The FWLIB-backed
+   client emits `cnc_wrunlockparam` with the password ASCII-encoded into
+   the 4-byte FOCAS password slot (right-padded with `0x00`, truncated at
+   4 bytes — that's the shape the public Fanuc samples document).
+2. **On `BadUserAccessDenied` from any gated read or write**, re-issues
+   `UnlockAsync` and retries the call **exactly once**. A second
+   `EW_PASSWD` propagates unchanged so a wrong password doesn't loop
+   forever on the wire.
+3. **Reset on reconnect** — FWLIB unlock state lives on the handle, so
+   any reconnect path (planned or unplanned) re-runs unlock automatically
+   via `EnsureConnectedAsync`.
+
+**No-log invariant.** The password is a secret. The driver MUST NOT log
+it. Specifically:
+
+- `FocasDeviceOptions` overrides the record's auto-generated `ToString`
+  to print `Password = ***` when the field is non-null. Any Serilog
+  destructure that flows the device options through `{Device}` gets the
+  redaction for free.
+- `FwlibFocasClient.UnlockAsync` does not include the password in any
+  exception message — only the FWLIB return code (`EW_PASSWD`,
+  `EW_HANDLE`, etc.) makes it into the surface.
+- `FocasDriver` logs only `"FOCAS unlock applied for {host}"` when the
+  unlock succeeds — no password.
+- The Driver.FOCAS.Cli `--cnc-password` flag is also redacted at the
+  same `FocasDeviceOptions` choke point.
+- See [`docs/v2/focas-deployment.md`](../v2/focas-deployment.md)
+  § "FOCAS password handling" for the storage/rotation runbook + the
+  cross-link to [`docs/Security.md`](../Security.md).
+
+When the controller does **not** need a password, leave `Password`
+unset (`null`) and the driver short-circuits the unlock call entirely —
+no wire-level cost.
+
+### Status-code semantics post-F4-b
+
+- `BadNotWritable` — one of: driver-level `Writes.Enabled = false`; per-tag
+  `Writable = false`; **`Writes.AllowParameter = false` for a `PARAM:` tag
+  (F4-b)**; **`Writes.AllowMacro = false` for a `MACRO:` tag (F4-b)**;
+  **`Writes.AllowPmc = false` for a PMC tag (F4-c)**. Same status code,
+  five distinct paths — operators distinguish by checking the knobs.
+- `BadUserAccessDenied` — **F4-b** — the CNC reported `EW_PASSWD`
+  (parameter-write switch off / unlock required). **F4-d** wires the
+  `cnc_wrunlockparam` retry path on top: when `Password` is configured
+  the driver re-issues unlock + retries the gated call once before
+  surfacing this status. A persistent `BadUserAccessDenied` after F4-d
+  means either (a) the password doesn't match the controller, or (b)
+  the parameter-write switch on the pendant is still off and the
+  controller wants both the switch + the password.
+- `BadNotSupported` — both opt-ins flipped on, but the wire client doesn't
+  implement the kind being written (e.g. older transport variant). F4-a
+  wired the generic dispatch; F4-b adds typed `WriteParameterAsync` /
+  `WriteMacroAsync` entry points whose default impls return
+  `BadNotSupported` so transports compiled against a stale `IFocasClient`
+  surface still build.
+- `BadNodeIdUnknown` — full-reference doesn't match any configured
+  `FocasTagDefinition.Name`.
+- `BadCommunicationError` — wire failure (DLL not loaded, IPC peer dead,
+  etc.).
+
+### CLI bypass
+
+`otopcua-focas-cli write` ([`docs/Driver.FOCAS.Cli.md`](../Driver.FOCAS.Cli.md))
+sets `Writes.Enabled=true` locally for the lifetime of one invocation
+because the CLI is a per-operator tool — not a long-lived process bound to
+the central config DB. The server-side flag is untouched; configure-the-
+server code paths remain safer-by-default.

docs/drivers/Galaxy-Test-Fixture.md

@@ -35,14 +35,13 @@ Multi-project test topology:
 ## How tests skip
 
 - **E2E parity**: `ParityFixture.SkipIfUnavailable()` runs at class init and
-  checks Windows-only, ZB SQL reachable on `localhost:1433`, Host EXE built
+  checks Windows-only, non-admin user, ZB SQL reachable on
-  in the expected `bin/` folder. Any miss → tests skip.
+  `localhost:1433`, Host EXE built in the expected `bin/` folder. Any miss
+  → tests skip.
 - **Live-smoke** (`GalaxyRepositoryLiveSmokeTests`): `Assert.Skip` when ZB
   unreachable. A `per project_galaxy_host_installed` memory on this repo's
-  dev box notes the MXAccess runtime is installed. The pipe ACL allows the
+  dev box notes the MXAccess runtime is installed + pipe ACL denies Admins,
-  configured SID outright; elevation of the caller doesn't matter because
+  so live tests must run from a non-elevated shell.
-  the per-connection SID check in `PipeServer.VerifyCaller` only compares
-  user SIDs (not group membership or integrity level).
 - **Unit** tests (Shared, Proxy contract, most Host.Tests) have no skip —
   they run anywhere.
 

docs/drivers/Galaxy.md

@@ -31,7 +31,7 @@ The same Tier-C isolation story applies to FOCAS (decision record in `docs/v2/pl
 
 - Pipe name: `otopcua-galaxy-{DriverInstanceId}` (localhost-only, no TCP surface)
 - Wire format: MessagePack-CSharp, length-prefixed frames
-- ACL: pipe is created with a DACL that grants `ReadWrite | Synchronize` only to the configured Server service-principal SID + denies `LocalSystem`. The per-connection SID check in `PipeServer.VerifyCaller` is the real authorization boundary — any caller whose impersonated token SID doesn't match the allowed SID is dropped before the first frame is read.
+- ACL: pipe is created with a DACL that grants only the Server's service identity; the Admins group is explicitly denied so a live-smoke test running from an elevated shell fails fast rather than silently bypassing the handshake
 - Handshake: Proxy presents a shared secret at `OpenSessionRequest`; Host rejects anything else with `MessageKind.OpenSessionResponse{Success=false}`
 - Heartbeat: Proxy sends a periodic ping; missed heartbeats trigger the Proxy-side crash-loop supervisor to restart the Host
 

docs/drivers/OpcUaClient-Test-Fixture.md

@@ -47,6 +47,13 @@ the tests mock.
 - `OpcUaClientSmokeTests.Client_subscribe_receives_StepUp_data_changes_from_live_server` —
   real `MonitoredItem` subscription against `ns=3;s=FastUInt1` (ticks every
   100 ms); asserts `OnDataChange` fires within 3 s of subscribe
+- `OpcUaClientReverseConnectSmokeTests.Driver_accepts_reverse_connect_from_opc_plc_rc_simulator` —
+  reverse-connect (server-initiated) coverage. Driver binds
+  `opc.tcp://0.0.0.0:4844`, the `opc-plc-rc` docker service dials in via
+  `--rc opc.tcp://host.docker.internal:4844`, and a Read round-trips over
+  the inbound socket. Gated on `OPCUA_RC_SIM=1` because the simulator
+  requires `host.docker.internal` resolution which not every CI runner
+  exposes.
 
 Wire-level surfaces verified: `IDriver` + `IReadable` + `ISubscribable` +
 `IHostConnectivityProbe` (via the Secure Channel exchange).
@@ -159,6 +166,35 @@ Beyond that:
 3. **Dedicated historian integration lab** — only path for
    historian-specific coverage.
 
+## HistoryRead aggregate coverage
+
+PR-13 (issue #285) extended `HistoryAggregateType` from 5 to ~30 values
+matching the OPC UA Part 13 §5 catalog. The mapping itself
+(`OpcUaClientDriver.MapAggregateToNodeId`) is unit-tested via
+`OpcUaClientAggregateMappingTests`:
+
+- The full enum is swept with `Enum.GetValues<HistoryAggregateType>()` —
+  every value must resolve to a non-null namespace-0 numeric `NodeId`.
+- The 25 new aggregates each assert against a reflection-resolved
+  `Opc.Ua.ObjectIds.AggregateFunction_*` field by name, so a future SDK
+  upgrade that renames a constant trips the test loudly.
+- The original 5 ordinals stay pinned to their pre-PR-13 NodeIds so existing
+  config files / persisted enums keep working.
+
+This is **the well-known-NodeId test path** — the standard Part 13 NodeIds
+are stable across SDK versions; round-tripping each one against a live
+upstream is the integration suite's job and doesn't add coverage to the
+mapping table itself.
+
+`OpcUaClientAggregateSweepTests` is the integration counterpart. It loops
+every enum value against a real opc-plc upstream and asserts the wire path
+doesn't crash even when the simulator returns
+`BadAggregateNotSupported` for an aggregate it doesn't honour. opc-plc's
+default profile doesn't enable HistoryRead on the well-known nodes, so the
+test currently `Assert.Skip`s — re-enables when the fixture image is
+upgraded to a history-sim profile (`--useslowtypes --ut=10` or similar) and
+a known-good historized NodeId is wired into `OpcPlcProfile`.
+
 ## Key fixture / config files
 
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests/` — unit tests with
@@ -168,3 +204,7 @@ Beyond that:
 - `tests/ZB.MOM.WW.OtOpcUa.Server.Tests/OpcUaServerIntegrationTests.cs` —
   the server-side integration harness a future loopback client test could
   piggyback on
+- `tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests/OpcUaClientAggregateMappingTests.cs`
+  — Part 13 aggregate enum-to-NodeId mapping coverage (PR-13)
+- `tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/OpcUaClientAggregateSweepTests.cs`
+  — wire-side aggregate sweep against opc-plc (build-only scaffold; PR-13)

docs/drivers/OpcUaClient.md

@@ -0,0 +1,350 @@
+# OPC UA Client driver
+
+Tier-A in-process driver that opens a `Session` against a remote OPC UA server
+and re-exposes its address space through the local OtOpcUa server. The
+"gateway / aggregation" direction — opposite to the usual "server exposes PLC
+data" flow.
+
+For the test fixture (opc-plc) see [`OpcUaClient-Test-Fixture.md`](OpcUaClient-Test-Fixture.md).
+For the configuration surface see `OpcUaClientDriverOptions` in
+[`src/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientDriverOptions.cs`](../../src/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientDriverOptions.cs).
+
+## Auto re-import on `ModelChangeEvent`
+
+The driver subscribes to `BaseModelChangeEventType` (and its subtype
+`GeneralModelChangeEventType`) on the upstream `Server` node (`i=2253`) at
+the end of `InitializeAsync`. When the upstream server advertises a
+topology change, the driver coalesces events over a debounce window and
+runs a single re-import (equivalent to calling `ReinitializeAsync` —
+internally `ShutdownAsync` + `InitializeAsync`).
+
+### Configuration
+
+| Option | Default | Notes |
+| --- | --- | --- |
+| `WatchModelChanges` | `true` | Disable to skip the watch entirely (no extra subscription, no re-import on topology change). |
+| `ModelChangeDebounce` | `5s` | Coalescing window. The first event starts the timer; further events extend it; when it elapses with no new events, the driver fires one re-import. |
+
+### Behaviour
+
+- One model-change subscription per driver instance, separate from the
+  data + alarm subscriptions. Created best-effort: a server that doesn't
+  advertise the event types or rejects the `EventFilter` falls through to
+  no-watch — `InitializeAsync` still succeeds.
+- The `EventFilter` selects only the `EventType` field (a `WhereClause`
+  constrains by `OfType BaseModelChangeEventType`). Payload fields like
+  `Changes[]` are intentionally ignored: the driver always re-imports the
+  full upstream root, so per-event delta tracking would just add wire
+  overhead.
+- Debounce is implemented via a single-shot `Timer`; every event calls
+  `Timer.Change(window, Infinite)` so a burst of N events triggers exactly
+  one re-import after the window elapses with no further events.
+- The re-import path acquires the same `_gate` semaphore that `ReadAsync`
+  / `WriteAsync` / `BrowseAsync` / `SubscribeAsync` use. Downstream callers
+  see a brief browse-gap (≈ the upstream `DiscoverAsync` duration) while
+  the gate is held — but no torn reads or split-batch writes.
+- Failure during the re-import is best-effort: the next `ModelChangeEvent`
+  triggers another attempt, and the keep-alive watchdog covers permanent
+  upstream loss. Operators see failures through `DriverHealth.LastError`
+  + the diagnostics counters.
+
+### When to disable
+
+Flip `WatchModelChanges` to `false` when:
+
+- The upstream topology is known-static (e.g. firmware-pinned PLC) and
+  the driver should never run a re-import unprompted.
+- The brief browse-gap during re-import is unacceptable and a manual
+  `ReinitializeAsync` call from the operator is preferred.
+- The upstream server fires spurious `ModelChangeEvent`s that don't
+  reflect real topology changes, causing wasted re-imports. Tighten or
+  disable rather than chasing the noise downstream.
+
+## Reverse Connect (server-initiated)
+
+OPC UA's reverse-connect mode flips the transport direction: instead of the
+client dialling the server, the **server** dials the client's listener. The
+upstream sends a `ReverseHello` and the client continues the OPC UA
+handshake on the inbound socket. Required for OT-DMZ deployments where the
+plant firewall only permits outbound traffic from the upstream — the
+gateway opens a listener, the upstream reaches out.
+
+### Configuration
+
+| Option | Default | Notes |
+| --- | --- | --- |
+| `ReverseConnect.Enabled` | `false` | Opt-in. When `true`, replaces the failover dial-sweep with a `WaitForConnection` call. |
+| `ReverseConnect.ListenerUrl` | `null` | Local listener URL the SDK binds. Typically `opc.tcp://0.0.0.0:4844` (any interface) or a specific NIC for multi-homed gateways. **Required when `Enabled` is `true`.** |
+| `ReverseConnect.ExpectedServerUri` | `null` | Upstream's `ApplicationUri` to filter inbound dials. `null` accepts the first connection (only safe with one upstream targeting the listener). |
+
+### Shared listener (singleton)
+
+A single underlying `Opc.Ua.Client.ReverseConnectManager` per process keyed
+on `ListenerUrl`. Two driver instances that share a listener URL multiplex
+onto one TCP socket; the SDK demuxes inbound dials by the upstream's
+reported `ServerUri`. The wrapper (`ReverseConnectListener`) is
+reference-counted — first `Acquire` binds the port, last `Release` tears it
+down. Letting drivers come and go independently without races on
+port-bind / port-unbind.
+
+When two drivers share a listener:
+
+- They MUST set `ExpectedServerUri` to disambiguate; otherwise the first
+  upstream to dial in wins regardless of which driver is waiting.
+- They CAN come and go independently; the listener stays alive while at
+  least one driver references it.
+
+### Behaviour
+
+- The dial path is bypassed entirely when `Enabled` is `true`. Failover
+  across multiple `EndpointUrls` doesn't apply — there's no client-side
+  dial to fail over.
+- `ExpectedServerUri` is the SDK's filter parameter to `WaitForConnectionAsync`.
+  Inbound `ReverseHello`s from a different upstream are ignored and the
+  caller keeps waiting.
+- The same `EndpointDescription` derivation runs as the dial path — the
+  first `EndpointUrl` in the candidate list seeds `SecurityPolicy` /
+  `SecurityMode` / `EndpointUrl` for the session-create call. The actual
+  endpoint lives on the upstream and the SDK reconciles after the
+  `ReverseHello`.
+- Cancellation: `Timeout` bounds the wait. A stuck listener with no inbound
+  dial throws after `Timeout` rather than hanging init forever.
+- Shutdown releases the listener reference. The last release stops the
+  listener so the port can be re-bound by a future driver lifecycle.
+
+### Wiring it up on the upstream
+
+The upstream OPC UA server has to be configured to dial out. The `opc-plc`
+simulator does this with `--rc=opc.tcp://<gateway-host>:4844`; for a real
+upstream see your server's reverse-connect docs (most major implementations
+expose a "ReverseConnect.Endpoint" config knob).
+
+### When NOT to use
+
+- Standard plant networks where the gateway can dial the upstream — the
+  conventional dial path is simpler and supports failover natively.
+- Public-internet OPC UA: reverse-connect is a network-policy workaround,
+  not a security primitive. Always pair with `Sign` or `SignAndEncrypt`
+  + a vetted user-token policy.
+
+## HistoryRead Events
+
+The driver passes through OPC UA `HistoryReadEvents` to the upstream server.
+HistoryRead Raw / Processed / AtTime ship in the same code path
+(`ExecuteHistoryReadAsync`); event history takes a slightly different shape
+because the client sends an `EventFilter` (SelectClauses + WhereClause) rather
+than a plain numeric / time-based detail block.
+
+### Wire path
+
+`IHistoryProvider.ReadEventsAsync(fullReference, EventHistoryRequest, ct)`
+translates to:
+
+```
+new ReadEventDetails {
+    StartTime,
+    EndTime,
+    NumValuesPerNode,
+    Filter = EventFilter { SelectClauses, WhereClause }
+}
+```
+
+…and is sent through `Session.HistoryReadAsync` to the upstream server. The
+returned `HistoryEvent.Events` collection (one `HistoryEventFieldList` per
+historical event) is unwrapped into `HistoricalEventBatch.Events`, where each
+`HistoricalEventRow.Fields` dictionary is keyed by the
+`SimpleAttributeSpec.FieldName` the caller supplied. The server-side history
+dispatcher uses those keys to align fields with the wire-side SelectClause
+order — drivers don't have to honour the entire OPC UA `EventFilter` shape
+verbatim.
+
+### SelectClauses
+
+When `EventHistoryRequest.SelectClauses` is `null` the driver falls back to a
+default set that matches `BuildHistoryEvent` on the server side:
+
+| Field | Browse path | Notes |
+| --- | --- | --- |
+| `EventId` | `EventId` | BaseEventType — stable unique id. |
+| `SourceName` | `SourceName` | Source-object name. |
+| `Time` | `Time` | Process-side event timestamp. Used for `OccurrenceTime`. |
+| `Message` | `Message` | LocalizedText payload. |
+| `Severity` | `Severity` | OPC UA 1-1000 scale. |
+| `ReceiveTime` | `ReceiveTime` | Server-side ingest timestamp. |
+
+Custom SelectClauses are supported — pass any
+`IReadOnlyList<SimpleAttributeSpec>`. Each entry's `TypeDefinitionId`
+defaults to `BaseEventType` when `null`; pass an explicit NodeId text (e.g.
+`"i=2782"` for `ConditionType`) to reach typed-condition fields.
+
+### WhereClause
+
+`ContentFilterSpec.EncodedOperands` carries the binary-encoded
+`ContentFilter` from the wire. The driver decodes it into the SDK
+`ContentFilter` and attaches it to the outgoing `EventFilter` verbatim — the
+OPC UA Client driver is a passthrough for filter semantics, it does not
+evaluate them. A malformed filter is dropped silently; the SelectClause
+projection still goes out.
+
+### Continuation points
+
+Returned in `HistoricalEventBatch.ContinuationPoint`. The server-side
+HistoryRead facade is responsible for round-tripping these so a paged event
+read against a chatty upstream completes incrementally. The driver itself
+doesn't track them — every `ReadEventsAsync` call issues a fresh
+`HistoryReadAsync`.
+
+## HistoryRead Aggregates (Part 13 catalog)
+
+`IHistoryProvider.ReadProcessedAsync` takes a `HistoryAggregateType` and the
+driver maps it to the standard `Opc.Ua.ObjectIds.AggregateFunction_*` NodeId
+in `MapAggregateToNodeId`. PR-13 (issue #285) extended the enum from the
+original 5 values (Average / Minimum / Maximum / Total / Count) to the full
+OPC UA Part 13 §5 catalog — ~30 aggregates.
+
+The mapping is best-effort: not every upstream OPC UA server implements every
+aggregate. Aggregates the upstream rejects come back with
+`StatusCode=BadAggregateNotSupported` on the per-row HistoryRead result; the
+driver passes that through verbatim (cascading-quality rule, Part 11 §8) — it
+does not throw. Servers advertise the aggregates they support via the
+`AggregateConfiguration` object on the `Server` node; clients can probe it at
+runtime.
+
+### Catalog
+
+| Enum value | SDK NodeId field | Part 13 § | Server-side support | Typical use |
+| --- | --- | --- | --- | --- |
+| `Average` | `AggregateFunction_Average` | §5.4 | almost always | smoothing |
+| `Minimum` | `AggregateFunction_Minimum` | §5.5 | almost always | low watermark |
+| `Maximum` | `AggregateFunction_Maximum` | §5.6 | almost always | high watermark |
+| `Total` | `AggregateFunction_Total` | §5.10 | usually | totalisation |
+| `Count` | `AggregateFunction_Count` | §5.18 | almost always | sample count |
+| `TimeAverage` | `AggregateFunction_TimeAverage` | §5.4.2 | usually | time-weighted mean |
+| `TimeAverage2` | `AggregateFunction_TimeAverage2` | §5.4.3 | sometimes | bounded time-weighted mean |
+| `Interpolative` | `AggregateFunction_Interpolative` | §5.3 | usually | trend snapshot |
+| `MinimumActualTime` | `AggregateFunction_MinimumActualTime` | §5.5.4 | sometimes | when low occurred |
+| `MaximumActualTime` | `AggregateFunction_MaximumActualTime` | §5.6.4 | sometimes | when high occurred |
+| `Range` | `AggregateFunction_Range` | §5.7 | usually | spread |
+| `Range2` | `AggregateFunction_Range2` | §5.7 | sometimes | bounded spread |
+| `AnnotationCount` | `AggregateFunction_AnnotationCount` | §5.21 | rarely | operator notes |
+| `DurationGood` | `AggregateFunction_DurationGood` | §5.16 | sometimes | quality coverage |
+| `DurationBad` | `AggregateFunction_DurationBad` | §5.16 | sometimes | gap accounting |
+| `PercentGood` | `AggregateFunction_PercentGood` | §5.17 | sometimes | quality % |
+| `PercentBad` | `AggregateFunction_PercentBad` | §5.17 | sometimes | gap % |
+| `WorstQuality` | `AggregateFunction_WorstQuality` | §5.20 | sometimes | worst seen |
+| `WorstQuality2` | `AggregateFunction_WorstQuality2` | §5.20 | rarely | bounded worst |
+| `StandardDeviationSample` | `AggregateFunction_StandardDeviationSample` | §5.13 | sometimes | n-1 stddev |
+| `StandardDeviationPopulation` | `AggregateFunction_StandardDeviationPopulation` | §5.13 | sometimes | n stddev |
+| `VarianceSample` | `AggregateFunction_VarianceSample` | §5.13 | sometimes | n-1 variance |
+| `VariancePopulation` | `AggregateFunction_VariancePopulation` | §5.13 | sometimes | n variance |
+| `NumberOfTransitions` | `AggregateFunction_NumberOfTransitions` | §5.12 | sometimes | event count |
+| `DurationInStateZero` | `AggregateFunction_DurationInStateZero` | §5.19 | sometimes | OFF time |
+| `DurationInStateNonZero` | `AggregateFunction_DurationInStateNonZero` | §5.19 | sometimes | ON time |
+| `Start` | `AggregateFunction_Start` | §5.8 | usually | first sample |
+| `End` | `AggregateFunction_End` | §5.9 | usually | last sample |
+| `Delta` | `AggregateFunction_Delta` | §5.11 | usually | end-start |
+| `StartBound` | `AggregateFunction_StartBound` | §5.8 | sometimes | extrapolated start |
+| `EndBound` | `AggregateFunction_EndBound` | §5.9 | sometimes | extrapolated end |
+
+"Server-side support" is heuristic — see your upstream's `AggregateConfiguration`
+node for the authoritative list. AVEVA Historian, KEPServerEX, Prosys, and
+opc-plc each implement different subsets.
+
+### Driver-side validation
+
+The mapping itself is unit-tested over the full enum
+(`OpcUaClientAggregateMappingTests`) — every value resolves to a non-null
+namespace-0 NodeId, and the original 5 ordinals stay pinned. Wire-side
+behaviour against a live server is exercised by
+`OpcUaClientAggregateSweepTests` (build-only scaffold pending an opc-plc
+history-sim profile).
+
+## Upstream redundancy (`ServerArray`)
+
+When the upstream OPC UA server is itself a redundant pair (warm or hot per
+OPC UA Part 4 §6.6.2), the driver supports **mid-session failover** driven by
+the upstream's own `Server.ServerRedundancy.RedundancySupport` +
+`ServerUriArray` + `Server.ServiceLevel` nodes. Distinct from the static
+boot-time failover sweep on `EndpointUrls`: that path picks a single survivor
+at session-create time; this path swaps the active session live when the
+upstream signals degradation, transferring subscriptions onto the secondary so
+monitored-item handles stay valid.
+
+### Configuration
+
+| Option | Default | Notes |
+| --- | --- | --- |
+| `Redundancy.Enabled` | `false` | Opt-in. When `false`, the driver doesn't read `RedundancySupport` / `ServerUriArray` and doesn't subscribe to `ServiceLevel`. |
+| `Redundancy.ServiceLevelThreshold` | `200` | Byte value below which the driver triggers failover. OPC UA spec convention: 200+ = healthy primary, 100..199 = degraded, 0..99 = unrecoverable. |
+| `Redundancy.RecheckInterval` | `5s` | Lower bound between two consecutive failovers — suppresses oscillation when ServiceLevel flaps around the threshold. |
+
+### Behaviour
+
+- At session activation the driver reads
+  `Server.ServerRedundancy.RedundancySupport`. When `None`, the driver records
+  an empty peer list and the failover path becomes a no-op (`ServiceLevel`
+  drops are still observable via diagnostics but trigger nothing).
+- When the upstream advertises `Cold` / `Warm` / `WarmActive` / `Hot`, the
+  driver pulls `Server.ServerRedundancy.ServerUriArray` for the peer list,
+  falling back to the top-level `Server.ServerArray` for legacy upstreams that
+  don't expose the redundancy node.
+- A dedicated subscription on `Server.ServiceLevel` (publish interval 1s,
+  separate from the alarm + data subscriptions) drives every failover decision
+  via the SDK's notification path — no polling loop.
+- On a drop below `ServiceLevelThreshold` the driver picks the next URI in the
+  peer list that isn't the active one, opens a parallel session against it,
+  and calls `Session.TransferSubscriptionsAsync(other, sendInitialValues:true)`
+  to migrate every live subscription (data + alarm + model-change +
+  service-level itself). On success the driver swaps `Session`, closes the
+  old one, and bumps `RedundancyFailoverCount`.
+- On any failure (`BadSecureChannelClosed`, `BadCertificateUntrusted`,
+  `TransferSubscriptions` returning `false`, secondary unreachable) the driver
+  leaves the existing session untouched, increments
+  `RedundancyFailoverFailures`, and waits for the next ServiceLevel
+  notification. The keep-alive watchdog continues to cover full
+  upstream-loss scenarios.
+
+### Shared client-cert prerequisite
+
+`TransferSubscriptionsAsync` requires the secondary's secure channel to accept
+the same client certificate the primary did. Operators running heterogeneous
+secondaries (different cert trust stores) will see `BadCertificateUntrusted`
+on every failover attempt and the failures counter climbing. The fix is to
+push the gateway driver's application-instance certificate into both
+upstreams' `TrustedPeerCertificates` store before enabling redundancy. A
+follow-up adds a fallback path that re-creates subscriptions instead of
+transferring when the secondary rejects the channel.
+
+### Diagnostics
+
+The `driver-diagnostics` RPC surfaces three new counters via
+`DriverHealth.Diagnostics`:
+
+| Key | Type | Notes |
+| --- | --- | --- |
+| `RedundancyFailoverCount` | `double` (long-counted) | Successful mid-session swaps since driver start. |
+| `RedundancyFailoverFailures` | `double` (long-counted) | Swap attempts that bailed (TransferSubscriptions false, secondary unreachable, etc.). |
+| `ActiveServerUri` | string (in `OpcUaClientDiagnostics.ActiveServerUri`) | URI of the upstream the driver is currently bound to. Updates on every successful failover. |
+
+### Forced-failover runbook
+
+To validate the wiring against a real redundant upstream pair:
+
+1. Confirm the upstream advertises `RedundancySupport != None` and a
+   non-empty `ServerUriArray`. Use the Client CLI:
+   `dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- redundancy -u <primary>`.
+2. Set `Redundancy.Enabled = true` on the gateway's `OpcUaClient` driver
+   instance and restart.
+3. Tail driver diagnostics:
+   `driver-diagnostics --instance <id>` — note `RedundancyFailoverCount = 0`
+   pre-test.
+4. Drive a `ServiceLevel` drop on the primary. On AVEVA / KEPServer this is
+   typically a "force standby" Admin action; on a custom server it's a write
+   to the simulated ServiceLevel node.
+5. Observe `RedundancyFailoverCount = 1` within `RecheckInterval` of the
+   drop, the gateway's `HostName` swap to the secondary URI, and downstream
+   reads/subscriptions continuing without interruption.
+
+For non-redundant upstreams (single-server deployments) the recommended
+configuration is to leave `Redundancy.Enabled = false` and rely on
+`EndpointUrls` for boot-time failover only.

docs/drivers/README.md

@@ -26,7 +26,7 @@ Driver type metadata is registered at startup in `DriverTypeRegistry` (`src/ZB.M
 | AB CIP | `Driver.AbCip` | A | libplctag CIP | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver, IAlarmSource | ControlLogix / CompactLogix. Tag discovery uses the `@tags` walker to enumerate controller-scoped + program-scoped symbols; UDT member resolution via the UDT template reader |
 | AB Legacy | `Driver.AbLegacy` | A | libplctag PCCC | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | SLC 500 / MicroLogix. File-based addressing (`N7:0`, `F8:0`) — no symbol table, tag list is user-authored in the config DB |
 | TwinCAT | `Driver.TwinCAT` | B | Beckhoff `TwinCAT.Ads` (`TcAdsClient`) | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | The only native-notification driver outside Galaxy — ADS delivers `ValueChangedCallback` events the driver forwards straight to `ISubscribable.OnDataChange` without polling. Symbol tree uploaded via `SymbolLoaderFactory` |
-| [FOCAS](FOCAS.md) | `Driver.FOCAS` | A | Pure-managed `FocasWireClient` — FOCAS/2 Ethernet binary protocol on TCP:8193, inlined into the driver assembly | IDriver, ITagDiscovery, IReadable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver, IAlarmSource | Read-only by design (WriteAsync returns `BadNotWritable`). CNC-shaped data model (axes, spindle, PMC, macros, alarms) not a flat tag map. Previously Tier-C (Host + P/Invoke + shim DLL); retired in the 2026-04-24 migration when the managed wire client landed |
+| FOCAS | `Driver.FOCAS` | C | FANUC FOCAS2 (`Fwlib32.dll` P/Invoke) | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | Tier C — FOCAS DLL has crash modes that warrant process isolation. CNC-shaped data model (axes, spindle, PMC, macros, alarms) not a flat tag map |
 | OPC UA Client | `Driver.OpcUaClient` | B | OPCFoundation `Opc.Ua.Client` | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IAlarmSource, IHistoryProvider, IHostConnectivityProbe | Gateway/aggregation driver. Opens a single `Session` against a remote OPC UA server and re-exposes its address space. Owns its own `ApplicationConfiguration` (distinct from `Client.Shared`) because it's always-on with keep-alive + `TransferSubscriptions` across SDK reconnect, not an interactive CLI |
 
 ## Per-driver documentation
@@ -35,9 +35,6 @@ Driver type metadata is registered at startup in `DriverTypeRegistry` (`src/ZB.M
   - [Galaxy.md](Galaxy.md) — COM bridge, STA pump, IPC, runtime probes
   - [Galaxy-Repository.md](Galaxy-Repository.md) — ZB SQL reader, `LocalPlatform` scope filter, change detection
 
-- **FOCAS** has a short getting-started doc because the Tier-C two-project deployment + backend-selection env var + alarm projection opt-in all need explaining up front:
-  - [FOCAS.md](FOCAS.md) — deployment, config, capability surface, alarm projection, troubleshooting
-
 - **All other drivers** share a single per-driver specification in [docs/v2/driver-specs.md](../v2/driver-specs.md) — addressing, data-type maps, connection settings, and quirks live there. That file is the authoritative per-driver reference; this index points at it rather than duplicating.
 
 ## Test-fixture coverage maps

docs/drivers/S7-TIA-Import.md

@@ -0,0 +1,338 @@
+# S7 — TIA Portal CSV & STEP 7 Classic AWL symbol import
+
+PR-S7-D1 / [#299](https://github.com/dohertj2/lmxopcua/issues/299) — bulk-import
+TIA Portal "Show all tags" CSV exports and STEP 7 Classic AWL declaration files
+into the S7 driver. Saves operators from hand-typing every `%MW0` /
+`%DB1.DBW0` row of a several-hundred-tag PLC into `appsettings.json`.
+
+## Supported formats — v1
+
+| Format | Status | Notes |
+|---|---|---|
+| TIA Portal `.CSV` ("Show all tags" export) | **supported** | Header columns `Name,Path,Data type,Logical address,Comment,Hmi accessible,…`; en-US (`,`) and DE-locale (`;` separator + `,` decimal) auto-detected |
+| STEP 7 Classic `.AWL` (`VAR_GLOBAL` + `DATA_BLOCK`) | **supported, best-effort** | Position-based offset assignment (no exact byte offsets in hand-exported AWL — see below) |
+| STEP 7 / TIA Portal native binary (`.s7p`, `.zap`) | **out of scope** | Proprietary; no community parser. Use TIA's "Show all tags" CSV export |
+| TIA Portal Openness API | **out of scope** | Requires a licensed TIA install + OpenAPI license; future PR |
+
+## TIA Portal CSV column reference
+
+| Column | Required | Notes |
+|---|---|---|
+| `Name` | yes | OPC UA tag name. TIA symbols are stable across deployments; the importer uses them verbatim |
+| `Logical address` (or `Address`) | yes | TIA-style address with leading `%` (e.g. `%MW0`, `%DB1.DBW10`, `%DB1.DBX2.3`). Stripped on import |
+| `Data type` | recommended | TIA primitive type (`Int`, `Real`, `Bool`, `String`, …) — drives the imported `S7DataType` |
+| `Comment` | no | Parsed but currently unused — `S7TagDefinition` has no `Description` field at the v2 schema layer (see [#248](https://github.com/dohertj2/lmxopcua/issues/248)). Held in the column contract for future schema bumps |
+| `Hmi accessible` | no | Filter — rows with `False` / `FALSCH` / `nein` are skipped (internal symbols TIA shows in the editor but doesn't expose to client interfaces). Missing column defaults to `True` |
+| `Hmi visible` / `Hmi writeable` | no | Currently unused — held for future Admin-UI-side metadata |
+| `Length` | no | For `String` rows: max length. Default 254. Drives `StringLength` on the imported tag |
+| `Path` | no | TIA tag-table path (`Default tag table`, custom names). Currently unused; held in the contract |
+
+### TIA `Data type` → `S7DataType` mapping
+
+| TIA type | Maps to | Notes |
+|---|---|---|
+| `Bool` | `Bool` | Bit access; address must include a `.bit` suffix |
+| `Byte`, `SInt`, `USInt` | `Byte` | 1-byte unsigned/signed |
+| `Int` | `Int16` | Signed 16-bit |
+| `Word`, `UInt` | `UInt16` | Unsigned 16-bit |
+| `DInt` | `Int32` | Signed 32-bit |
+| `DWord`, `UDInt` | `UInt32` | Unsigned 32-bit |
+| `LInt` | `Int64` | 64-bit signed (S7-1500 only) |
+| `LWord`, `ULInt` | `UInt64` | 64-bit unsigned (S7-1500 only) |
+| `Real` | `Float32` | IEEE-754 32-bit |
+| `LReal` | `Float64` | IEEE-754 64-bit (S7-1500 only) |
+| `String` | `String` | S7 STRING with 2-byte header; `Length` column drives `StringLength` |
+| `WString` | `WString` | S7 WSTRING (UTF-16BE) |
+| `Char` / `WChar` | `Char` / `WChar` | Single-character |
+| `Date` | `Date` | UInt16 days since 1990-01-01 |
+| `Time` | `Time` | Int32 ms |
+| `TOD` / `Time_Of_Day` | `TimeOfDay` | UInt32 ms since midnight |
+| `DT` / `Date_And_Time` | `DateAndTime` | 8-byte BCD |
+| `DTL` | `Dtl` | 12-byte structured (S7-1200 / S7-1500) |
+| `S5Time` | `S5Time` | 16-bit BCD duration |
+| `Struct` / quoted UDT name | UDT placeholder | See below |
+
+### UDT placeholders
+
+UDT-typed symbols (TIA `Data type` = `"MyUdt"` quoted, or the literal `Struct`)
+import as a **placeholder** — the resulting tag lands in the driver options so
+it shows up in the Admin UI tag list, but its data type is forced to `Byte`
+and the row is marked `Writable = false`.
+
+`S7ImportResult.UdtPlaceholderCount` tracks how many of the imported tags
+landed in this bucket.
+
+#### Cooperation with `Udts` declarations (PR-S7-D2 / #300)
+
+PR-S7-D2 ships UDT fan-out via `S7DriverOptions.Udts` + `S7TagDefinition.UdtName`.
+The importer and the `Udts` declaration cooperate as follows:
+
+1. The importer emits a placeholder row for each UDT-typed symbol — same as
+   today (data type forced to `Byte`, `Writable = false`).
+2. The operator hand-edits the placeholder row in the resulting JSON / options
+   object and:
+   - Sets `UdtName` to the UDT type name from the TIA "Data type" column
+   - Removes the `Writable: false` marker (UDT leaves inherit the parent's
+     writability)
+3. The operator declares the matching `S7UdtDefinition` in
+   `S7DriverOptions.Udts` (member offsets come from the TIA UDT definition
+   in the project file — TIA's "Show all tags" CSV does not export struct
+   field offsets, hence the manual layout step).
+4. At driver init, the fan-out replaces the placeholder with one scalar leaf
+   per UDT member.
+
+The importer does NOT auto-populate `Udts` — UDT layouts live in the project
+file, not the symbol-table CSV. A future enhancement may parse the SCL UDT
+declaration alongside the CSV; for now the cooperation is "importer flags it,
+operator declares the layout, driver fans out at init".
+
+See [`docs/v2/s7.md` "UDT / STRUCT support"](../v2/s7.md#udt--struct-support)
+for the full fan-out semantics, the 4-level nesting cap, and the
+Optimized-block-access prerequisite.
+
+## Instance DBs / FB parameters
+
+PR-S7-D3 / [#301](https://github.com/dohertj2/lmxopcua/issues/301) — multi-instance
+Function-Block (FB) instances are addressed symbolically inside the PLC program
+(`MyFB_Instance.MyParam`) but the runtime wire access still needs the absolute
+`DBn.DBW_offset`. TIA Portal's "Show all tags" CSV export distinguishes these
+rows from regular global DBs via the **`DB type`** column.
+
+### `DB type` column convention
+
+| `DB type` value | Meaning | Path |
+|---|---|---|
+| (empty) | Legacy export — no column at all (TIA pre-v15 / partial export). Treated as Global. | D1 (existing) |
+| `Global DB` / `Global` / `Global Data Block` | Standalone DB declared in the project tree. | D1 (existing) |
+| `Globaler Datenbaustein` | Same as above, DE locale. | D1 (existing) |
+| `Instance DB` / `Instance` / `Instance Data Block` | Multi-instance FB instance. Member tags are the FB's `IN` / `OUT` / `IN_OUT` / `STAT` parameters. | **D3 (new)** |
+| `Instance-DB` / `Instanz-DB` / `Instanz-Datenbaustein` | Same as above (locale + dashing variants). | **D3 (new)** |
+
+The `DB type` column is matched case-insensitively; quoting and surrounding
+whitespace are tolerated.
+
+### `MyFB_Instance.MyParam` → `DBn.DBW_offset`
+
+The TIA Portal export ships the **resolved absolute address** in the
+`Logical address` column for every instance-DB member — TIA itself walks the FB
+interface declaration at export time and writes out the byte-offset-anchored
+address verbatim. The importer accepts these rows the same way as a Global-DB
+row, with two differences:
+
+1. The row counts under `S7ImportResult.InstanceDbCount` (a sub-counter of
+   `ParsedCount`) so the operator can see how much of the import depends on the
+   FB-interface layout.
+2. The row is rejected from the UDT placeholder path even if the data type
+   column happens to match a UDT name pattern — instance-DB members always
+   import as fully-functional scalar tags.
+
+Example fixture row:
+
+```csv
+Name,Path,Data type,Logical address,Comment,Hmi accessible,DB type
+MotorFB_1.Speed,FB instances,Int,%DB7.DBW0,Speed setpoint,True,Instance DB
+```
+
+The imported `S7TagDefinition` ends up with:
+
+```csharp
+new S7TagDefinition(
+    Name: "MotorFB_1.Speed",
+    Address: "DB7.DBW0",
+    DataType: S7DataType.Int16,
+    Writable: true);
+```
+
+### Empty-`Logical address` fallback
+
+When TIA exports an instance-DB row with an empty `Logical address` column
+(rare in practice — happens when the export was generated against a
+not-yet-compiled project), `InstanceDbResolver` can compute the absolute
+address from explicit parent-DB / parent-base-offset / member-offset inputs.
+This fallback is exposed at the resolver-class level for advanced bootstrap
+scenarios; the CSV path itself does not currently parse interface declarations
+out of the file (TIA's CSV doesn't carry them).
+
+For now the operator workflow is: re-export from TIA after compiling the
+project so every instance-DB row carries a resolved `Logical address`.
+
+### Re-import on FB-interface edit — caveat
+
+When the FB interface changes — a member is added, removed, or reordered in
+TIA — the instance-DB layout shifts on the PLC side. Member byte offsets that
+worked yesterday point at the wrong word today; absolute-offset addressing has
+no in-band schema check.
+
+**The driver does not auto-detect this.** Operators must:
+
+1. Recompile the FB in TIA Portal.
+2. Download the updated program to the PLC.
+3. **Re-export "Show all tags" CSV** from the updated project.
+4. Re-import the CSV via `AddTiaCsvImport` or the `import-symbols` CLI.
+5. Restart the driver instance (Admin UI → Drivers → Reload).
+
+A stale import will silently read / write the wrong byte offsets — the values
+will look like valid PLC data but reference whichever member used to live at
+that offset before the interface edit. There is no runtime guard; this is the
+same caveat that applies to all absolute-offset DB addressing on S7-1200 /
+1500 (see [`docs/v2/s7.md` "UDT / STRUCT support"](../v2/s7.md#udt--struct-support)
+for the parallel UDT-edit story).
+
+A future enhancement may add a project-fingerprint compare at driver init —
+hashing the interface offsets at import time and re-checking against a known
+PLC system function. Tracked as a follow-up; not in PR-S7-D3.
+
+## DE locale handling
+
+TIA Portal honours the Windows display locale when writing CSV. A DE-locale
+install emits:
+
+- Field separator `;` (because `,` is the decimal separator)
+- Decimal-comma in addresses: `%MW0,5` rather than `%MW0.5` for bit addresses
+- Boolean column values `WAHR` / `FALSCH` rather than `True` / `False`
+
+The importer **auto-detects** the locale from the first non-blank line:
+
+- Field-separator detection: counts `;` vs `,` occurrences in the header
+- Decimal-comma detection: scans the first data row's address column for a
+  digit-comma-digit pattern
+- Boolean column values: recognises both languages (`true/false/wahr/falsch/yes/no/ja/nein`,
+  case-insensitive) plus bare `0`/`1`
+
+The address column is rewritten to en-US shape (`%MW0,5` → `MW0.5`) before the
+strict `S7AddressParser` runs, so the rest of the driver pipeline sees a
+single canonical address shape.
+
+## STEP 7 Classic AWL — `VAR_GLOBAL` + `DATA_BLOCK`
+
+Best-effort parser for legacy STEP 7 Classic projects:
+
+- `VAR_GLOBAL … END_VAR` — global memory area declarations. Each entry maps to
+  a sequential `M{B|W|D}{offset}` address based on declaration order.
+- `DATA_BLOCK DBn … END_DATA_BLOCK` — DB declarations. Each field maps to a
+  `DB{n}.DB{B|W|D}{offset}` address based on declaration order; the DB number
+  is parsed from the `DATA_BLOCK` line's `DBn` keyword.
+
+### Position-based addressing — heuristic
+
+Real STEP 7 Classic projects carry exact byte offsets in the symbol table /
+.gr8 deployment artefact, but a hand-exported AWL file omits them. The
+importer assumes:
+
+| Type | Bytes |
+|---|---|
+| `BOOL` | 1 (rounded up to byte alignment) |
+| `BYTE` / `SINT` / `USINT` / `CHAR` | 1 |
+| `INT` / `WORD` / `UINT` | 2 |
+| `DINT` / `DWORD` / `UDINT` / `REAL` | 4 |
+| `LREAL` / `LINT` / `ULINT` / `LWORD` | 8 |
+| `STRING[N]` | N + 2 (2-byte header) |
+| `STRING` (no length) | 256 |
+| `STRUCT` / `Array[…] of …` / quoted UDT name | UDT placeholder (8-bit Byte at next aligned offset) |
+
+S7 alignment rule: offsets round up to a 2-byte boundary for any 16-bit-or-larger
+type. Sites needing exact offsets should drive their symbol import from the
+TIA Portal CSV path instead — the CSV carries the offsets verbatim.
+
+Comments (`(* ... *)` block, `// ...` line) are stripped before declaration
+parsing. Initial-value clauses (`:= 0`) are recognised and discarded.
+
+## CLI subcommand — `import-symbols`
+
+```powershell
+otopcua-s7-cli import-symbols --help
+```
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-f` / `--file` | **required** | Path to the TIA CSV or `.AWL` file |
+| `--format` | `tia` | `tia` (CSV) or `awl` (STEP 7 Classic) |
+| `-d` / `--device` | none | Optional documentation tag (reserved for symmetry with `import-rslogix`) |
+| `--emit` | `appsettings-fragment` | `appsettings-fragment` (JSON) or `summary` (one-line counter) |
+| `-o` / `--output` | stdout | Optional path; when set the JSON fragment is written there + summary line goes to stdout |
+| `--max-rows` | unlimited | Defensive cap on rows imported |
+| `--strict` | off | Fail-fast on the first malformed row (default permissive: skip + log) |
+
+### `appsettings-fragment` output shape
+
+The default `--emit appsettings-fragment` mode writes a JSON object whose
+`Tags` array is shaped like the `S7DriverConfigDto.Tags` array — paste
+straight into the driver-instance config under
+`Drivers/<instance>/Config/Tags`.
+
+```json
+{
+  "Tags": [
+    {
+      "Name": "MotorSpeed",
+      "Address": "MW0",
+      "DataType": "Int16",
+      "Writable": true,
+      "StringLength": 254
+    },
+    …
+  ]
+}
+```
+
+### Summary line
+
+`--emit summary` writes a single line:
+
+```
+Imported 142 tag(s), skipped 3, errors 0, udt-placeholders 5, instance-db 9.
+```
+
+`Skipped` covers HMI-accessible-false rows + missing-required-field rows;
+`errors` covers rows whose `Address` failed to parse as an S7 address;
+`udt-placeholders` covers UDT-typed rows that imported as placeholders;
+`instance-db` (PR-S7-D3) covers rows whose `DB type` column tagged them as
+multi-instance FB-instance members.
+
+## API surface — `IS7SymbolImporter` + `AddTiaCsvImport` / `AddAwlImport`
+
+For server-side / bootstrap use-cases the importer is reachable via:
+
+```csharp
+using ZB.MOM.WW.OtOpcUa.Driver.S7;
+using ZB.MOM.WW.OtOpcUa.Driver.S7.SymbolImport;
+
+var options = new S7DriverOptions { Host = "192.168.1.30", CpuType = CpuType.S71500 };
+
+// Append imported tags onto an existing options object.
+var updated = options.AddTiaCsvImport(
+    path: @"C:\plc\tia-export.csv",
+    out var result);
+
+Console.WriteLine($"Imported {result.ParsedCount} tags ({result.UdtPlaceholderCount} placeholders)");
+
+// AWL variant — same shape.
+var withAwl = updated.AddAwlImport(
+    path: @"C:\plc\classic.awl",
+    out var awlResult);
+```
+
+For a hand-managed importer instance (e.g. supplying a custom `ILogger`) call
+`new TiaCsvImporter(logger).Parse(stream, opts)` or
+`new AwlImporter(logger).Parse(stream, opts)` directly.
+
+## Operational notes
+
+- The importers are **additive** — `AddTiaCsvImport` / `AddAwlImport` concatenate
+  onto the existing `Tags` list rather than replacing it. Hand-rolled tags
+  (system-status variables, computed fields the operator added by hand) survive
+  a re-import.
+- Re-imports are not idempotent — calling `AddTiaCsvImport` twice will produce
+  duplicate tag rows. Operators are expected to start from a clean options
+  object or de-duplicate themselves; a future schema rev may add a
+  `replace=true` switch.
+- UDT placeholders surface in the Admin UI as non-writable Byte tags. PR-S7-D2
+  added the runtime UDT fan-out (`S7DriverOptions.Udts` + `S7TagDefinition.UdtName`)
+  — operators upgrade a placeholder row by setting `UdtName` and declaring the
+  matching `S7UdtDefinition`; see "Cooperation with `Udts` declarations" above.
+  Placeholder-only rows still work as a Byte view of the first byte but
+  can't browse / read their members until the layout is declared.
+- Description metadata is dropped on the floor today — see the column
+  reference above. When [#248](https://github.com/dohertj2/lmxopcua/issues/248)
+  lands a `Description` field on `S7TagDefinition` the importer will start
+  populating it without further changes to the CSV contract.

docs/drivers/S7-Test-Fixture.md

@@ -44,6 +44,10 @@ The driver ctor change that made this possible:
   bool-with-bit in one batch call; proves typed decode per S7DataType
 - `S7_1500SmokeTests.Driver_write_then_read_round_trip_on_scratch_word` —
   `DB1.DBW100` write → read-back; proves write path + buffer visibility
+- `S7_1500DiagnosticsTests.Driver_exposes_negotiated_pdu_size_post_init` —
+  asserts `DriverHealth.Diagnostics["S7.NegotiatedPduSize"]` is non-zero
+  after `InitializeAsync`; proves the negotiated PDU size surfaces in
+  driver health (Snap7 fixture pins this at 240 bytes — see fixture README)
 
 ### Unit
 
@@ -84,10 +88,59 @@ real PLC latency is not exercised.
 S7-1200 vs S7-1500 vs S7-300/400 connection semantics (PG vs OP vs S7-Basic)
 not differentiated at test time.
 
+**Optimized DB / S7Plus** is the variant-shaped gap with the biggest field
+impact. snap7 happens to behave like a classic-S7comm-only PLC, so the
+integration suite cannot reproduce the shape that an S7-1500 with default
+"Optimized block access" checked would return (`BadDeviceFailure` on every
+absolute-offset read). The decision is documented at
+[`docs/v2/s7.md` § Optimized DB constraint (S7Plus)](../v2/s7.md#optimized-db-constraint-s7plus)
+and tracked in [`docs/featuregaps.md`](../featuregaps.md) row #1; the
+project ships **Track 1** (operator unchecks Optimized block access in TIA
+Portal) and **Track 3** (bridge via the `OpcUaClient` driver against the
+CPU's onboard OPC UA server). A custom S7Plus implementation is out of
+scope.
+
 ### 5. Data types beyond the scalars
 
-UDT fan-out, `STRING` with length-prefix quirks, `DTL` / `DATE_AND_TIME`,
+`STRING` with length-prefix quirks, `DTL` / `DATE_AND_TIME`, arrays of
-arrays of structs — not covered.
+structs — not covered. UDT fan-out IS covered (PR-S7-D2 / #300) via the
+`udt_layout` meta-seed in `Docker/profiles/s7_1500.json` and the
+`Driver_fans_out_udt_into_member_tags` integration test.
+
+### 6. SZL (System Status List) — `@System.*` virtual addresses
+
+PR-S7-E1 / [#302](https://github.com/dohertj2/dohertj2/lmxopcua/issues/302)
+adds a virtual `@System.*` address surface (CPU type, firmware, scan-cycle
+stats, diagnostic-buffer ring) backed by SZL reads. **snap7 does not
+implement SZL** — the simulator answers every SZL request with a function-
+not-supported error, so the integration profile exercises only the
+not-supported semantics (`@System.CpuType` against snap7 returns
+`BadNotSupported`). Live-firmware SZL coverage is parked behind a
+`[Fact(Skip = ...)]` until either S7netplus exposes a public `ReadSzlAsync`
+or we ship a raw S7comm PDU helper. See
+[`docs/v2/s7.md` "CPU diagnostics (SZL)"](../v2/s7.md#cpu-diagnostics-szl)
+for the wire-status detail.
+
+### 7. Password / protection levels — not modelled by snap7
+
+PR-S7-E2 / [#303](https://github.com/dohertj2/lmxopcua/issues/303) adds
+`Password` + `ProtectionLevel` options that emit a connection-level password
+right after `OpenAsync`. **snap7 does not model S7 protection levels** — the
+simulator accepts every connection regardless of the password set on the
+client, so the integration profile cannot distinguish "password sent
+correctly" from "password ignored". Coverage stays at the unit-test seam:
+`S7PasswordOptionsTests` injects a fake `IS7PlcAuthGate` to assert the
+dispatch contract (Password=null skips the call; Password+SupportsSendPassword
+calls the gate; auth-failed wraps to a clean `InvalidOperationException`),
+plus the no-log invariant on `S7DriverOptions.ToString()`.
+
+The wire path is also fundamentally limited until S7netplus 0.20 exposes a
+public `SendPassword` — the driver currently logs a warning and continues
+when the API is missing. See
+[`docs/v2/s7.md` "PLC password / protection levels"](../v2/s7.md#plc-password--protection-levels)
+for the library-limitation note. Live-firmware coverage of the unlock path
+requires a hardened S7-1500 lab rig with TIA Portal "Protection & Security"
+configured, which is parked as a follow-up.
 
 ## When to trust the S7 tests, when to reach for a rig
 
@@ -97,7 +150,7 @@ arrays of structs — not covered.
 | "Does the driver lifecycle hang / crash?" | yes | yes |
 | "Does a real read against an S7-1500 return correct bytes?" | no | yes (required) |
 | "Does mailbox serialization actually prevent PG timeouts?" | no | yes (required) |
-| "Does a UDT fan-out produce usable member variables?" | no | yes (required) |
+| "Does a UDT fan-out produce usable member variables?" | yes (Snap7 + `udt_layout` meta-seed) | yes |
 
 ## Follow-up candidates
 
@@ -109,6 +162,56 @@ arrays of structs — not covered.
    lab rig but not CI.
 3. **Real S7 lab rig** — cheapest physical PLC (CPU 1212C) on a dedicated
    network port, wired via self-hosted runner.
+4. **PR-S7-C5 — PUT/GET-disabled pre-flight rejection.** Snap7 does *not*
+   model the hardened-CPU PUT/GET response (it accepts every read once the
+   COTP handshake completes), so the **failure** path of the pre-flight
+   probe — `S7PutGetDisabledException` thrown from `InitializeAsync` when
+   the PLC rejects the probe read with `ErrorCode.WrongCPU_Type` /
+   `ErrorCode.ReadData` — needs a real S7-1500 with PUT/GET disabled in TIA
+   Portal. The integration suite covers the *happy* path
+   (`Driver_preflight_passes_when_probe_address_seeded`); the failure path
+   should be added as a `--with-real-plc` opt-in test that the self-hosted
+   runner with the lab rig executes. The classifier branch
+   (`S7PreflightClassifier.IsPutGetDisabled`) is unit-tested without a
+   network in `S7PreflightTests.Classifier_matches_only_PUT_GET_disabled_error_codes`.
+5. **Live-firmware Optimized-block-access toggle (PR-S7-F / [#304](https://github.com/dohertj2/lmxopcua/issues/304)).**
+   snap7 happens to behave like a classic-S7comm CPU, so the integration
+   profile cannot reproduce the failure that a default new TIA Portal V14+
+   project produces (`BadDeviceFailure` on `DB1.DBW0` against an Optimized
+   DB). A manual smoke test on the lab rig, gated behind `--with-real-plc`,
+   would close that loop. Suggested checklist on a real S7-1500 V2.5+:
+   1. Create `DB1` in TIA Portal with three INT members at offsets 0, 2, 4.
+      Leave **Optimized block access checked** (the default).
+   2. Compile + download to the PLC.
+   3. Drive the OtOpcUa S7 driver against `DB1.DBW0` — assert that the read
+      returns `BadDeviceFailure` (the Track-1-not-applied symptom). This is
+      the failure shape the docs warn about.
+   4. Open `DB1`'s properties → **uncheck Optimized block access** →
+      compile → download. Re-run the read; assert it returns the seeded
+      INT value at offset 0. (Track 1 verified end-to-end.)
+   5. **Track 3 verification (separate run on the same rig):** with
+      Optimized access re-enabled on `DB1`, activate the CPU's onboard
+      OPC UA server in TIA Portal, expose `DB1.<MemberName>` through a
+      Server interface, register an `OpcUaClient` driver against
+      `opc.tcp://<plc-ip>:4840`, and assert the symbolic read returns the
+      same seeded value. This proves the bridge path against a real
+      Optimized DB without the operator having to disable Optimized
+      access.
+
+   The test must stay manual: TIA Portal compile + download cannot be
+   automated from CI without a Siemens engineering toolchain license, and
+   download-with-CPU-stop is destructive on a shared lab rig. Document
+   results inline in PR descriptions when the rig is available.
+
+6. **PR-S7-E1 — live SZL test against a real S7-1500.** snap7 doesn't
+   implement SZL at all, and S7netplus 0.20 doesn't expose a public
+   `ReadSzlAsync`, so the `@System.*` virtual address surface currently
+   answers `BadNotSupported` against every backend. The parser
+   (`S7SzlParser`) is unit-tested against golden bytes; flipping the wire
+   path on requires either an S7netplus PR or a raw-PDU helper. Once that's
+   in, [`S7_1500SzlTests.System_CpuType_against_live_S7_1500_returns_non_empty_string`](../../tests/ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests/S7_1500/S7_1500SzlTests.cs)
+   should be flipped from `[Fact(Skip = ...)]` to env-var-gated against the
+   self-hosted runner with the lab rig.
 
 Without any of these, S7 driver correctness against real hardware is trusted
 from field deployments, not from the test suite.

docs/drivers/TwinCAT-Test-Fixture.md

@@ -2,85 +2,68 @@
 
 Coverage map + gap inventory for the Beckhoff TwinCAT ADS driver.
 
-**TL;DR:** Integration-test suite lives at
+**TL;DR:** Integration-test scaffolding lives at
-`tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/`. `TwinCATXarFixture`
+`tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/` (task #221).
-probes TCP 48898 on an operator-supplied runtime; the suite runs **14
+`TwinCATXarFixture` probes TCP 48898 on an operator-supplied VM; three
-`[TwinCATFact]` methods + one 16-case `[TwinCATTheory]` = 30 test cases** end-to-end
+smoke tests (read / write / native notification) run end-to-end through
-through the real ADS stack when the runtime is reachable, skips cleanly
+the real ADS stack when the VM is reachable, skip cleanly otherwise.
-otherwise. The runtime can be a Hyper-V XAR VM or a TCBSD VM
+**Remaining operational work**: stand up a TwinCAT 3 XAR runtime in a
-(`TwinCatProject/README.md` covers both). Unit tests via `FakeTwinCATClient`
+Hyper-V VM, author the `.tsproj` project documented at
-still carry the exhaustive contract coverage alongside.
+`TwinCatProject/README.md`, rotate the 7-day trial license (or buy a
+paid runtime). Unit tests via `FakeTwinCATClient` still carry the
+exhaustive contract coverage.
 
-TwinCAT is the only driver outside Galaxy that uses **native notifications**
+TwinCAT is the only driver outside Galaxy that uses **native
-(no polling) for `ISubscribable`. The integration suite verifies that path on
+notifications** (no polling) for `ISubscribable`, and the fake exposes a
-the wire; the fake exposes a fire-event harness so notification routing is
+fire-event harness so notification routing is contract-tested rigorously
-also contract-tested rigorously at the unit layer.
+at the unit layer.
 
 ## What the fixture is
 
-**Integration layer**: `tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/`
+**Integration layer** (task #221, scaffolded):
-— `TwinCATXarFixture` TCP-probes ADS port 48898 on the host supplied by
+`tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/` —
-`TWINCAT_TARGET_HOST` (defaults to `localhost`) + requires
+`TwinCATXarFixture` TCP-probes ADS port 48898 on the host specified by
-`TWINCAT_TARGET_NETID` (AmsNetId of the runtime). Optionally takes
+`TWINCAT_TARGET_HOST` + requires `TWINCAT_TARGET_NETID` (AmsNetId of the
-`TWINCAT_TARGET_PORT` (default `851` = TC3 PLC runtime 1). No fixture-owned
+VM). No fixture-owned lifecycle — XAR can't run in Docker because it
-lifecycle — XAR / TCBSD can't run in Docker because they bypass the host
+bypasses the Windows kernel scheduler, so the VM stays
-kernel scheduler, so the runtime stays operator-managed.
+operator-managed. `TwinCatProject/README.md` documents the required
-`TwinCatProject/README.md` documents the required project state; the tests
+`.tsproj` project state; the file itself lands once the XAR VM is up +
-gate on `[TwinCATFact]` / `[TwinCATTheory]` and skip cleanly when
+the project is authored. Three smoke tests:
-`TWINCAT_TARGET_NETID` is unset or the probe fails.
+`Driver_reads_seeded_DINT_through_real_ADS`,
+`Driver_write_then_read_round_trip_on_scratch_REAL`, and
+`Driver_subscribe_receives_native_ADS_notifications_on_counter_changes`
+— all skip cleanly via `[TwinCATFact]` when the runtime isn't
+reachable.
 
-**Unit layer**: `tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/` remains the
+**Unit layer**: `tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/` is
-primary contract coverage. `FakeTwinCATClient` fakes the
+still the primary coverage. `FakeTwinCATClient` also fakes the
-`AddDeviceNotification` flow so tests can trigger callbacks without a running
+`AddDeviceNotification` flow so tests can trigger callbacks without a
-runtime.
+running runtime.
 
 ## What it actually covers
 
-### Integration (live runtime)
+### Integration (XAR VM, task #221 — code scaffolded, needs VM + project)
 
-Every capability the driver implements is exercised on the wire:
+- `TwinCAT3SmokeTests.Driver_reads_seeded_DINT_through_real_ADS` — real AMS
+  handshake + ADS read of `GVL_Fixture.nCounter` (seeded at 1234, MAIN
+  increments each cycle)
+- `TwinCAT3SmokeTests.Driver_write_then_read_round_trip_on_scratch_REAL` —
+  real ADS write + read on `GVL_Fixture.rSetpoint`
+- `TwinCAT3SmokeTests.Driver_subscribe_receives_native_ADS_notifications_on_counter_changes`
+  — real `AddDeviceNotification` against the cycle-incrementing counter;
+  observes `OnDataChange` firing within 3 s of subscribe
 
-- **Read** — `Driver_reads_seeded_DINT_through_real_ADS` (AMS handshake +
+All three gated on `TWINCAT_TARGET_HOST` + `TWINCAT_TARGET_NETID` env
-  symbolic read of `GVL_Fixture.nCounter`)
+vars; skip cleanly via `[TwinCATFact]` when the VM isn't reachable or
-- **Write + read round-trip** — `Driver_write_then_read_round_trip_on_scratch_REAL`
+vars are unset.
-  on `GVL_Fixture.rSetpoint`
-- **Array element round-trip** — `Driver_round_trips_array_element_write_and_read`
-  on `GVL_Arrays.aReal1D[5]` (exercises `TwinCATSymbolPath` subscript
-  rendering)
-- **Subscribe (native ADS notifications)** —
-  `Driver_subscribe_receives_native_ADS_notifications_on_counter_changes`;
-  observes `OnDataChange` firing within 10 s of subscribe
-- **Symbol browse (direct client path)** —
-  `Driver_browses_committed_symbol_hierarchy_via_real_ADS` via
-  `ITwinCATClient.BrowseSymbolsAsync`
-- **Symbol browse (through DiscoverAsync + `IAddressSpaceBuilder` pipeline)** —
-  `DiscoverAsync_renders_declared_tags_and_controller_browse_hits_address_space_builder`
-  verifies the real `TwinCAT/ → device/ → Discovered/` folder tree
-- **Auto-reconnect** — `Driver_auto_reconnects_after_underlying_client_is_disposed`
-  disposes the `AdsClient` mid-flight; next read must re-establish
-- **Primitive type coverage** — `Driver_reads_every_primitive_type_with_correct_mapping`
-  runs as a `[Theory]` against the 16 primitives in `GVL_Primitives`
-  (Bool, SInt, USInt, Int, UInt, DInt, UDInt, LInt, ULInt, Real, LReal,
-  String, Time, TimeOfDay, Date, DateTime) — asserts status + CLR type +
-  seed value where ergonomic
-- **Bit-indexed BOOL** — `Driver_reads_bit_indexed_BOOL_from_word` against
-  `GVL_Primitives.vWord.3` + `.4` (bits of `0x​BEEF`)
-- **Nested UDT navigation** — `Driver_reads_deeply_nested_UDT_path` reads
-  `GVL_Plant.Line1.Stations[1].Axes[1].Motor.Temperature` (LREAL) + `.Running` (BOOL)
-- **Multi-device routing + isolation** —
-  `Driver_routes_reads_per_device_and_isolates_unreachable_peers` pairs the
-  real runtime with a bogus AmsNetId; healthy device reads still succeed
-- **Probe loop + `IHostConnectivityProbe`** —
-  `Probe_loop_raises_host_status_transition_to_Running_on_reachable_target`
-  asserts `OnHostStatusChanged → Running` and snapshot parity
-- **Negative error mappings** —
-  `Driver_reports_errors_for_unknown_tag_and_nonexistent_symbol_and_readonly_write`
-  covers `BadNodeIdUnknown`, ghost-symbol communication errors, and the
-  `BadNotWritable` short-circuit
 
-All tests gate on `TWINCAT_TARGET_NETID` (required) via `[TwinCATFact]` /
+PR 4.1 / #315 adds `TwinCATUdtBrowseTests.Driver_browses_UDT_tree_and_flattens_to_atomic_leaves`
-`[TwinCATTheory]`; `TWINCAT_TARGET_HOST` (default `localhost`) and
+which exercises `TwinCATDriver.DiscoverAsync` end-to-end against the
-`TWINCAT_TARGET_PORT` (default `851`) are optional overrides.
+`GVL_Plant` UDT fixture. Asserts the discovery surface emits one OPC UA
+variable per atomic leaf and folds `aAlarmRecords[1..2000]` into a
+single `IsArrayRoot` placeholder when the element count exceeds the
+default 1024-element cap (UDT per-member coverage; see
+`TwinCatProject/README.md §Complex hierarchy` for the supporting DUTs).
 
 ### Unit
 
@@ -90,69 +73,87 @@ All tests gate on `TWINCAT_TARGET_NETID` (required) via `[TwinCATFact]` /
 - `TwinCATReadWriteTests` — read + write through the fake, status mapping
 - `TwinCATSymbolPathTests` — symbol-path routing for nested struct members
 - `TwinCATSymbolBrowserTests` — `ITagDiscovery.DiscoverAsync` via
-  `BrowseSymbolsAsync` + system-symbol filtering
+  `ReadSymbolsAsync` (#188) + system-symbol filtering
-- `TwinCATNativeNotificationTests` — `AddDeviceNotification` registration,
+- `TwinCATTypeWalkerTests` — PR 4.1 / #315 nested-UDT decomposition:
-  callback-delivery-to-`OnDataChange` wiring, unregister on unsubscribe
+  atomic / single-level struct / nested struct / array-of-atomic
+  (in / over `MaxArrayExpansion`) / array-of-struct / alias chain /
+  pointer skip / self-referencing struct depth-cap / per-leaf
+  `MaxArrayExpansion` honored / ReadOnly propagation. Stub `IDataType`
+  / `IStructType` / `IArrayType` / `IMember` / `IDimensionCollection`
+  trees built in-test so the walker is exercised without
+  `Beckhoff.TwinCAT.Ads`-internal ctors.
+- `TwinCATNativeNotificationTests` — `AddDeviceNotification` (#189)
+  registration, callback-delivery-to-`OnDataChange` wiring, unregister on
+  unsubscribe
 - `TwinCATDriverTests` — `IDriver` lifecycle
 
-Capability surfaces whose contract is verified at the unit layer: `IDriver`,
+Capability surfaces whose contract is verified: `IDriver`, `IReadable`,
-`IReadable`, `IWritable`, `ITagDiscovery`, `ISubscribable`,
+`IWritable`, `ITagDiscovery`, `ISubscribable`, `IHostConnectivityProbe`,
-`IHostConnectivityProbe`, `IPerCallHostResolver`. The integration suite now
+`IPerCallHostResolver`, `IAlarmSource` (PR 5.1 / #316, gated behind
-verifies `ITagDiscovery` + `IHostConnectivityProbe` on the wire as well.
+`EnableAlarms=true` — see capability matrix below).
 
-## Bugs caught by live runs
+## Capability matrix
 
-The integration suite surfaced three driver defects that `FakeTwinCATClient`
+| Capability | Status | Notes |
-couldn't, since each lived below the abstraction boundary:
+| --- | --- | --- |
-
+| `IDriver` | yes | Lifecycle + health |
-1. **Notification cycle time unit** — `NotificationSettings(cycleTime, maxDelay)`
+| `IReadable` | yes | Sum-read for scalars; per-tag for bit / array |
-   takes **milliseconds** per Beckhoff InfoSys
+| `IWritable` | yes | Sum-write for scalars; per-tag for bit-RMW / array |
-   (`tcadsnetref/7313319051`), but the driver was multiplying by `10_000`
+| `ITagDiscovery` | yes | Pre-declared + opt-in symbol-table walk |
-   under a "100 ns units" assumption. A requested 250 ms cycle was being set
+| `ISubscribable` | yes | Native ADS notifications by default; poll fallback |
-   to ~41 minutes — subscribe never fired. Fix in `AdsTwinCATClient.AddNotificationAsync`.
+| `IHostConnectivityProbe` | yes | `ReadStateAsync` + system-symbol diagnostics |
-2. **`STRING(N)` / `WSTRING(N)` type mapper** — `MapSymbolTypeName` only
+| `IPerCallHostResolver` | yes | Tag → device hostAddress |
-   matched bare `"STRING"` / `"WSTRING"`, so sized strings (the common case)
+| `IAlarmSource` (PR 5.1 / #316) | partial | Scaffold + unit-tested; live wire decode is best-effort against AMS port 110, see `docs/v3/twincat-eventlogger-spike.md` |
-   fell off `BrowseSymbolsAsync` entirely. Fix: strip the `(…)` bound before
+| `IHistoryProvider` | no | Not in scope for this driver family |
-   the switch.
-3. **Bit-indexed BOOL path** — driver was sending `"GVL.vWord.3"` to ADS as
-   a BOOL read. TwinCAT's symbol table doesn't expose bit-access paths; the
-   read returned `DeviceSymbolNotFound`. Fix: strip the `.N` suffix, read
-   the parent word as `uint`, extract the bit locally via `ExtractBit`.
-
-All three paths are now pinned by live-wire tests.
 
 ## What it does NOT cover
 
-### 1. AMS / ADS wire framing
+### 1. AMS / ADS wire traffic
 
-No raw AMS packet is inspected. Beckhoff's `TwinCAT.Ads` NuGet (their own
+No real AMS router frame is exchanged. Beckhoff's `TwinCAT.Ads` NuGet (their
-.NET SDK, not libplctag-style OSS) has no in-process fake at the frame
+own .NET SDK, not libplctag-style OSS) has no in-process fake; tests stub
-level; tests run against a real router.
+the `ITwinCATClient` abstraction above it.
 
 ### 2. Multi-route AMS
 
 ADS supports chained routes (`<localNetId> → <routerNetId> → <targetNetId>`)
 for PLCs behind an EC master / IPC gateway. Parse coverage exists; wire-path
-coverage is single-hop only.
+coverage doesn't.
 
-### 3. Notification coalescing under jitter
+### 3. Notification reliability under jitter
 
-`AddDeviceNotification` delivers at the runtime's cycle boundary; under
+`AddDeviceNotification` delivers at the runtime's cycle boundary; under high
-sustained CPU load or network jitter real notifications can coalesce. The
+CPU load or network jitter real notifications can coalesce. The fake fires
-live test only asserts at-least-one delivery within a generous window —
+one callback per test invocation — real callback-coalescing behavior is
-coalescing behavior under stress isn't verified.
+untested.
+
+PR 3.1 (#313) makes the per-tag `MaxDelay` configurable via
+`TwinCATTagDefinition.MaxDelayMs` — the runtime can buffer changes for up to
+that many milliseconds before dispatch, deliberately coalescing bursty
+high-frequency signals so the OPC UA queue downstream doesn't flood. Default
+`null` / `0` preserves the pre-PR-3.1 "fire ASAP" behaviour.
+`TwinCATMaxDelayTests.Driver_coalesces_notifications_at_max_delay` exercises
+the wire-side coalescer end-to-end against `GVL_Fixture.nCounter`; the unit
+suite (`TwinCATNativeNotificationTests`) covers the plumbing contract via
+the `FakeTwinCATClient.FakeNotification.MaxDelayMs` capture.
 
 ### 4. TC2 vs TC3 variant handling
 
 TwinCAT 2 (ADS v1) and TwinCAT 3 (ADS v2) have subtly different
-`GetSymbolInfoByName` semantics + symbol-table layouts. Driver + tests target
+`GetSymbolInfoByName` semantics + symbol-table layouts. Driver targets TC3;
-TC3; TC2 compatibility is not exercised.
+TC2 compatibility is not exercised.
 
-### 5. Alarms / history
+### 5. Cycle-time alignment for `ISubscribable`
 
-Driver doesn't implement `IAlarmSource` or `IHistoryProvider` — not in scope
+Native ADS notifications fire on the PLC cycle boundary. The fake test
-for this driver family. TwinCAT 3's TcEventLogger could theoretically back
+harness assumes notifications fire on a timer the test controls;
-an `IAlarmSource`, but shipping that is a separate feature.
+cycle-aligned firing under real PLC control is not verified.
+
+### 6. History
+
+Driver doesn't implement `IHistoryProvider` — not in scope for this
+driver family. (Alarms now have a dedicated `IAlarmSource` bridge — see
+the capability matrix below + `docs/drivers/TwinCAT.md`.)
 
 ## When to trust TwinCAT tests, when to reach for a rig
 
@@ -162,25 +163,135 @@ an `IAlarmSource`, but shipping that is a separate feature.
 | "Does notification → `OnDataChange` wire correctly?" | yes (contract) | yes |
 | "Does symbol browsing filter TwinCAT internals?" | yes | yes |
 | "Does a real ADS read return correct bytes?" | no | yes (required) |
-| "Does auto-reconnect work on router restart?" | no (contract only) | yes (required) |
+| "Do notifications coalesce under load?" | no | yes (required) |
-| "Do notifications coalesce under sustained load?" | no | yes (required) |
 | "Does a TC2 PLC work the same as TC3?" | no | yes (required) |
 
+## Performance
+
+PR 2.1 (Sum-read / Sum-write, IndexGroup `0xF080..0xF084`) replaced the per-tag
+`ReadValueAsync` loop in `TwinCATDriver.ReadAsync` / `WriteAsync` with a
+bucketed bulk dispatch — N tags addressed against the same device flow through a
+single ADS sum-command round-trip via `SumInstancePathAnyTypeRead` (read) and
+`SumWriteBySymbolPath` (write). Whole-array tags + bit-extracted BOOL tags
+remain on the per-tag fallback path because the sum surface only marshals
+scalars and bit-RMW writes need the per-parent serialisation lock.
+
+**Baseline → Sum-command delta** (dev box, 1000 × DINT, XAR VM over LAN):
+
+| Path | Round-trips | Wall-clock |
+| --- | --- | --- |
+| Per-tag loop (pre-PR 2.1) | 1000 | ~5–8 s |
+| Sum-command bulk (PR 2.1) | 1 | ~250–600 ms |
+| Ratio | — | ≥ 10× typical, ≥ 5× CI floor |
+
+The perf-tier test
+`TwinCATSumCommandPerfTests.Driver_sum_read_1000_tags_beats_loop_baseline_by_5x`
+asserts the ratio with a conservative 5× lower bound that survives noisy CI /
+VM scheduling. It is gated behind both `TWINCAT_TARGET_NETID` (XAR reachable)
+and `TWINCAT_PERF=1` (operator opt-in) — perf runs aren't part of the default
+integration pass because they hit the wire heavily.
+
+The required fixture state (1000-DINT GVL + churn POU) is documented in
+`TwinCatProject/README.md §Performance scenarios`; XAE-form sources land at
+`TwinCatProject/PLC/GVLs/GVL_Perf.TcGVL` + `TwinCatProject/PLC/POUs/FB_PerfChurn.TcPOU`.
+
+### Handle caching (PR 2.2)
+
+Per-tag reads / writes route through an in-process ADS variable-handle cache.
+The first read of a symbol resolves a handle via `CreateVariableHandleAsync`;
+subsequent reads / writes of the same symbol issue against the cached handle.
+On the wire this trades a multi-byte symbolic path (`GVL_Perf.aTags[742]` =
+20+ bytes) for a 4-byte handle, and the device server skips name resolution
+on every subsequent op. Cache lifetime is process-scoped; entries are evicted
+on `AdsErrorCode.DeviceSymbolVersionInvalid` (with one retry against a fresh
+handle), wiped on reconnect (handles are per-AMS-session), and deleted
+best-effort on driver disposal.
+
+`TwinCATHandleCachePerfTests.Driver_handle_cache_avoids_repeat_symbol_resolution`
+asserts the contract on real XAR by reading 50 symbols twice and verifying
+the second pass issues zero new `CreateVariableHandleAsync` calls. It runs
+under the standard `[TwinCATFact]` gate (XAR reachable; no `TWINCAT_PERF`
+opt-in needed because 50 symbols is cheap).
+
+**Self-invalidation (PR 2.3)**: handle cache is now self-invalidating on
+TwinCAT online changes. `AdsTwinCATClient` registers an
+`AdsSymbolVersionChanged` event listener (Beckhoff's high-level wrapper
+around the SymbolVersion ADS notification, IndexGroup `0xF008`) on connect;
+when the PLC's symbol-version counter increments — full re-init after a
+download / activate-config — the listener fires and wipes the handle cache
+proactively. Three-layered defence in depth: (1) proactive listener
+preempts the next read entirely on full re-inits, (2) the
+`DeviceSymbolVersionInvalid` evict-and-retry path from PR 2.2 catches the
+narrower "symbol survives but its descriptor moved" race, and (3)
+operators can still call `ITwinCATClient.FlushOptionalCachesAsync` manually
+for the truly-paranoid case. The bulk Sum-read / Sum-write path remains
+on symbolic paths in PR 2.2 (the bulk path's per-call symbol resolution
+is already amortised across N tags; the perf delta vs. handle-batched
+bulk is marginal — tracked as a follow-up for the Phase-2 perf sweep).
+
+## Diagnostics
+
+PR 3.2 (#314) augments the probe loop. On every successful tick (post `ReadStateAsync`)
+the driver also reads four well-known system symbols off the AMS target and stashes
+them on `DeviceState.LastDiagnostics` as a `TwinCATDeviceDiagnostics` record. The same
+snapshot is folded into `DriverHealth.Diagnostics` so the cross-driver
+`driver-diagnostics` RPC (added for Modbus, task #154) renders TwinCAT cycle-time /
+jitter / online-change counters next to its peers without a per-driver special-case.
+
+| Symbol | Type | Diagnostic key | Notes |
+| --- | --- | --- | --- |
+| `TwinCAT_SystemInfoVarList._AppInfo.AppName` | `STRING(80)` | (record only) | Running PLC project name, e.g. `"Plc1"` |
+| `TwinCAT_SystemInfoVarList._AppInfo.OnlineChangeCnt` | `UDINT` | `TwinCAT.OnlineChangeCnt` | Increments on every accepted online change; informational |
+| `TwinCAT_SystemInfoVarList._TaskInfo[1].CycleTime` | `UDINT` (100 ns ticks) | `TwinCAT.CycleTimeMs` | Configured task period after `÷10000` ms conversion |
+| `TwinCAT_SystemInfoVarList._TaskInfo[1].LastExecTime` | `UDINT` (100 ns ticks) | `TwinCAT.LastExecTimeMs` | Wall-clock duration of the last task tick |
+| (computed) | `double` | `TwinCAT.JitterMs` | `LastExecTimeMs - CycleTimeMs`; positive = overrun |
+| (computed) | `long` | `TwinCAT.OnlineChangeIncrements` | Cumulative deltas observed since the driver started; only emitted once non-zero |
+
+Each individual read is wrapped in best-effort try/catch. A runtime that doesn't
+expose `_TaskInfo[1]` (older TwinCAT 2 builds, some soft-PLC implementations) still
+produces a partial snapshot; the missing fields fall back to the previous tick's value
+or the type default for the first probe tick. Wholesale failure of all four reads
+leaves the previous snapshot in place and the next tick retries.
+
+Single-device deployments produce flat keys (`TwinCAT.CycleTimeMs`); multi-device
+deployments prefix with the AMS host address (`TwinCAT.<hostAddress>.CycleTimeMs`)
+so the readout is unambiguous when one driver instance owns multiple AMS targets.
+
+Wire-level coverage lives in
+`TwinCATDiagnosticsIntegrationTests.Probe_loop_surfaces_cycle_time_and_online_change_count`
+(asserts `CycleTimeMs > 0` + `OnlineChangeCnt >= 0` within one probe interval against a
+reachable XAR runtime). Unit-level coverage of the dictionary shape, the per-symbol
+try/catch, and the multi-device prefixing lives in `TwinCATDeviceDiagnosticsTests` —
+the `FakeTwinCATClient.SetSystemSymbolValue` helper drives the surface deterministically.
+
 ## Follow-up candidates
 
-Deferred to v3 — see [`docs/v3/twincat-backlog.md`](../v3/twincat-backlog.md).
+1. **XAR VM live-population** — scaffolding is in place (this PR); the
-Covers TC2 coverage, notification-coalescing-under-load, multi-hop AMS,
+   remaining work is operational: stand up the Hyper-V VM, install XAR,
-license-rotation automation, and a dedicated lab IPC.
+   author the `.tsproj` per `TwinCatProject/README.md`, configure the
+   bilateral ADS route, set `TWINCAT_TARGET_HOST` + `TWINCAT_TARGET_NETID`
+   on the dev box. Then the three smoke tests transition skip → pass.
+   Tracked as #221.
+2. **License-rotation automation** — XAR's 7-day trial expires on
+   schedule. Either automate `TcActivate.exe /reactivate` via a
+   scheduled task on the VM (not officially supported; reportedly works
+   for some TC3 builds), or buy a paid runtime license (~$1k one-time
+   per runtime per CPU) to kill the rotation. The doc at
+   `TwinCatProject/README.md` §License rotation walks through both.
+3. **Lab rig** — cheapest IPC (CX7000 / CX9020) on a dedicated network;
+   the only route that covers TC2 + real EtherCAT I/O timing + cycle
+   jitter under CPU load.
 
 ## Key fixture / config files
 
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/TwinCATXarFixture.cs`
   — TCP probe + skip-attributes + env-var parsing
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/TwinCAT3SmokeTests.cs`
-  — wire-level test suite (14 `[TwinCATFact]` + 16-case `[TwinCATTheory]`)
+  — three wire-level smoke tests
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/TwinCatProject/README.md`
   — project spec + VM setup + license-rotation notes
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/FakeTwinCATClient.cs` —
-  in-process fake with the notification-fire harness
+  in-process fake with the notification-fire harness used by
-- `src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT/TwinCATDriver.cs` — ctor is
+  `TwinCATNativeNotificationTests`
-  `(TwinCATDriverOptions, string driverInstanceId, ITwinCATClientFactory? = null)`
+- `src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT/TwinCATDriver.cs` — ctor takes
+  `ITwinCATClientFactory`

docs/drivers/TwinCAT.md

@@ -0,0 +1,115 @@
+# TwinCAT driver — operator guide
+
+Beckhoff TwinCAT 2 / TwinCAT 3 ADS driver. Talks to the runtime via
+`Beckhoff.TwinCAT.Ads` v6 (managed); requires a reachable AMS router on
+the host (local TwinCAT XAR, the standalone `Beckhoff.TwinCAT.Ads.TcpRouter`
+NuGet, or any Windows box with TwinCAT installed and an authorised AMS
+route).
+
+## Configuration surface
+
+`TwinCATDriverOptions` (one instance supports N AMS targets, each a
+`TwinCATDeviceOptions`). Wire format mirrors the C# class on the JSON
+side — every `init`-only property round-trips through
+`System.Text.Json` with the default options.
+
+| Option | Type | Default | Notes |
+| --- | --- | --- | --- |
+| `Devices` | `TwinCATDeviceOptions[]` | `[]` | One entry per AMS target. |
+| `Tags` | `TwinCATTagDefinition[]` | `[]` | Pre-declared symbol set. |
+| `Probe.Enabled` | `bool` | `true` | Per-tick `ReadStateAsync` against the runtime. |
+| `Probe.Interval` | `TimeSpan` | `5 s` | |
+| `Timeout` | `TimeSpan` | `2 s` | Per-operation timeout. |
+| `UseNativeNotifications` | `bool` | `true` | False = fall through to PollGroupEngine. |
+| `EnableControllerBrowse` | `bool` | `false` | Walk symbol table on `DiscoverAsync`. |
+| `MaxArrayExpansion` | `int` | `1024` | Per-element cutoff during nested-UDT browse. |
+| `EnableAlarms` (PR 5.1) | `bool` | `false` | Opt-in TC3 EventLogger bridge — see "Alarms" below. |
+
+## Alarms (TC3 EventLogger bridge, PR 5.1 / #316)
+
+When `EnableAlarms=true`, the driver implements `IAlarmSource` by
+opening a second `AdsClient` against AMS port **110**
+(`AMSPORT_EVENTLOG`) and adding a device notification on
+`ADSIGRP_TCEVENTLOG_ALARMS`. Subscribers receive `OnAlarmEvent`
+notifications for every transition the EventLogger surfaces (raise /
+clear / acknowledge).
+
+### Decode caveat
+
+Beckhoff doesn't ship a managed wrapper for `TcEventLogger` in the
+regular `Beckhoff.TwinCAT.Ads` v6 NuGet — only the C++ TcCOM headers
+exist. The driver therefore decodes the AMS-port-110 binary payload
+manually. The current implementation is best-effort: event class GUIDs
+and source names usually decode cleanly; some less-common fields may
+surface as `"Unknown"` until a follow-up PR lands a complete decoder.
+Spike output captured at
+[`docs/v3/twincat-eventlogger-spike.md`](../v3/twincat-eventlogger-spike.md).
+
+### Wire path
+
+| Layer | What it does |
+| --- | --- |
+| Primary `AdsClient` | The existing per-device session against the PLC runtime port (default `851`) — handles reads / writes / native subscriptions. |
+| Secondary `AdsClient` (alarms) | Opens against AMS port `110` on the same target NetId. Adds one device notification on `ADSIGRP_TCEVENTLOG_ALARMS` with a `length=...` payload covering the full alarm-list shape. |
+| `ITwinCATAlarmGate` (driver-internal) | Decodes incoming notifications into `TwinCATAlarmEvent` records (`EventClass`, `Source`, `Severity`, `Message`, `OccurrenceUtc`, `Acked`). |
+| `TwinCATAlarmSource` | Projects `TwinCATAlarmEvent` onto the driver-agnostic `IAlarmSource.OnAlarmEvent`. |
+
+### Severity mapping (TC3 → OPC UA AC)
+
+TC3 EventLogger severity is a 0–255 `USINT`. The driver maps it onto
+the four-bucket `AlarmSeverity` enum the OPC UA AC layer consumes:
+
+| TC3 severity | `AlarmSeverity` |
+| --- | --- |
+| 0–64 | `Low` |
+| 65–128 | `Medium` |
+| 129–192 | `High` |
+| 193–255 | `Critical` |
+
+### Acknowledge
+
+`AcknowledgeAsync` round-trips through `ITwinCATAlarmGate.AcknowledgeAsync`,
+which writes to the EventLogger ack index group. Best-effort — the wire
+format isn't documented in managed code, so individual ack failures don't
+poison the batch and the gate returns silently when the EventLogger isn't
+configured.
+
+### Disabling
+
+`EnableAlarms=false` (default) returns a sentinel handle from
+`SubscribeAlarmsAsync` and never opens the secondary `AdsClient`.
+`OnAlarmEvent` simply never fires. Capability negotiation still works,
+which is why the driver advertises `IAlarmSource` unconditionally.
+
+## CLI
+
+The `otopcua-twincat-cli` test client exposes an `alarms` subcommand
+that wraps the bridge end-to-end:
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli -- alarms `
+    --ams-net-id 5.23.91.23.1.1 --ams-port 851 `
+    --source Conveyor1.MotorOverload
+```
+
+See [`docs/Driver.TwinCAT.Cli.md`](../Driver.TwinCAT.Cli.md) for the
+full CLI surface.
+
+## Test coverage
+
+- **Unit**: `TwinCATAlarmSourceTests` covers (a) feature-gating off vs.
+  on, (b) gate-event projection shape, (c) multi-event ordering, (d)
+  source-filter matching, (e) acknowledge round-trip, (f) JSON DTO
+  round-trip.
+- **Integration**: `TwinCATAlarmIntegrationTests.Driver_raises_alarm_event_when_PLC_logs_event`
+  ships build-only in PR 5.1; the GVL + FB_AlarmHarness ship as XAE
+  stubs at `tests/.../TwinCatProject/PLC/`. Once the XAR project
+  imports them the test transitions skip → pass.
+
+## See also
+
+- [`docs/v3/twincat-eventlogger-spike.md`](../v3/twincat-eventlogger-spike.md)
+  — spike output for the managed-wrapper question
+- [`docs/drivers/TwinCAT-Test-Fixture.md`](TwinCAT-Test-Fixture.md)
+  — coverage map + capability matrix
+- [`docs/Driver.TwinCAT.Cli.md`](../Driver.TwinCAT.Cli.md) — CLI guide

docs/featuregaps.md

@@ -0,0 +1,20 @@
+# Feature gaps — driver-side limitations and decisions
+
+Cross-driver registry of known capability gaps, the workaround we ship, and
+whether the gap is on the roadmap. Each row links to the driver-specific
+deep-dive document. Closed entries stay in the table for traceability — they
+are not deleted, only marked.
+
+| # | Driver | Gap | Status | Workaround / decision | Roadmap | Reference |
+|---|--------|-----|--------|-----------------------|---------|-----------|
+| 1 | S7 | **Optimized DB / S7Plus** — S7netplus speaks classic S7comm only and cannot read S7-1200 / S7-1500 DBs that have "Optimized block access" checked (the TIA Portal V14+ default). Absolute-offset reads against an Optimized DB return `BadDeviceFailure`. | **Decided — Track 1 + Track 3 (closed by [#304](https://github.com/dohertj2/lmxopcua/issues/304))** | **Track 1 (docs):** operators uncheck "Optimized block access" in TIA Portal on every DB the driver reads, recompile, and download. **Track 3 (bridge):** for shops that won't or can't disable Optimized access, run an `OpcUaClient` driver instance against the S7-1500 V2.5+ CPU's onboard OPC UA server (Siemens runtime OPC UA license required). | **Track 2 (custom S7Plus library) is out of scope** unless a customer funds the ≥4-week initial implementation plus ongoing protocol-revision maintenance. Sharp7 / Snap7Net don't help — they are also classic-S7comm-only. | [`docs/v2/s7.md` § Optimized DB constraint](v2/s7.md#optimized-db-constraint-s7plus) · [`docs/drivers/OpcUaClient.md`](drivers/OpcUaClient.md) |
+
+## How to read this table
+
+- **Status** is one of `Open` (work pending), `Decided` (architectural
+  decision made; docs reflect it; no code change planned), or
+  `Closed` (delivered).
+- **Roadmap** captures whether the gap is funded for the next phase. A blank
+  cell means "no roadmap; doc-only outcome."
+- The numeric **#** is stable — new rows append at the bottom and keep their
+  number across deletions/edits so cross-references survive.

docs/v2/decisions.md

@@ -0,0 +1,73 @@
+# Decisions
+
+Architecture-level decisions taken during the v2 implementation, captured
+once and referenced from feature docs / PR descriptions / ADR-style
+follow-ups. Each entry lists the decision, the alternatives we considered,
+and the rationale that tipped the call.
+
+## FOCAS write-path opt-in
+
+**Issue:** [#268](https://github.com/dohertj2/lmxopcua/issues/268). **Plan PR:** F4-a.
+
+### Decision
+
+The FOCAS driver ships writes behind two independent opt-ins, both default
+off:
+
+1. **Driver-level master switch** — `FocasDriverOptions.Writes.Enabled`,
+   default `false`. When off, every entry in a `WriteAsync` batch short-
+   circuits to `BadNotWritable` with status text `writes disabled at
+   driver level`. The wire client is never touched.
+2. **Per-tag opt-in** — `FocasTagDefinition.Writable`, default `false`
+   (flipped from `true` in F4-a). A `Writable = false` tag returns
+   `BadNotWritable` even when the driver-level flag is on.
+
+`BadNotSupported` is reserved for kinds the wire client hasn't yet
+implemented; F4-b/c land actual macro / parameter / PMC writes that
+currently dispatch to `BadNotSupported` (or to `Good` against the F4-a
+fake) for unimplemented branches.
+
+### Alternatives considered
+
+- **Always-on writes (the pre-F4-a default).** Rejected: a single
+  misconfigured tag flipping `Writable = true` by accident would let an
+  operator overwrite a CNC parameter from any OPC UA client. The two-
+  opt-in posture means an accidental tag flip alone isn't enough.
+- **Driver-level switch only.** Rejected: doesn't protect against an
+  operator with admin rights flipping the master switch to do bulk diag
+  reads but inheriting write capability for tags that were intended
+  read-only.
+- **Per-tag opt-in only.** Rejected: doesn't give the deployment an "all
+  writes off" emergency lever — useful during a CNC commissioning where
+  writes are unsafe across the board for a period.
+
+### Rationale
+
+CNC writes are non-idempotent in the field's worst-case shape: feed
+overrides, M-code pulses, alarm acks, recipe-step advances. Two opt-ins
+is the cheapest defence-in-depth posture that still lets writes ship.
+Both default off so a fresh deployment is read-only — the explicit choice
+to enable writes lands at config time where it's reviewable, not at
+runtime where it's invisible.
+
+`WriteIdempotent` plumbs through `CapabilityInvoker.ExecuteWriteAsync`
+into the Polly retry pipeline; default `false` means failed writes are
+not auto-retried (plan decisions #44 / #45). Per-tag flip required for
+genuinely-idempotent writes.
+
+### CLI carve-out
+
+`otopcua-focas-cli write` sets `Writes.Enabled = true` locally for the
+lifetime of one process and synthesises a `Writable = true` tag. The CLI
+is a per-operator direct-to-CNC tool — not a long-lived process bound to
+the central config DB. Configuring the server still requires both opt-ins
+to be set explicitly in the DriverInstance JSON. The bypass is documented
+in `docs/Driver.FOCAS.Cli.md` so operators understand the asymmetry.
+
+### Migration
+
+Pre-F4-a deployments that relied on the `Writable = true` default need to
+add `"Writable": true` to every tag they intend to write + an enclosing
+`"Writes": { "Enabled": true }` block in their DriverInstance JSON.
+Bootstrap rows seeded before F4-a get `Writable = false` after upgrade —
+this is intentional; review-then-flip is the safer migration path.

docs/v2/driver-stability.md

@@ -174,7 +174,7 @@ Common contract for the proxy in the main server:
 
 Named pipes default to allowing connections from any local user. Without explicit ACLs, any process on the host machine that knows the pipe name could connect, bypass the OPC UA server's authentication and authorization layers, and issue reads, writes, or alarm acknowledgments directly against the driver host. **This is a real privilege-escalation surface** — a service account with no OPC UA permissions could write field values it should never have access to. Every Tier C driver enforces the following:
 
-1. **Pipe ACL**: the host creates the pipe with a `PipeSecurity` ACL that grants `ReadWrite | Synchronize` only to the OtOpcUa server's service principal SID. `LocalSystem` is explicitly denied. The ACL is set at pipe-creation time so it's atomic with the pipe being listenable. Administrators are **not** added to the deny list — UAC's filtered token carries the Admins group SID as deny-only, so a deny ACE on Administrators would fire even for non-elevated callers whose user account happens to be a member (common on dev boxes). The per-connection SID check in §2 remains the authorization boundary.
+1. **Pipe ACL**: the host creates the pipe with a `PipeSecurity` ACL that grants `ReadWrite | Synchronize` only to the OtOpcUa server's service principal SID. All other local users — including LocalSystem and Administrators — are explicitly denied. The ACL is set at pipe-creation time so it's atomic with the pipe being listenable.
 2. **Caller identity verification**: on each new pipe connection, the host calls `NamedPipeServerStream.GetImpersonationUserName()` (or impersonates and inspects the token) and verifies the connected client's SID matches the configured server service SID. Mismatches are logged and the connection is dropped before any RPC frame is read.
 3. **Per-message authorization context**: every RPC frame includes the operation's authenticated OPC UA principal (forwarded by the Core after it has done its own authn/authz). The host treats this as input only — the driver-level authorization (e.g. "is this principal allowed to write Tune attributes?") is performed by the Core, but the host's own audit log records the principal so post-incident attribution is possible.
 4. **No anonymous endpoints**: the heartbeat pipe has the same ACL as the data-plane pipe. There are no "open" pipes a generic client can probe.

docs/v2/focas-deployment.md

@@ -0,0 +1,321 @@
+# FOCAS deployment guide
+
+Per-driver runbook for deploying the FANUC FOCAS driver. See
+[`docs/drivers/FOCAS.md`](../drivers/FOCAS.md) for the per-feature
+reference and [`focas-version-matrix.md`](./focas-version-matrix.md) for
+the per-CNC-series capability surface.
+
+## Operator config-knob cheat sheet
+
+| Knob | Where | Default | Notes |
+| --- | --- | --- | --- |
+| `Devices[].HostAddress` | `FocasDriverOptions.Devices` | — | `focas://{ip}[:{port}]` |
+| `Devices[].Series` | `FocasDriverOptions.Devices` | `Unknown` | Drives per-series range validation in `FocasCapabilityMatrix`. |
+| `Devices[].OverrideParameters` | `FocasDriverOptions.Devices` | `null` | MTB-specific parameter numbers for Feed/Rapid/Spindle/Jog overrides. `null` suppresses the `Override/` subtree. |
+| `Probe.Enabled` | `FocasDriverOptions.Probe` | `true` | Background reachability probe. |
+| `Probe.Interval` | `FocasDriverOptions.Probe` | `00:00:05` | Probe cadence. |
+| `FixedTree.ApplyFigureScaling` | `FocasDriverOptions.FixedTree` | `true` | Divide position values by 10^decimal-places (issue #262). |
+| **`AlarmProjection.Mode`** | **`FocasDriverOptions.AlarmProjection`** | **`ActiveOnly`** | **`ActiveOnly` keeps today's behaviour. `ActivePlusHistory` polls `cnc_rdalmhistry` on connect + on `HistoryPollInterval` ticks (issue #267, plan PR F3-a).** |
+| **`AlarmProjection.HistoryPollInterval`** | **`FocasDriverOptions.AlarmProjection`** | **`00:05:00`** | **Cadence of the history poll. Operator dashboards run the default; high-frequency rigs can drop to 30 s.** |
+| **`AlarmProjection.HistoryDepth`** | **`FocasDriverOptions.AlarmProjection`** | **`100`** | **Most-recent-N ring-buffer entries pulled per poll. Hard-capped at `250` so misconfigured values can't blast the wire session.** |
+
+## Sample `appsettings.json` snippet for `ActivePlusHistory`
+
+```jsonc
+{
+  "Drivers": {
+    "FOCAS": {
+      "Devices": [
+        { "HostAddress": "focas://10.0.0.5:8193", "Series": "Series30i" }
+      ],
+      "AlarmProjection": {
+        "Mode": "ActivePlusHistory",
+        "HistoryPollInterval": "00:05:00",
+        "HistoryDepth": 100
+      }
+    }
+  }
+}
+```
+
+The history projection emits each unseen entry through
+`IAlarmSource.OnAlarmEvent` with `SourceTimestampUtc` set from the CNC's
+reported wall-clock — keep CNC clocks on UTC so the dedup key
+`(OccurrenceTime, AlarmNumber, AlarmType)` stays stable across DST
+transitions.
+
+## Derived telemetry — issue #272 (plan PR F5-a)
+
+The `Production/` subtree gains two **derived** nodes alongside the four
+F1-b wire-sourced fields:
+
+- `Production/LastCycleSeconds` (`Float64`)
+- `Production/LastCycleStartUtc` (`DateTime` UTC)
+
+**No new wire calls.** Both nodes are computed client-visible from the
+same `cnc_rdparam(6711)` + `cnc_rdtimer` poll the F1-b projection
+already runs on every probe tick. There is no per-device knob — the
+nodes are present for every CNC the driver connects to and surface
+`null` until the second observed parts-count increment produces the
+first delta.
+
+This means:
+
+- **No additional CNC load.** Probe-tick wire traffic is unchanged.
+- **No new opt-in.** The nodes ship enabled by default and are
+  read-only (`SecurityClassification.ViewOnly`); no LDAP group needs
+  the new permission.
+- **Reconnect re-baselines.** Per the FWLIB session boundary the
+  derivation state resets on reconnect / reinit, so the first cycle
+  observed after a reconnect re-establishes the baseline before
+  publishing the first post-reconnect delta.
+
+See [`docs/drivers/FOCAS.md`](../drivers/FOCAS.md) § "Fixed-tree
+`Production/` projection" for the full edge-case behaviour matrix
+(parts-count counter reset, cycle-timer rollover, parts-count jumps
+> 1).
+
+## Write safety — issue #269 (PARAM/MACRO, F4-b) + issue #270 (PMC, F4-c)
+
+The FOCAS driver supports `cnc_wrparam`, `cnc_wrmacro`, and `pmc_wrpmcrng`
+writes behind multiple independent opt-ins. A misdirected parameter write
+can put the CNC in a bad state; a misdirected PMC write can move motion or
+latch a feedhold. The runbook below MUST be followed before flipping any
+of the granular kill switches on.
+
+### Operator pre-checks (every deployment, every change)
+
+1. **CNC must be in MDI mode.** Most parameter writes fail with `EW_PASSWD`
+   (surfaces as `BadUserAccessDenied`) unless the CNC is in MDI. The
+   server-side write returns immediately with the access-denied status; no
+   value reaches the wire.
+2. **Parameter-write switch enabled on the CNC pendant.** Even in MDI mode
+   protected parameters require the operator to physically enable the
+   parameter-write switch. Without it `cnc_wrparam` returns `EW_PASSWD`.
+   Plan PR F4-d will land an OPC UA-side unlock workflow; today the only
+   path is the pendant.
+3. **Verify each tag's address against the FANUC manual.** Ranges vary per
+   CNC series; the
+   [`focas-version-matrix`](./focas-version-matrix.md) capability matrix
+   rejects out-of-range numbers at startup, but address-vs-meaning is the
+   operator's job.
+4. **Dry run with `Writable = true` but `Writes.AllowParameter = false`.**
+   Staged opt-in catches mis-mapped tags: every PARAM write returns
+   `BadNotWritable` until you flip the granular flag, so you can confirm
+   the tag list before any wire write fires.
+
+### PMC pre-checks (in addition to the above) — F4-c
+
+PMC writes have a higher blast radius than PARAM/MACRO writes because PMC
+is the ladder's working memory — bits in R/G/F/D directly drive servo
+enables, feedhold latches, and safety interlocks. Before flipping
+`Writes.AllowPmc` on:
+
+1. **E-stop verified live + reachable.** The first PMC write of a session
+   should be issued with the operator's hand on the e-stop. PMC writes
+   bypass the ladder's normal MDI-mode protections; a misdirected bit can
+   move motion the moment it lands on the wire.
+2. **Machine in JOG mode (or equivalent low-energy mode).** Auto / MEM
+   modes interpret PMC state immediately; JOG / MDI surface symptoms
+   slowly enough that the e-stop is the recovery path. **Never issue the
+   first PMC write of a deployment in Auto.**
+3. **Audit the PMC tag list against the ladder print-out.** `R100.3` on
+   one machine is "homing complete"; on another it's "feedhold released".
+   The driver has no way to distinguish — the ladder source is the only
+   ground truth.
+4. **Bit writes are read-modify-write — see
+   [`docs/drivers/FOCAS.md`](../drivers/FOCAS.md) "PMC bit-write read-modify-write semantics".**
+   `pmc_wrpmcrng` is byte-addressed; the driver reads the parent byte
+   first, masks the target bit, and writes the byte back. Concurrent
+   ladder writes to the same byte create a small race window. Coordinate
+   through a ladder-side handshake when this matters.
+5. **Dry run with `Writable = true` but `Writes.AllowPmc = false`.** Same
+   staged-opt-in pattern as PARAM/MACRO — confirm tag mapping before any
+   PMC byte hits the wire.
+
+### LDAP group requirements
+
+Per [`docs/security.md`](../security.md) the server-layer ACL maps
+`SecurityClassification` to LDAP groups. Post-F4-b:
+
+| Tag kind | LDAP group required |
+| --- | --- |
+| `PARAM:N` (writable) | **`WriteConfigure`** — heaviest write tier; matches commissioning roles |
+| `MACRO:N` (writable) | `WriteOperate` — standard HMI recipe / setpoint group |
+| PMC R/G/F (writable) | `WriteOperate` |
+| Read-only | `ReadOnly` |
+
+Per the `feedback_acl_at_server_layer` design note, the FOCAS driver
+declares the classification but does NOT enforce it; `DriverNodeManager`
+applies the gate before the driver's `WriteAsync` ever runs. A user
+without `WriteConfigure` who attempts a `PARAM:` write gets
+`BadUserAccessDenied` from the server with no driver-level audit entry —
+the OPC UA layer's audit log catches it.
+
+### Audit-log expectations
+
+Every successful write produces:
+
+- An OPC UA AuditWriteEvent (server layer — see
+  [`docs/security.md`](../security.md) "Audit logging").
+- A FOCAS driver-level Serilog entry tagged `Driver=FOCAS DriverInstanceId=...
+  TagName=... Address=... ResultStatus=...`.
+- A `Writes/LastWriteAt` and `Writes/LastWriteStatus` diagnostic counter
+  refresh on the device's `Diagnostics/` fixed-tree node (planned;
+  populated as F4-c lands).
+
+Failures to write (`BadUserAccessDenied`, `BadCommunicationError`, etc.)
+produce the same audit entries with the failure status code so a
+post-incident reviewer sees the same shape regardless of whether the write
+succeeded.
+
+**Audit PMC writes specifically.** Because PMC writes have the highest blast
+radius of the three write kinds, ops should set up a saved-search /
+dashboard query for `Driver=FOCAS` + `Address` matching the PMC letter
+prefixes (`R*`, `G*`, `F*`, `D*`, `Y*`, etc.) and review on the same
+cadence as ladder change reviews. A spike in PMC write rate or a write
+to an address outside the audited tag list is the leading indicator of a
+misconfigured client or compromised credential.
+
+### Granular config example
+
+```jsonc
+{
+  "Drivers": {
+    "FOCAS": {
+      "Devices": [
+        { "HostAddress": "focas://10.0.0.5:8193", "Series": "Series30i" }
+      ],
+      "Writes": {
+        "Enabled": true,
+        "AllowMacro": true,        // recipe / setpoint writes — operator role
+        "AllowParameter": false,   // commissioning only — keep locked except during planned work
+        "AllowPmc": false          // PMC writes — keep locked unless the deployment specifically needs them
+      },
+      "Tags": [
+        { "Name": "Recipe.PartCount", "DeviceHostAddress": "focas://10.0.0.5:8193",
+          "Address": "MACRO:500", "DataType": "Int32",
+          "Writable": true, "WriteIdempotent": true },
+        { "Name": "MaxFeedrate", "DeviceHostAddress": "focas://10.0.0.5:8193",
+          "Address": "PARAM:1815", "DataType": "Int32",
+          "Writable": false   /* keep read-only until commissioning window */ },
+        { "Name": "OperatorRequest", "DeviceHostAddress": "focas://10.0.0.5:8193",
+          "Address": "R100.3", "DataType": "Bit",
+          "Writable": false   /* keep PMC read-only until ladder handshake reviewed */ }
+      ]
+    }
+  }
+}
+```
+
+Flipping `AllowParameter` / `AllowPmc` on for the commissioning window
+(and back off afterward) is the recommended deployment cadence — the
+granular kill switches are lightweight runtime toggles, not config-DB
+redeploys. PMC in particular should default OFF in production and only
+flip on for windows where the ladder team has signed off on the write
+path.
+
+## FOCAS password handling — issue #271 (F4-d)
+
+Some controllers (16i + certain 30i firmwares with parameter-protect on)
+gate `cnc_wrparam` and selected reads behind a connection-level password.
+The driver supports this via the `Password` field on `FocasDeviceOptions`
+which is emitted via `cnc_wrunlockparam` on connect and re-emitted on any
+`EW_PASSWD` read/write retry path. See
+[`docs/drivers/FOCAS.md`](../drivers/FOCAS.md) § "FOCAS password" for the
+driver-side behaviour; this section covers the deployment side.
+
+### Storage in `appsettings.json`
+
+```jsonc
+{
+  "Drivers": {
+    "Focas01": {
+      "DriverConfigJson": {
+        "Backend": "fwlib",
+        "Series": "Sixteen_i",
+        "Devices": [
+          {
+            "HostAddress": "focas://10.0.0.5:8193",
+            "Password": "1234"
+          }
+        ]
+      }
+    }
+  }
+}
+```
+
+For dev environments, the password is materialised under
+`.local/focas-passwords.txt` (or whichever .local subkey the deployment
+team prefers); production deployments use the same secrets-store /
+KeyVault pattern the LDAP `Authentication.Ldap.Password` field follows.
+**The `.local/` directory is .gitignore'd** — this is the same posture
+as `.local/galaxy-host-secret.txt` and other dev secrets in this repo.
+
+### No-log invariant
+
+The driver guarantees the password is **never logged**:
+
+1. **`FocasDeviceOptions` ToString redaction.** The record overrides
+   `PrintMembers` so any Serilog destructure of the device options renders
+   `Password = ***` when the field is non-null. This catches the most
+   common leak path — a structured-log statement that included
+   `{@Device}` for diagnostic context.
+2. **No password in exception messages.** `FwlibFocasClient.UnlockAsync`
+   omits the password from its `InvalidOperationException` text — only
+   the FWLIB error code (`EW_PASSWD`, `EW_HANDLE`, etc.) makes it through.
+3. **Driver log line uses host only.** When unlock succeeds the driver
+   updates `DriverHealth.StatusText` to `"FOCAS unlock applied for
+   {host}"` — no password.
+4. **CLI flag covered by the same choke point.** The
+   `Driver.FOCAS.Cli --cnc-password` flag flows through
+   `FocasDeviceOptions.Password`, so its redaction is identical to the
+   server's. The PowerShell e2e harness (`scripts/e2e/test-focas.ps1
+   -CncPassword`) follows the same path.
+
+Any new logging surface that touches `FocasDeviceOptions` MUST continue
+to use the record's `ToString` (or otherwise omit `Password`). A code
+review checklist item: "no log statement contains `device.Options.Password`
+or `device.Password` directly."
+
+### Password-rotation runbook
+
+When the CNC password rotates (operator team flipped a parameter-protect
+gate, or your security policy requires periodic rotation):
+
+1. **Update the password on the controller** (CNC pendant or vendor's
+   admin tool). The exact path varies by series — Fanuc service manual
+   page reference depends on the MTB.
+2. **Update `appsettings.json`** in place with the new value.
+   - Production: bump the secrets-store entry that backs the
+     `Devices[*].Password` config-DB column. Same workflow as rotating
+     the LDAP service-account password.
+   - Dev: update `.local/focas-passwords.txt` (or wherever the dev
+     deployment sources the secret).
+3. **Restart the OtOpcUa server** (or trigger a config-DB bump that
+   forces driver reinitialise). The driver picks up the new password
+   on the next `EnsureConnectedAsync` call. **No need to manually
+   reconnect each device** — `cnc_wrunlockparam` emits on the next
+   wire-call boundary.
+4. **Verify**. The first wire call after restart logs
+   `"FOCAS unlock applied for focas://{host}:{port}"` at info. A wrong
+   password surfaces as `BadUserAccessDenied` on the next gated read or
+   write.
+5. **Audit.** OPC UA wrote-event entries (per
+   [`audit-log-rules.md`](audit-log-rules.md)) cover the
+   parameter/macro write paths. Password rotation itself is NOT logged
+   beyond "unlock applied" — same posture as LDAP service-account
+   rotation, where the password change is logged out-of-band by the IAM
+   system.
+
+### Cross-references
+
+- [`docs/Security.md`](../Security.md) — server-wide secrets handling +
+  the same `.local/` pattern used for LDAP and the Galaxy.Host pipe
+  secret. The FOCAS password follows the same posture.
+- [`docs/drivers/FOCAS.md`](../drivers/FOCAS.md) § "FOCAS password" —
+  driver-side behaviour, EW_PASSWD retry semantics, status-code
+  surface.
+- [`docs/v2/implementation/focas-wire-protocol.md`](implementation/focas-wire-protocol.md)
+  § "cnc_wrunlockparam" — wire-frame layout for the password buffer.

docs/v2/focas-version-matrix.md

@@ -6,7 +6,7 @@ enforces at driver init time. Every row cites the Fanuc FOCAS Developer
 Kit function whose documented input range determines the ceiling.
 
 **Why this exists** — we have no FOCAS hardware on the bench and no
-working simulator. FWLIB (Fwlib64, or Fwlib32 on legacy deployments) returns `EW_NUMBER` / `EW_PARAM` when you
+working simulator. Fwlib32 returns `EW_NUMBER` / `EW_PARAM` when you
 hand it an address outside the controller's supported range; the
 driver would map that to a per-read `BadOutOfRange` at steady state.
 Catching at `InitializeAsync` with this matrix surfaces operator
@@ -140,6 +140,6 @@ matrix: Macro variable #50000 is outside the documented range
 This validation closes the cheap half of the FOCAS hardware-free
 stability gap — config errors now fail at load instead of per-read.
 The expensive half is Tier-C process isolation so that a crashing
-`Fwlib64.dll` doesn't take the main OPC UA server down with it. See
+`Fwlib32.dll` doesn't take the main OPC UA server down with it. See
 [`docs/v2/implementation/focas-isolation-plan.md`](implementation/focas-isolation-plan.md)
 for that plan (task #220).

docs/v2/implementation/admin-ui-phase-6-status.md

@@ -1,38 +0,0 @@
-# Admin UI Phase 6 status audit (2026-04-24)
-
-Audit pass that closes the Phase 6 Admin-UI tasks that were tracked as still-open (#128–#131) but already had their Blazor pages shipped. Every page listed below compiles against the current `OtOpcUaConfigDbContext` schema + the current Admin service surface, has substantive (non-stub) content, and is covered by `ZB.MOM.WW.OtOpcUa.Admin.Tests` (112/112 green).
-
-## Task #128 — /hosts column refresh (Phase 6.1 Stream E.2/E.3)
-
-`Components/Pages/Hosts.razor` — 233 LOC. Route `/hosts`. Ships:
-
-- Per-driver circuit-breaker columns (`ConsecutiveFailures`, `LastCircuitBreakerOpenUtc`).
-- Stale-row detection via `HostStatusService.IsStale` (publisher heartbeat ≥ 30 s stale threshold).
-- Summary cards: Running / Stale / Faulted / total.
-- Auto-refresh every `RefreshIntervalSeconds` driven by the `FleetStatusHub` SignalR feed.
-- Health band via `DriverHostState` enum colour coding.
-
-## Task #129 — RoleGrantsTab + AclsTab + Probe (Phase 6.2 Stream D)
-
-- `Components/Pages/RoleGrants.razor` — 192 LOC. Route `/role-grants`. Edits LDAP-group → OPC-UA-role mappings with live reload over `AclChangeNotifier` SignalR.
-- `Components/Pages/Clusters/AclsTab.razor` — 279 LOC. NodeAcl CRUD + the **"Probe this permission"** form (task #196 slice 1, embedded at line 38 onward). Binds `_probeGroup` / `_probeNamespaceId` / `_probeUnsAreaId` / `_probeUnsLineId` / `_probeEquipmentId` / `_probeTagId` / `_probePermission` through `PermissionProbeService`.
-
-## Task #130 — RedundancyTab (Phase 6.3 Stream E)
-
-`Components/Pages/Clusters/RedundancyTab.razor` — 175 LOC. Topology table, per-peer reachability (via `FleetStatusHub`), ServiceLevel band + `ApplyLeaseRegistry` / `RecoveryStateManager` state surfaces, failover action button. Live updates over the same SignalR hub `RedundancyPublisherHostedService` ticks.
-
-## Task #131 — Draft / publish / diff / identification (Phase 6.4 Streams A–D)
-
-- `Components/Pages/Clusters/DraftEditor.razor` — 105 LOC. Route `/clusters/{ClusterId}/draft/{GenerationId:long}`. Calls `DraftValidationService` + `GenerationService`.
-- `Components/Pages/Clusters/Generations.razor` — 73 LOC. Publish flow (generation state transitions through `sp_PublishGeneration`).
-- `Components/Pages/Clusters/DiffViewer.razor` — 87 LOC. Route `/clusters/{ClusterId}/draft/{GenerationId:long}/diff`. Renders `sp_ComputeGenerationDiff` output.
-- `Components/Pages/Clusters/IdentificationFields.razor` — 49 LOC. OPC 40010 Identification folder editor bound to the `Equipment` entity.
-
-## What's NOT in this audit
-
-- `#124` — Phase 6.2 3-user interop matrix. Authz layer is now covered by `ThreeUserInteropMatrixTests` in `ZB.MOM.WW.OtOpcUa.Server.Tests` (drives the 5 GLAuth users + admin through `LdapUserAuthenticator` → `AuthorizationGate.IsAllowed` for the role × operation matrix). The wire-level OPC UA-client cross-vendor leg still needs a UserName-token endpoint policy + manual client drill — that part stays a manual deliverable.
-- `#119` — Phase 6.3 client interop matrix. Manual Ignition/Kepware/Aveva drills.
-- `#113` — OPC UA CTT conformance pass. Manual CTT run.
-- `#114` / `#115` — Redundancy cutover + deployment checklist. Manual.
-
-Those remain GA-gating but require a human at a console, not a code change.

docs/v2/implementation/exit-gate-phase-3.md

@@ -1,129 +0,0 @@
-# Phase 3 Exit Gate — Driver Fleet (reconstructed retroactively)
-
-> **Status**: **CLOSED (reconstructed 2026-04-23)**. The original plan split the
-> driver work across Phases 3 / 4 / 5 (Modbus alone → four PLC drivers → two
-> specialty drivers). In execution, all seven non-Galaxy drivers shipped under
-> one umbrella against `Core.Abstractions` + `Core`'s generic driver-hosting
-> machinery. This doc captures the closure retroactively; no forward work
-> remains under these three original phase numbers.
->
-> **Plan doc**: none — phases 3/4/5 were intentionally not split out into
-> separate plan docs once it was clear the capability-interface contract
-> introduced in Phase 1 (`Core.Abstractions` — plan decision #4) was stable
-> enough that each driver could land as its own stream rather than as a
-> gated mini-phase. See `docs/v2/plan.md` §6 for the now-consolidated
-> migration strategy.
-
-## Scope
-
-All seven drivers in the v2 target list (Decision #5) minus Galaxy (closed
-separately under Phase 2). The Galaxy Proxy+Host+Shared split exited under
-`exit-gate-phase-2-final.md`; this gate does not re-cover it.
-
-## What shipped
-
-### Drivers
-
-| Driver | Project | Capability surface | Test projects |
-|---|---|---|---|
-| Modbus TCP | `Driver.Modbus` + `Driver.Modbus.Cli` | `IDriver` + `ITagDiscovery` + `IReadable` + `IWritable` + `ISubscribable` + `IHostConnectivityProbe` | `Tests`, `IntegrationTests`, `Cli.Tests` |
-| AB CIP | `Driver.AbCip` + `Driver.AbCip.Cli` | all of the above + `IPerCallHostResolver` + `IAlarmSource` | `Tests`, `IntegrationTests`, `Cli.Tests` |
-| AB Legacy (PCCC / DF1) | `Driver.AbLegacy` + `Driver.AbLegacy.Cli` | `IDriver` + `IReadable` + `IWritable` + `ITagDiscovery` + `ISubscribable` + `IHostConnectivityProbe` + `IPerCallHostResolver` | `Tests`, `IntegrationTests`, `Cli.Tests` |
-| Siemens S7 | `Driver.S7` + `Driver.S7.Cli` | `IDriver` + `ITagDiscovery` + `IReadable` + `IWritable` + `ISubscribable` + `IHostConnectivityProbe` | `Tests`, `IntegrationTests`, `Cli.Tests` |
-| Beckhoff TwinCAT (ADS) | `Driver.TwinCAT` + `Driver.TwinCAT.Cli` | `IDriver` + `IReadable` + `IWritable` + `ITagDiscovery` + `ISubscribable` + `IHostConnectivityProbe` + `IPerCallHostResolver` | `Tests`, `IntegrationTests`, `Cli.Tests` |
-| FANUC FOCAS | `Driver.FOCAS` + `Driver.FOCAS.Host` + `Driver.FOCAS.Shared` + `Driver.FOCAS.Cli` | `IDriver` + `IReadable` + `IWritable` + `ITagDiscovery` + `ISubscribable` + `IHostConnectivityProbe` + `IPerCallHostResolver`; Tier-C out-of-process backend mirrors the Galaxy Proxy/Host split. `Fwlib64FocasBackend` shipped 2026-04-23 as the production backend (P/Invoke against `Fwlib64.dll`); Host retargeted from net48 x86 to net10.0-windows x64 at the same time. | `Tests`, `Host.Tests`, `Shared.Tests`, `Cli.Tests` |
-| OPC UA Client (gateway) | `Driver.OpcUaClient` | `IDriver` + `ITagDiscovery` + `IReadable` + `IWritable` + `ISubscribable` + `IHostConnectivityProbe` + `IAlarmSource` + `IHistoryProvider` (richest surface in the fleet — it's bridging another UA server) | `Tests`, `IntegrationTests` |
-
-### Supporting infrastructure
-
-| PR / Task | Summary |
-|---|---|
-| #248 | `DriverFactoryRegistry` + `DriverInstanceBootstrapper` — central DB `DriverInstance` rows materialise into live `IDriver` instances at server startup. |
-| #210 | Modbus server-side factory + seed SQL (closed first child of umbrella #209). |
-| #211 #212 #213 | AB CIP / S7 / AB Legacy server-side factories + seed SQL. |
-| #220 (FOCAS) | FOCAS factory wired into the bootstrap pipeline; Tier-C split (`Driver.FOCAS.Host` process launcher, named-pipe IPC, NSSM install scripts, post-mortem MMF) shipped across the five-PR series. |
-| (this session) | TwinCAT factory wired in + Server project reference added; all seven driver factories now register uniformly in `Server/Program.cs`. |
-| #249 #250 #251 | Per-driver test-client CLI suite (`otopcua-<driver>-cli`) — shared lib + one CLI per driver for direct-to-PLC smoke testing independent of the server. |
-| #253 + follow-ups | E2E CLI test scripts (`scripts/e2e/test-<driver>.ps1`) — five-stage bidirectional bridge + subscribe-sees-change assertions per driver, plus `test-all.ps1` matrix runner. |
-| (this session) | OPC UA Client e2e script shipped (`test-opcuaclient.ps1`, 8 stages) — the only driver that was missing an e2e script. |
-
-### Docs
-
-Per-driver test-fixture documentation:
-- `docs/drivers/Modbus-Test-Fixture.md`
-- `docs/drivers/AbServer-Test-Fixture.md` (covers AB CIP fixture)
-- `docs/drivers/AbLegacy-Test-Fixture.md`
-- `docs/drivers/S7-Test-Fixture.md`
-- `docs/drivers/TwinCAT-Test-Fixture.md`
-- `docs/drivers/FOCAS-Test-Fixture.md`
-- `docs/drivers/OpcUaClient-Test-Fixture.md`
-
-Driver-level ops docs:
-- `docs/Driver.Modbus.Cli.md`, `docs/Driver.AbCip.Cli.md`, `docs/Driver.AbLegacy.Cli.md`, `docs/Driver.S7.Cli.md`, `docs/Driver.TwinCAT.Cli.md`, `docs/Driver.FOCAS.Cli.md`
-- `docs/v2/driver-specs.md` — unified capability-matrix spec for all eight drivers (Galaxy + seven).
-
-## Compliance evidence
-
-No dedicated `phase-3-compliance.ps1` exists — scope was too broad to fit the
-single-script pattern that worked for Phases 6.x and 7. Verification instead
-takes the form of the per-driver test suites + e2e scripts:
-
-- [x] **Unit tests** — every driver has a `Tests` project with capability-interface contract tests; `dotnet test tests/ZB.MOM.WW.OtOpcUa.Driver.*.Tests` is green.
-- [x] **Integration tests** — `Driver.*.IntegrationTests` stands up Docker-hosted simulators (pymodbus, ab_server, python-snap7, opc-plc) at collection init and exercises real wire-level read/write/subscribe/probe per driver.
-- [x] **CLI tests** — `Driver.*.Cli.Tests` covers the per-driver test-client CLIs (#249–#251).
-- [x] **E2E scripts** — `scripts/e2e/test-<driver>.ps1` covers the driver-CLI → PLC → OtOpcUa server → OPC UA client round-trip for all seven drivers + Galaxy; `test-all.ps1` aggregates; README status section (rewritten this session) summarises live-boot evidence.
-- [x] **Factory registration** — all seven factories plus Galaxy register in `src/ZB.MOM.WW.OtOpcUa.Server/Program.cs` inside the `DriverFactoryRegistry` composition; the `DriverInstanceBootstrapper` can materialise any configured row.
-- [x] **Seed SQL** — #210–#213 provide per-driver Config DB seed scripts so a fresh Config DB is populatable without Admin UI interaction.
-
-### Live-boot verification
-
-Recorded across the session-level tracking tasks:
-
-| Driver | Fixture | Stages | Tracking |
-|---|---|---|---|
-| Modbus | pymodbus (dl205 profile) | 5/5 | #209 exit gate; bidirectional + subscribe-sees-change added in #253 follow-ups |
-| AB CIP | `ab_server` ControlLogix | 5/5 | #220 |
-| S7 | python-snap7 | 5/5 | #220 |
-| AB Legacy | `ab_server` SLC500 / MicroLogix / PLC-5 (requires `/1,0` cip-path for Docker fixture) | 5/5 | #222 partial |
-| OPC UA Client | opc-plc Docker fixture | 5/8 (probe, remote read, forward bridge, subscribe, browse) | (this session) |
-| TwinCAT | TCBSD VM @ 10.100.0.128 (AmsNetId `41.169.163.43.1.1`) — real TwinCAT runtime under FreeBSD on ESXi; bypasses the Hyper-V/RTIME conflict that blocks XAR on this dev box | features validated | fixture is the TCBSD VM; `TWINCAT_TRUST_WIRE=1` still gates the e2e script by default so unintentional runs against cold fixtures don't false-pass |
-| FOCAS | Lab-rig CNC + `Fwlib64.dll` | — | **deferred** — `Fwlib64FocasBackend` shipped 2026-04-23; wire-level live-boot gated `FOCAS_TRUST_WIRE=1`, lab rig tracked under #222 follow-up |
-| Galaxy | Live Galaxy + `OtOpcUaGalaxyHost` (this dev box) | 7/7 (read / write / subscribe / alarms / history) | closed under Phase 2 |
-
-## Deferred to post-gate follow-ups
-
-Items intentionally not blocking closure of this umbrella — each is hardware-
-dependent and tracked separately:
-
-- [ ] **FOCAS wire-level live-boot** — `test-focas.ps1` against a real CNC once `Fwlib64.dll` is on PATH and `FOCAS_TRUST_WIRE=1` (#222 follow-up). The `Fwlib64FocasBackend` shipped 2026-04-23 — code exists, unit-tests green; only the live-CNC smoke test remains.
-- [x] **FOCAS `Fwlib64FocasBackend`** — **CLOSED 2026-04-23**. The production backend in `src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Host/Backend/Fwlib64FocasBackend.cs` wraps `FwlibFocasClient` to fulfil `IFocasBackend` against the licensed `Fwlib64.dll`. Host project retargeted to `net10.0-windows` x64. Default when `OTOPCUA_FOCAS_BACKEND` is unset. 6 new backend tests green. Only wire-level live-boot against real hardware remains — see item above.
-- [ ] **OPC UA Client stages 5/7/8** — reverse-bridge, alarm, history stages are opt-in via sidecar NodeId params because opc-plc's default image has no writable nodes and doesn't historize. Against a richer upstream (Prosys, UA Expert sample server) all eight stages can run.
-
-## Completion checklist
-
-- [x] Modbus driver shipped + unit + integration + CLI tests green
-- [x] AB CIP driver shipped + tests green + live-boot 5/5
-- [x] AB Legacy driver shipped + tests green + live-boot 5/5
-- [x] S7 driver shipped + tests green + live-boot 5/5
-- [x] TwinCAT driver shipped + tests green + features validated against the TCBSD VM virtual-PLC fixture
-- [x] FOCAS driver shipped (Tier-C split) + tests green (wire-live deferred)
-- [x] OPC UA Client driver shipped + tests green + live-boot 5/8
-- [x] `DriverFactoryRegistry` + `DriverInstanceBootstrapper` shipped
-- [x] All seven factories registered in `Server/Program.cs`
-- [x] Per-driver test-client CLI suite shipped
-- [x] E2E test scripts shipped + `test-all.ps1` aggregator green
-- [x] Per-driver test-fixture docs present
-- [x] `docs/v2/driver-specs.md` unified capability spec present
-- [x] `scripts/e2e/README.md` status section reflects current live-boot matrix
-- [x] Exit gate doc checked in (this file)
-- [x] TwinCAT validated against the TCBSD VM virtual-PLC fixture — `TWINCAT_TRUST_WIRE=1` + e2e script still gated by default to prevent false-pass against cold fixtures
-- [ ] FOCAS lab-rig follow-up filed + tracked (#222)
-
-## Why no compliance script
-
-The Phases 6.1/6.2/6.3/6.4/7 pattern of a single `phase-N-compliance.ps1`
-worked because each of those phases touched a narrow slice of server-side
-runtime. A "phase-3-compliance.ps1" would have had to boot seven simulators,
-configure seven DriverInstance rows, and run seven e2e scripts — which is
-exactly what `scripts/e2e/test-all.ps1` already does. The aggregate runner
-+ its README is the compliance artefact for this umbrella.

docs/v2/implementation/exit-gate-phase-7.md

@@ -1,6 +1,6 @@
 # Phase 7 Exit Gate — Scripting, Virtual Tags, Scripted Alarms, Historian Sink
 
-> **Status**: **FULLY CLOSED** 2026-04-23 audit — the three original follow-ups (#239 / #240 / #241) were all shipped under later branches but this exit-gate doc wasn't updated at the time. All three verified against the repo + tests green.
+> **Status**: Open. Closed when every compliance check passes + every deferred item either ships or is filed as a post-v2-release follow-up.
 >
 > **Compliance script**: `scripts/compliance/phase-7-compliance.ps1`
 > **Plan doc**: `docs/v2/implementation/phase-7-scripting-and-alarming.md`
@@ -45,13 +45,13 @@ Covered by `scripts/compliance/phase-7-compliance.ps1`:
 - [x] Walker emits `NodeSourceKind.Virtual` + `NodeSourceKind.ScriptedAlarm` variables
 - [x] `DriverNodeManager` dispatch routes Reads by source; Writes to non-Driver rejected with `BadUserAccessDenied` (plan #6)
 
-## Deferred to Post-Gate Follow-ups (all closed as of 2026-04-23 audit)
+## Deferred to Post-Gate Follow-ups
 
-Originally kept out of the capstone so the gate could close cleanly. Each landed as a targeted follow-up PR; audit this session verified them against the repo:
+Kept out of the capstone so the gate can close cleanly while the less-critical wiring lands in targeted PRs:
 
-- [x] **SealedBootstrap composition root** (task #239) — **CLOSED**. `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7Composer.cs` instantiates `VirtualTagEngine` + `ScriptedAlarmEngine` via `Phase7EngineComposer.Compose`, and `SqliteStoreAndForwardSink` in `ResolveHistorianSink` when a registered driver provides `IAlarmHistorianWriter` (today: `GalaxyProxyDriver`). `OpcUaServerService.ExecuteAsync` calls `Phase7Composer.PrepareAsync` then `OpcUaApplicationHost.SetPhase7Sources` **before** `applicationHost.StartAsync` so `OtOpcUaServer` + `DriverNodeManager` capture the `VirtualReadable` / `ScriptedAlarmReadable` at construction. 38 tests green under `tests/ZB.MOM.WW.OtOpcUa.Server.Tests/Phase7/` + `SealedBootstrapIntegrationTests`. The work landed under the label "Phase 7 follow-up #246" and was never re-labelled against #239.
+- [ ] **SealedBootstrap composition root** (task #239) — instantiate `VirtualTagEngine` + `ScriptedAlarmEngine` + `SqliteStoreAndForwardSink` in `Program.cs`; pass `VirtualTagSource` + `ScriptedAlarmSource` as the new `IReadable` parameters on `DriverNodeManager`. Without this, the engines are dormant in production even though every piece is tested.
-- [x] **Live OPC UA end-to-end smoke** (task #240) — **CLOSED**. `scripts/e2e/test-phase7-virtualtags.ps1` drives a full Client.CLI read of a driver-sourced input, reads the VirtualTag computed off it, triggers a scripted alarm by writing the trigger value, and subscribes to the alarm condition — all through a running OtOpcUa server. Covered in `scripts/e2e/test-all.ps1` + `scripts/e2e/README.md` matrix.
+- [ ] **Live OPC UA end-to-end smoke** (task #240) — Client.CLI browse + read a virtual tag computed by Roslyn; Client.CLI acknowledge a scripted alarm via the Part 9 method node; historian-disabled deployment returns `BadNotFound` for virtual nodes rather than silent failure.
-- [x] **sp_ComputeGenerationDiff extension** (task #241) — **CLOSED**. Migration `20260420232000_ExtendComputeGenerationDiffWithPhase7.cs` extends the stored proc to emit Script / VirtualTag / ScriptedAlarm sections alongside the existing NodeAcl / Tag / Equipment / DriverInstance / Namespace output. Admin DiffViewer picks them up through its existing section-plugin architecture (Phase 6.4 Stream C).
+- [ ] **sp_ComputeGenerationDiff extension** (task #241) — emit Script / VirtualTag / ScriptedAlarm sections alongside the existing Namespace/DriverInstance/Equipment/Tag/NodeAcl rows so the Admin DiffViewer shows Phase 7 changes between generations.
 
 ## Completion Checklist
 
@@ -66,9 +66,9 @@ Originally kept out of the capstone so the gate could close cleanly. Each landed
 - [x] `phase-7-compliance.ps1` present and passes
 - [x] Full solution `dotnet test` passes (no new failures beyond pre-existing tolerated CLI flake)
 - [x] Exit-gate doc checked in
-- [x] `SealedBootstrap` composition follow-up shipped (#239 / Phase 7 follow-up #246)
+- [ ] `SealedBootstrap` composition follow-up filed + tracked
-- [x] Live end-to-end smoke follow-up shipped (#240 — `scripts/e2e/test-phase7-virtualtags.ps1`)
+- [ ] Live end-to-end smoke follow-up filed + tracked
-- [x] `sp_ComputeGenerationDiff` extension follow-up shipped (#241 — migration `ExtendComputeGenerationDiffWithPhase7`)
+- [ ] `sp_ComputeGenerationDiff` extension follow-up filed + tracked
 
 ## How to run
 

docs/v2/implementation/focas-isolation-plan.md

@@ -1,21 +1,10 @@
 # FOCAS Tier-C isolation — plan for task #220
 
-> **Status**: **FULLY SHIPPED** (code). PRs A–E shipped the architecture; the
+> **Status**: PRs A–E shipped. Architecture is in place; the only
-> 2026-04-23 follow-up shipped the production `Fwlib64FocasBackend` wrapping
+> remaining FOCAS work is the hardware-dependent production
-> the licensed `Fwlib64.dll`. Only the wire-level live-boot against real
+> integration of `Fwlib32.dll` into a real `IFocasBackend`
-> hardware remains (task #222 / requires a bench CNC).
+> (`FwlibHostedBackend`), which needs an actual CNC on the bench
->
+> and is tracked as a follow-up on #220.
-> **Major update 2026-04-23 — Host retargeted to .NET 10 x64 + Fwlib64**:
-> Both `Fwlib32.dll` and `Fwlib64.dll` are licensed for this project. The
-> original plan put the Host on .NET 4.8 x86 because Fwlib32 was assumed.
-> With Fwlib64 available, the Host moves to `net10.0-windows` x64 — same
-> runtime as the rest of the fleet. **Tier-C isolation stays anyway** — the
-> blast-radius argument against a closed-source vendor P/Invoke is independent
-> of bitness. Galaxy (forced x86 by MXAccess COM) is a pure bitness forcing;
-> FOCAS is a pure blast-radius choice. Body of this document still reflects
-> the original x86 assumptions in a few places — read them as historical
-> design context; the current shape is in `docs/drivers/FOCAS-Test-Fixture.md`
-> and `exit-gate-phase-3.md`.
 >
 > **Pre-reqs shipped**: version matrix + pre-flight validation
 > (PR #168 — the cheap half of the hardware-free stability gap).

docs/v2/implementation/focas-simulator-plan.md

@@ -0,0 +1,394 @@
+# FOCAS simulator (focas-mock) plan
+
+Notes on the focas-mock simulator that the FOCAS driver's integration
+tests will eventually talk to. Today there is no FOCAS integration-test
+project; this doc is the contract the future fixture will be built
+against. Keeping the contract tracked in repo means the wire-protocol
+command ids (and their request/response payloads) don't drift between the
+.NET wire client and a future Python implementation.
+
+## Ground rules
+
+- Append-only command ids. Mirror
+  [`focas-wire-protocol.md`](./focas-wire-protocol.md) verbatim.
+- Per-profile state. The simulator hosts N CNC profiles concurrently
+  (`Series0i`, `Series30i`, `PowerMotion`, ...). Each profile has its own
+  alarm-history ring buffer + its own override map.
+- Admin endpoints under `POST /admin/...` mutate state without going
+  through the wire protocol; integration tests use these to seed canned
+  inputs.
+
+## Protocol surface (current scope)
+
+| Cmd | API | State impact |
+| --- | --- | --- |
+| `0x0001` | `cnc_rdcncstat` | reads cached ODBST per profile |
+| `0x0002` | `cnc_rdparam` | reads parameter map per profile |
+| `0x0003` | `cnc_rdmacro` | reads macro variables per profile |
+| `0x0004` | `cnc_rddiag` | reads diagnostic map per profile |
+| `0x0010` | `pmc_rdpmcrng` | reads PMC byte ranges |
+| `0x0020` | `cnc_modal` | reads cached modal MSTB per profile |
+| ... | ... | ... |
+| **`0x0102`** | **`cnc_wrparam`** | **mutates per-profile parameter map; returns `EW_PASSWD` (`11`) when the profile's `unlock_state` is off (sets up F4-d's unlock workflow) — issue #269, plan PR F4-b** |
+| **`0x0103`** | **`cnc_wrmacro`** | **mutates per-profile macro map; integer-only writes for now (decimalPointCount=0) — issue #269, plan PR F4-b** |
+| **`0x0104`** | **`pmc_wrpmcrng`** | **mutates per-profile PMC byte tables; byte-aligned writes preserve untouched bytes; bit-level writes never reach the simulator (driver wraps with RMW) — issue #270, plan PR F4-c** |
+| **`0x0105`** | **`cnc_wrunlockparam`** | **flips the per-profile `unlock_state` to true when the supplied 4-byte password buffer matches the profile's `unlock_password`; otherwise returns `EW_PASSWD`. State persists for the connection lifetime (per-session). — issue #271, plan PR F4-d** |
+| **`0x0F1A`** | **`cnc_rdalmhistry`** | **dumps the per-profile alarm-history ring buffer (issue #267, plan PR F3-a)** |
+
+## `cnc_rdalmhistry` mock behaviour
+
+The simulator keeps a per-profile ring buffer of alarm-history entries.
+Default fixture seeds 5 profiles with 10 canned entries each (per the F3-a
+plan).
+
+### Request decode
+
+```
+[int16 LE depth]
+```
+
+### Response encode
+
+Use `FocasAlarmHistoryDecoder.Encode` semantics in reverse: emit the
+count followed by `ALMHIS_data` blocks padded to 4-byte boundaries. The
+.NET-side decoder consumes the same format verbatim, so a Python encoder
+written against the table in
+[`focas-wire-protocol.md`](./focas-wire-protocol.md) interoperates without
+extra glue.
+
+### Admin endpoint — `POST /admin/mock_patch_alarmhistory`
+
+Replaces the alarm-history ring buffer for a profile.
+
+```
+POST /admin/mock_patch_alarmhistory
+{
+  "profile": "Series30i",
+  "entries": [
+    {
+      "occurrenceTime": "2025-04-01T09:30:00Z",
+      "axisNo": 1,
+      "alarmType": 2,
+      "alarmNumber": 100,
+      "message": "Spindle overload"
+    },
+    ...
+  ]
+}
+```
+
+`entries` order is interpreted as ring-buffer order (most-recent first to
+match FANUC's natural surface).
+
+### `FocasSimFixture.SeedAlarmHistoryAsync`
+
+The future test-support helper wraps the admin endpoint:
+
+```csharp
+await fixture.SeedAlarmHistoryAsync(
+    profile: "Series30i",
+    entries: new []
+    {
+        new FocasAlarmHistoryEntry(
+            new DateTimeOffset(2025, 4, 1, 9, 30, 0, TimeSpan.Zero),
+            AxisNo: 1, AlarmType: 2, AlarmNumber: 100, Message: "Spindle overload"),
+    });
+```
+
+Integration test `Series/AlarmHistoryProjectionTests.cs` will assert:
+
+- historic events fire once with the seeded timestamps
+- second poll yields zero new events (dedup honoured end-to-end)
+- active-alarm raise/clear still works alongside the history poll
+
+These tests are blocked on the focas-mock + integration-test project
+landing; the unit-test coverage in `FocasAlarmProjectionTests` already
+exercises every same-process invariant.
+
+## `cnc_wrparam` / `cnc_wrmacro` mock behaviour — issue #269, plan PR F4-b
+
+When the focas-mock fixture lands, it MUST implement the contract below.
+The .NET side already ships against this contract (`FwlibFocasClient.cs`
+write helpers, `FakeFocasClient` round-trip support); writing the simulator
+to the same shape lets the existing integration-test scaffolds at
+`tests/.../IntegrationTests/Series/ParameterWriteTests.cs` and
+`MacroWriteTests.cs` (when they materialise) light up without driver
+changes.
+
+### Per-profile state
+
+Each profile owns:
+
+- `parameters: Dict[int, int]` — map from parameter number to current value.
+- `macros: Dict[int, int]` — map from macro number to current scaled-int
+  value (decimal-point count fixed at 0 for F4-b).
+- `unlock_state: bool` — defaults `False`. When `False`, every
+  `cnc_wrparam` returns `EW_PASSWD` (numeric `11`) regardless of
+  parameter. Macro writes are NOT gated by `unlock_state`.
+- `unlock_password: bytes` (4-byte buffer) — defaults to the profile's
+  fixture default (e.g. `b"1234"` for Series30i). Compared byte-for-byte
+  by the `cnc_wrunlockparam` handler; flips `unlock_state = True` on
+  match, leaves it untouched on mismatch (and returns `EW_PASSWD`).
+  Mutable via `POST /admin/mock_set_password` for tests that exercise
+  rotation. Issue #271, plan PR F4-d.
+- `last_write: Optional[LastWrite]` — most-recent successful
+  `(kind, number, value, ts)` tuple, surfaced via the admin endpoint
+  below for audit-log assertions.
+
+### `cnc_wrparam` request decode
+
+```
+[int16 LE datano][int16 LE axis][int8|int16|int32 LE value]
+```
+
+Width of the value field is determined by the request frame trailer
+length per the table in
+[`focas-wire-protocol.md`](./focas-wire-protocol.md). On
+`unlock_state == False` short-circuit to `[int16 LE 11]` (`EW_PASSWD`).
+Otherwise mutate `parameters[datano] = value`, set `last_write`, return
+`[int16 LE 0]`.
+
+### `cnc_wrmacro` request decode
+
+```
+[int16 LE number][int16 LE length=8][int32 LE mcr_val][int16 LE dec_val]
+```
+
+Always accept (no `unlock_state` gate). Mutate
+`macros[number] = mcr_val` (we ignore `dec_val` for F4-b — integer-only).
+Return `[int16 LE 0]`. Round-trip: a subsequent `cnc_rdmacro(number)`
+returns `(mcr_val, 0)`.
+
+### Admin endpoint — `POST /admin/mock_set_unlock_state`
+
+Toggles `unlock_state` for the F4-d unlock workflow tests. Without this,
+F4-b parameter-write integration tests can't reproduce the
+`EW_PASSWD` → `BadUserAccessDenied` mapping.
+
+```
+POST /admin/mock_set_unlock_state
+{ "profile": "Series30i", "unlocked": true }
+```
+
+### `cnc_wrunlockparam` request decode — issue #271, plan PR F4-d
+
+```
+[byte[4] password]
+```
+
+Match `password == profile.unlock_password` byte-for-byte. On match:
+flip `unlock_state = True`, return `[int16 LE 0]`. On mismatch: leave
+`unlock_state` untouched, return `[int16 LE 11]` (`EW_PASSWD`).
+
+The simulator deliberately keeps unlock state per-session (per OpenSession
+handle) so a reconnect drops back to `unlock_state = False` — matching the
+FWLIB lifetime semantics described in
+[`focas-wire-protocol.md`](./focas-wire-protocol.md) § "cnc_wrunlockparam".
+
+### Admin endpoint — `POST /admin/mock_set_password`
+
+Rotates the per-profile `unlock_password` for tests that exercise the
+F4-d password-rotation runbook (`docs/v2/focas-deployment.md`
+§ "FOCAS password handling"). Idempotent — call again to revert.
+
+```
+POST /admin/mock_set_password
+{ "profile": "Series30i", "password": "5678" }
+```
+
+The endpoint accepts the password as a UTF-8/ASCII string and applies
+the same right-pad-to-4-bytes / truncate-to-4-bytes normalisation the
+driver does, so simulator-side matching is byte-symmetric with the
+production wire encoder.
+
+### Admin endpoint — `GET /admin/mock_get_last_write`
+
+Returns the simulator's view of the most-recent successful write, used by
+F4-b audit-log integration assertions ("did the write actually reach the
+fixture, and is the audit log capturing the right kind/number/value?").
+
+```
+GET /admin/mock_get_last_write?profile=Series30i
+->
+{
+  "kind": "param",            // "param" | "macro"
+  "number": 1815,
+  "value": 100,
+  "writtenAt": "2026-04-25T13:30:00Z"
+}
+```
+
+When no write has happened the endpoint returns `null` rather than 404 so
+the test helper can assert "no writes since fixture reset" without
+exception handling.
+
+## `pmc_wrpmcrng` mock behaviour — issue #270, plan PR F4-c
+
+The simulator keeps a per-profile PMC byte table keyed by `(addr_type,
+byte_address)` — the same map the existing `pmc_rdpmcrng` handler reads
+from. The write handler mutates the same map so a subsequent read sees
+the written bytes.
+
+### Per-profile state
+
+Each profile carries:
+
+```python
+pmc: Dict[int, bytearray]  # addr_type -> bytearray (one per PMC letter, default 256 bytes each)
+```
+
+`addr_type` is the PMC area code (R=5, G=4, F=3, D=8, X=1, Y=2, K=10,
+A=11, E=12, T=6, C=7); the existing `pmc_rdpmcrng` fixture seeds the
+defaults (zeros + a few canned bits per the dl205-style profile fixtures).
+
+### `pmc_wrpmcrng` request decode
+
+| Offset | Width | Field |
+| --- | --- | --- |
+| 0 | int16 LE | `addr_type` |
+| 2 | int16 LE | `data_type` (must be `0` = byte; the driver only emits byte writes) |
+| 4 | uint16 LE | `datano_s` |
+| 6 | uint16 LE | `datano_e` |
+| 8 | bytes | `data[]` — `(datano_e - datano_s + 1)` bytes |
+
+Handler steps:
+
+1. Look up the per-profile bytearray for `addr_type` (allocate on first
+   write, default 256 zeros).
+2. **Validate** `0 <= datano_s <= datano_e < len(bytearray)` — otherwise
+   return `EW_NUMBER` (`4`).
+3. **Validate** `len(data) == datano_e - datano_s + 1` — otherwise
+   return `EW_LENGTH` (`14`).
+4. **Validate** `data_type == 0` — otherwise return `EW_DATA` (`9`)
+   because the driver only ever emits byte writes (bit writes wrap with
+   driver-side RMW so they reach the simulator as 1-byte writes).
+5. Copy `data[]` into `bytearray[datano_s:datano_e+1]`. Other bytes
+   in the array are untouched.
+6. Update `last_write` admin-endpoint state (kind=`pmc`, address-type,
+   start byte, length, bytes).
+7. Return `ew_status = 0`.
+
+### Round-trip invariant
+
+The simulator MUST satisfy:
+
+```
+write(R, [10..12], [0xAA, 0xBB, 0xCC]); read(R, [10..12]) == [0xAA, 0xBB, 0xCC]
+```
+
+and the **byte-isolation invariant**:
+
+```
+write(R, [11], [0xFF]); bytes[10] == prior bytes[10] && bytes[12] == prior bytes[12]
+```
+
+The integration tests `Series/PmcRangeWriteTests.cs` and
+`Series/PmcBitRmwIntegrationTests.cs` assert both shapes.
+
+### Admin endpoint — `GET /admin/mock_get_last_write` extension
+
+The `last_write` payload gains a `kind: "pmc"` variant:
+
+```
+{
+  "kind": "pmc",
+  "addr_type": 5,        // R
+  "datano_s": 100,
+  "datano_e": 100,
+  "bytes": "0x08",       // hex-encoded
+  "writtenAt": "2026-04-25T13:30:00Z"
+}
+```
+
+Bit-level writes never appear here as a separate kind — they reach the
+simulator as 1-byte writes after the driver's RMW wrapper, so the audit
+shape is identical to a byte write at the same address.
+
+## Cycle-time per part / last cycle delta — F5-a (issue #272)
+
+Plan PR F5-a derives `Production/LastCycleSeconds` +
+`Production/LastCycleStartUtc` from the existing `cnc_rdparam(6711)` +
+`cnc_rdtimer` snapshot stream — **pure derivation, no new wire calls**.
+The simulator does NOT need new wire commands; the existing
+`cnc_rdparam` + `cnc_rdtimer` handlers already cover the read surface.
+
+What focas-mock DOES need is an admin endpoint + test-fixture helper
+that lets integration tests atomically increment the parts-count
+counter alongside the cycle-time timer so the driver sees a clean
+"cycle completed" transition on the next probe tick.
+
+### Per-profile state
+
+Already covered by the existing F1-b state map:
+
+- `parameters: Dict[int, int]` (entry `6711` is the parts-count counter).
+- `timers: Dict[int, int]` (entry `0` is the live cycle-time counter,
+  in seconds).
+
+### Admin endpoint — `POST /admin/mock_simulate_cycle_completion`
+
+Atomically advances both values to model "the CNC just finished a
+cycle". Atomicity matters: the F5-a derivation samples both fields on
+every probe tick, so if the simulator updated parts-count and the
+timer in two separate writes the test could observe an intermediate
+state where parts-count incremented but the timer hasn't updated yet
+(producing a misleading `LastCycleSeconds`).
+
+```
+POST /admin/mock_simulate_cycle_completion
+{
+  "profile": "Series30i",
+  "partsDelta": 1,                  // default 1; tests asserting backfill use 3+
+  "newCycleTimerSeconds": 18        // absolute value, NOT a delta
+}
+```
+
+Handler steps:
+
+1. `parameters[6711] += partsDelta` (under the per-profile lock).
+2. `timers[0] = newCycleTimerSeconds`.
+3. Return `200 OK` with the new values for verification.
+
+The endpoint MUST hold the profile's update lock for the full
+read-modify-write so a concurrent `cnc_rdparam` + `cnc_rdtimer` poll
+sees both fields in their pre-update OR post-update state — never
+half-applied.
+
+### `FocasSimFixture.SimulateCycleCompletionAsync`
+
+The future test-support helper wraps the admin endpoint:
+
+```csharp
+await fixture.SimulateCycleCompletionAsync(
+    profile: "Series30i",
+    partsDelta: 1,
+    newCycleTimerSeconds: 18);
+```
+
+Integration test `Series/CycleDeltaTests.cs` will assert:
+
+- After a 5 -> 6 transition with `newCycleTimerSeconds=18`, the
+  driver's `Production/LastCycleSeconds` settles to `currentTimer -
+  prevTimer`.
+- `Production/LastCycleStartUtc` is within driver-tolerance of
+  `nowUtc - LastCycleSeconds` (allow a small window for probe-tick
+  jitter).
+- Counter reset (parts -> 0) preserves the last published values.
+- Cycle-timer rollover does not publish a negative delta.
+
+These tests are blocked on the focas-mock + integration-test project
+landing; the unit-test coverage in `FocasCycleDeltaTests` already
+exercises every same-process invariant of the derivation.
+
+### Status
+
+focas-mock simulator has not landed yet (tracked separately from F4-b /
+F4-c). F4-b + F4-c land the .NET-side wire encoders + dispatch + status
+mapping unconditionally; the integration-test scaffolds at
+`tests/.../IntegrationTests/Series/ParameterWriteTests.cs`,
+`MacroWriteTests.cs`, `PmcRangeWriteTests.cs`, and
+`PmcBitRmwIntegrationTests.cs` are deferred until the simulator +
+integration-test project land. Until then unit-test coverage in
+`FocasWriteParameterTests` / `FocasWriteMacroTests` /
+`FocasWritePmcTests` exercises every same-process invariant against the
+in-memory `FakeFocasClient`.

docs/v2/implementation/focas-wire-protocol.md

@@ -1,291 +1,267 @@
-# FOCAS wire protocol — what's authoritative vs. what's guessed
+# FOCAS wire protocol — packed-buffer surface
-
+
-Companion to [`focas-simulator-plan.md`](focas-simulator-plan.md). Written during
+Notes on the language-neutral packed-buffer encoding the FOCAS driver +
-Stream B on 2026-04-23 after a research pass through `strangesast/fwlib` +
+focas-mock simulator share. This format is **not** the FWLIB native struct
-public FOCAS documentation. Purpose: separate what we *know* about the FOCAS
+layout — Tier-C Fwlib32 backends marshal directly from the FANUC C struct.
-wire protocol (can quote with confidence) from what we're *guessing* (will need
+The packed surface exists so the simulator (Python / FastAPI) and the .NET
-Wireshark traces to validate in Stream C).
+wire client can speak a common format over IPC without piping a Win32 DLL
-
+through both ends.
-This document directly informs `tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/server/`.
+
-
+## Command id table
-## Authoritative — from Fanuc's public `fwlib32.h`
+
-
+Each FOCAS-equivalent call gets a stable wire-protocol command id. Ids are
-The header file is distributed with the FOCAS Developer Kit and mirrored in OSS
+**append-only** — never renumber, never reuse.
-repos (notably `strangesast/fwlib`). The **struct layouts** documented there
+
-are stable across FOCAS versions and authoritative for the payload shapes our
+| Id | FOCAS API | Surface |
-Python mock has to emit.
+| --- | --- | --- |
-
+| `0x0001` | `cnc_rdcncstat` | ODBST 9-field status struct |
-### ODBM — macro variable read buffer
+| `0x0002` | `cnc_rdparam` | parameter value (one number) |
-
+| `0x0003` | `cnc_rdmacro` | macro variable value |
-```c
+| `0x0004` | `cnc_rddiag` | diagnostic value |
-typedef struct odbm {
+| ... | ... | ... |
-    short datano;    // macro variable number
+| **`0x0102`** | **`cnc_wrparam`** | **IODBPSD parameter-write packet (issue #269, plan PR F4-b)** |
-    short dummy;     // reserved / alignment padding
+| **`0x0103`** | **`cnc_wrmacro`** | **ODBM macro-write packet (issue #269, plan PR F4-b)** |
-    long  mcr_val;   // 32-bit signed macro value
+| **`0x0104`** | **`pmc_wrpmcrng`** | **IODBPMC PMC range-write packet (issue #270, plan PR F4-c)** |
-    short dec_val;   // decimal-point count (0-9)
+| **`0x0105`** | **`cnc_wrunlockparam`** | **4-byte password buffer for the parameter-protect / read-protect unlock (issue #271, plan PR F4-d)** |
-} ODBM;
+| `0x0F1A` | **`cnc_rdalmhistry`** | **ODBALMHIS alarm-history ring-buffer dump (issue #267, plan PR F3-a)** |
-```
+
-
+## ODBALMHIS — alarm history (`cnc_rdalmhistry`, command `0x0F1A`)
-With `#pragma pack(push, 4)` (the FOCAS default), total size is **10 bytes** on
+
-Windows: 2 + 2 + 4 + 2. Our `FwlibNative.cs` matches this exactly.
+Issued by `FocasAlarmProjection` when
-
+`FocasDriverOptions.AlarmProjection.Mode == ActivePlusHistory`. Returns up
-Our mock's `_READ_RESP_STRUCT = struct.Struct(">iH")` is **only 6 bytes** —
+to `depth` most-recent ring-buffer entries.
-missing `datano` + `dummy`. A real Fwlib decoding the scaffold response will
+
-read garbage. Stream C fix: prepend two `short` fields.
+### Request
-
+
-### IODBPSD — CNC parameter read/write buffer
+| Offset | Width | Field | Notes |
-
+| --- | --- | --- | --- |
-```c
+| 0 | `int16 LE` | `depth` | clamped client-side to `[1..250]` (`FocasAlarmProjectionOptions.MaxHistoryDepth`) |
-typedef struct iodbpsd {
+
-    short datano;       // parameter number
+### Response (packed buffer, little-endian)
-    short type;         // axis index (0 for non-axis parameters)
+
-    union {
+| Offset | Width | Field |
-        char  cdata;
+| --- | --- | --- |
-        short idata;
+| 0 | `int16 LE` | `num_alm` — number of entries that follow. `< 0` indicates CNC error. |
-        long  ldata;
+| 2 | repeated | `ALMHIS_data alm[num_alm]` (see below) |
-        char  cdatas[MAX_AXIS];   // MAX_AXIS varies — 8 on 0i, 32 on 30i
+
-        short idatas[MAX_AXIS];
+Each entry block:
-        long  ldatas[MAX_AXIS];
+
-    } u;
+| Offset (rel.) | Width | Field |
-} IODBPSD;
+| --- | --- | --- |
-```
+| 0 | `int16 LE` | `year` |
-
+| 2 | `int16 LE` | `month` |
-With `pack(4)` and `MAX_AXIS=8`, total size = 2 + 2 + 32 = **36 bytes**. Our
+| 4 | `int16 LE` | `day` |
-`FwlibNative.cs` matches this (`[SizeConst = 32]` data buffer).
+| 6 | `int16 LE` | `hour` |
-
+| 8 | `int16 LE` | `minute` |
-Our mock's current param handler doesn't return bytes in IODBPSD shape —
+| 10 | `int16 LE` | `second` |
-response payload is just the raw value. Stream C fix: wrap in 4-byte header
+| 12 | `int16 LE` | `axis_no` (1-based; 0 = whole-CNC) |
-+ union-padded data.
+| 14 | `int16 LE` | `alm_type` (P/S/OT/SV/SR/MC/SP/PW/IO encoded numerically) |
-
+| 16 | `int16 LE` | `alm_no` |
-### ODBST — status info
+| 18 | `int16 LE` | `msg_len` (0..32 typical) |
-
+| 20 | `msg_len` | ASCII message (no null terminator) |
-```c
+| `20 + msg_len` | 0..3 | pad to 4-byte boundary so per-entry blocks stay self-delimiting |
-typedef struct odbst {
+
-    short dummy;      // reserved
+The CNC stamps `year..second` in **its own local time**. The deployment
-    short tmmode;     // Memory / Tape / MDI / EDIT / DNC
+guide instructs operators to keep CNC clocks on UTC so the projection's
-    short aut;        // automatic mode
+dedup key `(OccurrenceTime, AlarmNumber, AlarmType)` stays stable across
-    short run;        // running state
+DST transitions. The .NET decoder
-    short motion;     // motion state
+(`Wire/FocasAlarmHistoryDecoder.Decode`) constructs each
-    short mstb;       // M/S/T/B finish signal
+`DateTimeOffset` with `TimeSpan.Zero` (UTC) on that assumption.
-    short emergency;  // emergency stop
+
-    short alarm;      // alarm state
+### Error handling
-    short edit;       // edit mode sub-state
+
-} ODBST;
+- A negative `num_alm` short-circuits decode to an empty list — the
-```
+  projection treats it as "no history this tick" and the next poll
-
+  retries.
-9 × short = **18 bytes**. Our mock already emits 18 bytes via
+- Malformed timestamps (e.g. month=0) are skipped per-entry instead of
-`struct.Struct(">9h")`. ✓ correct.
+  faulting the whole decode; the dedup key for malformed entries would be
-
+  unstable anyway.
-### IODBPMC — PMC range read/write buffer
+- `msg_len` overrunning the payload truncates the entry list at the
-
+  malformed entry rather than throwing.
-```c
+
-typedef struct iodbpmc {
+## IODBPSD — parameter write (`cnc_wrparam`, command `0x0102`)
-    short type_a;       // PMC address letter encoded as ADR_* numeric code
+
-    short type_d;       // data type: 0=byte, 1=word, 2=long, 4=float, 5=double
+Issue #269, plan PR F4-b. The write-side payload is the **byte-symmetric
-    unsigned short datano_s;  // start address number
+inverse of the `cnc_rdparam` read** — the same `IODBPSD` struct shape, and
-    unsigned short datano_e;  // end address number
+the .NET wire client uses the read-side decoder reversed (`EncodeParamValue`
-    union {
+in `FwlibFocasClient.cs`) so the encoder/decoder are guaranteed to stay in
-        char   cdata[5];
+lock-step.
-        short  idata[5];
+
-        long   ldata[5];
+### Request
-        float  fdata[5];
+
-        double dbdata[5];
+| Offset | Width | Field |
-    } u;   // 40-byte union (widest = dbdata = 5×8 bytes)
+| --- | --- | --- |
-} IODBPMC;
+| 0 | `int16 LE` | `datano` — parameter number (e.g. `1815`) |
-```
+| 2 | `int16 LE` | `type` — axis index (1-based; `0` = whole-CNC parameter) |
-
+| 4 | `length` | `data` payload — width depends on parameter type |
-With `pack(4)` the union is 40 bytes; struct total = 8 + 40 = **48 bytes**.
+
-Our `FwlibNative.cs` matches this.
+`length` (request frame trailer, drives `data` width):
-
+
-Our mock's PMC handler takes a different layout (uint16 handle + uint8 letter
+| FocasDataType | `length` | Payload encoding |
-+ ...). Stream C fix: rewrite to IODBPMC shape.
+| --- | --- | --- |
-
+| `Byte` | `4 + 1` | one signed byte at offset 4 |
-## Reference trace findings (2026-04-23 dev-box reversing)
+| `Int16` | `4 + 2` | int16 LE at offset 4 |
-
+| `Int32` | `4 + 4` | int32 LE at offset 4 |
-**Good news** — we don't need a bench CNC for first-pass reversing. Loading
+
-`Fwlib64.dll` in `otopcua-focas-cli` + pointing it at our Python simulator on
+Bit-addressed parameters (`PARAM:1815/0` form) are not supported by F4-b
-`127.0.0.1:8193` + enabling `OTOPCUA_FOCAS_RAW_CAPTURE=1` on the sim lets us
+and surface as `BadNotSupported`; F4-c will land the read-modify-write
-observe Fwlib's outbound bytes + iterate on reply shapes. Each cycle is ~5s;
+helper alongside the PMC bit RMW path.
-progress measure is "Fwlib sends more bytes before disconnecting".
+
-
+### Response
-### Confirmed wire facts
+
-
+Single `int16 LE` return code per the standard FWLIB convention:
-**Magic prefix** — every frame Fwlib sends begins with `0xA0 0xA0 0xA0 0xA0`
+
-(4 bytes). This is NOT a length prefix — our scaffold tried to decode it as
+- `0` → `Good`
-uint32-big-endian = 2.7 GB and died. It's a fixed protocol marker.
+- `11` (`EW_PASSWD`) → **`BadUserAccessDenied`** (was `BadNotWritable`
-
+  pre-F4-b — see `FocasStatusMapper`). Means the parameter-write switch is
-**Handshake request** — `cnc_allclibhndl3` produces this 8-byte frame:
+  off or the CNC isn't in MDI mode; the F4-d unlock workflow will close
-
+  the loop on this from the OPC UA side.
-```
+- Other `EW_*` codes map per
-a0 a0 a0 a0   00 01 01 01
+  [`FocasStatusMapper.MapFocasReturn`](../../src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasStatusMapper.cs).
-└─ magic ─┘   └── negotiation ──┘
+
-```
+## ODBM — macro write (`cnc_wrmacro`, command `0x0103`)
-
+
-The 4-byte negotiation field is stable across our observations (always
+Issue #269, plan PR F4-b. The write-side payload mirrors the
-`00 01 01 01`). Interpretation TBD — possibly `(version_major=0x0001,
+`cnc_rdmacro` read shape: the same `(mcr_val, dec_val)` (integer +
-version_minor=0x0101)` or `(protocol=0x01, subtype=0x010101)`.
+decimal-point count) split, but emitted from the .NET side rather than
-
+decoded.
-**Handshake reply that Fwlib accepts** (empirically confirmed — doesn't
+
-disconnect):
+### Request
-
+
-```
+| Offset | Width | Field |
-a0 a0 a0 a0   00 01 01 01   00 XX   00 YY
+| --- | --- | --- |
-└─ magic ─┘   └── echo ──┘   handle  api_version
+| 0 | `int16 LE` | `number` — macro variable number (e.g. `500`) |
-```
+| 2 | `int16 LE` | `length` — fixed at `8` for ODBM |
-
+| 4 | `int32 LE` | `mcr_val` — scaled integer value |
-12 bytes: magic + echoed negotiation + 2-byte handle + 2-byte api_version code.
+| 8 | `int16 LE` | `dec_val` — decimal-point count |
-
+
-### Post-handshake frame shape — decoded via drain mode
+F4-b ships **integer-only writes** (`dec_val = 0`) to match the most
-
+common HMI pattern; a future `WriteMacroScaled` overload will land if the
-The simulator's `OTOPCUA_FOCAS_DRAIN_AFTER_HANDSHAKE=1` mode reads all inbound
+field calls for fractional macro setpoints. Read-side decoders apply
-bytes for 1000 ms after the handshake reply without attempting any decode.
+`mcr_val / 10^dec_val`, so a `dec_val = 0` write surfaces back as the
-Captured payload from `cnc_allclibhndl3`:
+integer it was emitted as.
-
+
-```
+### Response
-00 02 00 02   a0 a0 a0 a0   00 01 21 01 00 00
+
-└── prefix ─┘   └── magic ─┘   └─── body ────┘
+Same single-int16 envelope as `cnc_wrparam`. `EW_PASSWD` is rare on macro
-  4 bytes         4 bytes         6 bytes     (total = 14 bytes)
+writes (the gate-switch protection is parameter-specific) but the mapper
-```
+treats both kinds identically.
-
+
-**Key discovery**: post-handshake frames have a **4-byte prefix BEFORE the
+### Symmetry note
-magic**, not magic-first. Frame shape:
+
-
+The plan carries a "byte layout symmetry" requirement — the encoder for
-```
+each kind is the read-side decoder reversed. Adding a new parameter type
-uint16  msg_counter     // starts at 2; handshake was #1 implicitly
+(e.g. `Int64` parameters, when they ship) means extending both sides in
-uint16  handle_echo     // matches the handle our open reply returned
+the same PR; the unit test
-4 bytes FOCAS_MAGIC     // 0xA0A0A0A0
+`FocasWriteParameterTests.ParameterWrite_round_trip_stores_value_visible_to_subsequent_read`
-N bytes body            // function-specific
+exercises encode → store → decode with the fake wire client and is the
-```
+canary for symmetry regressions.
-
+
-Session 1's drain captured only the prefix (`00 02 00 01`) before timing
+## IODBPMC — PMC range write (`pmc_wrpmcrng`, command `0x0104`)
-out — TCP multiplexed the two test sessions's bytes differently. Session 2
+
-caught the full 14-byte frame.
+Issue #270, plan PR F4-c. The write-side payload is the read-side
-
+`pmc_rdpmcrng` IODBPMC packet with the data direction inverted: the
-### Body bytes — first post-handshake request
+caller fills the `data[]` byte run and the simulator / Fwlib32 stores
-
+it; the response is the small status envelope rather than the populated
-Body on `cnc_allclibhndl3` first post-handshake frame:
+data buffer the read side returns.
-
+
-```
+### Request
-00 01 21 01 00 00
+
-```
+| Offset | Width | Field |
-
+| --- | --- | --- |
-Informed guesses (unvalidated):
+| 0 | `int16 LE` | `type_a` — PMC address-type code (R=5, G=4, F=3, D=8, X=1, Y=2, K=10, A=11, E=12, T=6, C=7) |
-
+| 2 | `int16 LE` | `type_d` — data type (`0` = byte; only byte writes are issued — bit writes wrap the byte path with a read-modify-write helper) |
-- `00 01` = body length (1 useful byte?) or sub-request count
+| 4 | `uint16 LE` | `datano_s` — first byte address (inclusive) |
-- `21 01` = function code / operation tag — `0x21` is seen in public FOCAS
+| 6 | `uint16 LE` | `datano_e` — last byte address (inclusive) — `(datano_e - datano_s + 1)` is the byte count |
-  reverse-engineering notes associated with "system info" / "controller
+| 8 | `bytes` | `data[]` — payload, exactly `(datano_e - datano_s + 1)` bytes |
-  identification" queries
+
-- `00 00` = padding / reserved
+The header is 8 bytes; the FWLIB `IODBPMC.data` field caps at 32 bytes
+(40-byte total per call), so larger ranges are chunked into 32-byte
+sub-calls by the wire client. The simulator MUST honour the same chunk
+ceiling so chunked-vs-single round-trips produce the same final bytes.
+
+### Response
+
+Same single-int16 envelope as `cnc_wrparam` / `cnc_wrmacro`:
+
+| Offset | Width | Field |
+| --- | --- | --- |
+| 0 | `int16 LE` | `ew_status` — `0` = success, non-zero = FANUC `EW_*` |
+
+`EW_NOOPT` (option not installed), `EW_NUMBER` (out-of-range address),
+`EW_LENGTH` (chunk size mismatch) are the typical failures the simulator
+reproduces; the mapper translates them to OPC UA status codes the same
+way the read-side does.
+
+### Bit-level RMW (driver-side, no extra wire op)
 
-Likely this is Fwlib's "tell me what CNC you are" query — part of
+`pmc_wrpmcrng` is **byte-addressed** — there is no sub-byte write op on
-`cnc_allclibhndl3`'s internal handshake continuation before the handle is
+the wire. Bit writes go through `IFocasClient.WritePmcBitAsync` which:
-fully established. Returning an empty or malformed response causes Fwlib
+
-to declare the far end "not a CNC" and error with `EW_FUNC` (16).
+1. Issues a 1-byte `pmc_rdpmcrng` to fetch the parent byte.
+2. Masks the target bit (set: OR; clear: AND-NOT).
+3. Issues a 1-byte `pmc_wrpmcrng` with the modified byte.
+
+A per-byte semaphore in `FwlibFocasClient` serialises concurrent bit
+writes against the same byte so two updates that race never lose one
+another's bit. The simulator's handler implements the same byte-aligned
+semantics — bit writes never reach it as a separate frame.
 
-### Iteration 3 — echo response, error-code advances
+### Symmetry note
+
+The encoder is the `pmc_rdpmcrng` decoder reversed: the read side parses
+`(type_a, type_d, datano_s, datano_e)` from the request and emits the
+data buffer in the response; the write side parses all five fields plus
+the data buffer from the request and emits a status int16 in the
+response. Tests `FocasWritePmcTests.PMC_*` exercise the round-trip on
+the fake wire client.
+
+## cnc_wrunlockparam — connection-level password unlock (command `0x0105`)
+
+Issue #271, plan PR F4-d. Some controllers (notably 16i + certain 30i
+firmwares with parameter-protect on) gate `cnc_wrparam` and selected
+reads behind a connection-level password switch. The driver emits this
+frame on connect when `FocasDeviceOptions.Password` is configured, and
+re-emits it on any read/write that returns `EW_PASSWD` (then retries the
+gated call once).
+
+### Request
+
+| Offset | Width | Field |
+| --- | --- | --- |
+| 0 | `byte[4]` | `password[4]` — 4-byte password buffer. ASCII-encoded from `FocasDeviceOptions.Password`, right-padded with `0x00`, truncated at 4 bytes. |
+
+The 4-byte fixed slot matches the FANUC published shape — the controller
+compares byte-for-byte. Longer / shorter source strings are normalised at
+the driver layer before they hit this frame so the wire surface stays
+canonical.
+
+### Response
+
+Same single-int16 envelope as the write frames:
 
-Sending back `<prefix><magic><echoed body>` (14 bytes matching request shape)
+| Offset | Width | Field |
-advances Fwlib's client-side error code from **`EW_-16` (socket-level)** to
+| --- | --- | --- |
-**`EW_-17` (protocol-level rejection)**. Fwlib reads our response in full
+| 0 | `int16 LE` | `ew_status` — `0` = success (gate now lifted for the lifetime of this FWLIB handle), `EW_PASSWD` = supplied password did not match the controller's slot, `EW_HANDLE` = handle invalid. |
-before disconnecting with `peer closed mid-frame`.
+
+### Lifetime
+
+Unlock is bound to the FWLIB handle: it persists until the handle closes
+(disconnect / reconnect). The driver reinvokes unlock on every
+`EnsureConnectedAsync` reconnect path so a planned or unplanned wire
+restart self-heals without operator intervention. A `BadUserAccessDenied`
+on a read/write triggers a single-shot retry: re-emit unlock + redispatch
+the gated call once. A second `EW_PASSWD` propagates unchanged so a
+mismatched password doesn't loop forever on the wire.
+
+### No-log invariant
 
-Meaning: our **frame structure is correct enough** that Fwlib parses it as a
+The password is a secret. Wire-client implementations MUST NOT log the
-valid FOCAS frame; the **body content** (the 6 bytes after magic) is where
+password on either request or response. The current
-the semantic mismatch now lives. Fwlib expects specific bytes back for the
+`FwlibFocasClient.UnlockAsync` constructs an exception that includes
-`0x2101` system-info query and an echo doesn't match.
+only the `EW_*` return code; the `FocasDeviceOptions` record overrides
-
+its auto-generated `ToString` so any Serilog destructure renders
-### Current iteration block
+`Password = ***`. See
-
+[`docs/v2/focas-deployment.md`](../focas-deployment.md)
-Going deeper without reference requires either:
+§ "FOCAS password handling" for the deployment-side guarantees +
-
+rotation runbook.
-- **A bench CNC** (#54) to capture a real response to the `0x2101` query.
-  Stream C.2 Wireshark trace gives us the exact byte pattern Fwlib expects.
-- **Published FOCAS response specs** for sub-function `0x2101` — not present
-  in `strangesast/fwlib` headers; likely only in the licensed Developer Kit
-  binary docs.
-- **Blind enumeration** — try N variations of the 6-byte body response until
-  Fwlib's error code changes again. High cost, low signal.
-
-The first two are both blocked on resources we don't have. The third is
-~hundreds of cycles with no guarantee of convergence.
-
-### Diminishing-returns checkpoint
-
-**What we've proven without hardware**:
-1. Magic prefix `0xA0A0A0A0` confirmed
-2. Handshake request format decoded (`magic + 4-byte negotiation`)
-3. Handshake response format that Fwlib accepts (`magic + echo + handle + api`)
-4. Post-handshake frame format decoded (`prefix + magic + body`)
-5. First post-handshake function code observed (`0x2101` — likely system-info)
-6. Error code progression `EW_SOCKET` → `EW_PROTOCOL` confirms our framing is
-   structurally correct
-
-**What we can't prove without bench CNC or reference docs**:
-1. The exact 6-byte response body Fwlib expects for `0x2101`
-2. The full list of post-handshake function codes + their body shapes
-3. Whether subsequent frames use length prefixes or fixed body sizes
-
-**Recommendation**: checkpoint here. The framing discoveries above are
-preserved in `server/frames.py` + `server/state.py` + `server/focas_server.py`
-+ `server/handlers/__init__.py`. When bench-CNC access unblocks Stream C.2's
-reference trace, the iteration loop (with the framing work already done)
-should converge in hours rather than days.
-
-### Still unknown
-
-- **Response shape** for the post-handshake body request — we can frame the
-  prefix + magic correctly now, but what the 6-byte body response should
-  carry (CNC series ID? version? capability flags?) needs further iteration.
-- **Function-id numeric values** for the 9 FWLIB calls our driver makes —
-  one per call, need to be observed separately.
-- **Error encoding** on the wire.
-
-### Next iteration cycles
-
-With the handshake working, each subsequent function gets its own probe-and-observe
-loop. The simulator now has a `RAW_FRAME_MARKER = 0xFFFF` sentinel that lets a
-handler return exact wire bytes (bypassing the scaffold envelope) — use that to
-try different post-handshake replies and watch Fwlib's reaction.
-
-## Stream C work order
-
-Given what's authoritative vs. guessed, here's the most efficient path:
-
-### Phase 1 — payload shapes (no hardware required)
-
-- [ ] Rewrite `server/handlers/macro.py` response to return 10-byte ODBM:
-      `short datano, short dummy, int32 mcr_val, short dec_val`
-- [ ] Rewrite `server/handlers/param.py` response to return 36-byte IODBPSD:
-      `short datano, short type, bytes[32] u`
-- [ ] Rewrite `server/handlers/pmc.py` response to return 48-byte IODBPMC:
-      `short type_a, short type_d, uint16 datano_s, uint16 datano_e, bytes[40] u`
-- [ ] Add unit tests asserting byte-exact sizes
-- [ ] Update validate_harness.py to match the new shapes
-
-Effect: when Stream C gets its first Wireshark trace, the payload-layer of the
-mock is already correct. Only the framing layer needs iteration.
-
-### Phase 2 — framing (requires hardware)
-
-This is the iterative Wireshark loop — no point starting until the Windows rig
-+ licensed Fwlib64.dll + real CNC are all available. See the implementer's
-checklist in
-[`tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/README.md`](../../../tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/README.md).
-
-### Phase 3 — flip the C# test gate
-
-Once Phase 2 proves Fwlib64 can talk to the mock:
-
-- [ ] Flip `OTOPCUA_FOCAS_SIM_WIRE_COMPAT=1` in the CI env
-- [ ] Expand `tests/.../IntegrationTests/Series/WireCompatGatedTests.cs` with
-      real per-series assertions
-- [ ] Update `scripts/e2e/test-focas.ps1` to accept `-ProfileName`
-- [ ] Close Stream D
-
-## References
-
-- [`src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FwlibNative.cs`](../../../src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FwlibNative.cs) — P/Invoke surface, authoritative struct layouts
-- [`src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FwlibFocasClient.cs`](../../../src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FwlibFocasClient.cs) — reference C# implementation of each FWLIB call
-- [`src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasStatusMapper.cs`](../../../src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasStatusMapper.cs) — EW_* → OPC UA status mapping
-- Fanuc FOCAS Developer Kit (licensed, not in repo) — ultimate source of truth
-- `strangesast/fwlib` on GitHub — redistributes `fwlib32.h` + runtime binaries; no wire protocol docs

docs/v2/implementation/phase-2-galaxy-out-of-process.md

@@ -172,7 +172,7 @@ Lift the existing `GalaxyRuntimeProbeManager` into the new project. Behaviors pe
 #### Task B.6 — Named-pipe IPC server with mandatory ACL
 
 Per decision #76 + `driver-stability.md` §"IPC Security":
-- Pipe ACL on creation: `ReadWrite | Synchronize` granted only to the OtOpcUa server's service principal SID; LocalSystem **explicitly denied**. Administrators was dropped from the deny list so non-elevated admins on dev boxes aren't blocked via UAC-filtered-token deny-only semantics — the per-connection SID check (§2 of driver-stability.md) remains the real authorization boundary.
+- Pipe ACL on creation: `ReadWrite | Synchronize` granted only to the OtOpcUa server's service principal SID; LocalSystem and Administrators **explicitly denied**
 - Caller identity verification on each new connection: `GetImpersonationUserName()` cross-checked against configured server service SID; mismatches dropped before any RPC frame is read
 - Per-process shared secret: passed by the supervisor at spawn time, required on first frame of every connection
 - Heartbeat pipe: separate from data-plane pipe, same ACL

docs/v2/implementation/phase-6-1-resilience-and-observability.md

@@ -1,8 +1,6 @@
 # Phase 6.1 — Resilience & Observability Runtime
 
-> **Status**: **SHIPPED** 2026-04-19 — Streams A/B/C/D + E data layer merged to `v2` across PRs #78-82. Final exit-gate PR #83 turns the compliance script into real checks (all pass) and records this status update.
+> **Status**: **SHIPPED** 2026-04-19 — Streams A/B/C/D + E data layer merged to `v2` across PRs #78-82. Final exit-gate PR #83 turns the compliance script into real checks (all pass) and records this status update. One deferred piece: Stream E.2/E.3 SignalR hub + Blazor `/hosts` column refresh lands in a visual-compliance follow-up PR on the Phase 6.4 Admin UI branch.
->
-> **Stream E.2/E.3 closed 2026-04-23** — `FleetStatusPoller` now polls `DriverInstanceResilienceStatus`, detects per-`(DriverInstanceId, HostName)` deltas, and pushes `ResilienceStatusChangedMessage` via `FleetStatusHub` on the fleet group. Admin `/hosts` page subscribes on load and upserts the matching `HostStatusRow` in-memory on receipt, so operator-visible resilience state now reflects the runtime within one poller tick (~5 s) instead of the Admin page's own 10-second refresh. `FleetStatusPollerTests.Poller_pushes_ResilienceStatusChanged_on_delta` covers the first-observation push, the no-delta-no-push invariant, and the mutated-row re-push.
 >
 > Baseline: 906 solution tests → post-Phase-6.1: 1042 passing (+136 net). One pre-existing Client.CLI Subscribe flake unchanged.
 >
@@ -131,7 +129,7 @@ Closes these gaps flagged in the 2026-04-19 audit:
 - [ ] Stream B: Tier registry + generalised watchdog + scheduled recycle + wedge detector
 - [ ] Stream C: `/healthz` + `/readyz` + structured logging + JSON Serilog sink
 - [ ] Stream D: LiteDB cache + Polly fallback in Configuration
-- [x] Stream E: Admin `/hosts` page refresh (E.1 in PRs #78-82 with the data layer; E.2/E.3 closed 2026-04-23)
+- [ ] Stream E: Admin `/hosts` page refresh
 - [ ] Cross-cutting: `phase-6-1-compliance.ps1` exits 0; full solution `dotnet test` passes; exit-gate doc recorded
 
 ## Adversarial Review — 2026-04-19 (Codex, thread `019da489-e317-7aa1-ab1f-6335e0be2447`)

docs/v2/implementation/phase-6-2-authorization-runtime.md

@@ -1,9 +1,10 @@
 # Phase 6.2 — Authorization Runtime (ACL + LDAP grants)
 
-> **Status**: **FULLY SHIPPED** (updated 2026-04-23 audit). Streams A-D core merged to `v2` across PRs #84-87 + exit-gate PR #88 on 2026-04-19; both named deferrals landed separately and were confirmed against the repo this session:
+> **Status**: **SHIPPED (core)** 2026-04-19 — Streams A, B, C (foundation), D (data layer) merged to `v2` across PRs #84-87. Final exit-gate PR #88 turns the compliance stub into real checks (all pass, 2 deferred surfaces tracked).
 >
-> - **Task #143 Stream C dispatch wiring** — `DriverNodeManager` calls `AuthorizationGate.IsAllowed(context.UserIdentity, OpcUaOperation.<Op>, scope)` on Read (line 249), Write (line 536) with per-classification `OpcUaOperation.WriteOperate` / `WriteTune` / `WriteConfigure` routed via `WriteAuthzPolicy`, and HistoryRead (4 call sites). `TriePermissionEvaluator` + `PermissionTrieCache` back the gate.
+> Deferred follow-ups (tracked separately):
-> - **Task #144 Stream D Admin UI** — `RoleGrants.razor` (LDAP group → Admin role mapping) + `AclsTab.razor` (per-cluster node-ACL editor with a probe-this-permission surface via `PermissionProbeService`) + `AclChangeNotifier` SignalR hub for cache invalidation all present and wired.
+> - Stream C dispatch wiring on the 11 OPC UA operation surfaces (task #143).
+> - Stream D Admin UI — RoleGrantsTab, AclsTab Probe-this-permission, SignalR invalidation, draft-diff ACL section + visual-compliance reviewer signoff (task #144).
 >
 > Baseline pre-Phase-6.2: 1042 solution tests → post-Phase-6.2 core: 1097 passing (+55 net). One pre-existing Client.CLI Subscribe flake unchanged.
 >

docs/v2/implementation/phase-6-3-redundancy-runtime.md

@@ -1,20 +1,13 @@
 # Phase 6.3 — Redundancy Runtime
 
-> **Status**: **SHIPPED (core + Stream C)** — original body merged 2026-04-19; audit 2026-04-23 promoted **Stream C (task #147)** into shipped state.
+> **Status**: **SHIPPED (core)** 2026-04-19 — Streams B (ServiceLevelCalculator + RecoveryStateManager) and D core (ApplyLeaseRegistry) merged to `v2` in PR #89. Exit gate in PR #90.
 >
-> **In** (verified in repo):
+> Deferred follow-ups (tracked separately):
-> - Stream A — `ClusterTopologyLoader`, `RedundancyCoordinator`, `RedundancyTopology`, `PeerReachability` all present under `src/ZB.MOM.WW.OtOpcUa.Server/Redundancy/`. Coordinator is now also hosted by `Program.cs` via the new `RedundancyPublisherHostedService`, which calls `RefreshAsync` on startup.
+> - Stream A — RedundancyCoordinator cluster-topology loader (task #145).
-> - Stream B — `ServiceLevelCalculator` + `RecoveryStateManager`.
+> - Stream C — OPC UA node wiring: ServiceLevel + ServerUriArray + RedundancySupport (task #147).
-> - **Stream C (task #147) — OPC UA node wiring**. `ServerRedundancyNodeWriter` maintains `Server.ServiceLevel` (i=2267), `Server.ServerRedundancy.RedundancySupport` (i=2994), and `Server.ServerRedundancy.ServerUriArray` (non-transparent subtype) by writing the `PropertyState.Value` + calling `ClearChangeMasks`. `RedundancyPublisherHostedService` drives the publisher on a 1 s tick and fans `OnStateChanged` / `OnServerUriArrayChanged` into the writer. Mapping of `Configuration.RedundancyMode` → Part 4 `RedundancySupport` is Warm/Hot/None (v2 clusters don't enumerate Cold / HotAndMirrored per decision #85). Idempotent per-value dedupe prevents spurious OPC UA notifications. Unit coverage: `ServerRedundancyNodeWriterTests` (4 tests, green).
+> - Stream E — Admin UI RedundancyTab + OpenTelemetry metrics + SignalR (task #149).
-> - Stream D — `ApplyLeaseRegistry`.
+> - Stream F — client interop matrix + Galaxy MXAccess failover test (task #150).
-> - Stream E — `RedundancyTab.razor` with SignalR `RoleChanged` wiring (via `FleetStatusPoller` + `FleetStatusHub`) — stale-flag + role-swap banner.
+> - sp_PublishGeneration pre-publish validator rejecting unsupported RedundancyMode values (task #148 part 2 — SQL-side).
->
-> **Closed this session (2026-04-23)**:
-> - **Task #148 part 2** — `DraftValidator.ValidateClusterTopology(cluster, nodes)` now catches three pre-publish invariants the SQL CHECK can't see: (a) unsupported `NodeCount`/`RedundancyMode` pairs; (b) `Enabled`-node count vs. declared `NodeCount` mismatch (catches disabled-node drift with mode still Hot/Warm); (c) multiple-Primary per decision #84. Returns every failure in one pass — same shape as `Validate`. 8 new tests in `DraftValidatorTests` green.
-> - **Task #150 Stream F** — `docs/v2/redundancy-interop-playbook.md` captures the manual validation matrix against UaExpert + Kepware + AVEVA MXAccess failover. Automating these closed-source GUI clients in PR-CI is out of scope; the automatable half is already covered by `ServiceLevelCalculatorTests` / `RedundancyStatePublisherTests` / `ClusterTopologyLoaderTests` / `ServerRedundancyNodeWriterTests`.
->
-> **Remaining (documented limitation, not blocking v2.0)**:
-> - Non-transparent redundancy-state node upgrade — the SDK's default `Server.ServerRedundancy` object is the base `ServerRedundancyState`, so `ApplyServerUriArray` currently logs-and-skips. Operators on the rare deployment that needs `ServerUriArray` read-back get a clear warning with the upgrade path. Documented in the interop playbook's "Known limitations" section.
 >
 > Baseline pre-Phase-6.3: 1097 solution tests → post-Phase-6.3 core: 1137 passing (+40 net).
 >

docs/v2/implementation/phase-6-4-admin-ui-completion.md

@@ -1,17 +1,12 @@
 # Phase 6.4 — Admin UI Completion
 
-> **Status**: **SHIPPED (mostly)** 2026-04-19; audit 2026-04-23 confirms what landed separately after the data-layer PR #91:
+> **Status**: **SHIPPED (data layer)** 2026-04-19 — Stream A.2 (UnsImpactAnalyzer + DraftRevisionToken) and Stream B.1 (EquipmentCsvImporter parser) merged to `v2` in PR #91. Exit gate in PR #92.
 >
-> **In** (verified in repo):
+> Deferred follow-ups (Blazor UI + staging tables + address-space wiring):
-> - **Task #153 Stream A UI** — `UnsTab.razor` with drag/drop handlers + concurrent-edit via `DraftRevisionToken` + `UnsImpactAnalyzer`; Playwright smoke test in `tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/UnsTabDragDropE2ETests.cs`.
+> - Stream A UI — UnsTab MudBlazor drag/drop + 409 concurrent-edit modal + Playwright smoke (task #153).
-> - **Task #155 Stream B** — `EquipmentImportBatch` entity + migration, `EquipmentImportBatchService.CreateBatchAsync` / `FinaliseBatchAsync` / `DropBatchAsync` / `ListByUserAsync`, `ImportEquipment.razor` UI.
+> - Stream B follow-up — EquipmentImportBatch staging + FinaliseImportBatch transaction + CSV import UI (task #155).
-> - **Task #156 Stream C** — `DiffViewer.razor` + `DiffSection.razor` refactor in place.
+> - Stream C — DiffViewer refactor into base + 6 section plugins + 1000-row cap + SignalR paging (task #156).
-> - Admin UI `IdentificationFields.razor` surface shipped (part of #157).
+> - Stream D — IdentificationFields.razor + DriverNodeManager OPC 40010 sub-folder exposure (task #157).
->
-> **Closed this session (2026-04-23)**:
-> - **Task #157 Stream D server-side half** was a stale audit claim. `src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/IdentificationFolderBuilder.cs` ships the OPC 40010 Identification sub-folder materializer (Manufacturer / Model / SerialNumber / HardwareRevision / SoftwareRevision / YearOfConstruction / AssetLocation / ManufacturerUri / DeviceManualUri); `EquipmentNodeWalker.Walk` calls it per equipment; `IdentificationFolderBuilderTests` (158 lines) + two walker-level tests (`Walk_Materializes_Identification_Subfolder_When_AnyFieldPresent`, `Walk_Omits_Identification_Subfolder_When_AllFieldsNull`) cover the null-handling branches. The initial audit grepped only `src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/`; the builder lives in `Core/OpcUa/`.
->
-> **Phase 6.4 is now FULLY SHIPPED — no deferred surfaces remain.**
 >
 > Baseline pre-Phase-6.4: 1137 solution tests → post-Phase-6.4 data layer: 1159 passing (+22).
 >

docs/v2/implementation/phase-7-e2e-smoke.md

@@ -14,7 +14,7 @@ End-to-end validation that the Phase 7 production wiring chain (#243 / #244 / #2
 | SQL Server reachable, `OtOpcUaConfig` DB exists with all migrations applied | `sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "..." -Q "SELECT COUNT(*) FROM dbo.__EFMigrationsHistory"` returns ≥ 11 |
 | Server's `appsettings.json` `Node:ConfigDbConnectionString` matches your SQL Server | `cat src/ZB.MOM.WW.OtOpcUa.Server/appsettings.json` |
 
-> **Galaxy.Host pipe ACL.** The pipe allows the configured `OTOPCUA_ALLOWED_SID` (typically the user that runs `OtOpcUaGalaxyHost` — `dohertj2` on the dev box). Run the Server under the same user; elevation doesn't matter — `PipeAcl.cs` no longer denies `BUILTIN\Administrators` since UAC's deny-only Admins SID would have blocked non-elevated dev-box admins too.
+> **Galaxy.Host pipe ACL.** Per `docs/ServiceHosting.md`, the pipe ACL deliberately denies `BUILTIN\Administrators`. **Run the Server in a non-elevated shell** so its principal matches `OTOPCUA_ALLOWED_SID` (typically the same user that runs `OtOpcUaGalaxyHost` — `dohertj2` on the dev box).
 
 ## Setup
 
@@ -36,49 +36,11 @@ sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "OtOpcUaDev_2026!" `
 
 Expected output ends with `Phase 7 smoke seed complete.` plus a Cluster / Node / Generation summary. Idempotent — re-running wipes the prior smoke state and starts clean.
 
-The seed creates one each of: `ServerCluster`, `ClusterNode`, `ClusterNodeCredential` (binds the SQL login to the node — without this `sp_GetCurrentGenerationForCluster` returns `Unauthorized: caller X is not bound to NodeId p7-smoke-node`), `ConfigGeneration` (Published), `Namespace`, `UnsArea`, `UnsLine`, `Equipment`, `DriverInstance` (Galaxy proxy), `Tag`, two `Script` rows, one `VirtualTag` (`MachineStatus` = `Source > 0`, Boolean, historized), one `ScriptedAlarm` (`OverTemp` when `Source > 50`).
+The seed creates one each of: `ServerCluster`, `ClusterNode`, `ConfigGeneration` (Published), `Namespace`, `UnsArea`, `UnsLine`, `Equipment`, `DriverInstance` (Galaxy proxy), `Tag`, two `Script` rows, one `VirtualTag` (`Doubled` = `Source × 2`), one `ScriptedAlarm` (`OverTemp` when `Source > 50`).
 
-### 3. (Optional) Swap the Galaxy attribute
+### 3. Replace the Galaxy attribute placeholder
 
-The shipped seed points `dbo.Tag.TagConfig` at `TestMachine_001.TestHistoryValue` — the dev-box Galaxy ships it as Int32, writable (`security_classification = Operate`), and historized (`HistoryExtension` primitive), so every E2E stage has a real live target. To swap to another attribute on a different Galaxy, pick a candidate via the same shape:
+`scripts/smoke/seed-phase-7-smoke.sql` inserts a `dbo.Tag.TagConfig` JSON with `FullName = "REPLACE_WITH_REAL_GALAXY_ATTRIBUTE"`. Edit the SQL + re-run, or `UPDATE dbo.Tag SET TagConfig = N'{"FullName":"YourReal.GalaxyAttr","DataType":"Float64"}' WHERE TagId='p7-smoke-tag-source'`. Pick an attribute that exists on the running Galaxy + has a numeric value the script can multiply.
-
-```sql
--- Run against the Galaxy Repository DB (ZB).
-;WITH dpc AS (
-    SELECT g.gobject_id, p.package_id, p.derived_from_package_id, 0 AS depth
-    FROM gobject g INNER JOIN package p ON p.package_id = g.deployed_package_id
-    WHERE g.is_template = 0 AND g.deployed_package_id <> 0
-    UNION ALL
-    SELECT c.gobject_id, p.package_id, p.derived_from_package_id, c.depth + 1
-    FROM dpc c INNER JOIN package p ON p.package_id = c.derived_from_package_id
-    WHERE c.derived_from_package_id <> 0 AND c.depth < 10
-)
-SELECT DISTINCT g.tag_name + '.' + da.attribute_name AS full_ref,
-       dt.description AS dtype, da.security_classification
-FROM dpc
-INNER JOIN dynamic_attribute da ON da.package_id = dpc.package_id
-INNER JOIN gobject g ON g.gobject_id = dpc.gobject_id
-LEFT JOIN data_type dt ON dt.mx_data_type = da.mx_data_type
-WHERE da.attribute_name NOT LIKE '[_]%'
-  AND da.attribute_name NOT LIKE '%.Description'
-  AND da.mx_data_type IN (1, 2, 3, 4)
-  AND da.security_classification > 0  -- writable
-  AND EXISTS (
-      SELECT 1 FROM primitive_instance pi
-      INNER JOIN primitive_definition pd
-          ON pd.primitive_definition_id = pi.primitive_definition_id
-          AND pd.primitive_name = 'HistoryExtension'
-      WHERE pi.package_id = dpc.package_id AND pi.primitive_name = da.attribute_name)
-ORDER BY full_ref;
-```
-
-Then update the seed:
-
-```sql
-UPDATE dbo.Tag
-   SET TagConfig = N'{"FullName":"YourReal.GalaxyAttr","DataType":"Int32"}'
- WHERE TagId = 'p7-smoke-tag-source';
-```
 
 ### 4. Point Server.appsettings at the smoke node
 
@@ -92,38 +54,9 @@ UPDATE dbo.Tag
 }
 ```
 
-### 4a. (Optional) Enable LDAP + SecurityProfile for the write stage
-
-Anonymous OPC UA sessions are denied writes against `Operate`-classified tags by the PR 26 server-layer classification gate. To exercise the reverse-bridge + alarm-fires stages fully, the Server has to advertise a `UserName` UserTokenPolicy (any profile other than `None`) and authenticate against LDAP.
-
-```json
-{
-  "OpcUa": {
-    "SecurityProfile": "Basic256Sha256-Sign",
-    "Ldap": {
-      "Enabled": true,
-      "Server":  "localhost",
-      "Port":    3893,
-      "SearchBase": "dc=lmxopcua,dc=local",
-      "ServiceAccountDn": "cn=serviceaccount,dc=lmxopcua,dc=local",
-      "ServiceAccountPassword": "serviceaccount123",
-      "GroupToRole": {
-        "ReadOnly":       "ReadOnly",
-        "WriteOperate":   "WriteOperate",
-        "WriteTune":      "WriteTune",
-        "WriteConfigure": "WriteConfigure",
-        "AlarmAck":       "AlarmAck"
-      }
-    }
-  }
-}
-```
-
-Dev-box GLAuth ships `writeop` / `writeop123` in the `WriteOperate` group, `admin` / `admin123` across all write groups. See `C:\publish\glauth\auth.md`.
-
 ## Run
 
-### 5. Start the Server
+### 5. Start the Server (non-elevated shell)
 
 ```powershell
 dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server
@@ -149,39 +82,27 @@ Any line missing = follow up the failure surface (each step has its own log sign
 dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- browse -u opc.tcp://localhost:4840/OtOpcUa -r -d 5
 ```
 
-Expect to see under the namespace root: `lab-floor → galaxy-line → reactor-1` with three child variables: `Source` (driver-sourced Int32), `MachineStatus` (virtual tag Boolean, `Source > 0`), and `OverTemp` (scripted alarm Boolean, `Source > 50`). NodeIds are path-based per OPC UA Part 3 §5.2.2 — the walker mints them from `{driverId}/{folder-path}/{browseName}` and stores the driver-side FullReference in an internal NodeId→FullRef map, so client subscriptions survive backend address renames.
+Expect to see under the namespace root: `lab-floor → galaxy-line → reactor-1` with three child variables: `Source` (driver-sourced), `Doubled` (virtual tag, value should track Source×2), and `OverTemp` (scripted alarm, boolean reflecting whether Source > 50).
 
 #### Read the virtual tag
 
 ```powershell
-dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- read `
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- read -u opc.tcp://localhost:4840/OtOpcUa -n "ns=2;s=p7-smoke-vt-derived"
-    -u opc.tcp://localhost:4840/OtOpcUa `
-    -n "ns=2;s=p7-smoke-galaxy/lab-floor/galaxy-line/reactor-1/MachineStatus"
 ```
 
-Expected: `Boolean`. Push a value change into the Source Galaxy attribute and re-read — `MachineStatus` should follow within the bridge's publishing interval (1 second by default).
+Expected: a `Float64` value approximately equal to `2 × Source`. Push a value change in Galaxy + re-read — the virtual tag should follow within the bridge's publishing interval (1 second by default).
 
 #### Read the scripted alarm
 
 ```powershell
-dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- read `
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- read -u opc.tcp://localhost:4840/OtOpcUa -n "ns=2;s=p7-smoke-al-overtemp"
-    -u opc.tcp://localhost:4840/OtOpcUa `
-    -n "ns=2;s=p7-smoke-galaxy/lab-floor/galaxy-line/reactor-1/OverTemp"
 ```
 
 Expected: `Boolean` — `false` when Source ≤ 50, `true` when Source > 50.
 
 #### Drive the alarm + verify historian queue
 
-Push a Source value above 50 — either from Galaxy itself, or via the Server's OPC UA write path using LDAP credentials (step 4a). Within ~1 second, `OverTemp.Read` flips to `true`. The alarm engine emits a transition to `Phase7EngineComposer.RouteToHistorianAsync` → `SqliteStoreAndForwardSink.EnqueueAsync` → drain worker (every 2s) → `GalaxyHistorianWriter.WriteBatchAsync` → Galaxy.Host pipe → Aveva Historian alarm schema.
+In Galaxy, push a Source value above 50. Within ~1 second, `OverTemp.Read` flips to `true`. The alarm engine emits a transition to `Phase7EngineComposer.RouteToHistorianAsync` → `SqliteStoreAndForwardSink.EnqueueAsync` → drain worker (every 2s) → `GalaxyHistorianWriter.WriteBatchAsync` → Galaxy.Host pipe → Aveva Historian alarm schema.
-
-```powershell
-# OPC UA write path — requires LDAP from step 4a + a writeop-class user.
-dotnet run --project src/ZB.MOM.WW.OtOpcUa.Client.CLI -- write `
-    -u opc.tcp://localhost:4840/OtOpcUa -S sign `
-    -n "ns=2;s=p7-smoke-galaxy/lab-floor/galaxy-line/reactor-1/Source" `
-    -v 75 -U writeop -P writeop123
-```
 
 Verify the queue absorbed the event:
 
@@ -199,32 +120,14 @@ Open the Historian Client (or InTouch alarm summary) — the `OverTemp` activati
 
 - [ ] EF migrations applied through `20260420232000_ExtendComputeGenerationDiffWithPhase7`
 - [ ] Smoke seed completes without errors + creates exactly 1 Published generation
-- [ ] Server starts + logs the Phase 7 composition lines
+- [ ] Server starts in non-elevated shell + logs the Phase 7 composition lines
-- [ ] Client.CLI browse shows the UNS tree with Source / MachineStatus / OverTemp under reactor-1
+- [ ] Client.CLI browse shows the UNS tree with Source / Doubled / OverTemp under reactor-1
-- [ ] Read on `Source` returns a Good-quality Int32 value (proves MXAccess round-trip)
+- [ ] Read on `Doubled` returns `2 × Source` value
-- [ ] Read on `MachineStatus` returns the live boolean truth of `Source > 0`
 - [ ] Read on `OverTemp` returns the live boolean truth of `Source > 50`
-- [ ] `test-galaxy.ps1 -Username writeop -Password writeop123` drives Source past 50 and flips `OverTemp` to `true` within 1 s
+- [ ] Pushing Source past 50 in Galaxy flips `OverTemp` to `true` within 1 s
 - [ ] SQLite queue drains (`COUNT(*)` returns to 0 within 2 s of an alarm transition)
 - [ ] Historian shows the `OverTemp` activation event with the rendered message
 
-## Second-run evidence (2026-04-24 dev box)
-
-Full live stack ran end-to-end once the IPC unblocks (commit `d11dd05`), path-based NodeIds (commit `8be82e0`), cold-start engine guards (commit `69e1d32`), and seed retarget to `TestMachine_001.TestHistoryValue` (commit `ec1a590`) landed. Anonymous `scripts/e2e/test-galaxy.ps1` run reaches 3/7:
-
-```
-[PASS] source NodeId readable (Galaxy pipe → proxy → server → client chain up)
-[PASS] source value = System.Byte[]
-[INFO] BadUserAccessDenied — attribute's Galaxy-side ACL blocks writes for this session.
-```
-
-The `INFO` stage is correct behaviour — Source is `Operate`-classified and the anonymous session carries no LDAP roles. The Virtual-tag / Subscribe / Alarm / History stages stay at `[FAIL]` for two further environmental reasons once write is unblocked:
-
-1. `TestMachine_001.TestHistoryValue` is driven by whatever Galaxy code runs on the object — idle in the default dev-box state, so no subscription pushes fire.
-2. Historian writes require the Aveva Historian SDK to accept the alarm schema event — dev box doesn't have that path live.
-
-Running `./test-galaxy.ps1 -Username writeop -Password writeop123` with step 4a's LDAP + `SecurityProfile = Basic256Sha256-Sign` applied unblocks the reverse-bridge + alarm-fires stages. The virtual-tag, subscribe, and history stages depend on further deployment choices (pick an attribute Galaxy is actively writing to, wire Aveva Historian SDK).
-
 ## First-run evidence (2026-04-20 dev box)
 
 Ran the smoke against the live dev environment. Captured log signatures prove the Phase 7 wiring chain executes in production:

docs/v2/modbus-addressing.md

@@ -1,208 +0,0 @@
-# Modbus tag-addressing reference
-
-Foundational doc for the Modbus addressing grammar shipped across #136–#144.
-Covers the address-string parser (`ModbusAddressParser`) that the wire driver
-and the Admin UI both consume, the per-tag suffix modifiers, and the family-
-native branch.
-
-## Grammar
-
-```
-<region><offset>[.<bit>][:<type>[<len>]][:<order>][:<count>]
-```
-
-Each field is optional from left to right; the parser fills defaults.
-
-### Region + offset
-
-Three accepted forms — pick whichever matches your tag spreadsheet's
-convention. All three resolve to the same `(Region, ushort PduOffset)`
-on the wire.
-
-| Form | Example | Means |
-|---|---|---|
-| Modicon 5-digit | `40001` | Holding register 1 (PDU 0) |
-| Modicon 6-digit | `400001` | Holding register 1 (PDU 0); supports up to `465536` (PDU 65535) |
-| Mnemonic | `HR1`, `IR1`, `C100`, `DI1` | Same regions; `1`-based register number |
-
-Modicon leading-digit → region:
-
-| Digit | Region | OPC UA wire FC |
-|---|---|---|
-| `0` | Coils | FC01 / FC05 / FC15 |
-| `1` | DiscreteInputs | FC02 (read-only) |
-| `3` | InputRegisters | FC04 (read-only) |
-| `4` | HoldingRegisters | FC03 / FC06 / FC16 |
-
-### Bit suffix `.N`
-
-`40001.5` = bit 5 (LSB-first) of HR[0]. Implies `DataType=BitInRegister`;
-mixing with an explicit type or array-count is rejected.
-
-### Type code `:T`
-
-Codes verified 2026-04-25 against [Wonderware DASMBTCP user
-guide](https://cdn.logic-control.com/media/DASMBTCP.pdf) and the
-[Ignition Modbus addressing
-manual](https://www.docs.inductiveautomation.com/docs/8.1/ignition-modules/opc-ua/opc-ua-drivers/modbus/modbus-addressing).
-The `I` / `UI` / `I_64` / `UI_64` / `BCD_32` shapes match Wonderware's
-suffix convention and Ignition's underscore-N prefix variants where
-those vendors agree.
-
-| Code | Type | Registers | Vendor reference |
-|---|---|---|---|
-| `BOOL` | Boolean | 1 (region must be Coils / DiscreteInputs) | universal |
-| `S` | Int16 | 1 | Wonderware DASMBTCP `S` = 16-bit signed |
-| `US` | UInt16 | 1 | Ignition `HRUS` = Unsigned Short |
-| `I` | Int32 | 2 | Wonderware DASMBTCP `I` = 32-bit signed; Ignition `HRI` |
-| `UI` | UInt32 | 2 | Ignition `HRUI` |
-| `I_64` | Int64 | 4 | Ignition `HRI_64` |
-| `UI_64` | UInt64 | 4 | Ignition `HRUI_64` |
-| `F` | Float32 | 2 | Wonderware `F`; Ignition `HRF` |
-| `D` | Float64 | 4 | Ignition `HRD` |
-| `BCD` | 16-bit BCD | 1 | Ignition `HRBCD` |
-| `BCD_32` | 32-bit BCD | 2 | Ignition `HRBCD_32` |
-| `STR<len>` | ASCII string, `len` chars (2 chars / register) | `ceil(len/2)` | analogous to Ignition `HRS<addr>:<len>` |
-
-Default when omitted:
-- Coils / DiscreteInputs → `BOOL`
-- HoldingRegisters / InputRegisters → `S` (Int16) — matches Ignition's bare-`HR` default
-
-**Codes removed in #146** (silent wrong-data risk, never compatible with the
-two reference vendors): `:DI`, `:L`, `:UDI`, `:UL`, `:LI`, `:ULI`, `:LBCD`.
-Pre-#146 configs that use these get a clear "Unknown type code" diagnostic at
-parse time; rewrite to the post-#146 codes per the table above.
-
-### Byte order `:O`
-
-| Mnemonic | Meaning | Wire |
-|---|---|---|
-| `ABCD` | Big-endian (Modbus spec default) | `[A,B,C,D]` |
-| `CDAB` | Word swap (Siemens, several AB) | `[C,D,A,B]` |
-| `BADC` | Byte swap (legacy little-endian-internal devices) | `[B,A,D,C]` |
-| `DCBA` | Full reverse (some EtherNet/IP gateways) | `[D,C,B,A]` |
-
-For 8-byte values (Int64 / Float64) the same labels apply pairwise.
-
-### Array count `:N`
-
-`40001:F:5` = `Float32[5]` (consumes HR[0..9]). Array + bit suffix is
-rejected. Strings are not arrays.
-
-### Composition
-
-The 3-field shorthand `40001:F:5` is parsed as `(type=F, count=5)` because
-`5` isn't a valid byte-order mnemonic. Use the explicit 4-field form
-`40001:F:CDAB:5` when you need a non-default order.
-
-## Family-native syntax (#144)
-
-When the driver instance has `Family != Generic`, the parser tries the
-family's native syntax FIRST, then falls back to Modicon / mnemonic.
-
-### DL205 (AutomationDirect DirectLOGIC)
-
-| Form | Example | Mapping |
-|---|---|---|
-| `Vnnnn` (octal) | `V2000` | HoldingRegisters[1024] (octal 2000 = decimal 1024) |
-| `Ynn` (octal) | `Y17` | Coils[2048 + 15] (Y-output base + offset) |
-| `Cnn` (octal) | `C100` | Coils[3072 + 64] (C-relay base + offset) |
-| `Xnn` (octal) | `X17` | DiscreteInputs[15] |
-| `SPnn` (octal) | `SP10` | DiscreteInputs[1024 + 8] |
-
-**Cross-family ambiguity**: `C100` means Coils[99] under `Generic`
-(mnemonic) but Coils[3136] under `DL205`. Per-driver Family choice
-disambiguates.
-
-### MELSEC (Mitsubishi)
-
-| Form | Example | Mapping (sub-family Q_L_iQR / F_iQF) |
-|---|---|---|
-| `Dnnn` (decimal) | `D100` | HoldingRegisters[100] |
-| `Mnnn` (decimal) | `M50` | Coils[50] |
-| `Xnn` | `X20` | DiscreteInputs[32 hex / 16 octal] |
-| `Ynn` | `Y20` | Coils[32 hex / 16 octal] |
-
-X / Y digit interpretation depends on `MelsecSubFamily`:
-- `Q_L_iQR` → hex (default)
-- `F_iQF` → octal
-
-Bank-base offsets default to 0 in the grammar string. Sites with non-zero
-"Modbus Device Assignment" bases use the structured tag form.
-
-## Driver-instance options
-
-Beyond per-tag addressing, `ModbusDriverOptions` exposes (#139–#143):
-
-### Connection (#139)
-- `KeepAlive { Enabled, Time, Interval, RetryCount }` — TCP-level probes.
-  Defaults match the historical PR 53 wire output (Enabled=true, Time=30s,
-  Interval=10s, RetryCount=3).
-- `IdleDisconnectTimeout` — proactively close + reconnect after this much
-  socket idle time. Default null = disabled.
-- `Reconnect { InitialDelay, MaxDelay, BackoffMultiplier }` — geometric
-  backoff for the post-drop reconnect loop. Default
-  `(0, 30s, 2.0)` = immediate first retry, geometric thereafter.
-
-### Protocol (#140)
-- `MaxCoilsPerRead` (default 2000) — separate cap for FC01/FC02 coil reads.
-- `UseFC15ForSingleCoilWrites` — force FC15 (write multiple coils
-  qty=1) for single-coil writes. Safety/audit PLCs may require this.
-- `UseFC16ForSingleRegisterWrites` — same for FC16 vs FC06.
-- `DisableFC23` — kill switch for FC23 (currently unused; reserved).
-
-### Subscribe (#141)
-- Per-tag `Deadband` — suppress sub-threshold publishes on numeric tags.
-- `WriteOnChangeOnly` (driver-level) — short-circuit identical-value
-  writes. Cache invalidates on read-divergence.
-
-### Multi-unit (#142)
-- Per-tag `UnitId` — overrides the driver-level UnitId in the MBAP
-  header. Required for one-Ethernet-gateway / N-RTU-slave deployments.
-- `IPerCallHostResolver.ResolveHost` returns `host:port/unitN` per tag so
-  per-PLC circuit breakers fire per slave.
-- Per-tag `CoalesceProhibited` — escape hatch for #143's planner (read
-  this tag in isolation regardless of `MaxReadGap`).
-
-### Block-read coalescing (#143)
-- `MaxReadGap` (default 0 = off) — gap budget the planner is willing to
-  bridge between adjacent register tags. With `MaxReadGap=10`, three tags
-  at HR 100/102/110 collapse into one FC03 of quantity 11.
-
-## JSON DTO shape
-
-The factory accepts both the structured form (legacy) and the new
-`AddressString` form per-tag. Mix freely — newer pasted rows use the
-grammar string; legacy rows keep the structured fields.
-
-```json
-{
-  "host": "10.1.2.3",
-  "port": 502,
-  "unitId": 1,
-  "family": "DL205",
-  "keepAlive": { "enabled": true, "timeMs": 30000, "intervalMs": 10000, "retryCount": 3 },
-  "idleDisconnectMs": 120000,
-  "reconnect": { "initialDelayMs": 0, "maxDelayMs": 30000, "backoffMultiplier": 2.0 },
-  "maxCoilsPerRead": 2000,
-  "writeOnChangeOnly": false,
-  "maxReadGap": 8,
-  "tags": [
-    { "name": "Temp",        "addressString": "V2000:F:CDAB" },
-    { "name": "Setpoint",    "addressString": "40001:I" },
-    { "name": "Outputs",     "addressString": "Y0:5" },
-    { "name": "AlarmCount",  "region": "HoldingRegisters", "address": 200, "dataType": "Int16", "deadband": 5.0 }
-  ]
-}
-```
-
-## Vendor compatibility caveat
-
-The exact spelling of type codes (e.g. `I` vs `INT`, `BCD` vs `L_BCD`) and
-the byte-order mnemonics were synthesised from training-era vendor docs
-(Wonderware DASMBTCP, Kepware KEPServerEX, Ignition, Matrikon, OAS).
-Before locking the grammar for a production deployment, verify against
-the current Kepware "Modbus Ethernet Driver Help" PDF and Ignition's
-"Modbus Addressing" user-manual page — if a critical tool's mnemonics
-have shifted, add aliases in `ModbusAddressParser.TryParseType` rather
-than asking users to rewrite spreadsheets.

docs/v2/multi-host-dispatch.md

@@ -1,46 +0,0 @@
-# Multi-host dispatch — per-PLC circuit breakers
-
-Phase 6.1 decision #144 / task #135. Motivation: a single DriverInstance that fronts N PLCs (Modbus with multiple slaves, AB CIP with multiple ControlLogix chassis, etc.) must not let one dead PLC trip the resilience breaker for its healthy siblings.
-
-This note documents the shipped contract so future driver authors don't re-derive it.
-
-## Contract
-
-The resilience pipeline keys on `(DriverInstanceId, HostName, DriverCapability)`. One dead PLC opens only the pipeline keyed on its HostName; healthy sibling PLCs keep their own pipelines intact.
-
-Three participants:
-
-1. **`DriverResiliencePipelineBuilder.GetOrCreate(driverInstanceId, hostName, capability, options)`** — the pipeline cache. First call per key builds a Polly pipeline (timeout → retry → breaker). Subsequent calls return the cached instance. Covered by `DriverResiliencePipelineBuilderTests.Pipeline_IsIsolated_PerHost`.
-
-2. **`CapabilityInvoker.ExecuteAsync(capability, hostName, callSite, ct)`** — takes `hostName` per-call. Threads it straight through to the pipeline builder. Covered by `CapabilityInvokerTests`.
-
-3. **`IPerCallHostResolver.ResolveHost(fullReference)`** — an optional interface a multi-device driver implements. `DriverNodeManager.ResolveHostFor` calls it on every capability dispatch so the host flowing into the invoker comes from the tag's per-PLC metadata, not the driver instance. Single-device drivers don't implement it — `DriverNodeManager` falls back to `DriverInstanceId` as the hostname, which still flows through the same `(instance, host, capability)` key shape (one pipeline per single-device instance).
-
-End-to-end `dead PLC, healthy PLC` scenario proven by `PerCallHostResolverDispatchTests.DeadPlc_DoesNotOpenBreaker_For_HealthyPlc_With_Resolver`.
-
-## Driver author checklist
-
-To light up per-PLC circuit breakers on a multi-device driver:
-
-1. **Options model** — extend the driver's options type with an explicit device list. See `AbCipDriverOptions.Devices : IReadOnlyList<AbCipDeviceConfig>`.
-2. **Tag → device mapping** — parse the tag's `DeviceId` from `TagConfig`. The driver's per-tag definition records the device HostAddress alongside the wire address. See `AbCipTagDefinition.DeviceHostAddress`.
-3. **`IPerCallHostResolver`** — implement it on the driver. `ResolveHost(fullReference)` looks up the tag's definition and returns the device HostAddress. Unknown references should return a deterministic fallback (e.g. the first configured device's host) rather than throw — the invoker handles the mislookup at capability level when the actual read surfaces `BadNodeIdUnknown`.
-4. **Health surface** — `IHostConnectivityProbe.GetHostStatuses()` returns one `HostConnectivityStatus` per configured device so the Admin UI fleet page lights the per-PLC status distinctly.
-5. **Transport per device** — one network connection per PLC, serialized per device via `SemaphoreSlim` (or equivalent). Do not share a transport across PLCs; the breaker-isolation guarantee disappears if they share a queue.
-
-## Current fleet status (2026-04-24)
-
-| Driver | Per-tag device | `IPerCallHostResolver` | Per-PLC breaker isolation |
-|---|---|---|---|
-| AB CIP | ✅ `DeviceId` | ✅ | ✅ live |
-| AB Legacy | 1 device / instance | — (not needed) | trivial |
-| Modbus | 1 device / instance today | — | trivial — multi-device refactor tracked separately |
-| S7 | 1 device / instance today | — | trivial — same |
-| TwinCAT | 1 device / instance today | — | trivial — same |
-| FOCAS | 1 CNC / instance | — (not needed) | trivial |
-| Galaxy | 1 Galaxy Host / instance | — (not needed) | trivial — Host recycle runs per instance |
-| OPC UA Client | 1 upstream / instance | — (not needed) | trivial |
-
-"Trivial" above means the pipeline key ends up as `(DriverInstanceId, DriverInstanceId, capability)` via `DriverNodeManager.ResolveHostFor`'s fallback — one pipeline per driver instance, which is correct for single-device drivers.
-
-Extending Modbus / S7 / TwinCAT to multi-device follows the AB CIP template verbatim; it's per-driver surgery (schema row + options model + resolver implementation + transport fan-out) rather than shared-infrastructure work.

docs/v2/plan.md

@@ -689,7 +689,7 @@ Galaxy.Proxy ──→ Galaxy.Shared ←── Galaxy.Host
 
 **Decided:**
 - Mono-repo (Decision #31 above).
-- `Core.Abstractions` is **internal-only for now** — no standalone NuGet. Keep the contract mutable while the first 8 drivers are being built; revisit publishing after the driver fleet (originally Phase 5, folded into the Phase 3 umbrella — see exit gate) once the shape has stabilized. Design the contract *as if* it will eventually be public (no leaky types, stable names) to minimize churn later.
+- `Core.Abstractions` is **internal-only for now** — no standalone NuGet. Keep the contract mutable while the first 8 drivers are being built; revisit publishing after Phase 5 when the shape has stabilized. Design the contract *as if* it will eventually be public (no leaky types, stable names) to minimize churn later.
 
 ---
 
@@ -742,30 +742,24 @@ Each step leaves the system runnable. The generic extraction is effectively free
 10. **Build `Galaxy.Proxy`** — .NET 10 in-process proxy implementing IDriver interfaces, forwarding over IPC
 11. **Validate parity** — v2 Galaxy driver must pass the same integration tests as v1
 
-**Phase 3 — Driver fleet (all seven non-Galaxy drivers) — ✅ CLOSED 2026-04-23** (see [`implementation/exit-gate-phase-3.md`](implementation/exit-gate-phase-3.md))
+**Phase 3 — Modbus TCP driver (prove the abstraction)**
+12. **Build `Driver.ModbusTcp`** — NModbus, config-driven tags from central DB, internal poll loop, device-as-folder hierarchy
+13. **Add Modbus config screens to Admin** (first driver-specific config UI)
 
-Originally split across Phase 3 (Modbus alone), Phase 4 (PLC drivers), and
+**Phase 4 — PLC drivers**
-Phase 5 (specialty drivers). In execution, once `Core.Abstractions` had
+14. **Build `Driver.AbCip`** — libplctag, ControlLogix/CompactLogix symbolic tags + Admin config screens
-stabilised under Phase 1 + Phase 2, each driver landed as its own stream
+15. **Build `Driver.AbLegacy`** — libplctag, SLC 500/MicroLogix file-based addressing + Admin config screens
-rather than as a gated mini-phase; the phase numbers were folded into a
+16. **Build `Driver.S7`** — S7netplus, Siemens S7-300/400/1200/1500 + Admin config screens
-single umbrella. Shipped:
+17. **Build `Driver.TwinCat`** — Beckhoff.TwinCAT.Ads v6, native ADS notifications, symbol upload + Admin config screens
 
-12. **`Driver.Modbus`** — NModbus, config-driven tags, internal poll loop, device-as-folder hierarchy (umbrella closure #210)
+**Phase 5 — Specialty drivers**
-13. **`Driver.AbCip`** — libplctag, ControlLogix/CompactLogix symbolic tags (#211, live-booted under #220)
+18. **Build `Driver.Focas`** — FANUC FOCAS2 P/Invoke, pre-defined CNC tag set, PMC/macro config + Admin config screens
-14. **`Driver.AbLegacy`** — libplctag, SLC 500 / MicroLogix / PLC-5 file-based addressing (#213, live-booted under #222)
+19. **Build `Driver.OpcUaClient`** — OPC UA client gateway/aggregation, namespace remapping, subscription proxying + Admin config screens
-15. **`Driver.S7`** — S7netplus, Siemens S7-300/400/1200/1500 (#212, live-booted under #220)
-16. **`Driver.TwinCAT`** — Beckhoff.TwinCAT.Ads v7, native ADS notifications, symbol upload (factory wired 2026-04-23; wire-live deferred, #221)
-17. **`Driver.FOCAS`** — FANUC FOCAS2 P/Invoke via Tier-C out-of-process `Driver.FOCAS.Host` (#220 five-PR split; wire-live deferred, #222 follow-up)
-18. **`Driver.OpcUaClient`** — OPC UA client gateway / aggregation, namespace remapping, subscription proxying (scaffold #66; live-boot 5/8 stages via `test-opcuaclient.ps1`)
-
-Supporting infrastructure: `DriverFactoryRegistry` + `DriverInstanceBootstrapper`
-(#248); per-driver test-client CLI suite (#249–#251); e2e test scripts with
-aggregate runner (#253); server-side factory + seed SQL per driver (#210–#213).
 
 **Decided:**
 - **Parity test for Galaxy**: existing v1 IntegrationTests suite + scripted Client.CLI walkthrough (see Section 4 above).
 - **Timeline**: no hard deadline. Each phase ships when it's right — tests passing, Galaxy parity bar met. Quality cadence over calendar cadence.
-- **FOCAS SDK**: license already secured. FOCAS driver shipped as part of the Phase 3 umbrella with Tier-C host; `Fwlib64.dll` available for P/Invoke (wire-level live-boot gated on lab rig, #222 follow-up).
+- **FOCAS SDK**: license already secured. Phase 5 can proceed as scheduled; `Fwlib64.dll` available for P/Invoke.
 
 ---
 

docs/v2/redundancy-interop-playbook.md

@@ -1,128 +0,0 @@
-# Redundancy Interop Playbook (Phase 6.3 Stream F — task #150)
-
-> **Scope**: manual validation that third-party OPC UA clients + AVEVA MXAccess
-> observe our non-transparent redundancy signals (ServiceLevel, ServerUriArray,
-> RedundancySupport) and fail over to the Backup node when the Primary drops.
->
-> **Why manual**: the third-party clients named here are Windows-GUI binaries
-> (UaExpert, Kepware QuickClient) or embedded inside AVEVA System Platform.
-> Automating any of them into PR-CI is out of scope for v2. This playbook
-> captures the minimal dev-box-plus-VM setup and the expected pass criteria so
-> the work can be executed repeatably at v2 release readiness and after any
-> Phase 6.3 follow-up change.
-
-## Prerequisites
-
-1. Two `OtOpcUa.Server` nodes in one `ServerCluster`:
-   - Declared as `NodeCount = 2`, `RedundancyMode = Hot` (or `Warm`).
-   - Each with a distinct `ApplicationUri` (enforced by unique index per
-     decision #86).
-   - Each node's `StaticRoutes.xml` points at the other (`ServerCluster.Node[].Host`).
-2. `scripts/install/Install-Services.ps1` applied on each node so the
-   `RedundancyPublisherHostedService` is running.
-3. At least one `DriverInstance` with a reachable simulator or PLC so both
-   servers have a non-empty address space to browse.
-4. On the client host:
-   - `UaExpert` ≥ 1.7 installed
-   - Kepware `ClientAce QuickClient` (or equivalent) — optional, for a second
-     client
-5. For the AVEVA leg: a `Galaxy.Host` running against an MXAccess deployment
-   with an external OPC UA client object pointed at the cluster (not at a
-   single node).
-
-## Expected signals on a running cluster
-
-| Node | `ServiceLevel` | `RedundancySupport` | `ServerUriArray` |
-|---|---|---|---|
-| Primary, healthy, peer reachable | 200 | `Hot` (or `Warm`) | self + peer |
-| Primary, mid-apply | 75 (`PrimaryMidApply`) | same | same |
-| Primary, peer UNreachable | 150 (`PrimaryPeerDown`) | same | same |
-| Backup, healthy | 100 (`Secondary`) | same | same |
-| Either, dwelling in recovery | 50 (`Recovering`) | same | same |
-| Either, invariant violation (two Primary, disabled-node mismatch) | 2 (`InvalidTopology`) | same | same |
-
-(The band constants live in `ServiceLevelCalculator.Classify`.)
-
-## Test matrix
-
-Each row is one manual run; pass criterion in the right column.
-
-### Block A — UA protocol signals (UaExpert)
-
-| # | Scenario | Procedure | Pass criterion |
-|---|---|---|---|
-| A1 | ServiceLevel published | Connect UaExpert to Primary. Browse to `Server.ServerStatus.ServiceLevel`. | Value = 200 (or the expected Band byte per table above) |
-| A2 | ServiceLevel updates on peer down | Connect to Primary. Stop Backup (`sc stop OtOpcUa`). Watch `ServiceLevel`. | Transitions 200 → 150 within ~2 s of peer probe timeout |
-| A3 | RedundancySupport | Browse to `Server.ServerRedundancy.RedundancySupport`. | Value matches the declared `RedundancyMode` (Warm / Hot / None) |
-| A4 | ServerUriArray (non-transparent upgrade) | Requires a redundancy-object-type upgrade follow-up. | When upgrade lands: `ServerUriArray` reports both ApplicationUris, self first |
-| A5 | Mid-apply dip | On Primary trigger a `sp_PublishGeneration` apply. | `ServiceLevel` drops to 75 for the apply duration + dwell |
-
-### Block B — Client failover
-
-| # | Scenario | Procedure | Pass criterion |
-|---|---|---|---|
-| B1 | UaExpert picks Primary by ServiceLevel | In UaExpert configure a Redundancy Group with both endpoint URLs. | Client picks the Primary URL (higher ServiceLevel) |
-| B2 | UaExpert cuts over on Primary kill | Kill the Primary's `OtOpcUa` service. | Client session reconnects to Backup within UaExpert's reconnect timeout (default 5 s). Data-change monitored items resume. |
-| B3 | UaExpert cuts back when Primary returns | Start the Primary service. Wait ≥ recovery dwell (see `RecoveryStateManager.DwellTime`). | `ServiceLevel` on returning Primary goes through 50 (Recovering) → 200; UaExpert may or may not switch back (client-policy dependent; both are accepted outcomes) |
-| B4 | Kepware QuickClient failover | Repeat B1–B3 with Kepware in place of UaExpert. | Same pass criteria; establishes we're not UaExpert-specific |
-
-### Block C — Galaxy MXAccess failover
-
-This block validates that an AVEVA System Platform app consuming our cluster
-via MXAccess tolerates a Primary drop the same way a native OPC UA client does.
-The MXAccess toolkit internally wraps the OPC UA Client and does its own
-redundancy negotiation; we're asserting that negotiation honors our
-`ServiceLevel` signal.
-
-| # | Scenario | Procedure | Pass criterion |
-|---|---|---|---|
-| C1 | Galaxy binds to Primary on first connect | Bring the cluster up. Start a Galaxy `$MxAccessClient` object pointed at the cluster with both node URLs. | Galaxy reports `QUALITY = Good` + initial values from the Primary |
-| C2 | Galaxy redirects on Primary drop | Stop the Primary. | Galaxy's `QUALITY` briefly goes `Uncertain`, then back to `Good`; values continue streaming from the Backup within MXAccess's `ReconnectInterval` (default 20 s) |
-| C3 | Galaxy handles mid-apply dip | Trigger a generation apply on the Primary. | Galaxy continues reading — the mid-apply dip is advertisory (ServiceLevel 75), not a session drop; MXAccess should stay bound |
-
-## Recording results
-
-Copy the tables above into a tracking doc per run. The tracking doc shape:
-
-```
-Run date: 2026-MM-DD
-Cluster: <id>  Primary: <node>  Backup: <node>  Release: <sha>
-A1: PASS  evidence: UaExpert screenshot uaexpert-a1.png
-A2: PASS  evidence: ServiceLevel trend grafana-a2.png
-…
-```
-
-One pass of every row is the acceptance criterion. Re-run after any Phase 6.3
-follow-up ships (especially the non-transparent redundancy-type upgrade, which
-flips A4 from "deferred" to "expected pass").
-
-## Known limitations
-
-- **A4 pending**: `Server.ServerRedundancy` on our current SDK build lands as
-  the base `ServerRedundancyState`, which has no `ServerUriArray` child.
-  `ServerRedundancyNodeWriter.ApplyServerUriArray` logs-and-skips until the
-  redundancy-object-type upgrade follow-up lands.
-- **Recovery dwell default**: `RecoveryStateManager.DwellTime` defaults to 60 s
-  in `Program.cs`. Adjust via future config knob if B3 takes too long to
-  observe.
-- **C-block external dependency**: The `Galaxy.Host` side of the redundancy
-  story is largely out of our code — it's MXAccess's own client-redundancy
-  policy talking to our published ServiceLevel. A negative result on C1-C3
-  does not necessarily indicate an OtOpcUa bug; cross-check with UaExpert
-  (Block A / B) first.
-
-## Automation notes (why this is a playbook, not a test)
-
-- UaExpert and Kepware binaries are closed-source Windows GUIs; they don't
-  ship headless CLIs for the browse/connect/subscribe flows.
-- The OPC Foundation reference SDK *can* drive every scenario, but our own
-  `Driver.OpcUaClient` tests already cover that client's behaviour; Block B
-  adds value specifically because these two clients have independent
-  redundancy implementations we don't control.
-- For the sub-set of scenarios that *can* be automated — the self-loopback
-  case where our own `otopcua-cli` drives Primary + Backup — the existing
-  `tests/ZB.MOM.WW.OtOpcUa.Server.Tests/RedundancyStatePublisherTests` +
-  `ServiceLevelCalculatorTests` (unit) + `ClusterTopologyLoaderTests`
-  (integration) already cover the math + data path. The wire-level assertion
-  that the values actually land on the right OPC UA nodes is covered by
-  `ServerRedundancyNodeWriterTests`.

docs/v2/v2-release-readiness.md

@@ -1,7 +1,7 @@
 # v2 Release Readiness
 
-> **Last updated**: 2026-04-24 (Phase 5 driver complement closed — AB CIP, AB Legacy, TwinCAT, FOCAS all shipped; FOCAS Tier-C retired for a pure-managed in-process client)
+> **Last updated**: 2026-04-19 (all three release blockers CLOSED — Phase 6.3 Streams A/C core shipped)
-> **Status**: **RELEASE-READY (code-path)** for v2 GA. All three original code-path release blockers remain closed. Phase 5 is now complete. Remaining work is manual (live-hardware validations, client interop matrix, deployment checklist signoff, OPC UA CTT pass) + hardening follow-ups; see exit-criteria checklist below.
+> **Status**: **RELEASE-READY (code-path)** for v2 GA — all three code-path release blockers are closed. Remaining work is manual (client interop matrix, deployment checklist signoff, OPC UA CTT pass) + hardening follow-ups; see exit-criteria checklist below.
 
 This doc is the single view of where v2 stands against its release criteria. Update it whenever a deferred follow-up closes or a new release blocker is discovered.
 
@@ -14,78 +14,67 @@ This doc is the single view of where v2 stands against its release criteria. Upd
 | Phase 2 — Galaxy driver split (Proxy/Host/Shared) | ✓ | Shipped |
 | Phase 3 — OPC UA server + LDAP + security profiles | ✓ | Shipped |
 | Phase 4 — Redundancy scaffold (entities + endpoints) | ✓ | Shipped (runtime closes in 6.3) |
-| Phase 5 — Drivers | ✓ | **Shipped** — Galaxy, Modbus (+ DL205/S7/MELSEC profiles), S7 native, OPC UA Client, AB CIP, AB Legacy, TwinCAT ADS, FOCAS (managed wire client) |
+| Phase 5 — Drivers | ⚠ partial | Galaxy / Modbus / S7 / OpcUaClient shipped; AB CIP / AB Legacy / TwinCAT / FOCAS deferred (task #120) |
-| Phase 6.1 — Resilience & Observability | ✓ | Shipped (PRs #78–83) |
+| Phase 6.1 — Resilience & Observability | ✓ | **SHIPPED** (PRs #78–83) |
-| Phase 6.2 — Authorization runtime | ◐ core | Core shipped (PRs #84–88, #94 dispatch wiring); finer-grained Browse/Subscribe/Alarm/Call gating + 3-user interop matrix deferred |
+| Phase 6.2 — Authorization runtime | ◐ core | **SHIPPED (core)** (PRs #84–88); dispatch wiring + Admin UI deferred |
-| Phase 6.3 — Redundancy runtime | ◐ core | Core shipped (PRs #89–90, #98–99); peer-probe HostedServices, OPC UA variable-node binding, `sp_PublishGeneration` lease wrap, client interop matrix deferred |
+| Phase 6.3 — Redundancy runtime | ◐ core | **SHIPPED (core)** (PRs #89–90); coordinator + UA-node wiring + Admin UI + interop deferred |
-| Phase 6.4 — Admin UI completion | ◐ data layer + Identification | Data layer + OPC 40010 Identification folder shipped (PRs #91–92, Identification audit close-out 2026-04-23); Blazor UI pieces deferred |
+| Phase 6.4 — Admin UI completion | ◐ data layer | **SHIPPED (data layer)** (PRs #91–92); Blazor UI + OPC 40010 address-space wiring deferred |
 
-**Driver integration-test counts** (end-to-end against live or simulated targets): Modbus 26, FOCAS 9, AbCip 7, OpcUaClient 3, S7 3, AbLegacy 2, TwinCAT 2. Plus Galaxy's separate cross-FX parity/stability suite.
+**Aggregate test counts:** 906 baseline (pre-Phase-6) → **1159 passing** across Phase 6. One pre-existing Client.CLI `SubscribeCommandTests.Execute_PrintsSubscriptionMessage` flake tracked separately.
-
-**Aggregate test counts** (2026-04-19 baseline): 1159 passing across the solution. One pre-existing Client.CLI `SubscribeCommandTests.Execute_PrintsSubscriptionMessage` flake tracked separately. Rerun `dotnet test ZB.MOM.WW.OtOpcUa.slnx` after the FOCAS migration commits land to refresh the number.
 
 ## Release blockers (must close before v2 GA)
 
-All code-path release blockers are closed. The remaining items are live-hardware / manual validations listed under exit criteria.
+Ordered by severity + impact on production fitness.
 
 ### ~~Security — Phase 6.2 dispatch wiring~~ (task #143 — **CLOSED** 2026-04-19, PR #94)
 
-**Closed**. `AuthorizationGate` + `NodeScopeResolver` thread through `OpcUaApplicationHost → OtOpcUaServer → DriverNodeManager`. `OnReadValue` + `OnWriteValue` + all four HistoryRead paths call `gate.IsAllowed(identity, operation, scope)` before the invoker. Production deployments activate enforcement by constructing `OpcUaApplicationHost` with an `AuthorizationGate(StrictMode: true)` + populating the `NodeAcl` table.
+**Closed**. `AuthorizationGate` + `NodeScopeResolver` now thread through `OpcUaApplicationHost → OtOpcUaServer → DriverNodeManager`. `OnReadValue` + `OnWriteValue` + all four HistoryRead paths call `gate.IsAllowed(identity, operation, scope)` before the invoker. Production deployments activate enforcement by constructing `OpcUaApplicationHost` with an `AuthorizationGate(StrictMode: true)` + populating the `NodeAcl` table.
 
-Remaining Stream C surfaces (hardening, not release-blocking):
+Additional Stream C surfaces (not release-blocking, hardening only):
 
-- ~~Browse + TranslateBrowsePathsToNodeIds gating with ancestor-visibility logic per `acl-design.md` §Browse.~~ **Partial, 2026-04-24.** `DriverNodeManager.Browse` override post-filters the `ReferenceDescription` list via a new `FilterBrowseReferences` helper — denied nodes disappear silently per OPC UA convention. Ancestor-visibility implication (Read-grant at `Line/Tag` implying Browse on `Line`) still to ship; needs a subtree-has-any-grant query on the trie evaluator. `TranslateBrowsePathsToNodeIds` surface not yet wired.
+- Browse + TranslateBrowsePathsToNodeIds gating with ancestor-visibility logic per `acl-design.md` §Browse.
-- ~~CreateMonitoredItems + TransferSubscriptions gating with per-item `(AuthGenerationId, MembershipVersion)` stamp so revoked grants surface `BadUserAccessDenied` within one publish cycle (decision #153).~~ **Partial, 2026-04-24.** `DriverNodeManager.CreateMonitoredItems` override pre-gates each request and pre-populates `BadUserAccessDenied` into the errors slot for denied items (the base stack honours pre-set errors and skips those items). Decision #153's per-item `(AuthGenerationId, MembershipVersion)` stamp for detecting mid-subscription revocation is still to ship — needs subscription-layer plumbing. TransferSubscriptions not yet wired (same pattern).
+- CreateMonitoredItems + TransferSubscriptions gating with per-item `(AuthGenerationId, MembershipVersion)` stamp so revoked grants surface `BadUserAccessDenied` within one publish cycle (decision #153).
-- ~~Alarm Acknowledge / Confirm / Shelve gating.~~ **Partial, 2026-04-24.** Acknowledge + Confirm map to dedicated `OpcUaOperation.AlarmAcknowledge` / `AlarmConfirm` via `MapCallOperation`; Shelve falls through to generic `OpcUaOperation.Call` (needs per-instance method NodeId resolution to distinguish — follow-up).
+- Alarm Acknowledge / Confirm / Shelve gating.
-- ~~Call (method invocation) gating.~~ **Closed 2026-04-24.** `DriverNodeManager.Call` override pre-gates each `CallMethodRequest` via `GateCallMethodRequests`. Denied calls return `BadUserAccessDenied` without running the method. Alarm methods map to alarm-specific operation kinds; everything else gates as generic `Call`.
+- Call (method invocation) gating.
-- ~~Finer-grained scope resolution — current `NodeScopeResolver` returns a flat cluster-level scope. Joining against the live Configuration DB to populate UnsArea / UnsLine / Equipment path is tracked as Stream C.12.~~ **Closed 2026-04-24.** `AuthorizationBootstrap` now loads `NodeAcl` rows for the current generation into a `PermissionTrieCache`, builds the gate, and merges every registered driver's `EquipmentNamespaceContent` into a full-path `NodeScopeResolver` index. `OpcUaServerService` calls the bootstrap after the equipment registry is populated, before `OpcUaApplicationHost.StartAsync`. Disabled by default — operators flip `Node:Authorization:Enabled=true` to enforce, `StrictMode=true` to reject anonymous/no-groups identities.
+- Finer-grained scope resolution — current `NodeScopeResolver` returns a flat cluster-level scope. Joining against the live Configuration DB to populate UnsArea / UnsLine / Equipment path is tracked as Stream C.12.
 - 3-user integration matrix covering every operation × allow/deny.
 
+These are additional hardening — the three highest-value surfaces (Read / Write / HistoryRead) are now gated, which covers the base-security gap for v2 GA.
+
 ### ~~Config fallback — Phase 6.1 Stream D wiring~~ (task #136 — **CLOSED** 2026-04-19, PR #96)
 
-**Closed**. `SealedBootstrap` consumes `ResilientConfigReader` + `GenerationSealedCache` + `StaleConfigFlag` end-to-end; `/healthz` surfaces the stale flag.
+**Closed**. `SealedBootstrap` consumes `ResilientConfigReader` + `GenerationSealedCache` + `StaleConfigFlag` end-to-end: bootstrap calls go through the timeout → retry → fallback-to-sealed pipeline; every central-DB success writes a fresh sealed snapshot so the next cache-miss has a known-good fallback; `StaleConfigFlag.IsStale` is now consumed by `HealthEndpointsHost.usingStaleConfig` so `/healthz` body reports reality.
 
-Remaining follow-ups (hardening):
+Production activation: Program.cs switches `NodeBootstrap → SealedBootstrap` + constructs `OpcUaApplicationHost` with the `StaleConfigFlag` as an optional ctor parameter.
+
+Remaining follow-ups (hardening, not release-blocking):
 
 - A `HostedService` that polls `sp_GetCurrentGenerationForCluster` periodically so peer-published generations land in this node's cache without a restart.
-- Richer snapshot payload via `sp_GetGenerationContent` so fallback can serve full generation content (DriverInstance enumeration, ACL rows, etc.) from the sealed cache alone.
+- Richer snapshot payload via `sp_GetGenerationContent` so fallback can serve the full generation content (DriverInstance enumeration, ACL rows, etc.) from the sealed cache alone.
 
 ### ~~Redundancy — Phase 6.3 Streams A/C core~~ (tasks #145 + #147 — **CLOSED** 2026-04-19, PRs #98–99)
 
-**Closed**. `RedundancyCoordinator` + `RedundancyStatePublisher` + `PeerReachabilityTracker` orchestrate topology + apply lease + recovery state + peer reachability through `ServiceLevelCalculator` + emit `OnStateChanged` / `OnServerUriArrayChanged` edge-triggered events.
+**Closed**. The runtime orchestration layer now exists end-to-end:
+
+- `RedundancyCoordinator` reads `ClusterNode` + peer list at startup (Stream A shipped in PR #98). Invariants enforced: 1-2 nodes (decision #83), unique ApplicationUri (#86), ≤1 Primary in Warm/Hot (#84). Startup fails fast on violation; runtime refresh logs + flips `IsTopologyValid=false` so the calculator falls to band 2 without tearing down.
+- `RedundancyStatePublisher` orchestrates topology + apply lease + recovery state + peer reachability through `ServiceLevelCalculator` + emits `OnStateChanged` / `OnServerUriArrayChanged` edge-triggered events (Stream C core shipped in PR #99). The OPC UA `ServiceLevel` Byte variable + `ServerUriArray` String[] variable subscribe to these events.
 
 Remaining Phase 6.3 surfaces (hardening, not release-blocking):
 
-- ~~`PeerHttpProbeLoop` + `PeerUaProbeLoop` HostedServices populating `PeerReachabilityTracker` on each tick.~~ **Closed 2026-04-24.** Two-layer probe model shipped: HTTP probe at 2 s / 1 s timeout against `/healthz`; OPC UA probe at 10 s / 5 s timeout via `DiscoveryClient.GetEndpoints`, short-circuiting when HTTP reports the peer unhealthy. Registered on the Server as `AddHostedService<PeerHttpProbeLoop>` + `AddHostedService<PeerUaProbeLoop>`. Publisher now sees accurate `PeerReachability` per peer instead of degrading to `Unknown` → Isolated-Primary band (230).
+- `PeerHttpProbeLoop` + `PeerUaProbeLoop` HostedServices that poll the peer + write to `PeerReachabilityTracker` on each tick. Without these the publisher sees `PeerReachability.Unknown` for every peer → Isolated-Primary band (230) even when the peer is up. Safe default (retains authority) but not the full non-transparent-redundancy UX.
-- OPC UA variable-node wiring: bind `ServiceLevel` Byte + `ServerUriArray` String[] to the publisher's events via `BaseDataVariable.OnReadValue` / direct value push.
+- OPC UA variable-node wiring layer: bind the `ServiceLevel` Byte node + `ServerUriArray` String[] node to the publisher's events via `BaseDataVariable.OnReadValue` / direct value push. Scoped follow-up on the Opc.Ua.Server stack integration.
-- ~~`sp_PublishGeneration` wraps its apply in `await using var lease = coordinator.BeginApplyLease(...)` so the `PrimaryMidApply` band (200) fires during actual publishes (task #148 part 2).~~ **Closed 2026-04-24.** The apply loop now lives in `GenerationRefreshHostedService` — polls `sp_GetCurrentGenerationForCluster` every 5s, opens a lease when a new generation is detected, calls `RedundancyCoordinator.RefreshAsync` inside the `await using`, releases the lease on all exit paths. Replaces the previous "topology never refreshes without a process restart" behaviour.
+- `sp_PublishGeneration` wraps its apply in `await using var lease = coordinator.BeginApplyLease(...)` so the `PrimaryMidApply` band (200) fires during actual publishes (task #148 part 2).
-- Client interop matrix — Ignition / Kepware / Aveva OI Gateway (Stream F, task #150). Manual + doc-only.
+- Client interop matrix validation — Ignition / Kepware / Aveva OI Gateway (Stream F, task #150). Manual + doc-only work; doesn't block code ship.
 
-### ~~Phase 5 driver complement~~ (task #120 — **CLOSED** 2026-04-24)
+### Remaining drivers (task #120)
 
-**Closed**. All four deferred drivers shipped:
+AB CIP, AB Legacy, TwinCAT ADS, FOCAS drivers are planned but unshipped. Decision pending on whether these are release-blocking for v2 GA or can slip to a v2.1 follow-up.
-
-- **AB CIP** (PRs #202–222) — `Driver.AbCip`, `Driver.AbCip.IntegrationTests` (7 tests), AB CIP Cli. Live-boot verified against a ControlLogix rig.
-- **AB Legacy** (PRs #202, #223) — `Driver.AbLegacy`, `Driver.AbLegacy.IntegrationTests` (2 tests), AB Legacy Cli. PCCC cip-path workaround for SLC/MicroLogix.
-- **TwinCAT ADS** (PRs #205, this branch `task-galaxy-e2e`) — `Driver.TwinCAT`, `Driver.TwinCAT.IntegrationTests` (2 tests), TwinCAT Cli. TCBSD/ESXi fixture for e2e since local Hyper-V / TwinCAT RTIME are mutually exclusive on the dev box.
-- **FOCAS** (PRs #173, #199 + this session's migration) — `Driver.FOCAS` with an **in-process managed `FocasWireClient`** that speaks FOCAS/2 over TCP directly. Tier-C isolation retired — `Driver.FOCAS.Host` + `Driver.FOCAS.Shared` + `FwlibNative` P/Invoke + shim DLL + NSSM service all deleted. `Driver.FOCAS.IntegrationTests` covers 9 scenarios (fixed tree identity/axes/program/timers/spindle + user-authored PARAM/MACRO/PMC reads, Browse, Subscribe, IAlarmSource raise/clear, Probe transitions).
-
-Decision recorded: FOCAS is **read-only** against the CNC by design — writes return `BadNotWritable`. See `docs/drivers/FOCAS.md` + `docs/drivers/FOCAS-Test-Fixture.md` for the deployment + coverage map.
 
 ## Nice-to-haves (not release-blocking)
 
 - **Admin UI** — Phase 6.1 Stream E.2/E.3 (`/hosts` column refresh), Phase 6.2 Stream D (`RoleGrantsTab` + `AclsTab` Probe), Phase 6.3 Stream E (`RedundancyTab`), Phase 6.4 Streams A/B UI pieces, Stream C DiffViewer, Stream D `IdentificationFields.razor`. Tasks #134, #144, #149, #153, #155, #156, #157.
 - **Background services** — Phase 6.1 Stream B.4 `ScheduledRecycleScheduler` HostedService (task #137), Phase 6.1 Stream A analyzer (task #135 — Roslyn analyzer asserting every capability surface routes through `CapabilityInvoker`).
-- **Multi-host dispatch** — Phase 6.1 Stream A follow-up (task #135). Every driver currently gets a single pipeline keyed on `driver.DriverInstanceId`; multi-host drivers (Modbus with N PLCs) need per-PLC host resolution so failing PLCs trip per-PLC breakers without poisoning siblings. Decision #144 requires this but not wired.
+- **Multi-host dispatch** — Phase 6.1 Stream A follow-up (task #135). Currently every driver gets a single pipeline keyed on `driver.DriverInstanceId`; multi-host drivers (Modbus with N PLCs) need per-PLC host resolution so failing PLCs trip per-PLC breakers without poisoning siblings. Decision #144 requires this but we haven't wired it yet.
-- **Phase 7** — scripting + alarming + historian sink (plan drafted 2026-04-20 in `docs/v2/implementation/phase-7-*.md`). Out of scope for v2 GA.
-
-## Live-hardware validations (task #54 + task family)
-
-The code ships; these tasks remain open as lab/field verification:
-
-- **#54** — FOCAS live-CNC wire-level smoke against a real FANUC control. The mock's wire responder is PDU-verified against `fwlibe64.dll` upstream but OtOpcUa's managed client has not been pointed at a production CNC.
-- **AB CIP live-boot** — already passed on a ControlLogix rig (PR #222). Continue to run ahead of each release.
-- **TwinCAT wire-live** — TCBSD/ESXi fixture covers the common path; production PLC verification remains lab-gated.
 
 ## Running the release-readiness check
 
@@ -93,12 +82,7 @@ The code ships; these tasks remain open as lab/field verification:
 pwsh ./scripts/compliance/phase-6-all.ps1
 ```
 
-This meta-runner invokes each `phase-6-N-compliance.ps1` script in sequence and reports an aggregate PASS/FAIL:
+This meta-runner invokes each `phase-6-N-compliance.ps1` script in sequence and reports an aggregate PASS/FAIL. It is the single-command verification that what we claim is shipped still compiles + tests pass + the plan-level invariants are still satisfied.
-
-- `phase-6-1-compliance.ps1` — Resilience & Observability
-- `phase-6-2-compliance.ps1` — Authorization runtime
-- `phase-6-3-compliance.ps1` — Redundancy runtime
-- `phase-6-4-compliance.ps1` — Admin UI completion
 
 Exit 0 = every phase passes its compliance checks + no test-count regression.
 
@@ -108,23 +92,18 @@ v2 GA requires all of the following:
 
 - [ ] All four Phase 6.N compliance scripts exit 0.
 - [ ] `dotnet test ZB.MOM.WW.OtOpcUa.slnx` passes with ≤ 1 known-flake failure.
-- [x] Release blockers listed above all closed.
+- [ ] Release blockers listed above all closed (or consciously deferred to v2.1 with a written decision).
-- [x] Phase 5 driver complement shipped (Galaxy, Modbus, S7, OpcUaClient, AbCip, AbLegacy, TwinCAT, FOCAS).
 - [ ] Production deployment checklist (separate doc) signed off by Fleet Admin.
 - [ ] At least one end-to-end integration run against the live Galaxy on the dev box succeeds.
-- [ ] FOCAS live-CNC wire-level smoke (#54) runs clean against a real FANUC control.
 - [ ] OPC UA conformance test (CTT or UA Compliance Test Tool) passes against the live endpoint.
 - [ ] Non-transparent redundancy cutover validated with at least one production client (Ignition 8.3 recommended — see decision #85).
 
 ## Change log
 
-- **2026-04-24** — Phase 5 driver complement closed (task #120 CLOSED). AB CIP, AB Legacy, TwinCAT, FOCAS all shipped. FOCAS migration: retired the Tier-C split (`Driver.FOCAS.Host` + `Driver.FOCAS.Shared` + `FwlibNative` + shim DLL deleted) in favour of a pure-managed in-process `FocasWireClient` inlined into `Driver.FOCAS`; driver is now read-only against the CNC by design. Integration test matrix grew to cover Browse / Subscribe / IAlarmSource / Probe end-to-end.
+- **2026-04-19** — Release blocker #3 **closed** (PRs #98–99). Phase 6.3 Streams A + C core shipped: `ClusterTopologyLoader` + `RedundancyCoordinator` + `RedundancyStatePublisher` + `PeerReachabilityTracker`. Code-path release blockers all closed; remaining Phase 6.3 surfaces (peer-probe HostedServices, OPC UA variable-node binding, sp_PublishGeneration lease wrap, client interop matrix) are hardening follow-ups.
-- **2026-04-23** — Phase 6.4 audit close-out. IdentificationFolderBuilder + OPC 40010 Identification folder verified against the shipped code.
+- **2026-04-19** — Release blocker #2 **closed** (PR #96). `SealedBootstrap` consumes `ResilientConfigReader` + `GenerationSealedCache` + `StaleConfigFlag`; `/healthz` now surfaces the stale flag. Remaining follow-ups (periodic poller + richer snapshot payload) downgraded to hardening.
-- **2026-04-20** — Phase 7 plan drafted (`phase-7-scripting-and-alarming.md`, `phase-7-e2e-smoke.md`). Out of scope for v2 GA.
+- **2026-04-19** — Release blocker #1 **closed** (PR #94). `AuthorizationGate` wired into `DriverNodeManager` Read / Write / HistoryRead dispatch. Remaining Stream C surfaces (Browse / Subscribe / Alarm / Call + finer-grained scope resolution) downgraded to hardening follow-ups — no longer release-blocking.
-- **2026-04-19** — Release blocker #3 closed (PRs #98–99). Phase 6.3 Streams A + C core shipped: `ClusterTopologyLoader` + `RedundancyCoordinator` + `RedundancyStatePublisher` + `PeerReachabilityTracker`. Code-path release blockers all closed; remaining Phase 6.3 surfaces (peer-probe HostedServices, OPC UA variable-node binding, `sp_PublishGeneration` lease wrap, client interop matrix) are hardening follow-ups.
+- **2026-04-19** — Phase 6.4 data layer merged (PRs #91–92). Phase 6 core complete. Capstone doc created.
-- **2026-04-19** — Release blocker #2 closed (PR #96). `SealedBootstrap` consumes `ResilientConfigReader` + `GenerationSealedCache` + `StaleConfigFlag`; `/healthz` surfaces the stale flag. Remaining follow-ups (periodic poller + richer snapshot payload) downgraded to hardening.
-- **2026-04-19** — Release blocker #1 closed (PR #94). `AuthorizationGate` wired into `DriverNodeManager` Read / Write / HistoryRead dispatch. Remaining Stream C surfaces (Browse / Subscribe / Alarm / Call + finer-grained scope resolution) downgraded to hardening follow-ups — no longer release-blocking.
-- **2026-04-19** — Phase 6.4 data layer merged (PRs #91–92). Phase 6 core complete.
 - **2026-04-19** — Phase 6.3 core merged (PRs #89–90). `ServiceLevelCalculator` + `RecoveryStateManager` + `ApplyLeaseRegistry` land as pure logic; coordinator / UA-node wiring / Admin UI / interop deferred.
 - **2026-04-19** — Phase 6.2 core merged (PRs #84–88). `AuthorizationGate` + `TriePermissionEvaluator` + `LdapGroupRoleMapping` land; dispatch wiring + Admin UI deferred.
 - **2026-04-19** — Phase 6.1 shipped (PRs #78–83). Polly resilience + Tier A/B/C stability + health endpoints + LiteDB generation-sealed cache + Admin `/hosts` data layer all live.

docs/v3/twincat-backlog.md

@@ -1,31 +0,0 @@
-# TwinCAT driver — v3 backlog
-
-The v2 TwinCAT driver is considered solid: 28 integration tests (14 `[TwinCATFact]` +
-16-case `[TwinCATTheory]`) running live against the TCBSD fixture, 110 unit tests,
-three latent driver bugs shaken out (notification cycle units, `STRING(N)` mapper,
-bit-indexed BOOL path). Further work is deferred.
-
-Archived from `docs/drivers/TwinCAT-Test-Fixture.md` § Follow-up candidates.
-
-## Deferred items
-
-1. **TC2 coverage** — spin up a TC2 runtime (Windows CE IPC or legacy XAR)
-   and run the same suite; any delta surfaces. Blocked on hardware.
-
-2. **Notification coalescing under load** — run the subscribe test while
-   the PLC cycle is saturated (bump `lineSim` complexity, watch for
-   dropped notifications). Doable on current rig; deferred as lower
-   priority than v3 feature work.
-
-3. **Multi-hop AMS route** — add a test behind an IPC gateway with a
-   chained route entry. Blocked on hardware (gateway IPC).
-
-4. **License-rotation automation** — XAR's 7-day trial expires on
-   schedule. Either automate `TcActivate.exe /reactivate` via a scheduled
-   task on the VM (not officially supported; reportedly works for some
-   TC3 builds), or buy a paid runtime license (~$1k one-time per runtime
-   per CPU) to kill the rotation. Ops item, not code.
-
-5. **Lab rig** — cheapest IPC (CX7000 / CX9020) on a dedicated network;
-   the only route that covers TC2 + real EtherCAT I/O timing + cycle
-   jitter under CPU load. Blocked on hardware + budget.

docs/v3/twincat-eventlogger-spike.md

@@ -0,0 +1,101 @@
+# TC3 EventLogger spike — managed-wrapper investigation
+
+**Question (b) from the PR 5.1 / #316 plan**: Does Beckhoff publish a
+managed `TcEventLogger` wrapper that lets the driver subscribe to
+alarms via `EventLogger.AlarmRaised` instead of decoding AMS port 110
+notifications by hand?
+
+## TL;DR
+
+**No managed wrapper.** The `Beckhoff.TwinCAT.Ads` v6 NuGet (the regular
+managed SDK the driver already takes a dependency on) ships only the
+ADS read/write/notification surface — it does not surface
+`TcEventLogger` on the .NET side. The C++ TcCOM headers
+(`TcEventLogger.h` etc.) exist in the on-box TwinCAT install
+(`%TC_INSTALLPATH%\Components\TcEventLogger\`) but there is no managed
+projection of those COM interfaces in any official Beckhoff NuGet as
+of TC3 build 4024.x.
+
+Decision: **ship a binary-protocol decode against AMS port 110**
+(`AMSPORT_EVENTLOG`) with index group `ADSIGRP_TCEVENTLOG_ALARMS`. The
+decoder lands in `AdsTwinCATAlarmGate` (production) and `NullTwinCATAlarmGate`
+(default / no-op). Best-effort field decoding — fields the protocol
+analyzer hasn't yet identified surface as `"Unknown"`.
+
+## What was checked
+
+| Source | Result |
+| --- | --- |
+| `Beckhoff.TwinCAT.Ads` v6.x NuGet, namespace inventory | `TwinCAT.Ads`, `TwinCAT.Ads.SumCommand`, `TwinCAT.Ads.TypeSystem`, `TwinCAT.TypeSystem`. **No** `TcEventLogger` namespace. |
+| `Beckhoff.TwinCAT.Ads.TcpRouter` v6.x NuGet | Router only; no EventLogger surface. |
+| Beckhoff Information System (Infosys) → TwinCAT 3 → EventLogger → API reference | Documents only the C++ TcCOM API + the PLC-side `Tc3_EventLogger` library. No managed-language section. |
+| TwinCAT install on dev box → `Components\TcEventLogger\` | C++ headers + DLL only; the `.tlb` could be COM-imported via `tlbimp` but that creates a brittle install-path-coupled binding. |
+| Public Beckhoff GitHub orgs | `Beckhoff/TwinCAT-Tools-Library` etc. — no managed EventLogger wrapper. |
+
+## Why decode at the wire?
+
+A `tlbimp` projection of the on-box TcCOM `.tlb` would technically work
+but introduces three problems:
+
+1. **Install-path coupling** — the `.tlb` lives under
+   `%TC_INSTALLPATH%`; the driver would need to find / load it at
+   runtime + ship a per-build interop assembly.
+2. **Bitness lock-in** — TcCOM is x86; the driver builds AnyCPU.
+3. **No upgrade path** — Beckhoff makes no API-stability guarantees
+   on the TcCOM surface across TC3 builds.
+
+Direct AMS-port-110 notifications keep the driver coupled to **only**
+the `Beckhoff.TwinCAT.Ads` v6 NuGet's stable wire surface. Trade-off:
+the binary protocol is undocumented in managed-code form; we work
+around that by:
+
+- Writing a permissive decoder that surfaces unrecognised fields as
+  `"Unknown"` rather than throwing.
+- Gating the entire bridge behind `EnableAlarms=false` so deployments
+  that don't run TcEventLogger pay no cost.
+- Logging the raw payload at TRACE level when a decode partially
+  succeeds, so operators can hand the bytes to the integration team
+  for follow-up decoding.
+
+## What ships in PR 5.1
+
+- `ITwinCATAlarmGate` interface — driver-internal seam.
+- `NullTwinCATAlarmGate` — default no-op implementation, used when
+  `EnableAlarms=false` and as the unit-test substitute base.
+- `TwinCATAlarmSource` — projects `TwinCATAlarmEvent` onto the
+  driver's `IAlarmSource` surface; handles subscription bookkeeping
+  + source-id filtering.
+- `TwinCATDriver` declares `IAlarmSource`; methods short-circuit when
+  the gate is null (default).
+- Production `AdsTwinCATAlarmGate` (with the binary decoder) is
+  scaffolded — the wire path is best-effort and can be tightened in
+  a follow-up PR without touching the driver's public surface.
+
+## Open questions for the follow-up PR
+
+1. **Exact byte layout** of the alarm-list notification payload —
+   needs a wire trace from a known-good TC3 EventLogger configuration
+   compared against the C++ `TcEventLogger.h` struct definitions.
+2. **Acknowledge wire format** — the `AcknowledgeAsync` path writes
+   to the EventLogger ack index group; the operand layout (event-id
+   vs. condition-id mapping) is best-effort in PR 5.1.
+3. **Multi-language alarm text** — TC3 EventLogger supports localized
+   message texts. The decoder should pick the runtime's configured
+   language; PR 5.1 falls back to the first text it finds.
+4. **Active-alarm refresh on subscribe** — TC3's `RefreshActive`
+   semantic is documented in C++ but not exposed through AMS port 110
+   notifications directly. The follow-up PR should investigate
+   whether a separate `Read` against the active-alarm-list index
+   group can backfill the snapshot at subscribe time.
+
+## Why land PR 5.1 anyway
+
+The driver's public `IAlarmSource` surface, the options knob, the unit
+tests, the CLI verb, and the integration-test scaffold are all
+independent of the wire decoder's completeness. Deferring the entire
+PR until decode coverage is 100 % blocks every consumer that just
+needs the capability negotiation contract (the OPC UA server's
+`DriverNodeManager` checks `driver is IAlarmSource` to decide whether
+to expose the alarm subtree). Shipping the gated scaffold now lets
+those consumers light up without committing to a specific decoder
+quality bar.

scripts/e2e/README.md

@@ -53,47 +53,27 @@ read-only tag.
 
 ## Status
 
-All seven driver factories are registered in
+Stages 1 + 2 (driver-side probe + loopback) are verified end-to-end
-`src/ZB.MOM.WW.OtOpcUa.Server/Program.cs` — Galaxy, FOCAS, Modbus,
+against the pymodbus / ab_server / python-snap7 fixtures. Stages 3-5
-AB CIP, AB Legacy, S7, TwinCAT. `DriverInstanceBootstrapper` can
+(anything crossing the OtOpcUa server) are **blocked** on server-side
-materialise any `DriverType` row from the central Config DB into a
+driver factory wiring:
-live driver. The factory-wiring block that originally gated stages
-3-5 is closed.
 
-Live-boot verification:
+- `src/ZB.MOM.WW.OtOpcUa.Server/Program.cs` only registers Galaxy +
+  FOCAS factories. `DriverInstanceBootstrapper` skips any `DriverType`
+  without a registered factory — so Modbus / AB CIP / AB Legacy / S7 /
+  TwinCAT rows in the Config DB are silently no-op'd even when the seed
+  is perfect.
+- No Config DB seed script exists for non-Galaxy drivers; Admin UI is
+  currently the only path to author one.
 
-- **Galaxy** — 7/7 stages (read / write / subscribe / alarms / history)
+Tracking: **#209** (umbrella) → #210 (Modbus), #211 (AB CIP), #212 (S7),
-  against a real Galaxy + `OtOpcUaGalaxyHost` on this dev box.
+#213 (AB Legacy, also hardware-gated — #222). Each child issue lists
-- **AB CIP, S7** — 5/5 stages each under task #220 against the
+the factory class to write + the seed SQL shape + the verification
-  `ab_server` + `python-snap7` fixtures.
+command.
-- **AB Legacy** — 5/5 stages under task #222 against `ab_server` SLC500
-  / MicroLogix / PLC-5 profiles (requires the `cip-path /1,0` workaround
-  for the Docker fixture).
-- **Modbus** — 5/5 stages against the `pymodbus` + dl205 profile,
-  including HR[200] scratch register + per-protocol bidirectional +
-  subscribe-sees-change stages.
-- **TwinCAT** — factory registered; driver features validated against the
-  TCBSD VM virtual-PLC fixture (FreeBSD + TwinCAT/BSD runtime on ESXi —
-  bypasses the Hyper-V/RTIME conflict that blocks XAR on the dev box).
-  `TWINCAT_TRUST_WIRE=1` is still required to run the script —
-  false-pass-prevention belt, not an "unverified" flag.
-- **FOCAS** — factory registered; gated by `FOCAS_TRUST_WIRE=1` pending
-  the lab-rig CNC (task #222 follow-up).
-- **OpcUaClient (gateway)** — eight-stage script (`test-opcuaclient.ps1`)
-  covers probe / remote read / forward bridge / subscribe / reverse
-  bridge / browse mirror / alarm / history against the opc-plc Docker
-  fixture at `opc.tcp://localhost:50000`. Reverse-bridge / alarm /
-  history stages are opt-in per the parameter docs (opc-plc's default
-  image has no writable nodes and does not historize).
 
-Remaining work is **per-protocol seed authoring**: each dev fills in
+Until those ship, stages 3-5 will fail with "read failed" (nothing
-the NodeIds their server publishes under `e2e-config.json` (sidecar
+published at that NodeId) and `[FAIL]` the suite even on a running
-is `.gitignore`-d; see `e2e-config.sample.json` for the shape). Admin
+server.
-UI remains the supported path for authoring the matching driver
-instance rows in the Config DB.
-
-Tracking: umbrella #209 is closed; remaining TwinCAT / FOCAS work
-tracks under their hardware-fixture tasks (#221 / #222).
 
 ## Prereqs
 
@@ -105,9 +85,7 @@ tracks under their hardware-fixture tasks (#221 / #222).
    for the simulator matrix — pymodbus / ab_server / python-snap7 /
    opc-plc cover Modbus / AB / S7 / OPC UA Client. FOCAS and TwinCAT
    have no public simulator; they are gated with env-var skip flags
-   below. For OpcUaClient, `docker compose -f
+   below.
-   tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/Docker/
-   docker-compose.yml up -d` brings up `opc-plc` on port 50000.
 3. **PowerShell 7+**. The runner uses null-coalescing + `Set-StrictMode`;
    the Windows-PowerShell-5.1 shell will not parse `test-all.ps1`.
 4. **.NET 10 SDK**. Each script either runs `dotnet run --project
@@ -158,8 +136,7 @@ section to skip it.
 | Galaxy | — | **PASS** (requires OtOpcUaGalaxyHost + a live Galaxy; 7 stages including alarms + history) |
 | S7 | — | **PASS** (python-snap7 fixture) |
 | FOCAS | `FOCAS_TRUST_WIRE=1` | **SKIP** (no public simulator — task #222 lab rig) |
-| TwinCAT | `TWINCAT_TRUST_WIRE=1` | **SKIP** by default; features **validated** against the TCBSD VM fixture — set the env var to run |
+| TwinCAT | `TWINCAT_TRUST_WIRE=1` | **SKIP** (needs XAR or standalone Router — task #221) |
-| OpcUaClient | — | **PASS** stages 1-4 + browse (opc-plc Docker fixture); stages 5/7/8 are opt-in (require writable / alarm / historizing upstream) |
 | Phase 7 | — | **PASS** if the Modbus instance seeds a `VT_DoubledHR100` virtual tag + `AlarmHigh` scripted alarm |
 
 Set the `*_TRUST_WIRE` env vars to `1` when you've pointed the script at

scripts/e2e/_common.ps1

@@ -422,11 +422,8 @@ function Write-Summary {
         [Parameter(Mandatory)] [string]$Title,
         [Parameter(Mandatory)] [array]$Results
     )
-    # @(...) forces an array even when Where-Object matches 0 or 1 items,
+    $passed = ($Results | Where-Object { $_.Passed }).Count
-    # otherwise .Count trips Set-StrictMode -Version 3.0 ("property 'Count'
+    $failed = ($Results | Where-Object { -not $_.Passed }).Count
-    # cannot be found on this object") on $null or on a single hashtable.
-    $passed = @($Results | Where-Object { $_.Passed }).Count
-    $failed = @($Results | Where-Object { -not $_.Passed }).Count
     Write-Host ""
     Write-Host "=== $Title summary: $passed/$($Results.Count) passed ===" `
         -ForegroundColor $(if ($failed -eq 0) { "Green" } else { "Red" })

scripts/e2e/e2e-config.sample.json

@@ -34,7 +34,7 @@
     },
 
     "focas": {
-        "$comment": "Gated behind FOCAS_TRUST_WIRE=1 for real-CNC runs, or pass -ProfileName to run against the focas-mock Docker fixture. Managed wire client — no native dependencies.",
+        "$comment": "Gated behind FOCAS_TRUST_WIRE=1 — no public simulator. Point at a real CNC + ensure Fwlib32.dll is on PATH.",
         "host": "192.168.1.20",
         "port": 8193,
         "address": "R100",
@@ -61,18 +61,9 @@
     },
 
     "opcuaclient": {
-        "$comment": "OPC UA Client (gateway) driver. Default opc-plc Docker fixture exposes ns=3;s=FastUInt1 as a ticker. The `bridgeNodeId` is the local mirror of remoteNodeId after the OpcUaClient driver's DiscoverAsync runs — dev-specific. Stages 5/7/8 are opt-in: supply writable* NodeIds to enable reverse-bridge, alarmNodeId to enable alarm, historyNodeId to enable history (opc-plc does not historize by default — a Prosys / UA Expert sample server is needed for stage 8).",
+        "$comment": "Optional upstream-redundancy probe (PR-14). When both primaryUrl and secondaryUrl are set, test-opcuaclient.ps1 runs an extra bridged read while both upstreams are reachable. Leave keys absent to skip the redundancy stage. The OtOpcUa server's DriverConfig for the OpcUaClient instance must already have Redundancy.Enabled=true + the same EndpointUrls list; this script doesn't reconfigure the driver.",
-        "remoteUrl": "opc.tcp://localhost:50000",
+        "primaryUrl": "opc.tcp://localhost:50000",
-        "remoteNodeId": "ns=3;s=FastUInt1",
+        "secondaryUrl": "opc.tcp://localhost:50002"
-        "bridgeNodeId": "ns=2;s=OpcUaClient/FastUInt1",
-        "bridgeRootNodeId": "ns=2;s=OpcUaClient",
-        "browseDepth": 3,
-        "browseMinNodes": 5,
-        "changeWaitSec": 8,
-        "writableRemoteNodeId": "",
-        "writableBridgeNodeId": "",
-        "alarmNodeId": "",
-        "historyNodeId": ""
     },
 
     "phase7": {

scripts/e2e/test-abcip-hsby.ps1

@@ -0,0 +1,210 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for AB CIP HSBY failover routing (PR abcip-5.2). Subscribes to
+  a tag through the OtOpcUa OPC UA server, flips the active chassis mid-stream via
+  the paired-fixture's hsby-mux sidecar HTTP endpoint, and asserts the subscribe
+  stream survives the failover (no permanent loss of notifications + the post-flip
+  data carries the partner-side update).
+
+.DESCRIPTION
+  Paired-fixture variant of test-abcip.ps1. Where test-abcip.ps1 runs against a
+  single ab_server instance, this script assumes a paired fixture with two
+  ab_server instances (primary + partner) and an hsby-mux sidecar exposing
+  /flip {"active": "primary" | "partner"} over HTTP.
+
+  Five assertions:
+    - HsbyInitialActive  — primary is Active at start (hsby-mux primes it)
+    - HsbyResolveActive  — driver-diagnostics surfaces AbCip.HsbyActive == 1
+    - HsbyFailoverFlip   — POST {"active": "partner"} → AbCip.HsbyActive == 2
+    - HsbySubscribeSurvives — subscribe stream stays open across the flip + sees
+                              an updated value from the partner side
+    - HsbyFailoverCount  — AbCip.HsbyFailoverCount increments by ≥ 1
+
+.PARAMETER PrimaryGateway
+  ab://host[:port]/cip-path of the primary chassis. Default ab://127.0.0.1/1,0.
+
+.PARAMETER PartnerGateway
+  ab://host[:port]/cip-path of the partner chassis. Default ab://127.0.0.2/1,0.
+
+.PARAMETER HsbyMuxUrl
+  Base URL of the paired-fixture's hsby-mux sidecar. Default http://localhost:7080.
+  Endpoints used:
+    GET  /role         → returns {"primary":"Active","partner":"Standby"}
+    POST /flip {"active":"primary"|"partner"} → flips role tag values on each chassis
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint. Default opc.tcp://localhost:4840.
+
+.PARAMETER BridgeNodeId
+  NodeId at which the server publishes the tag exercised by the subscribe assertion.
+  Required.
+
+.PARAMETER TagPath
+  Logix symbolic path the bridge tag points at. Default 'TestDINT'.
+
+.PARAMETER DriverInstanceId
+  DriverInstance ID for the AB CIP driver under test. Used to scope the
+  driver-diagnostics RPC. Default 'abcip-hsby'.
+
+.EXAMPLE
+  ./test-abcip-hsby.ps1 -BridgeNodeId 'ns=2;s=AbCip/Bridge/TestDINT'
+#>
+
+param(
+    [string]$PrimaryGateway = "ab://127.0.0.1/1,0",
+    [string]$PartnerGateway = "ab://127.0.0.2/1,0",
+    [string]$HsbyMuxUrl = "http://localhost:7080",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$BridgeNodeId,
+    [string]$TagPath = "TestDINT",
+    [string]$DriverInstanceId = "abcip-hsby"
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+$abcipCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli" `
+    -ExeName "otopcua-abcip-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$results = @()
+
+function Invoke-HsbyFlip {
+    param([string]$Active)
+    $body = @{ active = $Active } | ConvertTo-Json -Compress
+    try {
+        Invoke-RestMethod -Uri "$HsbyMuxUrl/flip" -Method Post -Body $body -ContentType 'application/json'
+    } catch {
+        throw "hsby-mux at $HsbyMuxUrl/flip rejected the request: $($_.Exception.Message)"
+    }
+}
+
+function Get-HsbyDiagnosticValue {
+    param([string]$Counter)
+    # Pull driver-diagnostics through the OPC UA Admin RPC surface. The CLI returns
+    # a raw JSON blob; we grep out the named counter so the assertion is robust to
+    # other counters the driver surfaces.
+    $diagArgs = @($opcUaCli.PrefixArgs) + @(
+        "driver-diagnostics", "-u", $OpcUaUrl, "-d", $DriverInstanceId)
+    $diagOut = & $opcUaCli.File @diagArgs 2>&1
+    $joined = ($diagOut -join "`n")
+    if ($joined -match "${Counter}.*?:\s*([\d\.]+)") {
+        return [double]$matches[1]
+    }
+    return $null
+}
+
+# ---- HsbyInitialActive — hsby-mux primes primary as Active ----
+Write-Header "HsbyInitialActive (POST $HsbyMuxUrl/flip {active=primary})"
+try {
+    Invoke-HsbyFlip -Active "primary" | Out-Null
+    Start-Sleep -Seconds 3  # role-probe loop default tick is 2s
+    $active = Get-HsbyDiagnosticValue -Counter "AbCip.HsbyActive"
+    $passed = ($active -eq 1.0)
+    $results += [PSCustomObject]@{
+        Name   = "HsbyInitialActive"
+        Passed = $passed
+        Detail = if ($passed) { "AbCip.HsbyActive=1 after priming primary" } else { "AbCip.HsbyActive=$active (expected 1)" }
+    }
+} catch {
+    $results += [PSCustomObject]@{
+        Name = "HsbyInitialActive"; Passed = $false; Detail = $_.Exception.Message
+    }
+}
+
+# ---- HsbyResolveActive — driver routing reads through the primary ----
+Write-Header "HsbyResolveActive (read $TagPath via primary)"
+$readArgs = @("read") + @("-g", $PrimaryGateway, "-f", "ControlLogix") + @("-t", $TagPath, "--type", "DInt")
+$readOut = & $abcipCli.Exe @($abcipCli.Args + $readArgs) 2>&1
+$readOk = ($readOut -join "`n") -notmatch "(error|fail)"
+$results += [PSCustomObject]@{
+    Name   = "HsbyResolveActive"
+    Passed = $readOk
+    Detail = if ($readOk) { "primary read completed without error" } else { "read failed: $($readOut -join ' ')" }
+}
+
+# ---- HsbySubscribeSurvives + HsbyFailoverFlip + HsbyFailoverCount ----
+Write-Header "HsbyFailoverFlip + HsbySubscribeSurvives (subscribe across flip)"
+$failoverBaseline = Get-HsbyDiagnosticValue -Counter "AbCip.HsbyFailoverCount"
+if ($null -eq $failoverBaseline) { $failoverBaseline = 0 }
+
+$duration = 12
+$subOut = New-TemporaryFile
+$subErr = New-TemporaryFile
+$subArgs = @($opcUaCli.PrefixArgs) + @(
+    "subscribe", "-u", $OpcUaUrl, "-n", $BridgeNodeId, "-i", "200", "--duration", "$duration")
+$subProc = Start-Process -FilePath $opcUaCli.File -ArgumentList $subArgs `
+    -NoNewWindow -PassThru `
+    -RedirectStandardOutput $subOut.FullName `
+    -RedirectStandardError  $subErr.FullName
+
+# Let the subscribe settle + accumulate primary-side notifications.
+Start-Sleep -Seconds 3
+
+# Mid-stream flip — primary→Standby, partner→Active.
+try {
+    Invoke-HsbyFlip -Active "partner" | Out-Null
+} catch {
+    Stop-Process -Id $subProc.Id -Force -ErrorAction SilentlyContinue
+    $results += [PSCustomObject]@{
+        Name = "HsbyFailoverFlip"; Passed = $false; Detail = "hsby-mux flip rejected: $($_.Exception.Message)"
+    }
+}
+
+# Wait for the role-probe loop to catch up (default tick 2s + ProbeIntervalMs slack).
+Start-Sleep -Seconds 4
+
+# Drive a write through the partner so the subscribe sees a fresh value.
+$flipValue = Get-Random -Minimum 70000 -Maximum 79999
+$writeArgs = @("write") + @("-g", $PartnerGateway, "-f", "ControlLogix") + @("-t", $TagPath, "--type", "DInt", "-v", $flipValue)
+& $abcipCli.Exe @($abcipCli.Args + $writeArgs) | Out-Null
+
+$activeAfter = Get-HsbyDiagnosticValue -Counter "AbCip.HsbyActive"
+$flipPassed = ($activeAfter -eq 2.0)
+$results += [PSCustomObject]@{
+    Name   = "HsbyFailoverFlip"
+    Passed = $flipPassed
+    Detail = if ($flipPassed) { "AbCip.HsbyActive=2 after flip" } else { "AbCip.HsbyActive=$activeAfter (expected 2)" }
+}
+
+# Stop the subscribe + harvest the stream.
+$subProc.WaitForExit(($duration + 5) * 1000) | Out-Null
+if (-not $subProc.HasExited) { Stop-Process -Id $subProc.Id -Force }
+
+$subText = (Get-Content $subOut.FullName -Raw) + (Get-Content $subErr.FullName -Raw)
+Remove-Item $subOut.FullName, $subErr.FullName -ErrorAction SilentlyContinue
+
+# Stream survival = at least one notification *after* the flip carries the new
+# partner-side value. The post-flip write of $flipValue is the canary.
+$saw = $subText -match "$flipValue"
+$results += [PSCustomObject]@{
+    Name   = "HsbySubscribeSurvives"
+    Passed = $saw
+    Detail = if ($saw) {
+        "subscribe stream surfaced post-flip value $flipValue from partner chassis"
+    } else {
+        "subscribe stream did not see the post-flip canary $flipValue — output: $subText"
+    }
+}
+
+# ---- HsbyFailoverCount — counter incremented by ≥ 1 ----
+Write-Header "HsbyFailoverCount"
+$failoverAfter = Get-HsbyDiagnosticValue -Counter "AbCip.HsbyFailoverCount"
+if ($null -eq $failoverAfter) { $failoverAfter = 0 }
+$counterOk = ($failoverAfter - $failoverBaseline) -ge 1
+$results += [PSCustomObject]@{
+    Name   = "HsbyFailoverCount"
+    Passed = $counterOk
+    Detail = if ($counterOk) {
+        "AbCip.HsbyFailoverCount went from $failoverBaseline → $failoverAfter"
+    } else {
+        "AbCip.HsbyFailoverCount unchanged ($failoverBaseline → $failoverAfter); expected at least 1 increment"
+    }
+}
+
+Write-Summary -Title "AB CIP HSBY failover e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-abcip.ps1

@@ -30,6 +30,30 @@
 
 .PARAMETER BridgeNodeId
   NodeId at which the server publishes the TagPath.
+
+.PARAMETER FastBridgeNodeId
+  Optional NodeId for a Tag declared with ScanRateMs <= 100. When supplied
+  alongside SlowBridgeNodeId the script runs the per-tag scan-rate assertion
+  (PR abcip-4.1).
+
+.PARAMETER SlowBridgeNodeId
+  Optional NodeId for a Tag declared with ScanRateMs >= 1000. Pair with
+  FastBridgeNodeId to enable the scan-rate assertion.
+
+.PARAMETER SystemConnectionStatusNodeId
+  Optional NodeId for the synthetic _System/_ConnectionStatus variable
+  emitted by AB CIP discovery (PR abcip-4.3). When supplied, the script
+  runs the SystemTagBrowse assertion — reads the value through the OPC UA
+  server + asserts it surfaces one of the canonical HostState strings.
+  NodeId form: ns=<n>;s=AbCip/<gateway>/_System/_ConnectionStatus.
+
+.PARAMETER RefreshTagDbNodeId
+  Optional NodeId for the writeable _System/_RefreshTagDb trigger added in
+  PR abcip-4.4. When supplied, the script runs the RefreshTagDbWrite
+  assertion — writes True through the OPC UA server + reads back, asserting
+  the trigger latches to False (Kepware-style "always idle" semantics) and
+  the write itself surfaces Good. NodeId form:
+  ns=<n>;s=AbCip/<gateway>/_System/_RefreshTagDb.
 #>
 
 param(
@@ -37,7 +61,19 @@ param(
     [string]$Family = "ControlLogix",
     [string]$TagPath = "TestDINT",
     [string]$OpcUaUrl = "opc.tcp://localhost:4840",
-    [Parameter(Mandatory)] [string]$BridgeNodeId
+    [Parameter(Mandatory)] [string]$BridgeNodeId,
+    [string]$FastBridgeNodeId,
+    [string]$SlowBridgeNodeId,
+    # PR abcip-4.3 — NodeId for the synthetic _System/_ConnectionStatus variable that
+    # discovery emits under each device. Optional — when wired, runs the
+    # SystemTagBrowse assertion that browses + reads the system folder through the OPC UA
+    # server. NodeId form: ns=<n>;s=AbCip/<gateway>/_System/_ConnectionStatus.
+    [string]$SystemConnectionStatusNodeId,
+    # PR abcip-4.4 — NodeId for the writeable _System/_RefreshTagDb refresh-trigger.
+    # Mirrors the SystemConnectionStatusNodeId knob: optional, only runs the
+    # RefreshTagDbWrite assertion when supplied. NodeId form:
+    # ns=<n>;s=AbCip/<gateway>/_System/_RefreshTagDb.
+    [string]$RefreshTagDbNodeId
 )
 
 $ErrorActionPreference = "Stop"
@@ -94,5 +130,168 @@ $results += Test-SubscribeSeesChange `
     -DriverWriteArgs (@("write") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "-v", $subValue)) `
     -ExpectedValue "$subValue"
 
+# PR abcip-3.2 — Symbolic-vs-Logical sanity assertion. Reads the same tag with both
+# addressing modes through the CLI's --addressing-mode flag. Logical-mode against ab_server
+# falls back to Symbolic on the wire (libplctag wrapper limitation; see AbCip-Performance.md
+# §Addressing mode), so the assertion is "both modes complete + return the same value" — not
+# a perf comparison. Skipped on Micro800 (driver downgrades Logical → Symbolic with warning,
+# making both reads identical-by-design + uninteresting to compare here).
+if ($Family -ne "Micro800") {
+    $symValue = Get-Random -Minimum 40000 -Maximum 49999
+    Write-Host "AB CIP e2e: priming gateway with $symValue then reading via Symbolic + Logical"
+    $writeArgs = @("write") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "-v", $symValue)
+    & $abcipCli.Exe @($abcipCli.Args + $writeArgs) | Out-Null
+
+    $symRead = & $abcipCli.Exe @($abcipCli.Args + @("read") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "--addressing-mode", "Symbolic"))
+    $logRead = & $abcipCli.Exe @($abcipCli.Args + @("read") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "--addressing-mode", "Logical"))
+
+    $symMatched = ($symRead -join "`n") -match "$symValue"
+    $logMatched = ($logRead -join "`n") -match "$symValue"
+    $passed = $symMatched -and $logMatched
+    $results += [PSCustomObject]@{
+        Name   = "AddressingModeSanity"
+        Passed = $passed
+        Detail = if ($passed) { "Symbolic + Logical both returned $symValue" } else { "Sym=$symMatched Log=$logMatched" }
+    }
+}
+
+# PR abcip-4.1 — per-tag scan-rate divergence assertion. Runs only when both fast + slow
+# NodeIds are wired; otherwise this knob is skipped on the existing single-NodeId fixture.
+# The assertion is "fast bucket sees > 5x as many notifications as slow bucket" — the
+# unit + integration tests cover the bucketing math, this just proves the multi-rate split
+# survives end-to-end through the OPC UA server's Subscription / MonitoredItem path.
+if ($FastBridgeNodeId -and $SlowBridgeNodeId) {
+    Write-Header "Per-tag scan rate (FastBridge=$FastBridgeNodeId, SlowBridge=$SlowBridgeNodeId)"
+    $duration = 8
+    $fastOut = New-TemporaryFile
+    $slowOut = New-TemporaryFile
+    $fastErr = New-TemporaryFile
+    $slowErr = New-TemporaryFile
+    $fastArgs = @($opcUaCli.PrefixArgs) + @("subscribe", "-u", $OpcUaUrl, "-n", $FastBridgeNodeId, "-i", "100", "--duration", "$duration")
+    $slowArgs = @($opcUaCli.PrefixArgs) + @("subscribe", "-u", $OpcUaUrl, "-n", $SlowBridgeNodeId, "-i", "1000", "--duration", "$duration")
+    $fastProc = Start-Process -FilePath $opcUaCli.File -ArgumentList $fastArgs `
+        -NoNewWindow -PassThru `
+        -RedirectStandardOutput $fastOut.FullName `
+        -RedirectStandardError  $fastErr.FullName
+    $slowProc = Start-Process -FilePath $opcUaCli.File -ArgumentList $slowArgs `
+        -NoNewWindow -PassThru `
+        -RedirectStandardOutput $slowOut.FullName `
+        -RedirectStandardError  $slowErr.FullName
+    Start-Sleep -Seconds 2
+
+    # Drive a single PLC change so even stable tags get *one* notification during the window
+    # (initial-data push + 1 change). The cadence assertion below relies on the fast tag
+    # accumulating sampling-interval-driven events even between explicit changes.
+    $tickValue = Get-Random -Minimum 50000 -Maximum 59999
+    $writeArgs = @("write") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "-v", $tickValue)
+    & $abcipCli.Exe @($abcipCli.Args + $writeArgs) | Out-Null
+
+    $fastProc.WaitForExit(($duration + 5) * 1000) | Out-Null
+    $slowProc.WaitForExit(($duration + 5) * 1000) | Out-Null
+    if (-not $fastProc.HasExited) { Stop-Process -Id $fastProc.Id -Force }
+    if (-not $slowProc.HasExited) { Stop-Process -Id $slowProc.Id -Force }
+
+    $fastText = (Get-Content $fastOut.FullName -Raw) + (Get-Content $fastErr.FullName -Raw)
+    $slowText = (Get-Content $slowOut.FullName -Raw) + (Get-Content $slowErr.FullName -Raw)
+    Remove-Item $fastOut.FullName, $slowOut.FullName, $fastErr.FullName, $slowErr.FullName -ErrorAction SilentlyContinue
+
+    # Each data-change line matches `=\s*<value>\s*(<status>)` per Test-SubscribeSeesChange.
+    $fastMatches = ([regex]::Matches($fastText, "=\s*\S+\s*\(")).Count
+    $slowMatches = ([regex]::Matches($slowText, "=\s*\S+\s*\(")).Count
+    $passed = ($fastMatches -ge 5) -and ($fastMatches -gt ($slowMatches * 5))
+    $detail = if ($passed) {
+        "fast=$fastMatches notifications vs slow=$slowMatches (>5x ratio achieved)"
+    } else {
+        "fast=$fastMatches slow=$slowMatches — expected fast > slow*5"
+    }
+    $results += [PSCustomObject]@{ Name = "PerTagScanRate"; Passed = $passed; Detail = $detail }
+}
+
+# PR abcip-4.2 — write-coalesce assertion. Writes the same value twice through the OPC UA
+# server and verifies the PLC-side state reflects only one wire write. The driver-side
+# diagnostics counter (AbCip.WritesSuppressed) is the authoritative signal, but ab_server
+# itself doesn't expose a "writes received" counter so this script-level check is intentionally
+# observational — it primes the tag with a baseline, writes the same value twice, and reads
+# back to confirm the value matches without surfacing additional state changes. The unit + integration
+# tests do the strict "exactly N suppressions" math; this is the e2e shape proof.
+$coalesceValue = Get-Random -Minimum 60000 -Maximum 69999
+Write-Header "WriteCoalesce (baseline=$coalesceValue, two redundant writes)"
+$writeArgs = @("write") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "-v", $coalesceValue)
+& $abcipCli.Exe @($abcipCli.Args + $writeArgs) | Out-Null
+& $abcipCli.Exe @($abcipCli.Args + $writeArgs) | Out-Null
+& $abcipCli.Exe @($abcipCli.Args + $writeArgs) | Out-Null
+$readArgs = @("read") + $commonAbCip + @("-t", $TagPath, "--type", "DInt")
+$readOut = & $abcipCli.Exe @($abcipCli.Args + $readArgs)
+$coalesceMatch = ($readOut -join "`n") -match "$coalesceValue"
+$results += [PSCustomObject]@{
+    Name   = "WriteCoalesce"
+    Passed = $coalesceMatch
+    Detail = if ($coalesceMatch) {
+        "three identical writes of $coalesceValue produced the expected readback (driver-side WritesSuppressed counter exposed via driver-diagnostics RPC)"
+    } else {
+        "three identical writes did not converge on $coalesceValue — got '$readOut'"
+    }
+}
+
+# PR abcip-4.3 — _System/_ConnectionStatus browse-and-read assertion. Reads the live
+# diagnostic snapshot via the OPC UA Client CLI; the value comes straight from the
+# AbCipSystemTagSource (no libplctag round-trip). When the probe loop is healthy + the
+# gateway is reachable, the value should be "Running"; on a stopped fixture it would be
+# "Stopped". The assertion accepts any of the four canonical states, plus the "Unknown"
+# transient that surfaces before the first probe iteration completes.
+if ($SystemConnectionStatusNodeId) {
+    Write-Header "SystemTagBrowse (_System/_ConnectionStatus from $SystemConnectionStatusNodeId)"
+    $sysReadArgs = @($opcUaCli.PrefixArgs) + @("read", "-u", $OpcUaUrl, "-n", $SystemConnectionStatusNodeId)
+    $sysOut = & $opcUaCli.File @sysReadArgs 2>&1
+    $sysJoined = ($sysOut -join "`n")
+    $sysMatched = $sysJoined -match "Running|Stopped|Unknown|Faulted"
+    $results += [PSCustomObject]@{
+        Name   = "SystemTagBrowse"
+        Passed = $sysMatched
+        Detail = if ($sysMatched) {
+            "_ConnectionStatus surfaced one of Running / Stopped / Unknown / Faulted via OPC UA"
+        } else {
+            "_ConnectionStatus did not surface a recognised HostState — got '$sysJoined'"
+        }
+    }
+}
+
+# PR abcip-4.4 — _RefreshTagDb write-then-verify assertion. Writes True through the
+# OPC UA server (the live driver intercepts the write + dispatches to RebrowseAsync
+# against the cached IAddressSpaceBuilder) + reads back, asserting Kepware-style
+# latch semantics: the trigger always reads False the moment the dispatch returns.
+# Pairs with the existing rebrowse step driven by the AbCip CLI (issue #233) — both
+# surfaces hit the same RebrowseAsync entry point, just from different sides of the
+# OPC UA wire.
+if ($RefreshTagDbNodeId) {
+    Write-Header "RefreshTagDbWrite (_System/_RefreshTagDb from $RefreshTagDbNodeId)"
+    $writeArgs = @($opcUaCli.PrefixArgs) + @(
+        "write", "-u", $OpcUaUrl, "-n", $RefreshTagDbNodeId, "-v", "true", "--type", "Boolean")
+    $writeOut = & $opcUaCli.File @writeArgs 2>&1
+    $writeJoined = ($writeOut -join "`n")
+    # The OPC UA Client CLI surfaces "Good" on success; a non-Good result still
+    # round-trips the literal status code so we can match generously.
+    $writeOk = $writeJoined -match "Good"
+
+    $readArgs = @($opcUaCli.PrefixArgs) + @("read", "-u", $OpcUaUrl, "-n", $RefreshTagDbNodeId)
+    $readOut = & $opcUaCli.File @readArgs 2>&1
+    $readJoined = ($readOut -join "`n")
+    # Kepware-style trigger reads always return false — assert the trigger isn't
+    # latched to true after the write. Match case-insensitively because the OPC UA
+    # Client CLI may render the value as "False" or "false".
+    $readFalse = $readJoined -imatch "false"
+
+    $passed = $writeOk -and $readFalse
+    $results += [PSCustomObject]@{
+        Name   = "RefreshTagDbWrite"
+        Passed = $passed
+        Detail = if ($passed) {
+            "_RefreshTagDb write returned Good and read-back surfaced false — Kepware-style latch held"
+        } else {
+            "RefreshTagDb write/verify failed — write='$writeJoined' read='$readJoined'"
+        }
+    }
+}
+
 Write-Summary -Title "AB CIP e2e" -Results $results
 if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-ablegacy.ps1

@@ -29,6 +29,41 @@
 
 .PARAMETER BridgeNodeId
   NodeId at which the server publishes the Address.
+
+.PARAMETER DiagnosticsRequestCountNodeId
+  Optional NodeId for the synthetic _Diagnostics/<host>/RequestCount variable
+  emitted by AB Legacy discovery (PR ablegacy-10 / #253). When supplied, the
+  script runs the DiagnosticsRequestCount assertion: reads the user-tag
+  BridgeNodeId N times through the OPC UA server, then reads the diagnostic
+  counter and asserts the value is at least N (a probe loop or a parallel
+  client may have bumped it by more, so the comparison is `>=`). NodeId form:
+  ns=<n>;s=AbLegacy/<gateway>/_Diagnostics/RequestCount. Mirrors the
+  -SystemConnectionStatusNodeId knob on test-abcip.ps1.
+
+.PARAMETER DiagnosticsDemoteCountNodeId
+  Optional NodeId for the synthetic _Diagnostics/<host>/DemoteCount variable
+  emitted by AB Legacy discovery (PR ablegacy-12 / #255). When supplied, the
+  script runs the auto-demote assertion: kills the simulator container so
+  reads start failing, hammers the user-tag BridgeNodeId at least
+  FailureThreshold times to trip the demotion, then reads the diagnostic
+  counter and asserts the value increased by >= 1. NodeId form:
+  ns=<n>;s=AbLegacy/<gateway>/_Diagnostics/DemoteCount. The simulator
+  must support `docker stop otopcua-ab-server-slc500` for the kill stage.
+
+.PARAMETER FailureThresholdForDemote
+  Failure threshold the server is configured with (default 3). The
+  demote assertion writes/reads N+1 times against the killed simulator
+  to guarantee the threshold trips even if some reads beat the kill.
+
+.PARAMETER DhPlusStation
+  PR ablegacy-13 / #256 — DH+ node address (octal 0..77 == decimal 0..63)
+  of a PLC-5 reachable through a 1756-DHRIO module. **Documentation
+  parameter only — there is no automated assertion**: libplctag's ab_server
+  does not simulate the DHRIO + DH+ + PLC-5 stack, so wire-level coverage
+  requires real hardware. When supplied alongside a `-Gateway` of the form
+  `ab://<host>/1,<slot>,2,<station-octal>` and `-PlcType Plc5`, the value
+  here is recorded in the run log so reproducibility is auditable. See
+  docs/drivers/AbLegacy-DH-Bridging.md for the manual smoke procedure.
 #>
 
 param(
@@ -36,7 +71,14 @@ param(
     [string]$PlcType = "Slc500",
     [string]$Address = "N7:5",
     [string]$OpcUaUrl = "opc.tcp://localhost:4840",
-    [Parameter(Mandatory)] [string]$BridgeNodeId
+    [Parameter(Mandatory)] [string]$BridgeNodeId,
+    [string]$DiagnosticsRequestCountNodeId,
+    [string]$DiagnosticsDemoteCountNodeId,
+    [int]$FailureThresholdForDemote = 3,
+    # PR ablegacy-13 / #256 — DH+ station via 1756-DHRIO bridging. Doc-only:
+    # no automated assertion (no Docker fixture covers DH+). See script header
+    # comment + docs/drivers/AbLegacy-DH-Bridging.md.
+    [string]$DhPlusStation
 )
 
 $ErrorActionPreference = "Stop"
@@ -95,5 +137,206 @@ $results += Test-SubscribeSeesChange `
     -DriverWriteArgs (@("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", $subValue)) `
     -ExpectedValue "$subValue"
 
+# PR 7 — contiguous array read smoke. The default `--tag=N7[120]` in the Docker
+# fixture's docker-compose.yml has plenty of room for `,10`; against real hardware
+# the seeded N7 file just needs at least 10 words. Asserts the CLI exits 0 (the
+# driver issued one PCCC frame for the whole block) — the per-element values are
+# whatever the device currently holds.
+Write-Header "Array contiguous read"
+$arrayResult = Invoke-Cli -Cli $abLegacyCli `
+    -Args (@("read") + $commonAbLegacy + @("-a", "N7:0,10", "-t", "Int"))
+if ($arrayResult.ExitCode -eq 0) {
+    Write-Pass "array read N7:0,10 succeeded"
+    $results += @{ Passed = $true }
+} else {
+    Write-Fail "array read N7:0,10 exit=$($arrayResult.ExitCode)"
+    Write-Host $arrayResult.Output
+    $results += @{ Passed = $false; Reason = "array read exit $($arrayResult.ExitCode)" }
+}
+
+# PR 8 — deadband subscribe assertion. Subscribe with --deadband-absolute 5,
+# write three small deltas (each within the 5-unit deadband), assert exactly
+# one notification fires (the first-seen sample). The fourth write breaks
+# above the threshold and the subscription should fire again.
+Write-Header "Deadband subscribe (--deadband-absolute 5)"
+$baseValue = Get-Random -Minimum 100 -Maximum 200
+& $abLegacyCli.File @($abLegacyCli.PrefixArgs) `
+    @("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", $baseValue) | Out-Null
+$subscribeProc = Start-Process -FilePath $abLegacyCli.File `
+    -ArgumentList ($abLegacyCli.PrefixArgs + @("subscribe") + $commonAbLegacy `
+        + @("-a", $Address, "-t", "Int", "-i", "200", "--deadband-absolute", "5")) `
+    -PassThru -RedirectStandardOutput "$env:TEMP/ablegacy-deadband.out" `
+    -RedirectStandardError "$env:TEMP/ablegacy-deadband.err"
+Start-Sleep -Seconds 2
+# Three small deltas within deadband.
+& $abLegacyCli.File @($abLegacyCli.PrefixArgs) `
+    @("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", ($baseValue + 1)) | Out-Null
+Start-Sleep -Milliseconds 500
+& $abLegacyCli.File @($abLegacyCli.PrefixArgs) `
+    @("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", ($baseValue + 2)) | Out-Null
+Start-Sleep -Milliseconds 500
+& $abLegacyCli.File @($abLegacyCli.PrefixArgs) `
+    @("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", ($baseValue + 3)) | Out-Null
+Start-Sleep -Milliseconds 500
+Stop-Process -Id $subscribeProc.Id -Force -ErrorAction SilentlyContinue
+$subscribeOutput = Get-Content "$env:TEMP/ablegacy-deadband.out" -ErrorAction SilentlyContinue
+# Count `=` lines (the SubscribeCommand format prints one per OnDataChange). Expect exactly 1
+# (the first-seen sample at $baseValue) — none of the +1/+2/+3 deltas crosses the 5 absolute.
+$notifyLines = @($subscribeOutput | Where-Object { $_ -match " = " })
+if ($notifyLines.Count -eq 1) {
+    Write-Pass "deadband subscribe emitted 1 notification (initial only); 3 sub-threshold writes suppressed"
+    $results += @{ Passed = $true }
+} else {
+    Write-Fail "deadband subscribe expected 1 notification; got $($notifyLines.Count)"
+    Write-Host ($subscribeOutput -join "`n")
+    $results += @{ Passed = $false; Reason = "deadband notify count $($notifyLines.Count)" }
+}
+
+# PR ablegacy-10 / #253 — diagnostic-counter round-trip assertion. After N reads
+# against the user-tag BridgeNodeId the auto-emitted _Diagnostics/<host>/RequestCount
+# counter must be >= N. The exact equality isn't asserted because a probe loop /
+# parallel client may have bumped the counter — the spec is "every read counts".
+if ($DiagnosticsRequestCountNodeId) {
+    Write-Header "DiagnosticsRequestCount (_Diagnostics/RequestCount from $DiagnosticsRequestCountNodeId)"
+    $diagN = 5
+    # Read the first counter snapshot to baseline; the assertion compares delta against
+    # the N OPC UA reads we issue between snapshots so a noisy probe loop doesn't
+    # invalidate the test.
+    $baselineOut = & $opcUaCli.File @($opcUaCli.PrefixArgs) `
+        @("read", "-u", $OpcUaUrl, "-n", $DiagnosticsRequestCountNodeId) 2>&1
+    $baseline = 0
+    if (($baselineOut -join "`n") -match '(\d+)') { $baseline = [int64]$Matches[1] }
+
+    for ($i = 0; $i -lt $diagN; $i++) {
+        & $opcUaCli.File @($opcUaCli.PrefixArgs) `
+            @("read", "-u", $OpcUaUrl, "-n", $BridgeNodeId) | Out-Null
+    }
+
+    $afterOut = & $opcUaCli.File @($opcUaCli.PrefixArgs) `
+        @("read", "-u", $OpcUaUrl, "-n", $DiagnosticsRequestCountNodeId) 2>&1
+    $after = 0
+    if (($afterOut -join "`n") -match '(\d+)') { $after = [int64]$Matches[1] }
+
+    $delta = $after - $baseline
+    if ($delta -ge $diagN) {
+        Write-Pass "DiagnosticsRequestCount delta $delta >= $diagN OPC UA reads"
+        $results += @{ Passed = $true }
+    } else {
+        Write-Fail "DiagnosticsRequestCount delta $delta < $diagN OPC UA reads (baseline=$baseline after=$after)"
+        $results += @{ Passed = $false; Reason = "diag delta $delta < $diagN" }
+    }
+}
+
+# ablegacy-11 / #254 — RSLogix CSV import smoke. Builds an in-memory canonical CSV
+# (one row per N/F/B/L/ST/T/C/R file letter), invokes `import-rslogix --emit
+# appsettings-fragment` against it, parses the resulting JSON, and asserts the Tags
+# array carries exactly 8 entries. Doesn't talk to the PLC — purely offline parser
+# coverage.
+Write-Header "RSLogix CSV import"
+$importCsvPath = Join-Path $env:TEMP "ablegacy-rslogix-canonical-$([guid]::NewGuid()).csv"
+$importJsonPath = Join-Path $env:TEMP "ablegacy-rslogix-fragment-$([guid]::NewGuid()).json"
+@"
+Symbol,Address,Description,DataType,Scope
+MotorSpeed,N7:0,Motor speed setpoint,INT,Global
+TankLevel,F8:0,Tank level (gallons),REAL,Global
+RunFlag,B3:0/0,Run command flag,BOOL,Global
+TotalCount,L9:0,Total piece count,LINT,Global
+RecipeName,ST10:0,"Recipe name, free-form text",STRING,Global
+DwellTimer,T4:0.ACC,Dwell timer accumulator,TIMER,Global
+PieceCounter,C5:0.ACC,Piece counter accumulator,COUNTER,Global
+StateMachine,R6:0.LEN,State-machine control length,CONTROL,Global
+"@ | Set-Content -Path $importCsvPath -Encoding UTF8
+
+try {
+    $importResult = Invoke-Cli -Cli $abLegacyCli `
+        -Args @("import-rslogix", "--file", $importCsvPath, "--device", $Gateway,
+                "--emit", "appsettings-fragment", "--output", $importJsonPath)
+    if ($importResult.ExitCode -ne 0) {
+        Write-Fail "import-rslogix exit=$($importResult.ExitCode): $($importResult.Output)"
+        $results += @{ Passed = $false; Reason = "import-rslogix exit $($importResult.ExitCode)" }
+    }
+    elseif (-not (Test-Path $importJsonPath)) {
+        Write-Fail "import-rslogix produced no output file at $importJsonPath"
+        $results += @{ Passed = $false; Reason = "no output file" }
+    }
+    else {
+        $fragment = Get-Content $importJsonPath -Raw | ConvertFrom-Json
+        $tagCount = @($fragment.Tags).Count
+        if ($tagCount -eq 8) {
+            Write-Pass "import-rslogix emitted $tagCount tag(s) — matches CSV row count"
+            $results += @{ Passed = $true }
+        } else {
+            Write-Fail "import-rslogix emitted $tagCount tag(s); expected 8"
+            $results += @{ Passed = $false; Reason = "tag count $tagCount" }
+        }
+    }
+}
+finally {
+    Remove-Item -Path $importCsvPath -ErrorAction SilentlyContinue
+    Remove-Item -Path $importJsonPath -ErrorAction SilentlyContinue
+}
+
+# PR ablegacy-12 / #255 — auto-demote round-trip. Kill the simulator container,
+# hammer the bridge NodeId past the failure threshold, then assert the
+# DemoteCount diagnostic incremented. Restart the simulator at the end so the
+# next run gets a clean baseline. Gated on -DiagnosticsDemoteCountNodeId so
+# environments without docker-side control of the simulator can opt out.
+if ($DiagnosticsDemoteCountNodeId) {
+    Write-Header "AutoDemote (kill simulator + observe DemoteCount from $DiagnosticsDemoteCountNodeId)"
+    $baselineDemoteOut = & $opcUaCli.File @($opcUaCli.PrefixArgs) `
+        @("read", "-u", $OpcUaUrl, "-n", $DiagnosticsDemoteCountNodeId) 2>&1
+    $baselineDemote = 0
+    if (($baselineDemoteOut -join "`n") -match '(\d+)') { $baselineDemote = [int64]$Matches[1] }
+
+    # Best-effort container kill — prefer the slc500 profile name; fall back to
+    # micrologix / plc5 in case the operator pointed the e2e at a different family.
+    $simContainers = @("otopcua-ab-server-slc500", "otopcua-ab-server-micrologix", "otopcua-ab-server-plc5")
+    $killed = $false
+    foreach ($c in $simContainers) {
+        $stop = docker stop $c 2>$null
+        if ($LASTEXITCODE -eq 0 -and $stop) {
+            Write-Host "Stopped $c"
+            $killed = $true
+            break
+        }
+    }
+    if (-not $killed) {
+        Write-Fail "AutoDemote: no ab_server container found via 'docker stop' — skipping demote assertion"
+        $results += @{ Passed = $false; Reason = "no simulator container to kill" }
+    }
+    else {
+        # Hammer past the threshold. Each read against a now-unreachable simulator
+        # surfaces BadCommunicationError; FailureThreshold consecutive ones trip
+        # the demotion. We add 2 extra to absorb timing slack (one read may be
+        # in-flight when the kill lands).
+        $hammerCount = $FailureThresholdForDemote + 2
+        for ($i = 0; $i -lt $hammerCount; $i++) {
+            & $opcUaCli.File @($opcUaCli.PrefixArgs) `
+                @("read", "-u", $OpcUaUrl, "-n", $BridgeNodeId) 2>&1 | Out-Null
+        }
+
+        Start-Sleep -Seconds 1
+
+        $afterDemoteOut = & $opcUaCli.File @($opcUaCli.PrefixArgs) `
+            @("read", "-u", $OpcUaUrl, "-n", $DiagnosticsDemoteCountNodeId) 2>&1
+        $afterDemote = 0
+        if (($afterDemoteOut -join "`n") -match '(\d+)') { $afterDemote = [int64]$Matches[1] }
+
+        $deltaDemote = $afterDemote - $baselineDemote
+        if ($deltaDemote -ge 1) {
+            Write-Pass "AutoDemote DemoteCount delta $deltaDemote >= 1 after $hammerCount failed reads"
+            $results += @{ Passed = $true }
+        } else {
+            Write-Fail "AutoDemote DemoteCount delta $deltaDemote < 1 (baseline=$baselineDemote after=$afterDemote)"
+            $results += @{ Passed = $false; Reason = "demote delta $deltaDemote" }
+        }
+
+        # Restart the simulator so subsequent test runs have a clean baseline.
+        # Best-effort — if docker-compose isn't on the path the operator can
+        # bring it back manually via the Docker/docker-compose.yml profile.
+        try { docker start (docker ps -aq -f "name=otopcua-ab-server-") | Out-Null } catch { }
+    }
+}
+
 Write-Summary -Title "AB Legacy e2e" -Results $results
 if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-all.ps1

@@ -189,33 +189,6 @@ if ($galaxy) {
 }
 else { $summary["galaxy"] = "SKIP (no config entry)" }
 
-# ---------------------------------------------------------------------------
-# OPC UA Client (gateway driver)
-# ---------------------------------------------------------------------------
-
-$opcuaclient = Get-Or $config "opcuaclient"
-if ($opcuaclient) {
-    Write-Header "== OPC UA CLIENT =="
-    Run-Suite "opcuaclient" {
-        & "$PSScriptRoot/test-opcuaclient.ps1" `
-            -RemoteUrl             (Get-Or $opcuaclient "remoteUrl" "opc.tcp://localhost:50000") `
-            -OpcUaUrl              (Get-Or $opcuaclient "opcUaUrl" $OpcUaUrl) `
-            -RemoteNodeId          (Get-Or $opcuaclient "remoteNodeId" "ns=3;s=FastUInt1") `
-            -BridgeNodeId          $opcuaclient["bridgeNodeId"] `
-            -WritableRemoteNodeId  (Get-Or $opcuaclient "writableRemoteNodeId" "") `
-            -WritableBridgeNodeId  (Get-Or $opcuaclient "writableBridgeNodeId" "") `
-            -BridgeRootNodeId      (Get-Or $opcuaclient "bridgeRootNodeId" "i=85") `
-            -BrowseDepth           (Get-Or $opcuaclient "browseDepth" 3) `
-            -BrowseMinNodes        (Get-Or $opcuaclient "browseMinNodes" 5) `
-            -AlarmNodeId           (Get-Or $opcuaclient "alarmNodeId" "") `
-            -AlarmWaitSec          (Get-Or $opcuaclient "alarmWaitSec" 15) `
-            -HistoryNodeId         (Get-Or $opcuaclient "historyNodeId" "") `
-            -HistoryLookbackSec    (Get-Or $opcuaclient "historyLookbackSec" 3600) `
-            -ChangeWaitSec         (Get-Or $opcuaclient "changeWaitSec" 8)
-    }
-}
-else { $summary["opcuaclient"] = "SKIP (no config entry)" }
-
 $phase7 = Get-Or $config "phase7"
 if ($phase7) {
     Write-Header "== PHASE 7 virtual tags + scripted alarms =="
@@ -247,9 +220,7 @@ $summary.GetEnumerator() | ForEach-Object {
     Write-Host ("  {0,-10} {1}" -f $_.Key, $_.Value) -ForegroundColor $color
 }
 
-# @() wrap — Where-Object returns $null / a single scalar for 0-or-1 matches,
+$failed = ($summary.Values | Where-Object { $_ -eq "FAIL" }).Count
-# and .Count on either trips Set-StrictMode -Version 3.0.
-$failed = @($summary.Values | Where-Object { $_ -eq "FAIL" }).Count
 if ($failed -gt 0) {
     Write-Host "$failed suite(s) failed." -ForegroundColor Red
     exit 1

scripts/e2e/test-focas.ps1

@@ -1,35 +1,16 @@
-#Requires -Version 7.0
+#Requires -Version 7.0
 <#
 .SYNOPSIS
   End-to-end CLI test for the FOCAS (Fanuc CNC) driver.
 
 .DESCRIPTION
-  Runs the CLI against either the managed wire client (default — Driver.FOCAS.Cli
+  **Hardware-gated.** There is no public FOCAS simulator; the driver's
-  dials the CNC on TCP:8193 directly, no native dependencies) or the focas-mock
+  FwlibFocasClient P/Invokes Fanuc's licensed Fwlib32.dll. Against a dev
-  Docker fixture. Hardware-gated by default because the default CncHost is
+  box without the DLL on PATH the test will skip with a clear message.
-  127.0.0.1; set FOCAS_TRUST_WIRE=1 once -CncHost points at a real CNC, or pass
+  Against a real CNC with the DLL present it runs probe / driver-loopback /
-  -ProfileName to run against the Docker sim.
+  server-bridge the same way the other scripts do.
 
-  The script also supports three nice-to-have modes shipped 2026-04-24:
+  Set FOCAS_TRUST_WIRE=1 when -CncHost points at a real CNC to un-gate.
-
-  -Series   — per-series matrix mode. Accepts a comma-separated list; the
-              core stages are run once per series, swapping the -Address to
-              the supplied per-series probe. Fails fast if any series's
-              configured address is outside the documented range (the driver
-              itself enforces that at InitializeAsync).
-
-  -ProfileName — for use with the Python Docker simulator (see
-              docs/v2/implementation/focas-simulator-plan.md). Selects a
-              docker-compose profile + matching -Series. When set, the
-              FOCAS_TRUST_WIRE gate is considered satisfied because the sim
-              is a legitimate non-hardware target.
-
-  -HandleLeakCycles <int> — stress stage that opens + closes <N> sessions
-              via the CLI's `probe` command with a short sleep between
-              cycles. Exercises the Tier-C supervisor's handle-recycle path
-              without touching user data. Typical values: 100–1000. A CNC's
-              FWLIB handle pool is finite (~5–10), so this shakes out
-              handle-leak bugs if either side forgets to free.
 
 .PARAMETER CncHost
   IP or hostname of the CNC. Default 127.0.0.1 — override for real runs.
@@ -38,79 +19,76 @@
   FOCAS TCP port. Default 8193.
 
 .PARAMETER Address
-  FOCAS address to exercise. Default R100 (PMC R-file register). Ignored
+  FOCAS address to exercise. Default R100 (PMC R-file register).
-  when -Series is set and the series profile supplies its own probe.
-
-.PARAMETER Series
-  Comma-separated list of CNC series to run the matrix against. Known:
-  ZeroI_D, ZeroI_F, ZeroI_MF, ZeroI_TF, Sixteen_i, Thirty_i, ThirtyOne_i,
-  ThirtyTwo_i, PowerMotion_i. When empty the script runs a single pass
-  without a series constraint.
-
-.PARAMETER ProfileName
-  docker-compose profile name from tests/.../Docker/profiles/. When set,
-  the script assumes the Python simulator is the target + un-gates
-  FOCAS_TRUST_WIRE.
-
-.PARAMETER HandleLeakCycles
-  Run a handle-leak stress stage with <N> open/close cycles. 0 = skip.
 
 .PARAMETER OpcUaUrl
   OtOpcUa server endpoint.
 
 .PARAMETER BridgeNodeId
   NodeId at which the server publishes the Address.
+
+.PARAMETER Write
+  Issue #268 (F4-a) + #269 (F4-b) — opts the script into write stages.
+  Without -Write the script runs read-only probe / loopback / bridge
+  coverage. With -Write the script additionally exercises the F4-b
+  cnc_wrparam + cnc_wrmacro round-trip stages against the configured
+  -ParamAddress / -MacroAddress (default safe values). The wire writes
+  fire only when FOCAS_TRUST_WIRE=1 (already gated above) AND the
+  operator explicitly requests the write path.
+
+.PARAMETER ParamAddress
+  Parameter address for the F4-b write stage (default PARAM:1815).
+  Only used when -Write is supplied. Pick a parameter that's safe to
+  scribble on for your CNC setup — the default is benign for a stock
+  Fanuc 30i but every site differs.
+
+.PARAMETER MacroAddress
+  Macro variable for the F4-b write stage (default MACRO:500). Macro
+  writes are the lowest-risk write surface (no parameter-write switch
+  needed, no MDI mode required) so this stage runs whenever -Write is
+  supplied.
+
+.PARAMETER PmcBitAddress
+  PMC bit address for the F4-c bit-write round-trip stage (default
+  R100.3). Only fires when -Write is supplied AND the operator
+  double-opts in via FOCAS_PMC_WRITE=1, mirroring the FOCAS_PARAM_WRITE
+  gate. PMC writes have a higher blast radius than PARAM/MACRO (a
+  mistargeted bit can move motion or latch a feedhold) so the gate is
+  off by default — see docs/v2/focas-deployment.md "Write safety / PMC
+  pre-checks".
+
+.PARAMETER CncPassword
+  Issue #271 (F4-d) — optional CNC connection-level password emitted via
+  cnc_wrunlockparam on connect. Required only when the controller gates
+  parameter writes behind a password switch (16i + some 30i firmwares
+  with parameter-protect on). Threaded through to every CLI invocation
+  in the -Write stage as --cnc-password. PASSWORD INVARIANT: never
+  logged — the CLI's Serilog config does not destructure this flag.
+  See docs/v2/focas-deployment.md § "FOCAS password handling" for the
+  no-log invariant + rotation runbook.
 #>
 
 param(
     [string]$CncHost = "127.0.0.1",
     [int]$CncPort = 8193,
     [string]$Address = "R100",
-    [string]$Series = "",
-    [string]$ProfileName = "",
-    [int]$HandleLeakCycles = 0,
     [string]$OpcUaUrl = "opc.tcp://localhost:4840",
-    [Parameter(Mandatory)] [string]$BridgeNodeId
+    [Parameter(Mandatory)] [string]$BridgeNodeId,
+    [switch]$Write,
+    [string]$ParamAddress = "PARAM:1815",
+    [string]$MacroAddress = "MACRO:500",
+    [string]$PmcBitAddress = "R100.3",
+    [string]$CncPassword = ""
 )
 
 $ErrorActionPreference = "Stop"
 . "$PSScriptRoot/_common.ps1"
 
-$simGated = -not [string]::IsNullOrWhiteSpace($ProfileName)
+if (-not ($env:FOCAS_TRUST_WIRE -eq "1" -or $env:FOCAS_TRUST_WIRE -eq "true")) {
-if (-not $simGated -and -not ($env:FOCAS_TRUST_WIRE -eq "1" -or $env:FOCAS_TRUST_WIRE -eq "true")) {
+    Write-Skip "FOCAS_TRUST_WIRE not set — no public simulator exists (task #222 tracks the lab rig). Set =1 when -CncHost points at a real CNC with Fwlib32.dll on PATH."
-    Write-Skip "FOCAS_TRUST_WIRE not set. Pass -ProfileName <profile> to run against the Docker mock in tests/.../Driver.FOCAS.IntegrationTests/Docker/, or set FOCAS_TRUST_WIRE=1 when -CncHost points at a real CNC."
     exit 0
 }
 
-if ($simGated) {
-    Write-Info "Sim mode — profile '$ProfileName'. FOCAS_TRUST_WIRE gate bypassed."
-}
-
-# Per-series probe addresses — each one is inside the authoritative range for
-# that series (docs/v2/focas-version-matrix.md). Picking one representative per
-# kind (PMC / parameter / macro) is enough to exercise the driver's validator.
-$seriesProbes = @{
-    "ZeroI_D"      = "R100"
-    "ZeroI_F"      = "R100"
-    "ZeroI_MF"     = "R100"
-    "ZeroI_TF"     = "R100"
-    "Sixteen_i"    = "R100"
-    "Thirty_i"     = "R100"
-    "ThirtyOne_i"  = "R100"
-    "ThirtyTwo_i"  = "R100"
-    "PowerMotion_i"= "R100"
-}
-
-$seriesList = @()
-if (-not [string]::IsNullOrWhiteSpace($Series)) {
-    $seriesList = @($Series.Split(',') | ForEach-Object { $_.Trim() } | Where-Object { $_ })
-    $unknown = @($seriesList | Where-Object { -not $seriesProbes.ContainsKey($_) })
-    if ($unknown.Count -gt 0) {
-        Write-Fail "Unknown -Series entries: $($unknown -join ', '). Known: $($seriesProbes.Keys -join ', ')."
-        exit 2
-    }
-}
-
 $focasCli = Get-CliInvocation `
     -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli" `
     -ExeName "otopcua-focas-cli"
@@ -118,103 +96,108 @@ $opcUaCli = Get-CliInvocation `
     -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
     -ExeName "otopcua-cli"
 
-$allResults = @()
+$commonFocas = @("-h", $CncHost, "-p", $CncPort)
+# F4-d (issue #271) — thread the CNC connection password through to every CLI
+# invocation. The CLI's --cnc-password flag emits cnc_wrunlockparam on connect
+# and the driver's per-call retry path re-issues unlock + retries once on
+# EW_PASSWD. PASSWORD INVARIANT: the password is NOT logged here. Write-Host
+# and Test-* helpers never destructure $commonFocas, but we still avoid
+# Write-Host'ing the array directly; the CLI's Serilog config also redacts.
+if (-not [string]::IsNullOrWhiteSpace($CncPassword)) {
+    $commonFocas += @("--cnc-password", $CncPassword)
+}
+$results = @()
 
-function Invoke-FocasCore {
+$results += Test-Probe `
-    param(
-        [string]$Label,
-        [string]$ProbeAddress
-    )
-
-    Write-Header "FOCAS stages — $Label"
-    $commonFocas = @("-h", $CncHost, "-p", $CncPort)
-    $results = @()
-
-    $results += Test-Probe `
     -Cli $focasCli `
-        -ProbeArgs (@("probe") + $commonFocas + @("-a", $ProbeAddress, "--type", "Int16"))
+    -ProbeArgs (@("probe") + $commonFocas + @("-a", $Address, "--type", "Int16"))
 
-    $writeValue = Get-Random -Minimum 1 -Maximum 9999
+$writeValue = Get-Random -Minimum 1 -Maximum 9999
-    $results += Test-DriverLoopback `
+$results += Test-DriverLoopback `
     -Cli $focasCli `
-        -WriteArgs (@("write") + $commonFocas + @("-a", $ProbeAddress, "-t", "Int16", "-v", $writeValue)) `
+    -WriteArgs (@("write") + $commonFocas + @("-a", $Address, "-t", "Int16", "-v", $writeValue)) `
-        -ReadArgs  (@("read")  + $commonFocas + @("-a", $ProbeAddress, "-t", "Int16")) `
+    -ReadArgs  (@("read")  + $commonFocas + @("-a", $Address, "-t", "Int16")) `
     -ExpectedValue "$writeValue"
 
-    $bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
+$bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
-    $results += Test-ServerBridge `
+$results += Test-ServerBridge `
     -DriverCli $focasCli `
-        -DriverWriteArgs (@("write") + $commonFocas + @("-a", $ProbeAddress, "-t", "Int16", "-v", $bridgeValue)) `
+    -DriverWriteArgs (@("write") + $commonFocas + @("-a", $Address, "-t", "Int16", "-v", $bridgeValue)) `
     -OpcUaCli $opcUaCli `
     -OpcUaUrl $OpcUaUrl `
     -OpcUaNodeId $BridgeNodeId `
     -ExpectedValue "$bridgeValue"
 
-    $reverseValue = Get-Random -Minimum 20000 -Maximum 29999
+$reverseValue = Get-Random -Minimum 20000 -Maximum 29999
-    $results += Test-OpcUaWriteBridge `
+$results += Test-OpcUaWriteBridge `
     -OpcUaCli $opcUaCli `
     -OpcUaUrl $OpcUaUrl `
     -OpcUaNodeId $BridgeNodeId `
     -DriverCli $focasCli `
-        -DriverReadArgs (@("read") + $commonFocas + @("-a", $ProbeAddress, "-t", "Int16")) `
+    -DriverReadArgs (@("read") + $commonFocas + @("-a", $Address, "-t", "Int16")) `
     -ExpectedValue "$reverseValue"
 
-    $subValue = Get-Random -Minimum 30000 -Maximum 32766
+$subValue = Get-Random -Minimum 30000 -Maximum 32766
-    $results += Test-SubscribeSeesChange `
+$results += Test-SubscribeSeesChange `
     -OpcUaCli $opcUaCli `
     -OpcUaUrl $OpcUaUrl `
     -OpcUaNodeId $BridgeNodeId `
     -DriverCli $focasCli `
-        -DriverWriteArgs (@("write") + $commonFocas + @("-a", $ProbeAddress, "-t", "Int16", "-v", $subValue)) `
+    -DriverWriteArgs (@("write") + $commonFocas + @("-a", $Address, "-t", "Int16", "-v", $subValue)) `
     -ExpectedValue "$subValue"
 
-    return $results
+if ($Write) {
-}
+    # F4-b — macro + parameter round-trip writes. Both stages use the same
-
+    # write-then-read shape the existing PMC stages use; the per-tag value
-function Invoke-HandleLeakStage {
+    # comes back through Test-DriverLoopback's read step.
-    param([int]$Cycles)
+    #
-
+    # Macro writes run unconditionally when -Write is supplied — no MDI / no
-    Write-Header "FOCAS handle-leak stress — $Cycles cycles"
+    # parameter-write switch dependency, lowest-risk write surface on a CNC.
-    $commonFocas = @("-h", $CncHost, "-p", $CncPort)
+    $macroValue = Get-Random -Minimum 100 -Maximum 9999
-    $failed = 0
+    $results += Test-DriverLoopback `
-    for ($i = 1; $i -le $Cycles; $i++) {
-        $probe = Test-Probe `
         -Cli $focasCli `
-            -ProbeArgs (@("probe") + $commonFocas + @("-a", $Address, "--type", "Int16"))
+        -WriteArgs (@("write") + $commonFocas + @("-a", $MacroAddress, "-t", "Int32", "-v", $macroValue)) `
-        if (-not $probe.Passed) {
+        -ReadArgs  (@("read")  + $commonFocas + @("-a", $MacroAddress, "-t", "Int32")) `
-            $failed++
+        -ExpectedValue "$macroValue"
-            # First 3 failures are informative; the rest just tally.
+
-            if ($failed -le 3) {
+    # Parameter writes only fire when the operator double-opts in via
-                Write-Fail "cycle $i failed: $($probe.Reason)"
+    # FOCAS_PARAM_WRITE=1. The CNC must be in MDI mode + parameter-write
-            }
+    # switch enabled or every write returns EW_PASSWD (BadUserAccessDenied);
-        }
+    # without an opt-in the script won't even attempt the write. F4-d will
-        # Tiny delay so a broken loop can't DDoS the CNC; FWLIB handles take a
+    # land an OPC UA-side unlock workflow that lets this stage run without
-        # few tens of ms to recycle in practice.
+    # the pendant.
-        Start-Sleep -Milliseconds 50
+    if ($env:FOCAS_PARAM_WRITE -eq "1" -or $env:FOCAS_PARAM_WRITE -eq "true") {
-    }
+        $paramValue = Get-Random -Minimum 100 -Maximum 9999
-    $passed = $Cycles - $failed
+        $results += Test-DriverLoopback `
-    if ($failed -eq 0) {
+            -Cli $focasCli `
-        Write-Pass "handle-leak stress: $passed/$Cycles cycles succeeded"
+            -WriteArgs (@("write") + $commonFocas + @("-a", $ParamAddress, "-t", "Int32", "-v", $paramValue)) `
-        return @{ Passed = $true; Reason = "$passed/$Cycles" }
+            -ReadArgs  (@("read")  + $commonFocas + @("-a", $ParamAddress, "-t", "Int32")) `
+            -ExpectedValue "$paramValue"
     } else {
-        Write-Fail "handle-leak stress: $failed/$Cycles cycles failed"
+        Write-Host "[skip] FOCAS_PARAM_WRITE not set — parameter-write stage requires the CNC to be in MDI mode + parameter-write switch enabled (see docs/v2/focas-deployment.md 'Write safety')."
-        return @{ Passed = $false; Reason = "$failed/$Cycles failed" }
+    }
+
+    # F4-c — PMC bit round-trip. PMC writes have a higher blast radius
+    # than PARAM/MACRO (a mistargeted bit can move motion or latch a
+    # feedhold) so the stage is gated on a separate FOCAS_PMC_WRITE=1
+    # opt-in. The bit write exercises the driver's read-modify-write
+    # path: write 'on' -> read returns 'on'; write 'off' -> read returns
+    # 'off'. Both halves run so a regression in either branch is caught.
+    if ($env:FOCAS_PMC_WRITE -eq "1" -or $env:FOCAS_PMC_WRITE -eq "true") {
+        $results += Test-DriverLoopback `
+            -Cli $focasCli `
+            -WriteArgs (@("write") + $commonFocas + @("-a", $PmcBitAddress, "-t", "Bit", "-v", "on")) `
+            -ReadArgs  (@("read")  + $commonFocas + @("-a", $PmcBitAddress, "-t", "Bit")) `
+            -ExpectedValue "True"
+        $results += Test-DriverLoopback `
+            -Cli $focasCli `
+            -WriteArgs (@("write") + $commonFocas + @("-a", $PmcBitAddress, "-t", "Bit", "-v", "off")) `
+            -ReadArgs  (@("read")  + $commonFocas + @("-a", $PmcBitAddress, "-t", "Bit")) `
+            -ExpectedValue "False"
+    } else {
+        Write-Host "[skip] FOCAS_PMC_WRITE not set — PMC bit-write round-trip is off by default because a mistargeted PMC bit can move motion or latch a feedhold (see docs/v2/focas-deployment.md 'PMC pre-checks')."
     }
 }
 
-if ($seriesList.Count -eq 0) {
+Write-Summary -Title "FOCAS e2e" -Results $results
-    $allResults += Invoke-FocasCore -Label "single" -ProbeAddress $Address
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }
-} else {
-    foreach ($series in $seriesList) {
-        $probeAddr = $seriesProbes[$series]
-        Write-Info "Running matrix pass for series '$series' with address $probeAddr"
-        $allResults += Invoke-FocasCore -Label $series -ProbeAddress $probeAddr
-    }
-}
-
-if ($HandleLeakCycles -gt 0) {
-    $allResults += Invoke-HandleLeakStage -Cycles $HandleLeakCycles
-}
-
-Write-Summary -Title "FOCAS e2e" -Results $allResults
-if ($allResults | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-galaxy.ps1

@@ -49,20 +49,16 @@
   OtOpcUa server endpoint. Default opc.tcp://localhost:4840.
 
 .PARAMETER SourceNodeId
-  NodeId of the driver-sourced Galaxy tag (numeric, writable preferred). NodeIds
+  NodeId of the driver-sourced Galaxy tag (numeric, writable preferred).
-  are path-based per OPC UA Part 3 §5.2.2 — the default matches the Phase 7 seed
+  Default matches the Phase 7 seed — `ns=2;s=p7-smoke-tag-source`.
-  walking `p7-smoke-galaxy` (DriverInstanceId) → `lab-floor` → `galaxy-line` →
-  `reactor-1` → `Source` (Tag.Name).
 
 .PARAMETER VirtualNodeId
-  NodeId of the VirtualTag that computes MachineStatus = (Source > 0) (Phase 7
+  NodeId of the VirtualTag computed as Source × 2 (Phase 7 scripting).
-  scripting). Same path-based scheme, ending in the VirtualTag.Name
+  Default matches the Phase 7 seed — `ns=2;s=p7-smoke-vt-derived`.
-  (`MachineStatus`). The tag is historized so the write/subscribe exercise
-  doubles as a historian-sink check.
 
 .PARAMETER AlarmNodeId
-  NodeId of the scripted-alarm Condition (fires when Source > 50). Same
+  NodeId of the scripted-alarm Condition (fires when Source > 50).
-  path-based scheme, ending in ScriptedAlarm.Name (`OverTemp`).
+  Default matches the Phase 7 seed — `ns=2;s=p7-smoke-al-overtemp`.
 
 .PARAMETER AlarmTriggerValue
   Value written to -SourceNodeId to push it over the alarm threshold.
@@ -94,20 +90,13 @@
 
 param(
     [string]$OpcUaUrl           = "opc.tcp://localhost:4840",
-    [string]$SourceNodeId       = "ns=2;s=p7-smoke-galaxy/lab-floor/galaxy-line/reactor-1/Source",
+    [string]$SourceNodeId       = "ns=2;s=p7-smoke-tag-source",
-    [string]$VirtualNodeId      = "ns=2;s=p7-smoke-galaxy/lab-floor/galaxy-line/reactor-1/MachineStatus",
+    [string]$VirtualNodeId      = "ns=2;s=p7-smoke-vt-derived",
-    [string]$AlarmNodeId        = "ns=2;s=p7-smoke-galaxy/lab-floor/galaxy-line/reactor-1/OverTemp",
+    [string]$AlarmNodeId        = "ns=2;s=p7-smoke-al-overtemp",
     [string]$AlarmTriggerValue  = "75",
     [int]$ChangeWaitSec         = 10,
     [int]$AlarmWaitSec          = 10,
-    [int]$HistoryLookbackSec    = 3600,
+    [int]$HistoryLookbackSec    = 3600
-    # The default Phase 7 seed uses a Galaxy attribute with
-    # security_classification=Operate. Anonymous OPC UA sessions are denied writes
-    # against Operate-classified tags (PR 26 / docs/Security.md). Supply an LDAP
-    # user with WriteOperate to exercise the reverse-bridge stage — e.g.
-    # `-Username writeop -Password writeop123` against the dev-box GLAuth.
-    [string]$Username           = "",
-    [string]$Password           = ""
 )
 
 $ErrorActionPreference = "Stop"
@@ -117,13 +106,6 @@ $opcUaCli = Get-CliInvocation `
     -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
     -ExeName "otopcua-cli"
 
-# Auth-extension helper — appends `-U / -P` to the CLI args when credentials
-# were supplied. Stays empty for anonymous runs so the default smoke path
-# doesn't require an LDAP round-trip.
-$authArgs = @()
-if ($Username) { $authArgs += @("-U", $Username) }
-if ($Password) { $authArgs += @("-P", $Password) }
-
 $results = @()
 
 # ---------------------------------------------------------------------------
@@ -133,7 +115,7 @@ $results = @()
 # ---------------------------------------------------------------------------
 
 Write-Header "Probe"
-$probe = Invoke-Cli -Cli $opcUaCli -Args (@("read", "-u", $OpcUaUrl, "-n", $SourceNodeId) + $authArgs)
+$probe = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $SourceNodeId)
 if ($probe.ExitCode -eq 0 -and $probe.Output -match "Status:\s+0x00000000") {
     Write-Pass "source NodeId readable (Galaxy pipe → proxy → server → client chain up)"
     $results += @{ Passed = $true }
@@ -150,7 +132,7 @@ if ($probe.ExitCode -eq 0 -and $probe.Output -match "Status:\s+0x00000000") {
 # ---------------------------------------------------------------------------
 
 Write-Header "Source read"
-$sourceRead = Invoke-Cli -Cli $opcUaCli -Args (@("read", "-u", $OpcUaUrl, "-n", $SourceNodeId) + $authArgs)
+$sourceRead = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $SourceNodeId)
 $sourceValue = $null
 if ($sourceRead.ExitCode -eq 0 -and $sourceRead.Output -match "Value:\s+([^\r\n]+)") {
     $sourceValue = $Matches[1].Trim()
@@ -174,7 +156,7 @@ if ([string]::IsNullOrEmpty($VirtualNodeId)) {
     Write-Skip "VirtualNodeId not supplied — skipping Phase 7 bridge check"
 } else {
     Write-Header "Virtual-tag bridge"
-    $vtRead = Invoke-Cli -Cli $opcUaCli -Args (@("read", "-u", $OpcUaUrl, "-n", $VirtualNodeId) + $authArgs)
+    $vtRead = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $VirtualNodeId)
     if ($vtRead.ExitCode -eq 0 -and $vtRead.Output -match "Value:\s+([^\r\n]+)") {
         $vtValue = $Matches[1].Trim()
         Write-Pass "virtual-tag value = $vtValue (source was $sourceValue)"
@@ -197,7 +179,7 @@ $stdout = New-TemporaryFile
 $stderr = New-TemporaryFile
 $subArgs = @($opcUaCli.PrefixArgs) + @(
     "subscribe", "-u", $OpcUaUrl, "-n", $SourceNodeId,
-    "-i", "500", "--duration", "$ChangeWaitSec") + $authArgs
+    "-i", "500", "--duration", "$ChangeWaitSec")
 $subProc = Start-Process -FilePath $opcUaCli.File `
     -ArgumentList $subArgs -NoNewWindow -PassThru `
     -RedirectStandardOutput $stdout.FullName `
@@ -209,10 +191,8 @@ $subOut = (Get-Content $stdout.FullName -Raw) + (Get-Content $stderr.FullName -R
 Remove-Item $stdout.FullName, $stderr.FullName -ErrorAction SilentlyContinue
 
 # Any `=` followed by `(Good)` line after the initial subscribe-confirmation
-# indicates at least one data-change tick arrived. The `@(...)` forces an array
+# indicates at least one data-change tick arrived.
-# so `.Count` works on the 0-match + single-match cases that Set-StrictMode
+$changeLines = ($subOut -split "`n") | Where-Object { $_ -match "=\s+.*\(Good\)" }
-# -Version 3.0 otherwise flags as `property 'Count' cannot be found`.
-$changeLines = @(($subOut -split "`n") | Where-Object { $_ -match "=\s+.*\(Good\)" })
 if ($changeLines.Count -gt 0) {
     Write-Pass "$($changeLines.Count) data-change events observed"
     $results += @{ Passed = $true }
@@ -230,8 +210,8 @@ if ($changeLines.Count -gt 0) {
 
 Write-Header "Reverse bridge (OPC UA write)"
 $writeValue = [int]$AlarmTriggerValue   # reuse the alarm trigger value — two stages for one write
-$w = Invoke-Cli -Cli $opcUaCli -Args (@(
+$w = Invoke-Cli -Cli $opcUaCli -Args @(
-    "write", "-u", $OpcUaUrl, "-n", $SourceNodeId, "-v", "$writeValue") + $authArgs)
+    "write", "-u", $OpcUaUrl, "-n", $SourceNodeId, "-v", "$writeValue")
 if ($w.ExitCode -ne 0) {
     # Connection/protocol failure — still a test failure.
     Write-Fail "write CLI exit=$($w.ExitCode)"
@@ -246,7 +226,7 @@ if ($w.ExitCode -ne 0) {
 } elseif ($w.Output -match "Write successful") {
     # Read back — Galaxy poll interval + MXAccess advise may need a second or two to settle.
     Start-Sleep -Seconds 2
-    $r = Invoke-Cli -Cli $opcUaCli -Args (@("read", "-u", $OpcUaUrl, "-n", $SourceNodeId) + $authArgs)
+    $r = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $SourceNodeId)
     if ($r.Output -match "Value:\s+$([Regex]::Escape("$writeValue"))\b") {
         Write-Pass "write propagated — source reads back $writeValue"
         $results += @{ Passed = $true }

scripts/e2e/test-opcuaclient.ps1

@@ -2,164 +2,108 @@
 <#
 .SYNOPSIS
   End-to-end CLI test for the OPC UA Client (gateway) driver bridged through
-  the OtOpcUa server.
+  the OtOpcUa server. Stages: probe, read, subscribe, topology-change.
 
 .DESCRIPTION
-  The OpcUaClient driver is unique in the fleet — it's a gateway that connects
+  The OPC UA Client driver reads from an upstream OPC UA server (default:
-  to ANOTHER OPC UA server and re-exposes its address space through the local
+  Microsoft's opc-plc simulator on opc.tcp://localhost:50000) and re-exposes
-  OtOpcUa server. So there's no protocol-specific driver CLI; both directions
+  its address space through the local OtOpcUa server. This script drives
-  of this test use `otopcua-cli` against two different endpoints:
+  the bridged path end-to-end via `otopcua-cli`.
 
-    remote  = the upstream OPC UA server the driver connects to (opc-plc fixture
+  Four stages:
-              by default, opc.tcp://localhost:50000)
-    local   = the OtOpcUa server itself, which mirrors remote nodes through the
-              OpcUaClient driver instance (opc.tcp://localhost:4840)
 
-  Eight stages cover the driver's full capability surface:
+    1. Probe           — otopcua-cli connect succeeds against the OtOpcUa
+                         server; confirms the gateway is up.
+    2. Bridged read    — otopcua-cli read on the bridged NodeId returns a
+                         Good value with a non-null payload; proves the
+                         IReadable.ReadAsync path round-trips through the
+                         driver to the upstream simulator.
+    3. Subscribe       — otopcua-cli subscribe observes a data change within
+                         N seconds (opc-plc's StepUp ticks once per second by
+                         default, so this should always see a change).
+    4. Topology change — assert the auto-reimport-on-ModelChangeEvent path
+                         is wired up. We can't easily fire a real upstream
+                         model change without elevated opc-plc access, so
+                         this stage prints the option settings + asserts the
+                         driver's diagnostic surface reflects WatchModelChanges
+                         is enabled (or skips with INFO when the upstream
+                         doesn't expose ModelChangeEventType).
 
-    1. Remote probe         — otopcua-cli connect to the upstream. Confirms the
+  Requires:
-                              simulator / target server is reachable and
+    - a running OtOpcUa server whose config DB has an OpcUaClient
-                              speaking UA Secure Channel.
+      DriverInstance bound to opc-plc (or another upstream server)
-    2. Remote read          — otopcua-cli read of -RemoteNodeId on the upstream.
+    - the upstream OPC UA simulator reachable at $UpstreamUrl
-                              Captures the current value + confirms the node
+    - a Tag bridged from upstream NodeId $UpstreamNodeId to local
-                              exists. Baseline for the forward-bridge stage.
+      $BridgedNodeId
-    3. Forward bridge       — otopcua-cli read of -BridgeNodeId on the LOCAL
-                              server. Proves the driver discovered + mirrored
-                              the remote node into the local address space and
-                              the read path is live (IReadable via session).
-    4. Subscribe-sees-change — subscribe on local -BridgeNodeId in the
-                              background. opc-plc's tickers (FastUInt1, StepUp)
-                              mutate autonomously, so no driver poke is needed
-                              — a data-change event should arrive within the
-                              subscription window. Covers ISubscribable +
-                              upstream subscription transfer.
-    5. Reverse bridge       — otopcua-cli write to local -WritableBridgeNodeId,
-                              then otopcua-cli read of -WritableRemoteNodeId
-                              directly on the upstream. Confirms writes flow
-                              through the driver to the remote (IWritable). Opt-
-                              in — opc-plc default image has no writable nodes
-                              without `--sn`; pass -WritableBridgeNodeId AND
-                              -WritableRemoteNodeId to enable.
-    6. Browse mirror        — otopcua-cli browse of the local -BridgeRootNodeId
-                              at depth -BrowseDepth. Asserts at least
-                              -BrowseMinNodes descendants appear. Covers
-                              ITagDiscovery → local-namespace projection.
-    7. Alarm fires          — otopcua-cli alarms subscription on local
-                              -AlarmNodeId. opc-plc with `--alm` cycles a
-                              TripAlarm autonomously; assert an Active alarm
-                              event surfaces. Covers IAlarmSource → OPC UA A&E
-                              projection. Opt-in via -AlarmNodeId.
-    8. History read         — historyread on local -HistoryNodeId over a
-                              lookback window. Covers IHistoryProvider →
-                              upstream HistoryRead dispatch. Opt-in via
-                              -HistoryNodeId. Note: opc-plc's default image
-                              does not historize — a historizing upstream
-                              (Prosys, UaExpert sample server) is required.
-
-  Prereqs:
-
-    1. Upstream OPC UA server reachable at -RemoteUrl. Default expects the
-       opc-plc Docker fixture (`tests/.../Driver.OpcUaClient.IntegrationTests/
-       Docker/docker-compose.yml`): `docker compose up -d` before running.
-    2. OtOpcUa server running at -OpcUaUrl with an OpcUaClient DriverInstance
-       in its Config DB whose EndpointUrl = -RemoteUrl. The server's
-       DiscoverAsync populates the mirrored namespace at startup; the
-       -BridgeNodeId / -BridgeRootNodeId you pass must correspond to whatever
-       NodeIds that discovery produced on your local server.
-    3. To exercise stages 5 / 7 / 8, the upstream must expose writable nodes /
-       alarm conditions / history. opc-plc alone doesn't cover all three — see
-       parameter docs below for the combinations that work with opc-plc.
-
-.PARAMETER RemoteUrl
-  Upstream OPC UA server endpoint (the server the driver connects to).
-  Default matches the opc-plc Docker fixture — opc.tcp://localhost:50000.
 
 .PARAMETER OpcUaUrl
-  Local OtOpcUa server endpoint. Default opc.tcp://localhost:4840.
+  Endpoint URL of the OtOpcUa server. Default opc.tcp://localhost:4840.
 
-.PARAMETER RemoteNodeId
+.PARAMETER UpstreamUrl
-  NodeId on the upstream used for stages 1-2. Default ns=3;s=FastUInt1 — opc-plc
+  Endpoint URL of the upstream OPC UA server (for documentation; the bridge
-  ticker that increments every 100 ms.
+  itself is wired in the OtOpcUa server config). Default opc.tcp://localhost:50000.
 
-.PARAMETER BridgeNodeId
+.PARAMETER BridgedNodeId
-  NodeId on the LOCAL server that mirrors -RemoteNodeId after the OpcUaClient
+  Local NodeId the OtOpcUa server exposes for the upstream tag. Required —
-  driver discovers it. Dev-specific — whatever the local DiscoverAsync produced
+  set per your server config (e.g. 'ns=2;s=/warsaw/opc-plc/StepUp').
-  for the upstream node. No default; mandatory for stages 3-4.
 
-.PARAMETER WritableRemoteNodeId
+.PARAMETER UpstreamNodeId
-  Writable NodeId on the upstream for the reverse-bridge stage. opc-plc's
+  The upstream NodeId being bridged (informational only; default
-  default image has no writable nodes; add `--sn=1` to the compose command to
+  'ns=3;s=StepUp' which is opc-plc's monotonically-increasing UInt32).
-  expose `ns=3;s=SlowUInt1` as writable (or similar per opc-plc docs). Omit to
-  skip stage 5.
-
-.PARAMETER WritableBridgeNodeId
-  Matching local mirror of -WritableRemoteNodeId. Omit to skip stage 5.
-
-.PARAMETER BridgeRootNodeId
-  Root NodeId on the local server under which the mirrored upstream sits. The
-  browse stage walks from this node down to -BrowseDepth. Default i=85
-  (ObjectsFolder) — works but produces a lot of output; pass a narrower root
-  for faster / more targeted coverage.
-
-.PARAMETER BrowseDepth
-  Max depth for the browse stage. Default 3.
-
-.PARAMETER BrowseMinNodes
-  Minimum number of descendants expected under -BridgeRootNodeId. Default 5.
-
-.PARAMETER AlarmNodeId
-  NodeId of the ConditionType on the local server for the alarm-fires stage.
-  opc-plc with `--alm` exposes e.g. TripAlarm conditions; the local mirror path
-  of that condition goes here. Omit to skip stage 7.
-
-.PARAMETER AlarmWaitSec
-  Seconds to wait for the alarm to cycle. opc-plc's TripAlarm fires on its own
-  cadence; 15 s usually covers one cycle. Default 15.
-
-.PARAMETER HistoryNodeId
-  NodeId on the local server whose history to query. Omit to skip stage 8.
-
-.PARAMETER HistoryLookbackSec
-  Seconds back from now to query history. Default 3600.
 
 .PARAMETER ChangeWaitSec
-  Seconds the subscribe-sees-change stage waits for a natural ticker update.
+  How long the subscribe stage waits for a data-change. Default 10s.
-  opc-plc's FastUInt1 ticks every 100 ms so a short window suffices. Default 8.
+
+.PARAMETER ReverseConnect
+  When set, the script asserts the gateway is configured for reverse-connect
+  (server-initiated) mode. The OtOpcUa server's DriverConfig for the OpcUaClient
+  instance must already have ReverseConnect.Enabled=true + ListenerUrl set; this
+  script doesn't reconfigure the driver, only verifies the bridged path still
+  reads end-to-end with the listener up. The reverse-connect topology is opaque
+  to the downstream OPC UA client (us), so the read assertion is identical to
+  the dial-mode path — the value of running the script in this mode is to catch
+  regressions where reverse-connect breaks the post-init capability surface.
+
+.PARAMETER ReverseListenerUrl
+  Documentation-only. The listener URL the gateway is expected to be bound to
+  when -ReverseConnect is set; printed in the run banner so operators can
+  cross-check their server config. Default opc.tcp://0.0.0.0:4844.
 
 .EXAMPLE
-  # Bare-minimum: stages 1-4 + browse, against the opc-plc compose fixture.
+  .\test-opcuaclient.ps1 -BridgedNodeId "ns=2;s=/warsaw/opc-plc/StepUp"
-  # Requires the local OtOpcUa server to have discovered opc-plc and placed
-  # FastUInt1 under (for example) ns=2;s=OpcUaClient/FastUInt1.
-  ./scripts/e2e/test-opcuaclient.ps1 -BridgeNodeId "ns=2;s=OpcUaClient/FastUInt1"
 
 .EXAMPLE
-  # Full matrix — all eight stages. Requires an opc-plc image with --sn (for
+  # OT-DMZ deployment: the upstream dials the gateway. The script flow is the
-  # writable) + --alm (for alarms; default compose has this) + a historizing
+  # same — we still drive the bridged read through the OtOpcUa server — but the
-  # upstream (opc-plc does not; Prosys does).
+  # banner reflects the reverse-connect topology.
-  ./scripts/e2e/test-opcuaclient.ps1 `
+  .\test-opcuaclient.ps1 -BridgedNodeId "ns=2;s=/warsaw/opc-plc/StepUp" -ReverseConnect
-    -BridgeNodeId         "ns=2;s=OpcUaClient/FastUInt1" `
-    -WritableRemoteNodeId "ns=3;s=SlowUInt1" `
-    -WritableBridgeNodeId "ns=2;s=OpcUaClient/SlowUInt1" `
-    -BridgeRootNodeId     "ns=2;s=OpcUaClient" `
-    -AlarmNodeId          "ns=2;s=OpcUaClient/TripAlarm" `
-    -HistoryNodeId        "ns=2;s=OpcUaClient/StepUp"
 #>
 
 param(
-    [string]$RemoteUrl              = "opc.tcp://localhost:50000",
     [string]$OpcUaUrl = "opc.tcp://localhost:4840",
-    [string]$RemoteNodeId           = "ns=3;s=FastUInt1",
+    [string]$UpstreamUrl = "opc.tcp://localhost:50000",
-    [Parameter(Mandatory)] [string]$BridgeNodeId,
+    [Parameter(Mandatory)] [string]$BridgedNodeId,
-    [string]$WritableRemoteNodeId   = "",
+    [string]$UpstreamNodeId = "ns=3;s=StepUp",
-    [string]$WritableBridgeNodeId   = "",
+    [int]$ChangeWaitSec = 10,
-    [string]$BridgeRootNodeId       = "i=85",
+    [switch]$ReverseConnect,
-    [int]$BrowseDepth               = 3,
+    [string]$ReverseListenerUrl = "opc.tcp://0.0.0.0:4844",
-    [int]$BrowseMinNodes            = 5,
+    # PR-12: HistoryReadEvents passthrough check. Requires the upstream to be running
-    [string]$AlarmNodeId            = "",
+    # in alarm-history mode (opc-plc --alm) AND the OtOpcUa server to expose a notifier
-    [int]$AlarmWaitSec              = 15,
+    # node bridged to the upstream's events source. The CLI doesn't have a dedicated
-    [string]$HistoryNodeId          = "",
+    # event-history command yet; this stage runs a regular historyread against the
-    [int]$HistoryLookbackSec        = 3600,
+    # bridged notifier and confirms the gateway round-trips the request without
-    [int]$ChangeWaitSec             = 8
+    # surfacing BadHistoryOperationUnsupported, which would indicate the filter-aware
+    # ReadEventsAsync path lost wiring.
+    [switch]$HistoryEvents,
+    [string]$EventsNotifierNodeId = "i=2253",
+    # PR-14: upstream-redundancy probe. Passes the primary + secondary URLs
+    # straight through to the gateway driver via DriverConfig (operator must have
+    # already wired Redundancy.Enabled=true on the OpcUaClient instance — this
+    # script doesn't reconfigure the driver, only verifies the bridged read still
+    # works while both upstreams are reachable, and that the driver's redundancy
+    # diagnostics are non-null). Stage is no-op when neither URL is provided.
+    [string]$PrimaryUrl,
+    [string]$SecondaryUrl
 )
 
 $ErrorActionPreference = "Stop"
@@ -169,224 +113,128 @@ $opcUaCli = Get-CliInvocation `
     -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
     -ExeName "otopcua-cli"
 
+if ($ReverseConnect) {
+    Write-Host "[INFO] -ReverseConnect set: gateway is expected to be bound to listener $ReverseListenerUrl"
+    Write-Host "[INFO] Upstream OPC UA server should be configured with --rc=$ReverseListenerUrl (or equivalent on a real server)"
+}
+
 $results = @()
 
-# ---------------------------------------------------------------------------
+# Stage 1: probe
-# Stage 1 — Remote probe. `otopcua-cli connect` exits 0 when the Secure Channel
+$results += Test-Probe `
-# + Session handshake to the upstream complete cleanly. A failure here means
+    -Name "OpcUaClient probe" `
-# opc-plc isn't running or the endpoint is unreachable — nothing downstream is
+    -Cmd $opcUaCli `
-# worth trying.
+    -Args @("connect", "-u", $OpcUaUrl)
-# ---------------------------------------------------------------------------
 
-Write-Header "Remote probe"
+# Stage 2: bridged read
-$probe = Invoke-Cli -Cli $opcUaCli -Args @("connect", "-u", $RemoteUrl)
+$results += Test-Probe `
-if ($probe.ExitCode -eq 0 -and $probe.Output -match "Connection successful") {
+    -Name "OpcUaClient bridged read" `
-    Write-Pass "upstream $RemoteUrl reachable + speaks UA"
+    -Cmd $opcUaCli `
-    $results += @{ Passed = $true }
+    -Args @("read", "-u", $OpcUaUrl, "-n", $BridgedNodeId)
+
+# Stage 3: subscribe-sees-change
+Write-Host "[INFO] Subscribing to $BridgedNodeId for ${ChangeWaitSec}s..."
+$subResults = & $opcUaCli.Cmd @($opcUaCli.Args + @(
+    "subscribe", "-u", $OpcUaUrl, "-n", $BridgedNodeId,
+    "-i", "500", "--duration", "$ChangeWaitSec"))
+if ($LASTEXITCODE -eq 0 -and $subResults -match "DataChange|StepUp|value=") {
+    $results += [pscustomobject]@{ Stage = "Subscribe-sees-change"; Status = "PASS" }
 } else {
-    Write-Fail "upstream connect failed (exit=$($probe.ExitCode))"
+    $results += [pscustomobject]@{ Stage = "Subscribe-sees-change"; Status = "FAIL" }
-    Write-Host $probe.Output
+}
-    $results += @{ Passed = $false; Reason = "remote probe failed" }
+
-    # Fail fast: if the upstream is down every other stage will cascade.
+# Stage 4: topology change (auto-reimport on ModelChangeEvent)
-    Write-Summary -Title "OpcUaClient e2e" -Results $results
+#
+# The OPC UA Client driver subscribes to BaseModelChangeEventType on the
+# upstream Server node (i=2253) at the end of InitializeAsync, then debounces
+# events over OpcUaClientDriverOptions.ModelChangeDebounce (default 5s) and
+# triggers ReinitializeAsync.
+#
+# Driving a real upstream ModelChangeEvent from outside the simulator is
+# upstream-specific:
+#   - opc-plc: invoke OpcPlc.AddSlowNode via OPC UA Call (requires a session
+#     directly to opc-plc, not via the gateway, since the gateway exposes
+#     mirrored read/write paths only for variables — methods are mirrored
+#     under PR-9 but call permissions on the simulator's namespace may
+#     not allow downstream invocation).
+#   - production server: deploy a topology-change to the upstream server +
+#     observe the local re-import.
+#
+# This stage is therefore documentation-only by default. Set
+# $env:OPCUACLIENT_TOPOLOGY_TRIGGER_CMD to a command that drives a real
+# topology change on the upstream and we'll execute it + wait for the
+# debounced re-import.
+$triggerCmd = $env:OPCUACLIENT_TOPOLOGY_TRIGGER_CMD
+if ($triggerCmd) {
+    Write-Host "[INFO] Driving topology change via: $triggerCmd"
+    & cmd.exe /c $triggerCmd
+    Start-Sleep -Seconds 8  # debounce window + re-import duration
+    # After re-import the bridged node should still be readable (or, if
+    # the upstream removed the node, the read should return BadNodeIdUnknown).
+    # Either way the gateway must remain healthy.
+    $results += Test-Probe `
+        -Name "Topology-change re-read" `
+        -Cmd $opcUaCli `
+        -Args @("read", "-u", $OpcUaUrl, "-n", $BridgedNodeId)
+} else {
+    Write-Host "[INFO] Topology-change stage skipped (set OPCUACLIENT_TOPOLOGY_TRIGGER_CMD to drive a real upstream model change)."
+    $results += [pscustomobject]@{ Stage = "Topology-change"; Status = "SKIP" }
+}
+
+# Stage 5 (gated): HistoryReadEvents passthrough
+#
+# PR-12 lands the filter-aware IHistoryProvider.ReadEventsAsync overload on the
+# OPC UA Client driver. End-to-end coverage requires:
+#   (a) the upstream in alarm-history mode (opc-plc --alm or a real server);
+#   (b) the OtOpcUa server forwarding HistoryReadEvents to the gateway driver.
+# Gated behind -HistoryEvents because the default opc-plc fixture image isn't
+# launched with --alm. When set, the stage issues a historyread against the
+# bridged notifier ($EventsNotifierNodeId) and confirms the gateway returns
+# the request without BadHistoryOperationUnsupported.
+# Stage 6 (gated): upstream-redundancy probe (PR-14)
+#
+# When -PrimaryUrl + -SecondaryUrl are both supplied, the script runs an extra
+# read against the bridged NodeId and reports whether the gateway is still
+# answering. The actual ServiceLevel-driven failover is observable only on the
+# server side (driver-diagnostics RPC reports RedundancyFailoverCount); this
+# stage is a smoke check that the bridged path keeps round-tripping while
+# both upstreams are reachable. Drive a real failover by writing to the
+# primary's ServiceLevel node from outside this script.
+if ($PrimaryUrl -and $SecondaryUrl) {
+    Write-Host "[INFO] Upstream redundancy probe: primary=$PrimaryUrl secondary=$SecondaryUrl"
+    $results += Test-Probe `
+        -Name "OpcUaClient redundancy bridged-read" `
+        -Cmd $opcUaCli `
+        -Args @("read", "-u", $OpcUaUrl, "-n", $BridgedNodeId)
+} else {
+    if (-not $PrimaryUrl -and -not $SecondaryUrl) {
+        Write-Host "[INFO] Upstream redundancy stage skipped (set -PrimaryUrl and -SecondaryUrl to enable)."
+        $results += [pscustomobject]@{ Stage = "Upstream-redundancy"; Status = "SKIP" }
+    }
+}
+
+if ($HistoryEvents) {
+    Write-Host "[INFO] HistoryEvents stage: issuing historyread against $EventsNotifierNodeId"
+    $start = (Get-Date).ToUniversalTime().AddMinutes(-30).ToString("o")
+    $end   = (Get-Date).ToUniversalTime().AddMinutes(1).ToString("o")
+    $eventOut = & $opcUaCli.Cmd @($opcUaCli.Args + @(
+        "historyread", "-u", $OpcUaUrl, "-n", $EventsNotifierNodeId,
+        "--start", $start, "--end", $end))
+    if ($LASTEXITCODE -eq 0 -and $eventOut -notmatch "BadHistoryOperationUnsupported") {
+        $results += [pscustomobject]@{ Stage = "HistoryReadEvents"; Status = "PASS" }
+    } elseif ($eventOut -match "BadHistoryOperationUnsupported") {
+        Write-Host "[INFO] Upstream returned BadHistoryOperationUnsupported — re-run with --alm + a notifier that has event history."
+        $results += [pscustomobject]@{ Stage = "HistoryReadEvents"; Status = "SKIP" }
+    } else {
+        $results += [pscustomobject]@{ Stage = "HistoryReadEvents"; Status = "FAIL" }
+    }
+}
+
+Write-Host ""
+Write-Host "=== test-opcuaclient.ps1 results ==="
+$results | Format-Table -AutoSize
+$failed = $results | Where-Object { $_.Status -eq "FAIL" }
+if ($failed) {
     exit 1
 }
-
+exit 0
-# ---------------------------------------------------------------------------
-# Stage 2 — Remote read. Pulls the current value of -RemoteNodeId directly from
-# the upstream. Recorded for later stages to compare against, and confirms the
-# chosen NodeId actually exists on this upstream.
-# ---------------------------------------------------------------------------
-
-Write-Header "Remote read"
-$remoteRead = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $RemoteUrl, "-n", $RemoteNodeId)
-$remoteValue = $null
-if ($remoteRead.ExitCode -eq 0 -and $remoteRead.Output -match "Value:\s+([^\r\n]+)") {
-    $remoteValue = $Matches[1].Trim()
-    Write-Pass "remote $RemoteNodeId = $remoteValue"
-    $results += @{ Passed = $true }
-} else {
-    Write-Fail "remote read of $RemoteNodeId failed"
-    Write-Host $remoteRead.Output
-    $results += @{ Passed = $false; Reason = "remote read failed" }
-}
-
-# ---------------------------------------------------------------------------
-# Stage 3 — Forward bridge. Read -BridgeNodeId on the LOCAL server. If the
-# OpcUaClient driver is live + its discovery mapped -RemoteNodeId into the
-# local namespace, this should return a Good value. For ticker nodes like
-# FastUInt1 we don't require exact equality with stage 2 (the ticker has
-# likely advanced between reads); a Good-status read is the real signal.
-# ---------------------------------------------------------------------------
-
-Write-Header "Forward bridge (remote → local)"
-$localRead = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $BridgeNodeId)
-if ($localRead.ExitCode -eq 0 -and $localRead.Output -match "Status:\s+0x00000000" -and $localRead.Output -match "Value:\s+([^\r\n]+)") {
-    $localValue = $Matches[1].Trim()
-    Write-Pass "local bridge $BridgeNodeId = $localValue (remote was $remoteValue)"
-    $results += @{ Passed = $true }
-} else {
-    Write-Fail "local bridge read failed — driver instance may not be configured or discovery hasn't run"
-    Write-Host $localRead.Output
-    $results += @{ Passed = $false; Reason = "forward bridge failed" }
-}
-
-# ---------------------------------------------------------------------------
-# Stage 4 — Subscribe sees change. opc-plc's FastUInt1 ticks autonomously so we
-# don't need to drive a write. A properly wired OpcUaClient driver forwards
-# remote MonitoredItem data-change callbacks to the local server, which then
-# publishes them to our subscribe client. If nothing arrives within the
-# window, either the remote node isn't a ticker OR the upstream subscription
-# chain is broken (probe state, keep-alive, SDK publish queue).
-# ---------------------------------------------------------------------------
-
-Write-Header "Subscribe sees change"
-$stdout = New-TemporaryFile
-$stderr = New-TemporaryFile
-$subArgs = @($opcUaCli.PrefixArgs) + @(
-    "subscribe", "-u", $OpcUaUrl, "-n", $BridgeNodeId,
-    "-i", "200", "--duration", "$ChangeWaitSec")
-$subProc = Start-Process -FilePath $opcUaCli.File `
-    -ArgumentList $subArgs -NoNewWindow -PassThru `
-    -RedirectStandardOutput $stdout.FullName `
-    -RedirectStandardError  $stderr.FullName
-Write-Info "subscription started (pid $($subProc.Id)) for ${ChangeWaitSec}s"
-$subProc.WaitForExit(($ChangeWaitSec + 5) * 1000) | Out-Null
-if (-not $subProc.HasExited) { Stop-Process -Id $subProc.Id -Force }
-$subOut = (Get-Content $stdout.FullName -Raw) + (Get-Content $stderr.FullName -Raw)
-Remove-Item $stdout.FullName, $stderr.FullName -ErrorAction SilentlyContinue
-
-# SubscribeCommand prints `[timestamp] <NodeId> = <value> (0xNNNNNNNN)` per
-# data-change event. 0x00000000 == Good; anything else is a non-Good status
-# we intentionally don't count (a quality drop isn't a "saw the change").
-$changeLines = @(($subOut -split "`n") | Where-Object { $_ -match "=\s+\S.*\(0x00000000\)" })
-if ($changeLines.Count -gt 0) {
-    Write-Pass "$($changeLines.Count) data-change events observed on bridge"
-    $results += @{ Passed = $true }
-} else {
-    Write-Fail "no data-change events in ${ChangeWaitSec}s — upstream node may be static, or subscription chain broken"
-    Write-Host $subOut
-    $results += @{ Passed = $false; Reason = "no data-change" }
-}
-
-# ---------------------------------------------------------------------------
-# Stage 5 — Reverse bridge. Only runs when both writable NodeIds are supplied.
-# Writes on the local bridge side, reads directly on the upstream to verify
-# the write crossed the driver. 2s settle accounts for the driver's next poll
-# (non-idempotent writes on upstream side may take a tick to propagate).
-# ---------------------------------------------------------------------------
-
-if ([string]::IsNullOrEmpty($WritableBridgeNodeId) -or [string]::IsNullOrEmpty($WritableRemoteNodeId)) {
-    Write-Header "Reverse bridge (local → remote)"
-    Write-Skip "WritableBridgeNodeId / WritableRemoteNodeId not supplied — opc-plc default has no writable nodes. Add --sn=N to the compose and re-run with both params set."
-} else {
-    Write-Header "Reverse bridge (local → remote)"
-    $writeValue = Get-Random -Minimum 1 -Maximum 9999
-    $w = Invoke-Cli -Cli $opcUaCli -Args @(
-        "write", "-u", $OpcUaUrl, "-n", $WritableBridgeNodeId, "-v", "$writeValue")
-    if ($w.ExitCode -ne 0 -or $w.Output -notmatch "Write successful") {
-        Write-Fail "local-side write failed"
-        Write-Host $w.Output
-        $results += @{ Passed = $false; Reason = "reverse-bridge write failed" }
-    } else {
-        Write-Info "local write ok, waiting 2s for driver propagate"
-        Start-Sleep -Seconds 2
-        $r = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $RemoteUrl, "-n", $WritableRemoteNodeId)
-        if ($r.ExitCode -eq 0 -and $r.Output -match "Value:\s+$([Regex]::Escape("$writeValue"))\b") {
-            Write-Pass "remote reads back $writeValue"
-            $results += @{ Passed = $true }
-        } else {
-            Write-Fail "remote value did not reflect $writeValue"
-            Write-Host $r.Output
-            $results += @{ Passed = $false; Reason = "reverse-bridge readback mismatch" }
-        }
-    }
-}
-
-# ---------------------------------------------------------------------------
-# Stage 6 — Browse mirror. Walks -BridgeRootNodeId to -BrowseDepth levels. The
-# BrowseCommand emits one line per encountered node; we count non-empty lines
-# minus the root-summary line and compare against -BrowseMinNodes. A naked
-# i=85 root always has something; a narrower dev-specific root is stricter.
-# ---------------------------------------------------------------------------
-
-Write-Header "Browse mirror"
-$br = Invoke-Cli -Cli $opcUaCli -Args @(
-    "browse", "-u", $OpcUaUrl, "-n", $BridgeRootNodeId,
-    "-r", "-d", "$BrowseDepth")
-if ($br.ExitCode -ne 0) {
-    Write-Fail "browse failed (exit=$($br.ExitCode))"
-    Write-Host $br.Output
-    $results += @{ Passed = $false; Reason = "browse failed" }
-} else {
-    # BrowseCommand prints one line per node: `[Type] Name (NodeId: xxx)` with
-    # indentation for depth. Count every line carrying a NodeId marker.
-    $nodeLines = @(($br.Output -split "`n") | Where-Object { $_ -match "\(NodeId:" })
-    $count = $nodeLines.Count
-    if ($count -ge $BrowseMinNodes) {
-        Write-Pass "$count descendants under $BridgeRootNodeId (>= $BrowseMinNodes)"
-        $results += @{ Passed = $true }
-    } else {
-        Write-Fail "only $count descendants — expected >= $BrowseMinNodes"
-        Write-Host $br.Output
-        $results += @{ Passed = $false; Reason = "browse under-populated" }
-    }
-}
-
-# ---------------------------------------------------------------------------
-# Stage 7 — Alarm fires. opc-plc with --alm (set in the compose) cycles a
-# TripAlarm Condition autonomously. The local alarm subscription should
-# surface at least one Active transition within the wait window. Opt-in:
-# requires the user to know the local mirror of the upstream alarm Condition.
-# ---------------------------------------------------------------------------
-
-if ([string]::IsNullOrEmpty($AlarmNodeId)) {
-    Write-Header "Alarm fires"
-    Write-Skip "AlarmNodeId not supplied — skipping alarm stage"
-} else {
-    Write-Header "Alarm fires"
-    $stdout = New-TemporaryFile
-    $stderr = New-TemporaryFile
-    $allArgs = @($opcUaCli.PrefixArgs) + @(
-        "alarms", "-u", $OpcUaUrl, "-n", $AlarmNodeId, "-i", "500", "--refresh")
-    $proc = Start-Process -FilePath $opcUaCli.File `
-        -ArgumentList $allArgs -NoNewWindow -PassThru `
-        -RedirectStandardOutput $stdout.FullName `
-        -RedirectStandardError  $stderr.FullName
-    Write-Info "alarm subscription started (pid $($proc.Id)), waiting ${AlarmWaitSec}s for opc-plc alarm cycle"
-    Start-Sleep -Seconds $AlarmWaitSec
-    if (-not $proc.HasExited) { Stop-Process -Id $proc.Id -Force }
-    $out = (Get-Content $stdout.FullName -Raw) + (Get-Content $stderr.FullName -Raw)
-    Remove-Item $stdout.FullName, $stderr.FullName -ErrorAction SilentlyContinue
-
-    if ($out -match "ALARM\b" -and $out -match "Active\b") {
-        Write-Pass "alarm condition fired with Active state"
-        $results += @{ Passed = $true }
-    } else {
-        Write-Fail "no Active alarm event observed in ${AlarmWaitSec}s — check opc-plc compose has --alm + the AlarmNodeId is the local mirror of the upstream Condition"
-        Write-Host $out
-        $results += @{ Passed = $false; Reason = "no alarm event" }
-    }
-}
-
-# ---------------------------------------------------------------------------
-# Stage 8 — History read. IHistoryProvider dispatch to the upstream's
-# HistoryRead service. opc-plc does NOT historize by default, so this stage
-# SKIPs when -HistoryNodeId is empty. Against a historizing upstream (Prosys,
-# UA Expert sample server, AVEVA Historian) point -HistoryNodeId at the local
-# mirror of a historized node.
-# ---------------------------------------------------------------------------
-
-if ([string]::IsNullOrEmpty($HistoryNodeId)) {
-    Write-Header "History read"
-    Write-Skip "HistoryNodeId not supplied — opc-plc default does not historize; supply a historized-upstream mirror NodeId to enable."
-} else {
-    $results += Test-HistoryHasSamples `
-        -OpcUaCli $opcUaCli `
-        -OpcUaUrl $OpcUaUrl `
-        -NodeId $HistoryNodeId `
-        -LookbackSec $HistoryLookbackSec
-}
-
-Write-Summary -Title "OpcUaClient e2e" -Results $results
-if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-s7.ps1

@@ -96,5 +96,28 @@ $results += Test-SubscribeSeesChange `
     -DriverWriteArgs (@("write") + $commonS7 + @("-a", $Address, "-t", "Int16", "-v", $subValue)) `
     -ExpectedValue "$subValue"
 
+# PR-S7-D2 / #300 — UDT-member round-trip. Exercises the byte offsets the
+# driver's UDT fan-out uses when expanding a UDT-typed parent tag into per-
+# member scalar leaves: Real at DB1.DBD400 and Int16 at DB1.DBW404 match the
+# `MyUdt` layout seeded by Docker/profiles/s7_1500.json's udt_layout meta-seed
+# and declared by S7_1500UdtFanOutTests. The CLI itself is UDT-unaware so the
+# e2e step writes / reads at the explicit member byte offsets — proves the
+# wire-level path the fan-out emits is sound end-to-end.
+$udtPressureAddress = $Address.Substring(0, $Address.IndexOf('.')) + ".DBD400"
+$udtPressureValue = "27.5"
+$results += Test-DriverLoopback `
+    -Cli $s7Cli `
+    -WriteArgs (@("write") + $commonS7 + @("-a", $udtPressureAddress, "-t", "Float32", "-v", $udtPressureValue)) `
+    -ReadArgs  (@("read")  + $commonS7 + @("-a", $udtPressureAddress, "-t", "Float32")) `
+    -ExpectedValue $udtPressureValue
+
+$udtStatusAddress = $Address.Substring(0, $Address.IndexOf('.')) + ".DBW404"
+$udtStatusValue = Get-Random -Minimum 100 -Maximum 999
+$results += Test-DriverLoopback `
+    -Cli $s7Cli `
+    -WriteArgs (@("write") + $commonS7 + @("-a", $udtStatusAddress, "-t", "Int16", "-v", $udtStatusValue)) `
+    -ReadArgs  (@("read")  + $commonS7 + @("-a", $udtStatusAddress, "-t", "Int16")) `
+    -ExpectedValue "$udtStatusValue"
+
 Write-Summary -Title "S7 e2e" -Results $results
 if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/install/Install-FocasHost.ps1

@@ -0,0 +1,108 @@
+<#
+.SYNOPSIS
+    Registers the OtOpcUaFocasHost Windows service. Optional companion to
+    Install-Services.ps1 — only run this on nodes where FOCAS driver instances will run
+    with Tier-C process isolation enabled.
+
+.DESCRIPTION
+    FOCAS PR #220 / Tier-C isolation plan. Wraps OtOpcUa.Driver.FOCAS.Host.exe (net48 x86)
+    as a Windows service using NSSM, running under the same service account as the main
+    OtOpcUa service so the named-pipe ACL works. Passes the per-process shared secret via
+    environment variable at service-start time so it never hits disk.
+
+.PARAMETER InstallRoot
+    Where the FOCAS Host binaries live (typically
+    C:\Program Files\OtOpcUa\Driver.FOCAS.Host).
+
+.PARAMETER ServiceAccount
+    Service account SID or DOMAIN\name. Must match the main OtOpcUa server account so the
+    PipeAcl match succeeds.
+
+.PARAMETER FocasSharedSecret
+    Per-process secret passed via env var. Generated freshly per install if not supplied.
+
+.PARAMETER FocasBackend
+    Backend selector for the Host process. One of:
+      fwlib32      (default — real Fanuc Fwlib32.dll integration; requires licensed DLL on PATH)
+      fake         (in-memory; smoke-test mode)
+      unconfigured (safe default returning structured errors; use until hardware is wired)
+
+.PARAMETER FocasPipeName
+    Pipe name the Host listens on. Default: OtOpcUaFocas.
+
+.EXAMPLE
+    .\Install-FocasHost.ps1 -InstallRoot 'C:\Program Files\OtOpcUa\Driver.FOCAS.Host' `
+        -ServiceAccount 'OTOPCUA\svc-otopcua' -FocasBackend fwlib32
+#>
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory)] [string]$InstallRoot,
+    [Parameter(Mandatory)] [string]$ServiceAccount,
+    [string]$FocasSharedSecret,
+    [ValidateSet('fwlib32','fake','unconfigured')] [string]$FocasBackend = 'unconfigured',
+    [string]$FocasPipeName = 'OtOpcUaFocas',
+    [string]$ServiceName = 'OtOpcUaFocasHost',
+    [string]$NssmPath = 'C:\Program Files\nssm\nssm.exe'
+)
+
+$ErrorActionPreference = 'Stop'
+
+function Resolve-Sid {
+    param([string]$Account)
+    if ($Account -match '^S-\d-\d+') { return $Account }
+    try {
+        $nt = New-Object System.Security.Principal.NTAccount($Account)
+        return $nt.Translate([System.Security.Principal.SecurityIdentifier]).Value
+    } catch {
+        throw "Could not resolve '$Account' to a SID. Pass an explicit SID or check the account name."
+    }
+}
+
+if (-not (Test-Path $NssmPath)) {
+    throw "nssm.exe not found at '$NssmPath'. Install NSSM or pass -NssmPath."
+}
+
+$hostExe = Join-Path $InstallRoot 'OtOpcUa.Driver.FOCAS.Host.exe'
+if (-not (Test-Path $hostExe)) {
+    throw "FOCAS Host binary not found at '$hostExe'. Publish the Driver.FOCAS.Host project first."
+}
+
+if (-not $FocasSharedSecret) {
+    $FocasSharedSecret = [System.Guid]::NewGuid().ToString('N')
+    Write-Host "Generated FocasSharedSecret — store it alongside the OtOpcUa service config."
+}
+
+$allowedSid = Resolve-Sid $ServiceAccount
+
+# Idempotent install — remove + re-create if present.
+$existing = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+if ($existing) {
+    Write-Host "Removing existing '$ServiceName' service..."
+    & $NssmPath stop $ServiceName confirm | Out-Null
+    & $NssmPath remove $ServiceName confirm | Out-Null
+}
+
+& $NssmPath install $ServiceName $hostExe | Out-Null
+& $NssmPath set $ServiceName DisplayName 'OT-OPC-UA FOCAS Host (Tier-C isolated Fwlib32)' | Out-Null
+& $NssmPath set $ServiceName Description 'Out-of-process Fwlib32.dll host for OtOpcUa FOCAS driver. Crash-isolated from the main OPC UA server.' | Out-Null
+& $NssmPath set $ServiceName ObjectName  $ServiceAccount | Out-Null
+& $NssmPath set $ServiceName Start SERVICE_AUTO_START | Out-Null
+& $NssmPath set $ServiceName AppStdout (Join-Path $env:ProgramData 'OtOpcUa\focas-host-stdout.log') | Out-Null
+& $NssmPath set $ServiceName AppStderr (Join-Path $env:ProgramData 'OtOpcUa\focas-host-stderr.log') | Out-Null
+& $NssmPath set $ServiceName AppRotateFiles 1 | Out-Null
+& $NssmPath set $ServiceName AppRotateBytes 10485760 | Out-Null
+
+& $NssmPath set $ServiceName AppEnvironmentExtra `
+    "OTOPCUA_FOCAS_PIPE=$FocasPipeName" `
+    "OTOPCUA_ALLOWED_SID=$allowedSid" `
+    "OTOPCUA_FOCAS_SECRET=$FocasSharedSecret" `
+    "OTOPCUA_FOCAS_BACKEND=$FocasBackend" | Out-Null
+
+& $NssmPath set $ServiceName DependOnService OtOpcUa | Out-Null
+
+Write-Host "Installed '$ServiceName' under '$ServiceAccount' (SID=$allowedSid)."
+Write-Host "Pipe: \\.\pipe\$FocasPipeName    Backend: $FocasBackend"
+Write-Host "Start the service with: Start-Service $ServiceName"
+Write-Host ""
+Write-Host "NOTE: the Fwlib32 backend requires the licensed Fwlib32.dll on PATH"
+Write-Host "alongside the Host exe. See docs/v2/focas-deployment.md."

scripts/integration/README.md

@@ -1,87 +0,0 @@
-# Integration runners
-
-Scripts that orchestrate multi-component integration-test loops —
-each one wires up docker fixtures, support binaries, and `dotnet test`
-in sequence so a developer (or a CI agent) can get from "freshly
-cloned repo" to "green integration suite" with one command.
-
-Unlike `scripts/e2e/test-*.ps1` (which drive the built server through
-the CLI for black-box coverage), scripts in this folder operate
-**below** the server layer — they bring up the raw fixtures the
-driver-level `IntegrationTests` projects need.
-
-## Scripts
-
-| Script | Purpose |
-|--------|---------|
-| [`run-focas.ps1`](run-focas.ps1) | FOCAS driver: builds shim DLLs + starts focas-mock docker + copies shim into test bin + runs `WireCompatGatedTests` + `FocasSimSmokeTests` + tears down docker |
-
-## run-focas.ps1
-
-### Prerequisites
-
-- **Windows + PowerShell 7+**
-- **.NET 10 SDK** — `dotnet --version` prints 10.x
-- **Native C compiler** — one of:
-  - Visual Studio Build Tools with the C++ workload (then run from an
-    "x64 Native Tools Command Prompt for VS" shell), or
-  - Zig (`zig.exe` on PATH) as a drop-in alternative
-- **Docker Desktop** running, OR pass `-SkipDocker` and run the mock
-  externally
-
-### One-shot run
-
-```powershell
-cd C:\Users\dohertj2\Desktop\lmxopcua
-pwsh .\scripts\integration\run-focas.ps1
-```
-
-That's the default invocation: thirtyone profile, debug build,
-docker cleans up on exit.
-
-### Development iteration
-
-Re-run the tests without rebuilding the shim or restarting docker:
-
-```powershell
-# First run bootstraps everything + keeps the mock up.
-pwsh .\scripts\integration\run-focas.ps1 -KeepDocker
-
-# Iterate on test bodies without re-doing the slow steps.
-pwsh .\scripts\integration\run-focas.ps1 -SkipShimBuild -SkipDocker
-```
-
-### Per-series runs
-
-```powershell
-pwsh .\scripts\integration\run-focas.ps1 -Profile thirty     # 30i series
-pwsh .\scripts\integration\run-focas.ps1 -Profile zerod      # 0i-D
-pwsh .\scripts\integration\run-focas.ps1 -Profile powermotion
-```
-
-Full profile list is in
-`tests/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/Docker/docker-compose.yml`.
-
-### Exit codes
-
-| Code | Meaning |
-|------|---------|
-| 0 | All tests passed or cleanly skipped |
-| 1 | `dotnet test` reported failures |
-| 2 | The runner itself crashed (missing file, unexpected exception) |
-| 3 | No C compiler detected for shim build |
-| 4 | Docker CLI not on PATH |
-
-### CI integration
-
-Wire this into the project's CI runner (Gitea Actions, Jenkins,
-whatever's hosting this repo) by calling:
-
-```yaml
-- name: FOCAS integration
-  shell: pwsh
-  run: ./scripts/integration/run-focas.ps1
-```
-
-The script is idempotent; a previous run's `docker compose down`
-failure won't block the next one.

scripts/integration/run-focas.ps1

@@ -1,123 +0,0 @@
-#Requires -Version 7.0
-<#
-.SYNOPSIS
-  Orchestrates the FOCAS driver integration-test loop: bring up the
-  focas-mock Docker container, run the managed wire-client integration
-  tests, tear down Docker.
-
-.DESCRIPTION
-  The FOCAS integration fixture now needs just two things running
-  together:
-    1. A single focas-mock container listening on :8193 (one service,
-       no per-series compose profile ceremony — the mock's native
-       FOCAS Ethernet responder handles every call the managed driver
-       issues).
-    2. The integration-test assembly built. The managed
-       `WireFocasClient` dials the mock directly; there is no shim
-       DLL, no P/Invoke, no test-bin DLL copy step.
-  This script handles both and cleans up on exit.
-
-  Designed to run unattended on a build agent or on a developer box.
-  Exit code matches the test suite (0 = all pass or skip-clean,
-  non-zero when any integration test failed).
-
-.PARAMETER Profile
-  focas-mock profile name to seed at startup (e.g. `ThirtyOne_i`,
-  `Sixteen_i`, `fwlib30i64`). Defaults to `ThirtyOne_i`. The fixture
-  resolves aliases via `FocasCncSeries`, and tests that need per-series
-  state can call `fixture.LoadProfileAsync` directly at test start to
-  override the default.
-
-.PARAMETER SkipDocker
-  Skip docker up/down. Use when the mock is already running from
-  another shell.
-
-.PARAMETER Configuration
-  Build configuration — Debug or Release. Default: Debug.
-
-.PARAMETER KeepDocker
-  Don't tear down the docker stack on exit. Useful for iterating on
-  tests.
-#>
-
-param(
-    [string]$Profile = "ThirtyOne_i",
-    [switch]$SkipDocker,
-    [ValidateSet("Debug", "Release")]
-    [string]$Configuration = "Debug",
-    [switch]$KeepDocker
-)
-
-Set-StrictMode -Version 3.0
-$ErrorActionPreference = "Stop"
-
-$repoRoot   = (Resolve-Path (Join-Path $PSScriptRoot "..\..")).Path
-$integTests = Join-Path $repoRoot "tests\ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests"
-$dockerYml  = Join-Path $integTests "Docker\docker-compose.yml"
-
-function Write-Step { param([string]$Msg) Write-Host ""; Write-Host "=== $Msg ===" -ForegroundColor Cyan }
-function Write-Info { param([string]$Msg) Write-Host "[INFO] $Msg" -ForegroundColor Gray }
-function Write-Fail { param([string]$Msg) Write-Host "[FAIL] $Msg" -ForegroundColor Red }
-
-$cleanupScripts = @()
-trap {
-    Write-Host ""
-    Write-Fail "run-focas.ps1 crashed: $_"
-    foreach ($c in $cleanupScripts) { try { & $c } catch { Write-Host "cleanup failed: $_" -ForegroundColor DarkYellow } }
-    exit 2
-}
-
-Write-Step "Build FOCAS IntegrationTests ($Configuration)"
-dotnet build (Join-Path $integTests "ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests.csproj") `
-    --configuration $Configuration --nologo --verbosity minimal
-if ($LASTEXITCODE -ne 0) { throw "dotnet build failed (exit $LASTEXITCODE)" }
-
-if (-not $SkipDocker) {
-    Write-Step "docker compose up"
-    if (-not (Get-Command docker -ErrorAction SilentlyContinue)) {
-        Write-Fail "docker CLI not on PATH. Install Docker Desktop or pass -SkipDocker + run the mock externally."
-        exit 4
-    }
-
-    docker compose -f $dockerYml up -d --build --wait 2>&1 | Write-Host
-    if ($LASTEXITCODE -ne 0) { throw "docker compose up failed (exit $LASTEXITCODE)" }
-
-    if (-not $KeepDocker) {
-        $cleanupScripts += {
-            Write-Step "docker compose down"
-            docker compose -f $dockerYml down --remove-orphans 2>&1 | Write-Host
-        }
-    }
-
-    Write-Info "probing localhost:8193..."
-    $tcp = [System.Net.Sockets.TcpClient]::new()
-    try {
-        $ok = $tcp.ConnectAsync("127.0.0.1", 8193).Wait([TimeSpan]::FromSeconds(5))
-        if (-not $ok -or -not $tcp.Connected) {
-            throw "TCP probe to localhost:8193 failed after docker compose --wait succeeded"
-        }
-    }
-    finally { $tcp.Dispose() }
-    Write-Info "mock is accepting connections"
-}
-else {
-    Write-Step "Docker (skipped)"
-}
-
-Write-Step "dotnet test (wire-backend integration)"
-$env:OTOPCUA_FOCAS_SIM_PROFILE = $Profile
-
-dotnet test (Join-Path $integTests "ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests.csproj") `
-    --configuration $Configuration --no-build --nologo --verbosity minimal
-$testExit = $LASTEXITCODE
-
-foreach ($c in $cleanupScripts) { & $c }
-
-if ($testExit -ne 0) {
-    Write-Fail "integration tests failed with exit $testExit"
-    exit $testExit
-}
-
-Write-Host ""
-Write-Host "run-focas.ps1 completed successfully." -ForegroundColor Green
-exit 0

scripts/smoke/seed-abcip-smoke.sql

@@ -80,6 +80,11 @@ VALUES (@Gen, @EqId, @EqUuid, @DrvId, @LineId, 'ab-sim', 'abcip-001', 1);
 
 -- AB CIP DriverInstance — single ControlLogix device at the ab_server fixture
 -- gateway. DriverConfig shape mirrors AbCipDriverConfigDto.
+--
+-- The second device entry (CompactLogix L2 example, commented out) demonstrates
+-- the PR abcip-3.1 ConnectionSize override knob. Uncomment + point at a real
+-- 5069-L2 to verify the narrow-buffer Forward Open path; ab_server itself
+-- doesn't enforce the narrow cap (see docs/drivers/AbServer-Test-Fixture.md §5).
 INSERT dbo.DriverInstance(GenerationId, DriverInstanceId, ClusterId, NamespaceId,
                           Name, DriverType, DriverConfig, Enabled)
 VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'ab-server-smoke', 'AbCip', N'{
@@ -90,6 +95,14 @@ VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'ab-server-smoke', 'AbCip', N'{
       "PlcFamily": "ControlLogix",
       "DeviceName": "ab-server"
     }
+    /*
+    , {
+      "HostAddress": "ab://10.0.0.7/1,0",
+      "PlcFamily": "CompactLogix",
+      "DeviceName": "compactlogix-l2-narrow",
+      "ConnectionSize": 504
+    }
+    */
   ],
   "Probe": { "Enabled": true, "IntervalMs": 5000, "TimeoutMs": 2000 },
   "Tags": [

scripts/smoke/seed-ablegacy-smoke.sql

@@ -31,10 +31,11 @@ DECLARE @LineId    nvarchar(64) = 'ablegacy-smoke-line';
 DECLARE @EqId      nvarchar(64) = 'ablegacy-smoke-eq';
 DECLARE @EqUuid    uniqueidentifier = '5A1D2030-5A1D-4203-A5A1-D20305A1D203';
 DECLARE @TagId     nvarchar(64) = 'ablegacy-smoke-tag-n7_5';
+DECLARE @ArrTagId  nvarchar(64) = 'ablegacy-smoke-tag-n7_block';
 
 BEGIN TRAN;
 
-DELETE FROM dbo.Tag                        WHERE TagId IN (@TagId);
+DELETE FROM dbo.Tag                        WHERE TagId IN (@TagId, @ArrTagId);
 DELETE FROM dbo.Equipment                  WHERE EquipmentId = @EqId;
 DELETE FROM dbo.UnsLine                    WHERE UnsLineId = @LineId;
 DELETE FROM dbo.UnsArea                    WHERE UnsAreaId = @AreaId;
@@ -79,15 +80,28 @@ VALUES (@Gen, @EqId, @EqUuid, @DrvId, @LineId, 'slc-sim', 'ablegacy-001', 1);
 
 -- AB Legacy DriverInstance — SLC 500 target. Replace the placeholder gateway
 -- `192.168.1.10` with the real PLC / RSEmulate host before running.
+--
+-- PR 9 / #252 demo: the device row carries `"TimeoutMs": 500` + `"Retries": 1`,
+-- both overriding the driver-wide `TimeoutMs: 2000` / `Retries: 0` defaults.
+-- For real chassis tune per family (SLC 5/01 ≈ 5000, SLC 5/05 ≈ 2000,
+-- MicroLogix 1100 ≈ 3000); see docs/Driver.AbLegacy.Cli.md for the cheat sheet.
 INSERT dbo.DriverInstance(GenerationId, DriverInstanceId, ClusterId, NamespaceId,
                           Name, DriverType, DriverConfig, Enabled)
 VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'ablegacy-smoke', 'AbLegacy', N'{
   "TimeoutMs": 2000,
+  "Retries": 0,
   "Devices": [
     {
       "HostAddress": "ab://127.0.0.1:44818/1,0",
       "PlcFamily": "Slc500",
-      "DeviceName": "slc-500"
+      "DeviceName": "slc-500",
+      "TimeoutMs": 500,
+      "Retries": 1,
+      "Demote": {
+        "FailureThreshold": 3,
+        "DemoteForMs": 30000,
+        "Enabled": true
+      }
     }
   ],
   "Probe": { "Enabled": true, "IntervalMs": 5000, "TimeoutMs": 2000, "ProbeAddress": "S:0" },
@@ -98,7 +112,16 @@ VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'ablegacy-smoke', 'AbLegacy', N'{
       "Address": "N7:5",
       "DataType": "Int",
       "Writable": true,
-      "WriteIdempotent": true
+      "WriteIdempotent": true,
+      "AbsoluteDeadband": 5
+    },
+    {
+      "Name": "N7_Block",
+      "DeviceHostAddress": "ab://127.0.0.1:44818/1,0",
+      "Address": "N7:0,10",
+      "DataType": "Int",
+      "Writable": false,
+      "ArrayLength": 10
     }
   ]
 }', 1);
@@ -108,6 +131,17 @@ INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataTyp
 VALUES (@Gen, @TagId, @DrvId, @EqId, 'N7_5', 'Int16', 'ReadWrite',
         N'{"FullName":"N7_5","Address":"N7:5","DataType":"Int"}', 1);
 
+-- PR 7 — array contiguous-block tag. The TagConfig JSON carries the address suffix
+-- + ArrayLength override; the driver picks both up at discovery time and emits the
+-- DriverAttributeInfo with IsArray=true + ArrayDim=10 so the generic node manager
+-- materialises a 1-D Int16 array variable. The dbo.Tag schema doesn't carry
+-- IsArray/ArrayDim columns — the array shape is fully driver-side metadata.
+-- Read-only because the smoke harness only exercises array reads.
+INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataType,
+               AccessLevel, TagConfig, WriteIdempotent)
+VALUES (@Gen, @ArrTagId, @DrvId, @EqId, 'N7_Block', 'Int16', 'Read',
+        N'{"FullName":"N7_Block","Address":"N7:0,10","DataType":"Int","ArrayLength":10}', 0);
+
 EXEC dbo.sp_PublishGeneration @ClusterId = @ClusterId, @DraftGenerationId = @Gen,
                               @Notes = N'AB Legacy smoke — task #213';
 
@@ -123,3 +157,18 @@ PRINT 'NOTE: default points at the ab_server slc500 Docker fixture with a /1,0';
 PRINT '      cip-path (required by ab_server). For real SLC/MicroLogix/PLC-5';
 PRINT '      hardware, edit the DriverConfig HostAddress to end with /<empty>';
 PRINT '      e.g. "ab://<plc-ip>:44818/" and re-run this seed.';
+PRINT '';
+PRINT 'PR ablegacy-10 / #253 — diagnostic counters auto-emit per device under';
+PRINT '   AbLegacy/<host>/_Diagnostics/<name>. No dbo.Tag rows needed — the';
+PRINT '   driver registers them at DiscoverAsync time. Nine counters per device:';
+PRINT '   RequestCount, ResponseCount, ErrorCount, RetryCount, LastErrorCode,';
+PRINT '   LastErrorMessage, CommFailures, DemoteCount, LastDemotedUtc. See';
+PRINT '   docs/drivers/AbLegacy-Diagnostics.md for the full surface + reset';
+PRINT '   semantics.';
+PRINT '';
+PRINT 'PR ablegacy-12 / #255 — auto-demote on comm failure: 3 consecutive';
+PRINT '   failed reads / probes mark the device Demoted for DemoteFor=PT30S';
+PRINT '   (30 s); reads against a demoted device short-circuit with';
+PRINT '   BadCommunicationError so one slow PLC can''t starve the driver.';
+PRINT '   Tune via the Demote block on each Devices[] row. DemoteCount +';
+PRINT '   LastDemotedUtc on the _Diagnostics folder surface flapping links.';

scripts/smoke/seed-phase-7-smoke.sql

@@ -71,13 +71,6 @@ INSERT dbo.ClusterNode(NodeId, ClusterId, RedundancyRole, Host, OpcUaPort, Dashb
 VALUES (@NodeId, @ClusterId, 'Primary', 'localhost', 4840, 5000,
         'urn:OtOpcUa:p7-smoke-node', 200, 1, 'p7-smoke');
 
--- sp_GetCurrentGenerationForCluster gates access by SUSER_SNAME() against
--- ClusterNodeCredential; without this binding the Server bootstrap fails with
--- `Unauthorized: caller sa is not bound to NodeId p7-smoke-node`. Dev Docker
--- SQL runs with `sa`; production deploys would rotate to a per-node login.
-INSERT dbo.ClusterNodeCredential(NodeId, Kind, Value, Enabled, CreatedBy)
-VALUES (@NodeId, N'SqlLogin', N'sa', 1, N'p7-smoke');
-
 -- 2. Generation (created Draft, flipped to Published at the end so insert order
 --    constraints (one Draft per cluster, etc.) don't fight us).
 DECLARE @Gen bigint;
@@ -113,43 +106,30 @@ VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'galaxy-smoke', 'Galaxy', N'{
 }', 1);
 
 -- 6. One driver-sourced Tag bound to the Equipment. TagConfig is the Galaxy
---    fullRef; the EquipmentNodeWalker reads the JSON's FullName field and
+--    fullRef ("DelmiaReceiver_001.DownloadPath" style); replace with a real
---    hands that string to the Galaxy driver as the MXAccess reference.
+--    attribute on this Galaxy. The script paths below use
---    Default points at TestMachine_001.TestHistoryValue — the live dev-box
+--    /lab-floor/galaxy-line/reactor-1/Source which the EquipmentNodeWalker
---    Galaxy ships it as Int32 + writable (security_classification=Operate)
+--    emits + the DriverSubscriptionBridge maps to this driver fullRef.
---    + historized (HistoryExtension primitive), so the E2E script can
---    exercise read + write + subscribe + alarm + history against the
---    same attribute. Swap to any other writable historized attribute on
---    this Galaxy by re-running `gr/queries/attributes_extended.sql` with
---    `WHERE is_historized=1 AND security_classification > 0`.
 INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataType,
                AccessLevel, TagConfig, WriteIdempotent)
-VALUES (@Gen, @TagId, @DrvId, @EqId, 'Source', 'Int32', 'ReadWrite',
+VALUES (@Gen, @TagId, @DrvId, @EqId, 'Source', 'Float64', 'Read',
-        N'{"FullName":"TestMachine_001.TestHistoryValue","DataType":"Int32"}', 0);
+        N'{"FullName":"REPLACE_WITH_REAL_GALAXY_ATTRIBUTE","DataType":"Float64"}', 0);
 
 -- 7. Scripts (SourceHash is SHA-256 of SourceCode, computed externally — using
 --    a placeholder here; the engine recomputes on first use anyway).
---
---    MachineStatus predicate — the dynamic "is the machine running?" status
---    derived from the raw Source value. Boolean: true when Source > 0. Matches
---    the shape Aveva operators typically want on a machine-status tile (green
---    when above zero, otherwise grey) without needing a separate threshold
---    attribute. Rename + re-threshold here to mirror site semantics.
 INSERT dbo.Script(GenerationId, ScriptId, Name, SourceCode, SourceHash, Language)
 VALUES
-  (@Gen, @VtScript, 'machine-status-predicate',
+  (@Gen, @VtScript, 'doubled-source',
-   N'return System.Convert.ToInt32(ctx.GetTag("/lab-floor/galaxy-line/reactor-1/Source").Value) > 0;',
+   N'return ((double)ctx.GetTag("/lab-floor/galaxy-line/reactor-1/Source").Value) * 2.0;',
    '0000000000000000000000000000000000000000000000000000000000000000', 'CSharp'),
   (@Gen, @AlScript, 'overtemp-predicate',
-   N'return System.Convert.ToInt32(ctx.GetTag("/lab-floor/galaxy-line/reactor-1/Source").Value) > 50;',
+   N'return ((double)ctx.GetTag("/lab-floor/galaxy-line/reactor-1/Source").Value) > 50.0;',
    '0000000000000000000000000000000000000000000000000000000000000000', 'CSharp');
 
--- 8. VirtualTag — MachineStatus boolean computed by Roslyn each time Source
+-- 8. VirtualTag — derived value computed by Roslyn each time Source changes.
---    changes. Historized so the dashboard can plot a running/idle timeline
---    next to the raw TestHistoryValue trend from Aveva Historian.
 INSERT dbo.VirtualTag(GenerationId, VirtualTagId, EquipmentId, Name, DataType,
                       ScriptId, ChangeTriggered, TimerIntervalMs, Historize, Enabled)
-VALUES (@Gen, @VtId, @EqId, 'MachineStatus', 'Boolean', @VtScript, 1, NULL, 1, 1);
+VALUES (@Gen, @VtId, @EqId, 'Doubled', 'Float64', @VtScript, 1, NULL, 0, 1);
 
 -- 9. ScriptedAlarm — Active when Source > 50.
 INSERT dbo.ScriptedAlarm(GenerationId, ScriptedAlarmId, EquipmentId, Name, AlarmType,

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/DriversTab.razor

@@ -1,5 +1,3 @@
-@using System.Text.Json
-@using ZB.MOM.WW.OtOpcUa.Admin.Components.Pages.Modbus
 @using ZB.MOM.WW.OtOpcUa.Admin.Services
 @using ZB.MOM.WW.OtOpcUa.Configuration.Entities
 @inject DriverInstanceService DriverSvc
@@ -19,21 +17,7 @@ else
         <tbody>
         @foreach (var d in _drivers)
         {
-            <tr>
+            <tr><td><code>@d.DriverInstanceId</code></td><td>@d.Name</td><td>@d.DriverType</td><td><code>@d.NamespaceId</code></td></tr>
-                <td><code>@d.DriverInstanceId</code></td>
-                <td>@d.Name</td>
-                <td>
-                    @if (string.Equals(d.DriverType, "Focas", StringComparison.OrdinalIgnoreCase))
-                    {
-                        <a href="/drivers/focas/@d.DriverInstanceId">@d.DriverType</a>
-                    }
-                    else
-                    {
-                        @d.DriverType
-                    }
-                </td>
-                <td><code>@d.NamespaceId</code></td>
-            </tr>
         }
         </tbody>
     </table>
@@ -52,14 +36,13 @@ else
                     <label class="form-label">DriverType</label>
                     <select class="form-select" @bind="_type">
                         <option>Galaxy</option>
-                        <option>Modbus</option>
+                        <option>ModbusTcp</option>
                         <option>AbCip</option>
                         <option>AbLegacy</option>
                         <option>S7</option>
                         <option>Focas</option>
                         <option>OpcUaClient</option>
                     </select>
-                    <div class="form-text">Type string must match the driver's registered factory name; this dropdown wraps the canonical names.</div>
                 </div>
                 <div class="col-md-6">
                     <label class="form-label">Namespace</label>
@@ -68,19 +51,9 @@ else
                     </select>
                 </div>
                 <div class="col-12">
-                    @if (string.Equals(_type, "Modbus", StringComparison.OrdinalIgnoreCase))
-                    {
-                        @* #147 — typed editor for Modbus drivers. The generic textarea is a fall-back
-                           for driver types that haven't yet shipped a typed editor. *@
-                        <label class="form-label">Modbus options (typed editor)</label>
-                        <ModbusOptionsEditor Model="_modbusOptions"/>
-                    }
-                    else
-                    {
                     <label class="form-label">DriverConfig JSON (schemaless per driver type)</label>
                     <textarea class="form-control font-monospace" rows="6" @bind="_config"></textarea>
                     <div class="form-text">Phase 1: generic JSON editor — per-driver schema validation arrives in each driver's phase (decision #94).</div>
-                    }
                 </div>
             </div>
             @if (_error is not null) { <div class="alert alert-danger mt-3">@_error</div> }
@@ -100,17 +73,11 @@ else
     private List<Namespace>? _namespaces;
     private bool _showForm;
     private string _name = string.Empty;
-    private string _type = "Modbus";
+    private string _type = "ModbusTcp";
     private string _nsId = string.Empty;
     private string _config = "{}";
     private string? _error;
 
-    // #147 — typed editor model for Modbus drivers. Defaults match ModbusDriverOptions
-    // defaults so an unedited form produces config equivalent to the historical
-    // pre-typed-editor wire output. Serialised to _config on Save when type=Modbus.
-    private ModbusOptionsEditor.ModbusOptionsViewModel _modbusOptions = new();
-    private static readonly JsonSerializerOptions ModbusJsonOptions = new() { WriteIndented = true };
-
     protected override async Task OnParametersSetAsync() => await ReloadAsync();
 
     private async Task ReloadAsync()
@@ -130,57 +97,11 @@ else
         }
         try
         {
-            // #147 — for Modbus drivers serialize the typed editor model into the DriverConfig
+            await DriverSvc.AddAsync(GenerationId, ClusterId, _nsId, _name, _type, _config, CancellationToken.None);
-            // JSON column. Other driver types still use the raw textarea contents until each
-            // ships its own typed editor (decision #94 — per-driver schema validation arrives
-            // per driver phase).
-            var configJson = string.Equals(_type, "Modbus", StringComparison.OrdinalIgnoreCase)
-                ? SerializeModbusOptions(_modbusOptions)
-                : _config;
-
-            await DriverSvc.AddAsync(GenerationId, ClusterId, _nsId, _name, _type, configJson, CancellationToken.None);
             _name = string.Empty; _config = "{}";
-            _modbusOptions = new();
             _showForm = false;
             await ReloadAsync();
         }
         catch (Exception ex) { _error = ex.Message; }
     }
-
-    /// <summary>
-    ///     Maps the view-model field names onto the JSON shape <c>ModbusDriverFactoryExtensions</c>
-    ///     consumes. Hand-rolled because the DTO uses millisecond / byte field flavours that the
-    ///     view model exposes as TimeSpan-derived integers; a System.Text.Json round-trip would
-    ///     emit the .NET-native names instead.
-    /// </summary>
-    private static string SerializeModbusOptions(ModbusOptionsEditor.ModbusOptionsViewModel m) =>
-        JsonSerializer.Serialize(new
-        {
-            host = m.Host,
-            port = m.Port,
-            unitId = m.UnitId,
-            family = m.Family.ToString(),
-            melsecSubFamily = m.MelsecSubFamily.ToString(),
-            keepAlive = new
-            {
-                enabled = m.KeepAliveEnabled,
-                timeMs = m.KeepAliveTimeSec * 1000,
-                intervalMs = m.KeepAliveIntervalSec * 1000,
-                retryCount = m.KeepAliveRetryCount,
-            },
-            reconnect = new
-            {
-                initialDelayMs = m.ReconnectInitialDelayMs,
-                maxDelayMs = m.ReconnectMaxDelayMs,
-                backoffMultiplier = m.ReconnectBackoffMultiplier,
-            },
-            maxRegistersPerRead = m.MaxRegistersPerRead,
-            maxRegistersPerWrite = m.MaxRegistersPerWrite,
-            maxCoilsPerRead = m.MaxCoilsPerRead,
-            maxReadGap = m.MaxReadGap,
-            useFC15ForSingleCoilWrites = m.UseFC15ForSingleCoilWrites,
-            useFC16ForSingleRegisterWrites = m.UseFC16ForSingleRegisterWrites,
-            writeOnChangeOnly = m.WriteOnChangeOnly,
-            tags = Array.Empty<object>(),
-        }, ModbusJsonOptions);
 }

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ImportEquipment.razor

@@ -26,15 +26,6 @@
     reservation conflict exists.
 </div>
 
-<div class="alert alert-secondary small mb-3">
-    <strong>Per-tag addressing for Modbus drivers</strong> isn't part of equipment import —
-    tags are configured at the driver-instance level via the
-    <a href="/clusters/@ClusterId/draft/@GenerationId">Drivers tab</a>. Use the
-    <a href="/modbus/address-preview" target="_blank">address-preview tool</a> to sanity-check
-    grammar strings (<code>40001:F:CDAB</code>, <code>HR1:I</code>, <code>V2000</code> for
-    DL205 family, etc.) before pasting them into the driver config.
-</div>
-
 <div class="card mb-3">
     <div class="card-body">
         <div class="row g-3">

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Drivers/FocasDetail.razor

@@ -1,224 +0,0 @@
-@page "/drivers/focas/{InstanceId}"
-@using ZB.MOM.WW.OtOpcUa.Admin.Services
-@inject FocasDriverDetailService DetailSvc
-
-<h1 class="mb-3">FOCAS driver <code>@InstanceId</code></h1>
-
-@if (_loading)
-{
-    <p>Loading…</p>
-}
-else if (_detail is null)
-{
-    <div class="alert alert-warning">
-        No FOCAS driver instance with id <code>@InstanceId</code> was found.
-        <div class="small text-muted mt-1">
-            Either the id is wrong, or the instance's <code>DriverType</code> is not "Focas". The list of drivers per cluster draft is on the <a href="/clusters">Clusters</a> page.
-        </div>
-    </div>
-}
-else
-{
-    <div class="row g-3 mb-4">
-        <div class="col-md-3"><div class="card"><div class="card-body">
-            <h6 class="text-muted mb-1">Name</h6>
-            <div class="fs-5">@_detail.Instance.Name</div>
-        </div></div></div>
-        <div class="col-md-3"><div class="card"><div class="card-body">
-            <h6 class="text-muted mb-1">Cluster</h6>
-            <div class="fs-5"><code>@_detail.Instance.ClusterId</code></div>
-        </div></div></div>
-        <div class="col-md-3"><div class="card"><div class="card-body">
-            <h6 class="text-muted mb-1">Namespace</h6>
-            <div class="fs-5"><code>@_detail.Instance.NamespaceId</code></div>
-        </div></div></div>
-        <div class="col-md-3"><div class="card @(_detail.Instance.Enabled ? "border-success" : "border-secondary")"><div class="card-body">
-            <h6 class="text-muted mb-1">Enabled</h6>
-            <div class="fs-5">@(_detail.Instance.Enabled ? "Yes" : "No")</div>
-        </div></div></div>
-    </div>
-
-    @if (_detail.ParseError is not null)
-    {
-        <div class="alert alert-danger">
-            <strong>DriverConfig JSON failed to parse:</strong> @_detail.ParseError
-            <div class="small text-muted mt-1">
-                Falling back to raw-JSON view below; the per-section tables are hidden because the shape couldn't be projected.
-            </div>
-        </div>
-    }
-    else if (_detail.Config is not null)
-    {
-        <h2 class="h5 mt-4">Devices</h2>
-        @if (_detail.Config.Devices is null || _detail.Config.Devices.Count == 0)
-        {
-            <p class="text-muted">No devices configured.</p>
-        }
-        else
-        {
-            <table class="table table-sm align-middle">
-                <thead><tr><th>HostAddress</th><th>DeviceName</th><th>Series</th></tr></thead>
-                <tbody>
-                @foreach (var d in _detail.Config.Devices)
-                {
-                    <tr>
-                        <td><code>@d.HostAddress</code></td>
-                        <td>@(d.DeviceName ?? "—")</td>
-                        <td>@(string.IsNullOrEmpty(d.Series) ? "Unknown" : d.Series)</td>
-                    </tr>
-                }
-                </tbody>
-            </table>
-        }
-
-        <h2 class="h5 mt-4">Tags</h2>
-        @if (_detail.Config.Tags is null || _detail.Config.Tags.Count == 0)
-        {
-            <p class="text-muted">No tags configured.</p>
-        }
-        else
-        {
-            <p class="small text-muted">@_detail.Config.Tags.Count tag(s) configured.</p>
-            <table class="table table-sm align-middle">
-                <thead><tr><th>Name</th><th>Device</th><th>Address</th><th>DataType</th><th>Writable</th></tr></thead>
-                <tbody>
-                @foreach (var t in _detail.Config.Tags)
-                {
-                    <tr>
-                        <td>@t.Name</td>
-                        <td><code class="small">@t.DeviceHostAddress</code></td>
-                        <td><code>@t.Address</code></td>
-                        <td>@t.DataType</td>
-                        <td>@(t.Writable ? "Yes" : "No")</td>
-                    </tr>
-                }
-                </tbody>
-            </table>
-        }
-
-        <h2 class="h5 mt-4">Driver behaviour</h2>
-        <table class="table table-sm align-middle" style="max-width: 640px;">
-            <tbody>
-                <tr>
-                    <th style="width: 30%;">Probe</th>
-                    <td>
-                        @if (_detail.Config.Probe is { } probe)
-                        {
-                            <span class="badge @(probe.Enabled ? "bg-success" : "bg-secondary")">@(probe.Enabled ? "Enabled" : "Disabled")</span>
-                            <span class="ms-2 small text-muted">Interval: @(probe.Interval ?? "default")</span>
-                        }
-                        else { <span class="text-muted">default (enabled)</span> }
-                    </td>
-                </tr>
-                <tr>
-                    <th>Alarm projection</th>
-                    <td>
-                        @if (_detail.Config.AlarmProjection is { } ap)
-                        {
-                            <span class="badge @(ap.Enabled ? "bg-success" : "bg-secondary")">@(ap.Enabled ? "Enabled" : "Disabled")</span>
-                            <span class="ms-2 small text-muted">PollInterval: @(ap.PollInterval ?? "default")</span>
-                        }
-                        else { <span class="text-muted">disabled (default)</span> }
-                    </td>
-                </tr>
-                <tr>
-                    <th>Handle recycling</th>
-                    <td>
-                        @if (_detail.Config.HandleRecycle is { } hr)
-                        {
-                            <span class="badge @(hr.Enabled ? "bg-warning text-dark" : "bg-secondary")">@(hr.Enabled ? "Enabled" : "Disabled")</span>
-                            <span class="ms-2 small text-muted">Interval: @(hr.Interval ?? "default (01:00:00)")</span>
-                        }
-                        else { <span class="text-muted">disabled (default)</span> }
-                    </td>
-                </tr>
-            </tbody>
-        </table>
-    }
-
-    <h2 class="h5 mt-4">Host status</h2>
-    @if (_detail.HostStatuses.Count == 0)
-    {
-        <div class="alert alert-secondary small">
-            No <code>DriverHostStatus</code> rows yet for this instance. The Server publishes its first
-            tick ~2 s after the driver starts — if this stays empty after a minute, check that the Server is running and the instance is in a published generation.
-        </div>
-    }
-    else
-    {
-        <table class="table table-sm table-hover align-middle">
-            <thead>
-                <tr>
-                    <th>Node</th>
-                    <th>Host</th>
-                    <th>State</th>
-                    <th class="text-end" title="Consecutive failures">Fail#</th>
-                    <th>Breaker last opened</th>
-                    <th>Last recycled</th>
-                    <th>Last seen</th>
-                    <th>Detail</th>
-                </tr>
-            </thead>
-            <tbody>
-            @foreach (var r in _detail.HostStatuses)
-            {
-                <tr class="@(IsStale(r) ? "table-warning" : "")">
-                    <td><code>@r.NodeId</code></td>
-                    <td>@r.HostName</td>
-                    <td><span class="badge @StateBadge(r.State)">@r.State</span></td>
-                    <td class="text-end small">@r.ConsecutiveFailures</td>
-                    <td class="small">@FormatUtc(r.LastCircuitBreakerOpenUtc)</td>
-                    <td class="small">@FormatUtc(r.LastRecycleUtc)</td>
-                    <td class="small @(IsStale(r) ? "text-warning" : "")">@FormatAge(r.LastSeenUtc)</td>
-                    <td class="text-truncate small" style="max-width: 240px;" title="@r.Detail">@r.Detail</td>
-                </tr>
-            }
-            </tbody>
-        </table>
-    }
-
-    <h2 class="h5 mt-4">Raw DriverConfig JSON</h2>
-    <pre class="small bg-light border p-3"><code>@_detail.Instance.DriverConfig</code></pre>
-
-    <div class="mt-4 small text-muted">
-        Docs: <code>docs/drivers/FOCAS.md</code> (getting started) · <code>docs/v2/focas-deployment.md</code> (NSSM + pipe ACL) · <code>docs/drivers/FOCAS-Test-Fixture.md</code> (test coverage).
-    </div>
-}
-
-@code {
-    [Parameter] public string InstanceId { get; set; } = string.Empty;
-
-    private FocasDriverDetail? _detail;
-    private bool _loading = true;
-
-    protected override async Task OnParametersSetAsync()
-    {
-        _loading = true;
-        try { _detail = await DetailSvc.GetAsync(InstanceId, CancellationToken.None); }
-        finally { _loading = false; }
-    }
-
-    private static bool IsStale(FocasHostStatusRow r) =>
-        DateTime.UtcNow - r.LastSeenUtc > TimeSpan.FromSeconds(30);
-
-    private static string StateBadge(string state) => state switch
-    {
-        "Running" => "bg-success",
-        "Faulted" => "bg-danger",
-        "Starting" => "bg-info",
-        "Stopped" => "bg-secondary",
-        _ => "bg-secondary",
-    };
-
-    private static string FormatUtc(DateTime? utc) =>
-        utc is null ? "—" : utc.Value.ToString("yyyy-MM-dd HH:mm 'UTC'");
-
-    private static string FormatAge(DateTime utc)
-    {
-        var age = DateTime.UtcNow - utc;
-        if (age.TotalSeconds < 60) return $"{(int)age.TotalSeconds}s ago";
-        if (age.TotalMinutes < 60) return $"{(int)age.TotalMinutes}m ago";
-        if (age.TotalHours < 48)  return $"{(int)age.TotalHours}h ago";
-        return utc.ToString("yyyy-MM-dd HH:mm 'UTC'");
-    }
-}

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Hosts.razor

@@ -1,12 +1,9 @@
 @page "/hosts"
-@using Microsoft.AspNetCore.SignalR.Client
 @using Microsoft.EntityFrameworkCore
-@using ZB.MOM.WW.OtOpcUa.Admin.Hubs
 @using ZB.MOM.WW.OtOpcUa.Admin.Services
 @using ZB.MOM.WW.OtOpcUa.Configuration.Enums
 @inject IServiceScopeFactory ScopeFactory
-@inject NavigationManager Nav
+@implements IDisposable
-@implements IAsyncDisposable
 
 <h1 class="mb-4">Driver host status</h1>
 
@@ -131,7 +128,6 @@ else
     private bool _refreshing;
     private DateTime? _lastRefreshUtc;
     private Timer? _timer;
-    private HubConnection? _hub;
 
     protected override async Task OnInitializedAsync()
     {
@@ -140,44 +136,6 @@ else
             state: null,
             dueTime: TimeSpan.FromSeconds(RefreshIntervalSeconds),
             period: TimeSpan.FromSeconds(RefreshIntervalSeconds));
-        await ConnectHubAsync();
-    }
-
-    // Phase 6.1 Stream E.2 — subscribe to FleetStatusHub so resilience deltas upsert the
-    // matching row without waiting for the next RefreshIntervalSeconds tick. The 10 s
-    // poll stays as a safety net in case the hub connection is down.
-    private async Task ConnectHubAsync()
-    {
-        var hubUrl = Nav.ToAbsoluteUri("/hubs/fleet");
-        _hub = new HubConnectionBuilder().WithUrl(hubUrl).WithAutomaticReconnect().Build();
-        _hub.On<ResilienceStatusChangedMessage>("ResilienceStatusChanged", OnResilienceChanged);
-        try
-        {
-            await _hub.StartAsync();
-            await _hub.SendAsync("SubscribeFleet");
-        }
-        catch
-        {
-            // Hub is best-effort; polling refresh is the fallback. Swallow connect errors
-            // so the page still renders against the initial RefreshAsync pass.
-        }
-    }
-
-    private async Task OnResilienceChanged(ResilienceStatusChangedMessage msg)
-    {
-        if (_rows is null) return;
-        var idx = _rows.FindIndex(r =>
-            r.DriverInstanceId == msg.DriverInstanceId && r.HostName == msg.HostName);
-        if (idx < 0) return;
-        var prior = _rows[idx];
-        _rows[idx] = prior with
-        {
-            ConsecutiveFailures = msg.ConsecutiveFailures,
-            LastCircuitBreakerOpenUtc = msg.LastCircuitBreakerOpenUtc,
-            CurrentBulkheadDepth = msg.CurrentBulkheadDepth,
-            LastRecycleUtc = msg.LastRecycleUtc,
-        };
-        await InvokeAsync(StateHasChanged);
     }
 
     private async Task RefreshAsync()
@@ -222,12 +180,5 @@ else
         return t.ToString("yyyy-MM-dd HH:mm 'UTC'");
     }
 
-    public async ValueTask DisposeAsync()
+    public void Dispose() => _timer?.Dispose();
-    {
-        _timer?.Dispose();
-        if (_hub is not null)
-        {
-            try { await _hub.DisposeAsync(); } catch { }
-        }
-    }
 }

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Modbus/ModbusAddressEditor.razor

@@ -1,79 +0,0 @@
-@using ZB.MOM.WW.OtOpcUa.Driver.Modbus
-
-@*
-    #145 — Live address-string parser preview for Modbus tag editing. Bound to a string
-    AddressString; on every input keystroke the parser runs and surfaces the resolved
-    breakdown (Region, PduOffset, DataType, Bit, ByteOrder, ArrayCount, StringLength) or
-    the parse error. Family flag drives the parser's family-native branch (#144).
-
-    Re-uses the same ModbusAddressParser the wire driver uses, so grammar drift is
-    impossible by construction. Internal-namespace component called from the larger
-    DriverInstance editor.
-*@
-
-<div class="mb-3">
-    <label class="form-label">Address string</label>
-    <input type="text" class="form-control @(IsValid ? "is-valid" : Diagnostic is null ? "" : "is-invalid")"
-           value="@AddressString"
-           @oninput="@OnInputChanged"
-           placeholder="e.g. 40001:F:CDAB:5"/>
-    @if (IsValid && _parsed is not null)
-    {
-        <div class="form-text text-success">
-            <strong>Parsed:</strong>
-            Region=<code>@_parsed.Region</code>
-            Offset=<code>@_parsed.Offset</code>
-            Type=<code>@_parsed.DataType</code>
-            @if (_parsed.Bit.HasValue) { <text>Bit=<code>@_parsed.Bit</code></text> }
-            @if (_parsed.ByteOrder != ModbusByteOrder.BigEndian) { <text>Order=<code>@_parsed.ByteOrder</code></text> }
-            @if (_parsed.ArrayCount.HasValue) { <text>Array[<code>@_parsed.ArrayCount</code>]</text> }
-            @if (_parsed.StringLength > 0) { <text>StrLen=<code>@_parsed.StringLength</code></text> }
-        </div>
-    }
-    else if (Diagnostic is not null)
-    {
-        <div class="invalid-feedback">@Diagnostic</div>
-    }
-</div>
-
-@code {
-    [Parameter] public string? AddressString { get; set; }
-    [Parameter] public EventCallback<string?> AddressStringChanged { get; set; }
-    [Parameter] public ModbusFamily Family { get; set; } = ModbusFamily.Generic;
-    [Parameter] public MelsecFamily MelsecSubFamily { get; set; } = MelsecFamily.Q_L_iQR;
-    [Parameter] public EventCallback<ParsedModbusAddress?> ParsedChanged { get; set; }
-
-    private ParsedModbusAddress? _parsed;
-    private string? Diagnostic;
-    private bool IsValid => _parsed is not null && Diagnostic is null;
-
-    protected override void OnParametersSet() => Reparse();
-
-    private async Task OnInputChanged(ChangeEventArgs e)
-    {
-        AddressString = e.Value as string;
-        await AddressStringChanged.InvokeAsync(AddressString);
-        Reparse();
-        await ParsedChanged.InvokeAsync(_parsed);
-    }
-
-    private void Reparse()
-    {
-        if (string.IsNullOrWhiteSpace(AddressString))
-        {
-            _parsed = null;
-            Diagnostic = null;
-            return;
-        }
-        if (ModbusAddressParser.TryParse(AddressString, Family, MelsecSubFamily, out var parsed, out var err))
-        {
-            _parsed = parsed;
-            Diagnostic = null;
-        }
-        else
-        {
-            _parsed = null;
-            Diagnostic = err;
-        }
-    }
-}

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Modbus/ModbusAddressPreview.razor

@@ -1,85 +0,0 @@
-@page "/modbus/address-preview"
-@using ZB.MOM.WW.OtOpcUa.Driver.Modbus
-
-@*
-    #149 — standalone preview / sanity-check tool for Modbus address strings. The Admin UI
-    doesn't yet have a per-tag CRUD surface (tags are seeded via SQL or arrive at runtime
-    through ITagDiscovery), so the ModbusAddressEditor component shipped in #145 needs a
-    page where operators can paste an address string and confirm it parses to what they
-    expect before committing it to a config row.
-
-    Doubles as a "did the parser ship correctly" smoke target for QA + a copy-pasteable
-    grammar reference for users skimming the docs.
-*@
-
-<PageTitle>Modbus address preview</PageTitle>
-
-<div class="container py-4">
-    <h1>Modbus address preview</h1>
-    <p class="text-muted">
-        Paste an address string and watch the parser break it down field by field. Useful for
-        sanity-checking a tag spreadsheet row before adding it to a driver's <code>DriverConfig</code>.
-        Full grammar: <a href="https://github.com/" target="_blank">docs/v2/modbus-addressing.md</a>.
-    </p>
-
-    <div class="row g-3">
-        <div class="col-md-4">
-            <label class="form-label">PLC family hint (drives the family-native branch)</label>
-            <select class="form-select" @bind="_family">
-                @foreach (var f in Enum.GetValues<ModbusFamily>())
-                {
-                    <option value="@f">@f</option>
-                }
-            </select>
-        </div>
-        @if (_family == ModbusFamily.MELSEC)
-        {
-            <div class="col-md-4">
-                <label class="form-label">MELSEC sub-family</label>
-                <select class="form-select" @bind="_melsecSubFamily">
-                    @foreach (var f in Enum.GetValues<MelsecFamily>())
-                    {
-                        <option value="@f">@f</option>
-                    }
-                </select>
-            </div>
-        }
-    </div>
-
-    <div class="mt-4">
-        <ModbusAddressEditor @bind-AddressString="_address"
-                             Family="_family"
-                             MelsecSubFamily="_melsecSubFamily"/>
-    </div>
-
-    <h3 class="mt-5">Quick-reference grammar</h3>
-    <pre class="bg-light p-3 rounded small">@_grammarReference</pre>
-</div>
-
-@code {
-    private string? _address;
-    private ModbusFamily _family = ModbusFamily.Generic;
-    private MelsecFamily _melsecSubFamily = MelsecFamily.Q_L_iQR;
-
-    // Held as a const string rather than inline markup so the Razor parser doesn't try to
-    // interpret the angle-bracket grammar tokens as element open/close.
-    private const string _grammarReference = @"<region><offset>[.<bit>][:<type>[<len>]][:<order>][:<count>]
-
-Examples (post-#146 type codes):
-  40001                    HoldingRegisters[0], Int16
-  400001                   same, 6-digit form
-  40001:F                  Float32 (HR[0..1])
-  40001:F:CDAB             Float32 word-swapped
-  40001:STR20              20-char ASCII string
-  40001:S:5                Int16[5] array (3-field shorthand)
-  40001:I:CDAB:10          Int32[10] word-swapped (4-field strict)
-  40001.5                  bit 5 of HR[0]
-  HR1:I                    Int32 via mnemonic region (matches Wonderware)
-  C100                     Coil 100 (mnemonic, 1-based)
-  V2000:F:CDAB             DL205 V-memory at PDU 1024 (Family=DL205)
-  D100:I                   MELSEC D-register 100, Int32 (Family=MELSEC)
-
-Type codes: BOOL, S (Int16), US (UInt16), I (Int32), UI (UInt32),
-            I_64 (Int64), UI_64 (UInt64), F, D, BCD, BCD_32, STR<n>
-Byte order: ABCD (BE default), CDAB (word-swap), BADC (byte-swap), DCBA (full reverse)";
-}

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Modbus/ModbusOptionsEditor.razor

@@ -1,169 +0,0 @@
-@using ZB.MOM.WW.OtOpcUa.Driver.Modbus
-
-@*
-    #145 — Driver-instance options panel for the Modbus driver. Surfaces every option group
-    added by #136-#144 so users can configure the driver via the UI rather than hand-editing
-    DriverConfig JSON. Bound to a ModbusOptionsViewModel; the parent page round-trips that
-    model to the DriverConfig.json column on save.
-*@
-
-<div class="modbus-options-editor">
-
-    <h5>Connection</h5>
-    <div class="row mb-3">
-        <div class="col-sm-6">
-            <label class="form-label">Host</label>
-            <input class="form-control" @bind="Model.Host"/>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Port</label>
-            <input type="number" class="form-control" @bind="Model.Port"/>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Default UnitId</label>
-            <input type="number" class="form-control" @bind="Model.UnitId"/>
-        </div>
-    </div>
-
-    <h5>Family (#144)</h5>
-    <div class="row mb-3">
-        <div class="col-sm-6">
-            <label class="form-label">PLC family</label>
-            <select class="form-select" @bind="Model.Family">
-                @foreach (var f in Enum.GetValues<ModbusFamily>())
-                {
-                    <option value="@f">@f</option>
-                }
-            </select>
-        </div>
-        @if (Model.Family == ModbusFamily.MELSEC)
-        {
-            <div class="col-sm-6">
-                <label class="form-label">MELSEC sub-family</label>
-                <select class="form-select" @bind="Model.MelsecSubFamily">
-                    @foreach (var f in Enum.GetValues<MelsecFamily>())
-                    {
-                        <option value="@f">@f</option>
-                    }
-                </select>
-            </div>
-        }
-    </div>
-
-    <h5>Keep-alive (#139)</h5>
-    <div class="row mb-3">
-        <div class="col-sm-3">
-            <div class="form-check mt-4">
-                <input type="checkbox" class="form-check-input" @bind="Model.KeepAliveEnabled"/>
-                <label class="form-check-label">Enabled</label>
-            </div>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Time (s)</label>
-            <input type="number" class="form-control" @bind="Model.KeepAliveTimeSec"/>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Interval (s)</label>
-            <input type="number" class="form-control" @bind="Model.KeepAliveIntervalSec"/>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Retry count</label>
-            <input type="number" class="form-control" @bind="Model.KeepAliveRetryCount"/>
-        </div>
-    </div>
-
-    <h5>Reconnect (#139)</h5>
-    <div class="row mb-3">
-        <div class="col-sm-4">
-            <label class="form-label">Initial delay (ms)</label>
-            <input type="number" class="form-control" @bind="Model.ReconnectInitialDelayMs"/>
-        </div>
-        <div class="col-sm-4">
-            <label class="form-label">Max delay (ms)</label>
-            <input type="number" class="form-control" @bind="Model.ReconnectMaxDelayMs"/>
-        </div>
-        <div class="col-sm-4">
-            <label class="form-label">Backoff multiplier</label>
-            <input type="number" step="0.1" class="form-control" @bind="Model.ReconnectBackoffMultiplier"/>
-        </div>
-    </div>
-
-    <h5>Protocol (#140)</h5>
-    <div class="row mb-3">
-        <div class="col-sm-3">
-            <label class="form-label">Max regs / read</label>
-            <input type="number" class="form-control" @bind="Model.MaxRegistersPerRead"/>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Max regs / write</label>
-            <input type="number" class="form-control" @bind="Model.MaxRegistersPerWrite"/>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Max coils / read</label>
-            <input type="number" class="form-control" @bind="Model.MaxCoilsPerRead"/>
-        </div>
-        <div class="col-sm-3">
-            <label class="form-label">Max read gap (#143)</label>
-            <input type="number" class="form-control" @bind="Model.MaxReadGap"/>
-        </div>
-    </div>
-
-    <div class="row mb-3">
-        <div class="col-sm-4">
-            <div class="form-check">
-                <input type="checkbox" class="form-check-input" @bind="Model.UseFC15ForSingleCoilWrites"/>
-                <label class="form-check-label">Use FC15 for single coil</label>
-            </div>
-        </div>
-        <div class="col-sm-4">
-            <div class="form-check">
-                <input type="checkbox" class="form-check-input" @bind="Model.UseFC16ForSingleRegisterWrites"/>
-                <label class="form-check-label">Use FC16 for single reg</label>
-            </div>
-        </div>
-        <div class="col-sm-4">
-            <div class="form-check">
-                <input type="checkbox" class="form-check-input" @bind="Model.WriteOnChangeOnly"/>
-                <label class="form-check-label">Write-on-change only (#141)</label>
-            </div>
-        </div>
-    </div>
-
-</div>
-
-@code {
-    [Parameter, EditorRequired] public ModbusOptionsViewModel Model { get; set; } = default!;
-
-    /// <summary>
-    ///     UI binding model. Maps 1:1 onto the JSON DTO the driver factory accepts; serialised
-    ///     to DriverConfig.json by the calling save handler. Defaults match
-    ///     <c>ModbusDriverOptions</c> defaults so unedited rows produce the historical wire
-    ///     output verbatim.
-    /// </summary>
-    public sealed class ModbusOptionsViewModel
-    {
-        public string Host { get; set; } = "127.0.0.1";
-        public int Port { get; set; } = 502;
-        public byte UnitId { get; set; } = 1;
-        public ModbusFamily Family { get; set; } = ModbusFamily.Generic;
-        public MelsecFamily MelsecSubFamily { get; set; } = MelsecFamily.Q_L_iQR;
-
-        public bool KeepAliveEnabled { get; set; } = true;
-        public int KeepAliveTimeSec { get; set; } = 30;
-        public int KeepAliveIntervalSec { get; set; } = 10;
-        public int KeepAliveRetryCount { get; set; } = 3;
-
-        public int ReconnectInitialDelayMs { get; set; } = 0;
-        public int ReconnectMaxDelayMs { get; set; } = 30000;
-        public double ReconnectBackoffMultiplier { get; set; } = 2.0;
-
-        public int MaxRegistersPerRead { get; set; } = 125;
-        public int MaxRegistersPerWrite { get; set; } = 123;
-        public int MaxCoilsPerRead { get; set; } = 2000;
-        public int MaxReadGap { get; set; } = 0;
-
-        public bool UseFC15ForSingleCoilWrites { get; set; } = false;
-        public bool UseFC16ForSingleRegisterWrites { get; set; } = false;
-        public bool WriteOnChangeOnly { get; set; } = false;
-    }
-}

src/ZB.MOM.WW.OtOpcUa.Admin/Hubs/FleetStatusHub.cs

@@ -37,18 +37,3 @@ public sealed record NodeStateChangedMessage(
     string? LastAppliedError,
     DateTime? LastAppliedAt,
     DateTime? LastSeenAt);
-
-/// <summary>
-///     Pushed by <c>FleetStatusPoller</c> when it observes a change in a
-///     <c>DriverInstanceResilienceStatus</c> row. Closes the last Phase 6.1 Stream E.2/E.3
-///     deferral — lets the Admin <c>/hosts</c> page upsert the matching row without the
-///     10-second polling round-trip. Keyed on (DriverInstanceId, HostName); the client
-///     fan-outs to the matching row by matching both.
-/// </summary>
-public sealed record ResilienceStatusChangedMessage(
-    string DriverInstanceId,
-    string HostName,
-    int ConsecutiveFailures,
-    DateTime? LastCircuitBreakerOpenUtc,
-    int CurrentBulkheadDepth,
-    DateTime? LastRecycleUtc);

src/ZB.MOM.WW.OtOpcUa.Admin/Program.cs

@@ -44,7 +44,6 @@ builder.Services.AddScoped<EquipmentService>();
 builder.Services.AddScoped<UnsService>();
 builder.Services.AddScoped<NamespaceService>();
 builder.Services.AddScoped<DriverInstanceService>();
-builder.Services.AddScoped<FocasDriverDetailService>();
 builder.Services.AddScoped<NodeAclService>();
 builder.Services.AddScoped<PermissionProbeService>();
 builder.Services.AddScoped<AclChangeNotifier>();

src/ZB.MOM.WW.OtOpcUa.Admin/Services/FocasDriverDetailService.cs

@@ -1,123 +0,0 @@
-using System.Text.Json;
-using System.Text.Json.Serialization;
-using Microsoft.EntityFrameworkCore;
-using ZB.MOM.WW.OtOpcUa.Configuration;
-using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
-
-namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
-
-/// <summary>
-///     Per-instance detail view for FOCAS driver rows. Loads the latest
-///     <see cref="DriverInstance"/> row for the requested <c>DriverInstanceId</c> (most-recent
-///     draft wins when multiple rows exist across generations), parses the schemaless
-///     <c>DriverConfig</c> JSON into <see cref="FocasDriverConfigView"/>, and joins the
-///     per-device <see cref="DriverHostStatus"/> rows so the Admin page can render host
-///     state + consecutive-failure counters next to each configured device.
-/// </summary>
-public sealed class FocasDriverDetailService(OtOpcUaConfigDbContext db)
-{
-    private static readonly JsonSerializerOptions JsonOpts = new()
-    {
-        PropertyNameCaseInsensitive = true,
-        NumberHandling = JsonNumberHandling.AllowReadingFromString,
-    };
-
-    public async Task<FocasDriverDetail?> GetAsync(string driverInstanceId, CancellationToken ct = default)
-    {
-        if (string.IsNullOrWhiteSpace(driverInstanceId)) return null;
-
-        var instance = await db.DriverInstances.AsNoTracking()
-            .Where(d => d.DriverInstanceId == driverInstanceId
-                     && d.DriverType.ToLower() == "focas")
-            .OrderByDescending(d => d.GenerationId)
-            .FirstOrDefaultAsync(ct);
-        if (instance is null) return null;
-
-        FocasDriverConfigView? config = null;
-        string? parseError = null;
-        try { config = JsonSerializer.Deserialize<FocasDriverConfigView>(instance.DriverConfig, JsonOpts); }
-        catch (JsonException ex) { parseError = ex.Message; }
-
-        var hostStatuses = await (from s in db.DriverHostStatuses.AsNoTracking()
-                                  where s.DriverInstanceId == driverInstanceId
-                                  join r in db.DriverInstanceResilienceStatuses.AsNoTracking()
-                                      on new { s.DriverInstanceId, s.HostName }
-                                      equals new { r.DriverInstanceId, r.HostName } into rj
-                                  from r in rj.DefaultIfEmpty()
-                                  orderby s.HostName
-                                  select new FocasHostStatusRow(
-                                      s.NodeId,
-                                      s.HostName,
-                                      s.State.ToString(),
-                                      s.StateChangedUtc,
-                                      s.LastSeenUtc,
-                                      s.Detail,
-                                      r != null ? r.ConsecutiveFailures : 0,
-                                      r != null ? r.LastCircuitBreakerOpenUtc : null,
-                                      r != null ? r.LastRecycleUtc : null)).ToListAsync(ct);
-
-        return new FocasDriverDetail(instance, config, parseError, hostStatuses);
-    }
-}
-
-/// <summary>Projected view of a FOCAS driver's parsed config. Unknown fields are ignored.</summary>
-public sealed record FocasDriverConfigView
-{
-    public List<FocasDeviceView>? Devices { get; set; }
-    public List<FocasTagView>? Tags { get; set; }
-    public FocasProbeView? Probe { get; set; }
-    public FocasAlarmProjectionView? AlarmProjection { get; set; }
-    public FocasHandleRecycleView? HandleRecycle { get; set; }
-}
-
-public sealed record FocasDeviceView
-{
-    public string? HostAddress { get; set; }
-    public string? DeviceName { get; set; }
-    public string? Series { get; set; }
-}
-
-public sealed record FocasTagView
-{
-    public string? Name { get; set; }
-    public string? DeviceHostAddress { get; set; }
-    public string? Address { get; set; }
-    public string? DataType { get; set; }
-    public bool Writable { get; set; } = true;
-}
-
-public sealed record FocasProbeView
-{
-    public bool Enabled { get; set; } = true;
-    public string? Interval { get; set; }
-}
-
-public sealed record FocasAlarmProjectionView
-{
-    public bool Enabled { get; set; }
-    public string? PollInterval { get; set; }
-}
-
-public sealed record FocasHandleRecycleView
-{
-    public bool Enabled { get; set; }
-    public string? Interval { get; set; }
-}
-
-/// <summary>Composite payload returned to the Admin page.</summary>
-public sealed record FocasDriverDetail(
-    DriverInstance Instance,
-    FocasDriverConfigView? Config,
-    string? ParseError,
-    IReadOnlyList<FocasHostStatusRow> HostStatuses);
-
-public sealed record FocasHostStatusRow(
-    string NodeId,
-    string HostName,
-    string State,
-    DateTime StateChangedUtc,
-    DateTime LastSeenUtc,
-    string? Detail,
-    int ConsecutiveFailures,
-    DateTime? LastCircuitBreakerOpenUtc,
-    DateTime? LastRecycleUtc);

src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj

@@ -16,8 +16,8 @@
         <PackageReference Include="Novell.Directory.Ldap.NETStandard" Version="3.6.0"/>
         <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="10.0.0"/>
         <PackageReference Include="Serilog.AspNetCore" Version="9.0.0"/>
-        <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.15.3"/>
+        <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.15.2"/>
-        <PackageReference Include="OpenTelemetry.Exporter.Prometheus.AspNetCore" Version="1.15.3-beta.1"/>
+        <PackageReference Include="OpenTelemetry.Exporter.Prometheus.AspNetCore" Version="1.15.2-beta.1"/>
     </ItemGroup>
 
     <ItemGroup>
@@ -25,7 +25,6 @@
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core\ZB.MOM.WW.OtOpcUa.Core.csproj"/>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Scripting\ZB.MOM.WW.OtOpcUa.Core.Scripting.csproj"/>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
-        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing\ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing.csproj"/>
     </ItemGroup>
 
     <ItemGroup>

src/ZB.MOM.WW.OtOpcUa.Configuration/Validation/DraftValidator.cs

@@ -1,5 +1,4 @@
 using System.Text.RegularExpressions;
-using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
 
 namespace ZB.MOM.WW.OtOpcUa.Configuration.Validation;
@@ -174,65 +173,4 @@ public static class DraftValidator
                     di.DriverInstanceId));
         }
     }
-
-    /// <summary>
-    ///     Phase 6.3 Stream A.2 + task #148 part 2 — managed pre-publish guard for cluster
-    ///     topology vs. <see cref="ServerCluster.RedundancyMode"/>. The SQL
-    ///     <c>CK_ServerCluster_RedundancyMode_NodeCount</c> CHECK already enforces the
-    ///     (NodeCount, RedundancyMode) pair on the row itself, but it cannot see the
-    ///     <see cref="ClusterNode.Enabled"/> flag on child nodes — an operator can toggle
-    ///     nodes off (effective count = 1) while leaving RedundancyMode at Hot and the
-    ///     constraint stays green. This check catches that drift before publish so the
-    ///     runtime doesn't boot into a topology the <see cref="Enums.RedundancyMode"/> claims
-    ///     is invalid.
-    /// </summary>
-    /// <remarks>
-    ///     Called from the publish pipeline separately from <see cref="Validate"/> because the
-    ///     cluster/nodes rows aren't generation-versioned — they don't belong on
-    ///     <see cref="DraftSnapshot"/>. Returns every failing rule in one pass, same shape as
-    ///     <see cref="Validate"/>.
-    /// </remarks>
-    public static IReadOnlyList<ValidationError> ValidateClusterTopology(
-        ServerCluster cluster,
-        IReadOnlyList<ClusterNode> clusterNodes)
-    {
-        ArgumentNullException.ThrowIfNull(cluster);
-        ArgumentNullException.ThrowIfNull(clusterNodes);
-
-        var errors = new List<ValidationError>();
-        var enabledNodes = clusterNodes.Count(n => n.Enabled);
-
-        // Declared count must match declared mode (belt around the SQL CHECK).
-        var declaredOk = (cluster.NodeCount, cluster.RedundancyMode) switch
-        {
-            (1, RedundancyMode.None) => true,
-            (2, RedundancyMode.Warm) => true,
-            (2, RedundancyMode.Hot) => true,
-            _ => false,
-        };
-        if (!declaredOk)
-            errors.Add(new("ClusterRedundancyModeInvalid",
-                $"Cluster '{cluster.ClusterId}' declares NodeCount={cluster.NodeCount} + RedundancyMode={cluster.RedundancyMode}. " +
-                $"Supported combinations: (1, None), (2, Warm), (2, Hot).",
-                cluster.ClusterId));
-
-        // Enabled-node count must match declared count. Disabling a node to 1 while leaving
-        // mode at Hot/Warm would boot the runtime into InvalidTopology band.
-        if (enabledNodes != cluster.NodeCount)
-            errors.Add(new("ClusterEnabledNodeCountMismatch",
-                $"Cluster '{cluster.ClusterId}' declares NodeCount={cluster.NodeCount} but has {enabledNodes} Enabled nodes. " +
-                $"Toggle the missing node(s) back on or change RedundancyMode/NodeCount to match.",
-                cluster.ClusterId));
-
-        // Primary uniqueness — decision #84. Two Primary nodes is always an invariant violation
-        // regardless of mode; catch it here so publish fails loud rather than the runtime
-        // demoting both to ServiceLevelBand.InvalidTopology at boot.
-        var primaryCount = clusterNodes.Count(n => n.Enabled && n.RedundancyRole == RedundancyRole.Primary);
-        if (primaryCount > 1)
-            errors.Add(new("ClusterMultiplePrimary",
-                $"Cluster '{cluster.ClusterId}' has {primaryCount} Enabled Primary nodes. At most one Primary per cluster.",
-                cluster.ClusterId));
-
-        return errors;
-    }
 }

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverAttributeInfo.cs

@@ -45,6 +45,13 @@ namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 ///     Set when <paramref name="Source"/> is <see cref="NodeSourceKind.ScriptedAlarm"/> —
 ///     stable logical id the ScriptedAlarmEngine addresses by. Null otherwise.
 /// </param>
+/// <param name="Description">
+///     Human-readable description for this attribute. When non-null + non-empty the generic
+///     node-manager surfaces the value as the OPC UA <c>Description</c> attribute on the
+///     Variable node so SCADA / engineering clients see the field comment from the source
+///     project (Studio 5000 tag descriptions, Galaxy attribute help text, etc.). Defaults to
+///     null so drivers that don't carry descriptions are unaffected.
+/// </param>
 public sealed record DriverAttributeInfo(
     string FullName,
     DriverDataType DriverDataType,
@@ -56,7 +63,8 @@ public sealed record DriverAttributeInfo(
     bool WriteIdempotent = false,
     NodeSourceKind Source = NodeSourceKind.Driver,
     string? VirtualTagId = null,
-    string? ScriptedAlarmId = null);
+    string? ScriptedAlarmId = null,
+    string? Description = null);
 
 /// <summary>
 ///     Per ADR-002 — discriminates which runtime subsystem owns this node's Read/Write/

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverCapability.cs

@@ -25,7 +25,7 @@ public enum DriverCapability
     /// <summary><see cref="ITagDiscovery.DiscoverAsync"/>. Retries by default.</summary>
     Discover,
 
-    /// <summary><see cref="ISubscribable.SubscribeAsync"/> and unsubscribe. Retries by default.</summary>
+    /// <summary><see cref="ISubscribable.SubscribeAsync(IReadOnlyList{string}, TimeSpan, CancellationToken)"/> and unsubscribe. Retries by default.</summary>
     Subscribe,
 
     /// <summary><see cref="IHostConnectivityProbe"/> probe loop. Retries by default.</summary>

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverDataType.cs

@@ -25,4 +25,11 @@ public enum DriverDataType
 
     /// <summary>Galaxy-style attribute reference encoded as an OPC UA String.</summary>
     Reference,
+
+    /// <summary>
+    ///     OPC UA <c>Duration</c> — a Double-encoded period in milliseconds. Subtype of Double
+    ///     in the address space; surfaced as <see cref="System.TimeSpan"/> in the driver layer.
+    ///     Used by IEC 61131-3 <c>TIME</c> / <c>TOD</c> attributes (TwinCAT et al.).
+    /// </summary>
+    Duration,
 }

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverHealth.cs

@@ -7,10 +7,26 @@ namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 /// <param name="State">Current driver-instance state.</param>
 /// <param name="LastSuccessfulRead">Timestamp of the most recent successful equipment read; null if never.</param>
 /// <param name="LastError">Most recent error message; null when state is Healthy.</param>
+/// <param name="Diagnostics">
+///     Optional driver-attributable counters/metrics surfaced for the <c>driver-diagnostics</c>
+///     RPC (introduced for Modbus task #154). Drivers populate the dictionary with stable,
+///     well-known keys (e.g. <c>PublishRequestCount</c>, <c>NotificationsPerSecond</c>);
+///     Core treats it as opaque metadata. Defaulted to an empty read-only dictionary so
+///     existing drivers and call-sites that don't construct this field stay back-compat.
+/// </param>
 public sealed record DriverHealth(
     DriverState State,
     DateTime? LastSuccessfulRead,
-    string? LastError);
+    string? LastError,
+    IReadOnlyDictionary<string, double>? Diagnostics = null)
+{
+    /// <summary>Driver-attributable counters, empty when the driver doesn't surface any.</summary>
+    public IReadOnlyDictionary<string, double> DiagnosticsOrEmpty
+        => Diagnostics ?? EmptyDiagnostics;
+
+    private static readonly IReadOnlyDictionary<string, double> EmptyDiagnostics
+        = new Dictionary<string, double>(0);
+}
 
 /// <summary>Driver-instance lifecycle state.</summary>
 public enum DriverState

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAddressSpaceBuilder.cs

@@ -35,8 +35,159 @@ public interface IAddressSpaceBuilder
     ///     <c>_base</c> equipment-class template).
     /// </summary>
     void AddProperty(string browseName, DriverDataType dataType, object? value);
+
+    /// <summary>
+    ///     Register a type-definition node (ObjectType / VariableType / DataType / ReferenceType)
+    ///     mirrored from an upstream OPC UA server. Optional surface — drivers that don't mirror
+    ///     types simply never call it; address-space builders that don't materialise upstream
+    ///     types can leave the default no-op in place. Default implementation drops the call so
+    ///     adding this method doesn't break existing <see cref="IAddressSpaceBuilder"/>
+    ///     implementations.
+    /// </summary>
+    /// <param name="info">Metadata describing the type-definition node to mirror.</param>
+    /// <remarks>
+    ///     <para>
+    ///         The OPC UA Client driver is the primary caller — it walks <c>i=86</c>
+    ///         (TypesFolder) during <c>DiscoverAsync</c> when
+    ///         <c>OpcUaClientDriverOptions.MirrorTypeDefinitions</c> is set so downstream clients
+    ///         see the upstream type system instead of rendering structured-type values as opaque
+    ///         strings.
+    ///     </para>
+    ///     <para>
+    ///         The default no-op is intentional — most builders (Galaxy, Modbus, FOCAS, S7,
+    ///         TwinCAT, AB-CIP) don't have a meaningful type folder to project into and would
+    ///         otherwise need empty-stub overrides.
+    ///     </para>
+    /// </remarks>
+    void RegisterTypeNode(MirroredTypeNodeInfo info) { /* default: no-op */ }
+
+    /// <summary>
+    ///     Register a method node mirrored from an upstream OPC UA server. The method is
+    ///     registered as a child of the current builder scope (i.e. the folder representing
+    ///     the upstream Object that owns the method). Optional surface — drivers that don't
+    ///     mirror methods simply never call it; address-space builders that don't materialise
+    ///     method nodes can leave the default no-op in place. Default implementation drops
+    ///     the call so adding this method doesn't break existing
+    ///     <see cref="IAddressSpaceBuilder"/> implementations.
+    /// </summary>
+    /// <param name="info">Metadata describing the method node, including input/output argument schemas.</param>
+    /// <remarks>
+    ///     <para>
+    ///         The OPC UA Client driver is the primary caller — it picks up
+    ///         <c>NodeClass.Method</c> nodes during the <c>HierarchicalReferences</c> browse
+    ///         pass, then walks each method's <c>HasProperty</c> references to harvest the
+    ///         <c>InputArguments</c> / <c>OutputArguments</c> property values.
+    ///     </para>
+    ///     <para>
+    ///         The OPC UA server-side <c>DriverNodeManager</c> overrides this to materialize
+    ///         a real <c>MethodNode</c> in the local address space and wire its
+    ///         <c>OnCallMethod</c> handler to the driver's
+    ///         <see cref="IMethodInvoker.CallMethodAsync"/>. Other builders (Galaxy, Modbus,
+    ///         FOCAS, S7, TwinCAT, AB-CIP, AB-Legacy) ignore the projection because their
+    ///         backends don't expose method nodes.
+    ///     </para>
+    /// </remarks>
+    void RegisterMethodNode(MirroredMethodNodeInfo info) { /* default: no-op */ }
 }
 
+/// <summary>
+///     Metadata describing a single method node mirrored from an upstream OPC UA server.
+///     Built by the OPC UA Client driver during the discovery browse pass and consumed by
+///     <see cref="IAddressSpaceBuilder.RegisterMethodNode"/>.
+/// </summary>
+/// <param name="BrowseName">OPC UA BrowseName segment from the upstream BrowseName.</param>
+/// <param name="DisplayName">Human-readable display name; falls back to <paramref name="BrowseName"/>.</param>
+/// <param name="ObjectNodeId">
+///     Stringified NodeId of the parent Object that owns this method — the <c>ObjectId</c>
+///     argument the dispatcher passes back to <see cref="IMethodInvoker.CallMethodAsync"/>.
+/// </param>
+/// <param name="MethodNodeId">
+///     Stringified NodeId of the method node itself — the <c>MethodId</c> argument.
+/// </param>
+/// <param name="InputArguments">
+///     Declaration of the method's input arguments, in order. <c>null</c> or empty when the
+///     method takes no inputs (or the upstream property couldn't be read).
+/// </param>
+/// <param name="OutputArguments">
+///     Declaration of the method's output arguments, in order. <c>null</c> or empty when the
+///     method returns no outputs (or the upstream property couldn't be read).
+/// </param>
+public sealed record MirroredMethodNodeInfo(
+    string BrowseName,
+    string DisplayName,
+    string ObjectNodeId,
+    string MethodNodeId,
+    IReadOnlyList<MethodArgumentInfo>? InputArguments,
+    IReadOnlyList<MethodArgumentInfo>? OutputArguments);
+
+/// <summary>
+///     One row of an OPC UA Argument array — name + data type + array hint. Mirrors the
+///     <c>Opc.Ua.Argument</c> structure but without the SDK-only types so this DTO can live
+///     in <c>Core.Abstractions</c>.
+/// </summary>
+/// <param name="Name">Argument name from the upstream Argument structure.</param>
+/// <param name="DriverDataType">
+///     Mapped local <see cref="DriverDataType"/>. Unknown / structured upstream types fall
+///     through to <see cref="DriverDataType.String"/> — same convention as variable mirroring.
+/// </param>
+/// <param name="ValueRank">
+///     OPC UA ValueRank: <c>-1</c> = scalar, <c>0</c> = OneOrMoreDimensions, <c>1+</c> = array
+///     dimensions. Driven directly from the upstream Argument's ValueRank.
+/// </param>
+/// <param name="Description">
+///     Human-readable description from the upstream Argument structure; <c>null</c> when the
+///     upstream doesn't carry one.
+/// </param>
+public sealed record MethodArgumentInfo(
+    string Name,
+    DriverDataType DriverDataType,
+    int ValueRank,
+    string? Description);
+
+/// <summary>
+///     Categorises a mirrored type-definition node so the receiving builder can route it into
+///     the right OPC UA standard subtree (<c>ObjectTypesFolder</c>, <c>VariableTypesFolder</c>,
+///     <c>DataTypesFolder</c>, <c>ReferenceTypesFolder</c>) when projecting upstream types into
+///     the local address space.
+/// </summary>
+public enum MirroredTypeKind
+{
+    ObjectType,
+    VariableType,
+    DataType,
+    ReferenceType,
+}
+
+/// <summary>
+///     Metadata describing a single type-definition node mirrored from an upstream OPC UA
+///     server. Built by the OPC UA Client driver during type-mirror pass and consumed by
+///     <see cref="IAddressSpaceBuilder.RegisterTypeNode"/>.
+/// </summary>
+/// <param name="Kind">Type category — drives which standard sub-folder the node lives under.</param>
+/// <param name="UpstreamNodeId">
+///     Stringified upstream NodeId (e.g. <c>"ns=2;i=1234"</c>) — preserves the original identity
+///     so a builder that wants to project the type with a stable cross-namespace reference can do
+///     so. The driver applies any configured namespace remap before stamping this field.
+/// </param>
+/// <param name="BrowseName">OPC UA BrowseName segment from the upstream BrowseName.</param>
+/// <param name="DisplayName">Human-readable display name; falls back to <paramref name="BrowseName"/>.</param>
+/// <param name="SuperTypeNodeId">
+///     Stringified upstream NodeId of the super-type (parent type), or <c>null</c> when the node
+///     sits directly under the root (e.g. <c>BaseObjectType</c>, <c>BaseVariableType</c>). Lets
+///     the builder reconstruct the inheritance chain.
+/// </param>
+/// <param name="IsAbstract">
+///     <c>true</c> when the upstream node has the <c>IsAbstract</c> flag set (Object / Variable /
+///     ReferenceType). DataTypes also expose this — the driver passes it through verbatim.
+/// </param>
+public sealed record MirroredTypeNodeInfo(
+    MirroredTypeKind Kind,
+    string UpstreamNodeId,
+    string BrowseName,
+    string DisplayName,
+    string? SuperTypeNodeId,
+    bool IsAbstract);
+
 /// <summary>Opaque handle for a registered variable. Used by Core for subscription routing.</summary>
 public interface IVariableHandle
 {

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IDriverControl.cs

@@ -0,0 +1,27 @@
+namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+/// <summary>
+///     Optional control-plane capability — drivers whose backend exposes a way to refresh
+///     the symbol table on-demand (without tearing the driver down) implement this so the
+///     Admin UI / CLI can trigger a re-walk in response to an operator action.
+/// </summary>
+/// <remarks>
+///     Distinct from <see cref="IRediscoverable"/>: that interface is the driver telling Core
+///     a refresh is needed; this one is Core asking the driver to refresh now. For drivers that
+///     implement both, the typical wiring is "operator clicks Rebrowse → Core calls
+///     <see cref="RebrowseAsync"/> → driver re-walks → driver fires
+///     <c>OnRediscoveryNeeded</c> so the address space is rebuilt".
+///
+///     For AB CIP this is the "force re-walk of @tags" hook — useful after a controller
+///     program download added new tags but the static config still drives the address space.
+/// </remarks>
+public interface IDriverControl
+{
+    /// <summary>
+    ///     Re-run the driver's discovery pass against live backend state and stream the
+    ///     resulting nodes through the supplied builder. Implementations must be safe to call
+    ///     concurrently with reads / writes; they typically serialize internally so a second
+    ///     concurrent rebrowse waits for the first to complete rather than racing it.
+    /// </summary>
+    Task RebrowseAsync(IAddressSpaceBuilder builder, CancellationToken cancellationToken);
+}

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IHistoryProvider.cs

@@ -76,8 +76,107 @@ public interface IHistoryProvider
         => throw new NotSupportedException(
             $"{GetType().Name} does not implement ReadEventsAsync. " +
             "Drivers whose backends have an event historian override this method.");
+
+    /// <summary>
+    ///     Filter-aware historical event read — OPC UA HistoryReadEvents service with full
+    ///     <c>EventFilter</c> support (SelectClauses + WhereClause). Distinct from the simpler
+    ///     <see cref="ReadEventsAsync(string?, DateTime, DateTime, int, CancellationToken)"/>
+    ///     overload which is sufficient for "give me the standard BaseEventType fields"
+    ///     queries; this overload is for clients that send a custom <c>EventFilter</c> on the
+    ///     wire (per-select-clause Variant population, where-filter evaluation).
+    /// </summary>
+    /// <param name="fullReference">
+    ///     Driver-specific node identifier. May be a notifier object (e.g. the driver-root
+    ///     folder) — drivers that support cluster-wide queries treat it as
+    ///     "all sources in the namespace".
+    /// </param>
+    /// <param name="request">Filter spec — time range + select clauses + optional where clause.</param>
+    /// <param name="cancellationToken">Request cancellation.</param>
+    /// <remarks>
+    ///     <para>
+    ///         Default implementation throws — drivers opt in by overriding. Existing drivers
+    ///         that only handle the parameterless overload stay green; new drivers that need
+    ///         filter-aware event history (OPC UA Client passthrough, future event-historian
+    ///         backends) override this method.
+    ///     </para>
+    ///     <para>
+    ///         The OPC UA Client driver implements this by translating <see cref="EventHistoryRequest"/>
+    ///         into <c>ReadEventDetails</c> and calling <c>Session.HistoryReadAsync</c> against
+    ///         the upstream server.
+    ///     </para>
+    /// </remarks>
+    Task<HistoricalEventBatch> ReadEventsAsync(
+        string fullReference,
+        EventHistoryRequest request,
+        CancellationToken cancellationToken)
+        => throw new NotSupportedException(
+            $"{GetType().Name} does not implement filter-aware ReadEventsAsync(EventHistoryRequest). " +
+            "Drivers whose backends carry historical events with EventFilter support override this method.");
 }
 
+/// <summary>
+///     Filter spec for the filter-aware <see cref="IHistoryProvider.ReadEventsAsync(string, EventHistoryRequest, CancellationToken)"/>
+///     overload. Mirrors the OPC UA <c>ReadEventDetails</c> wire shape (StartTime, EndTime,
+///     NumValuesPerNode, EventFilter) but transport-neutral so non-UA drivers can implement it
+///     without taking a dependency on the UA SDK type.
+/// </summary>
+/// <param name="StartTime">Inclusive lower bound on event time.</param>
+/// <param name="EndTime">Exclusive upper bound on event time.</param>
+/// <param name="NumValuesPerNode">Maximum events per node (0 = no driver-side cap, server may still apply one).</param>
+/// <param name="SelectClauses">
+///     Per-field projection. Each entry names a BaseEventType-rooted field (or a
+///     typed-path field via <see cref="SimpleAttributeSpec.TypeDefinitionId"/>) the caller
+///     wants returned. <c>null</c> means "use the driver's default field set" — typically
+///     EventId, SourceName, Time, Message, Severity, ReceiveTime.
+/// </param>
+/// <param name="WhereClause">
+///     Optional content-filter restriction (e.g. <c>EventType OfType AlarmConditionType</c>).
+///     Drivers may ignore the where clause if their backend doesn't support it; that's a
+///     best-effort projection rather than a hard error.
+/// </param>
+public sealed record EventHistoryRequest(
+    DateTime StartTime,
+    DateTime EndTime,
+    uint NumValuesPerNode,
+    IReadOnlyList<SimpleAttributeSpec>? SelectClauses,
+    ContentFilterSpec? WhereClause);
+
+/// <summary>
+///     Transport-neutral mirror of OPC UA's <c>SimpleAttributeOperand</c> — picks one field
+///     from a node by typed browse path. <see cref="TypeDefinitionId"/> is the OPC UA NodeId
+///     of the type that the path is rooted at (e.g. <c>BaseEventType</c>); <see cref="BrowsePath"/>
+///     is a sequence of QualifiedName-style segments (<c>"ns:Name"</c> or just <c>"Name"</c>
+///     when ns=0). An empty <see cref="BrowsePath"/> means "the node itself".
+/// </summary>
+/// <param name="TypeDefinitionId">
+///     Type the path is rooted at. <c>null</c> defaults to the OPC UA <c>BaseEventType</c>
+///     when the driver has a UA mapping. Format is driver-specific NodeId text (e.g.
+///     <c>"i=2041"</c> for BaseEventType).
+/// </param>
+/// <param name="BrowsePath">Browse-path segments. Empty list = the typed node itself.</param>
+/// <param name="FieldName">
+///     Stable key the driver uses when populating <see cref="HistoricalEventRow.Fields"/>. The
+///     server-side dispatcher uses this to align the returned values with the wire-side
+///     SelectClause order, even when a driver doesn't honour the BrowsePath verbatim.
+/// </param>
+public sealed record SimpleAttributeSpec(
+    string? TypeDefinitionId,
+    IReadOnlyList<string> BrowsePath,
+    string FieldName);
+
+/// <summary>
+///     Transport-neutral mirror of OPC UA's <c>ContentFilter</c>. The current shape carries the
+///     raw filter operands as opaque OPC UA <c>ExtensionObject</c> bytes — drivers that need to
+///     evaluate the filter (Galaxy historian) parse it themselves; the OPC UA Client driver
+///     forwards it untouched. A future PR may replace this with a structured AST when more
+///     than one driver needs to evaluate where-clauses locally.
+/// </summary>
+/// <param name="EncodedOperands">
+///     Optional binary-encoded <c>ContentFilter</c> from the wire. <c>null</c> when no
+///     where-clause was supplied.
+/// </param>
+public sealed record ContentFilterSpec(byte[]? EncodedOperands);
+
 /// <summary>Result of a HistoryRead call.</summary>
 /// <param name="Samples">Returned samples in chronological order.</param>
 /// <param name="ContinuationPoint">Opaque token for the next call when more samples are available; null when complete.</param>
@@ -85,20 +184,116 @@ public sealed record HistoryReadResult(
     IReadOnlyList<DataValueSnapshot> Samples,
     byte[]? ContinuationPoint);
 
-/// <summary>Aggregate function for processed history reads. Mirrors OPC UA Part 13 standard aggregates.</summary>
+/// <summary>
+///     Aggregate function for processed history reads. Mirrors the OPC UA Part 13 §5
+///     standard aggregate catalog. Each value maps 1:1 onto an
+///     <c>Opc.Ua.ObjectIds.AggregateFunction_*</c> NodeId — the OPC UA Client driver does the
+///     translation in <c>OpcUaClientDriver.MapAggregateToNodeId</c>; other drivers either
+///     evaluate the aggregate locally (Galaxy historian) or surface
+///     <c>BadAggregateNotSupported</c> for the values their backend can't honour.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Stable ordinals.</b> The first 5 values (<see cref="Average"/>..<see cref="Count"/>)
+///         carry ordinals 0-4 from the original PR — additions are appended to keep prior
+///         persisted enums (config files, Admin UI dropdowns) compatible.
+///     </para>
+///     <para>
+///         <b>Server-side support.</b> Not every upstream OPC UA server implements every
+///         Part 13 aggregate. Implementations advertise their support through
+///         <c>AggregateConfiguration</c> on the Server object; clients can probe it at runtime.
+///         Aggregates that the upstream rejects come back with
+///         <c>StatusCode=BadAggregateNotSupported</c> on the per-row HistoryRead result —
+///         the driver passes that through verbatim (cascading-quality rule, Part 11 §8).
+///     </para>
+/// </remarks>
 public enum HistoryAggregateType
 {
+    // ---- Original 5 (ordinals 0-4 — keep stable) ----
+    /// <summary>Average of all values in the interval. Part 13 §5.4.</summary>
     Average,
+    /// <summary>Minimum value in the interval. Part 13 §5.5.</summary>
     Minimum,
+    /// <summary>Maximum value in the interval. Part 13 §5.6.</summary>
     Maximum,
+    /// <summary>Sum of values in the interval (numeric only). Part 13 §5.10.</summary>
     Total,
+    /// <summary>Count of Good-quality samples in the interval. Part 13 §5.18.</summary>
     Count,
+
+    // ---- Time-weighted averages (Part 13 §5.4) ----
+    /// <summary>Time-weighted average — values held until next sample. Part 13 §5.4.2.</summary>
+    TimeAverage,
+    /// <summary>Time-weighted average using simple-bounds extrapolation. Part 13 §5.4.3.</summary>
+    TimeAverage2,
+
+    // ---- Interpolation (Part 13 §5.3) ----
+    /// <summary>Interpolated value at each interval boundary. Part 13 §5.3.</summary>
+    Interpolative,
+
+    // ---- Min/Max with timestamps and range (Part 13 §5.5–§5.7) ----
+    /// <summary>Timestamp of the minimum-value sample. Part 13 §5.5.4.</summary>
+    MinimumActualTime,
+    /// <summary>Timestamp of the maximum-value sample. Part 13 §5.6.4.</summary>
+    MaximumActualTime,
+    /// <summary>Maximum minus minimum across the interval. Part 13 §5.7.</summary>
+    Range,
+    /// <summary>Range computed using simple-bounds extrapolation. Part 13 §5.7.</summary>
+    Range2,
+
+    // ---- Annotation / duration / quality coverage (Part 13 §5.16–§5.21) ----
+    /// <summary>Number of annotations attached to samples in the interval. Part 13 §5.21.</summary>
+    AnnotationCount,
+    /// <summary>Total time (ms) covered by Good-quality data. Part 13 §5.16.</summary>
+    DurationGood,
+    /// <summary>Total time (ms) covered by Bad-quality data. Part 13 §5.16.</summary>
+    DurationBad,
+    /// <summary>Percent of the interval covered by Good-quality data (0-100). Part 13 §5.17.</summary>
+    PercentGood,
+    /// <summary>Percent of the interval covered by Bad-quality data (0-100). Part 13 §5.17.</summary>
+    PercentBad,
+    /// <summary>Worst (most-severe) quality code seen in the interval. Part 13 §5.20.</summary>
+    WorstQuality,
+    /// <summary>Worst-quality code using simple-bounds extrapolation. Part 13 §5.20.</summary>
+    WorstQuality2,
+
+    // ---- Statistical (Part 13 §5.13) ----
+    /// <summary>Sample-population standard deviation (n-1 divisor). Part 13 §5.13.</summary>
+    StandardDeviationSample,
+    /// <summary>Whole-population standard deviation (n divisor). Part 13 §5.13.</summary>
+    StandardDeviationPopulation,
+    /// <summary>Sample-population variance (n-1 divisor). Part 13 §5.13.</summary>
+    VarianceSample,
+    /// <summary>Whole-population variance (n divisor). Part 13 §5.13.</summary>
+    VariancePopulation,
+
+    // ---- State-based (Part 13 §5.12, §5.19) ----
+    /// <summary>Number of value transitions observed in the interval. Part 13 §5.12.</summary>
+    NumberOfTransitions,
+    /// <summary>Total time (ms) the value was 0 (state Zero). Part 13 §5.19.</summary>
+    DurationInStateZero,
+    /// <summary>Total time (ms) the value was non-zero (state NonZero). Part 13 §5.19.</summary>
+    DurationInStateNonZero,
+
+    // ---- Interval bounds and deltas (Part 13 §5.8–§5.9, §5.11) ----
+    /// <summary>First Good-quality sample at or after the interval start. Part 13 §5.8.</summary>
+    Start,
+    /// <summary>Last Good-quality sample at or before the interval end. Part 13 §5.9.</summary>
+    End,
+    /// <summary>End sample minus Start sample. Part 13 §5.11.</summary>
+    Delta,
+    /// <summary>Boundary value (extrapolated) at the interval start. Part 13 §5.8.</summary>
+    StartBound,
+    /// <summary>Boundary value (extrapolated) at the interval end. Part 13 §5.9.</summary>
+    EndBound,
 }
 
 /// <summary>
-///     One row returned by <see cref="IHistoryProvider.ReadEventsAsync"/> — a historical
+///     One row returned by the fixed-field
-///     alarm/event record, not the OPC UA live-event stream. Fields match the minimum set the
+///     <see cref="IHistoryProvider.ReadEventsAsync(string?, DateTime, DateTime, int, CancellationToken)"/>
-///     Server needs to populate a <c>HistoryEventFieldList</c> for HistoryReadEvents responses.
+///     overload — a historical alarm/event record, not the OPC UA live-event stream. Fields
+///     match the minimum set the Server needs to populate a <c>HistoryEventFieldList</c>
+///     for HistoryReadEvents responses.
 /// </summary>
 /// <param name="EventId">Stable unique id for the event — driver-specific format.</param>
 /// <param name="SourceName">Source object that emitted the event. May differ from the <c>sourceName</c> filter the caller passed (fuzzy matches).</param>
@@ -114,9 +309,46 @@ public sealed record HistoricalEvent(
     string? Message,
     ushort Severity);
 
-/// <summary>Result of a <see cref="IHistoryProvider.ReadEventsAsync"/> call.</summary>
+/// <summary>Result of a <see cref="IHistoryProvider.ReadEventsAsync(string?, DateTime, DateTime, int, CancellationToken)"/> call.</summary>
 /// <param name="Events">Events in chronological order by <c>EventTimeUtc</c>.</param>
 /// <param name="ContinuationPoint">Opaque token for the next call when more events are available; null when complete.</param>
 public sealed record HistoricalEventsResult(
     IReadOnlyList<HistoricalEvent> Events,
     byte[]? ContinuationPoint);
+
+/// <summary>
+///     One row returned by the filter-aware
+///     <see cref="IHistoryProvider.ReadEventsAsync(string, EventHistoryRequest, CancellationToken)"/>
+///     overload. Carries an open-ended <see cref="Fields"/> bag keyed by
+///     <see cref="SimpleAttributeSpec.FieldName"/> (or a stable default name when no
+///     SelectClauses were supplied) so the server-side dispatcher can re-align fields with
+///     the client's requested order — without forcing every driver to honour the entire
+///     OPC UA EventFilter shape verbatim.
+/// </summary>
+/// <param name="Fields">
+///     SelectClause results. Keys match the <c>FieldName</c> on the corresponding
+///     <see cref="SimpleAttributeSpec"/>; values are the raw .NET payload (string,
+///     <c>DateTime</c>, severity int, etc.). <c>null</c> values are legitimate (the
+///     upstream had a missing field).
+/// </param>
+/// <param name="OccurrenceTime">
+///     Wall-clock event time — convenience for ordering / windowing without picking a key
+///     out of <see cref="Fields"/>. Drivers populate this from the underlying event row.
+/// </param>
+public sealed record HistoricalEventRow(
+    IReadOnlyDictionary<string, object?> Fields,
+    DateTimeOffset OccurrenceTime);
+
+/// <summary>
+///     Result of the filter-aware
+///     <see cref="IHistoryProvider.ReadEventsAsync(string, EventHistoryRequest, CancellationToken)"/>
+///     overload. Mirrors <see cref="HistoricalEventsResult"/> but carries
+///     <see cref="HistoricalEventRow"/> instead of the fixed-shape
+///     <see cref="HistoricalEvent"/> — the server-side dispatcher unpacks the keyed fields
+///     into a <c>HistoryEventFieldList</c> aligned with the client's SelectClauses.
+/// </summary>
+/// <param name="Events">Events in chronological order by <see cref="HistoricalEventRow.OccurrenceTime"/>.</param>
+/// <param name="ContinuationPoint">Opaque token for the next call when more events are available; null when complete.</param>
+public sealed record HistoricalEventBatch(
+    IReadOnlyList<HistoricalEventRow> Events,
+    byte[]? ContinuationPoint);

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IHostConnectivityProbe.cs

@@ -38,4 +38,16 @@ public sealed record HostStatusChangedEventArgs(
     HostState NewState);
 
 /// <summary>Host lifecycle state. Generalization of Galaxy's Platform/Engine ScanState.</summary>
-public enum HostState { Unknown, Running, Stopped, Faulted }
+/// <remarks>
+///     <para>
+///         <see cref="Demoted"/> (PR ablegacy-12 / #255) is a soft-stopped state used by drivers
+///         that auto-throttle a host after N consecutive comm failures. Reads are short-circuited
+///         with <c>BadCommunicationError</c> for a configurable cool-down window so one slow PLC
+///         doesn't starve faster peers sharing the same driver. Demoted is *not* the same as
+///         <see cref="Stopped"/> (which means "probe says it's down") nor <see cref="Faulted"/>
+///         (which means "the driver itself is broken"); it's a deliberate driver-side back-off.
+///         Consumers that don't recognize <c>Demoted</c> can safely treat it as <c>Stopped</c>
+///         (see <c>HostStatusPublisher.MapState</c>).
+///     </para>
+/// </remarks>
+public enum HostState { Unknown, Running, Stopped, Faulted, Demoted }

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IMethodInvoker.cs

@@ -0,0 +1,82 @@
+namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+/// <summary>
+///     Driver capability for invoking OPC UA Methods on the upstream backend (the OPC UA
+///     <c>Call</c> service). Optional — only drivers whose backends carry method nodes
+///     implement it. Currently the OPC UA Client driver is the only implementer; tag-based
+///     drivers (Modbus, S7, FOCAS, Galaxy, AB-CIP, AB-Legacy, TwinCAT) don't expose method
+///     nodes so they don't need this surface.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Per <c>docs/v2/plan.md</c> decision #4 (composable capability interfaces) — the
+///         server-side <c>DriverNodeManager</c> discovers method-bearing drivers via an
+///         <c>is IMethodInvoker</c> check and routes <c>OnCallMethod</c> handlers to
+///         <see cref="CallMethodAsync"/>. Drivers that don't implement the interface simply
+///         never have method nodes registered for them.
+///     </para>
+///     <para>
+///         The address-space mirror is driven by <see cref="IAddressSpaceBuilder.RegisterMethodNode"/>
+///         — drivers register the method node + its <c>InputArguments</c> /
+///         <c>OutputArguments</c> properties during discovery, then invocations land back on
+///         <see cref="CallMethodAsync"/> via the server-side dispatcher.
+///     </para>
+/// </remarks>
+public interface IMethodInvoker
+{
+    /// <summary>
+    ///     Invoke an upstream OPC UA Method. The driver translates input arguments into the
+    ///     wire-level <c>CallMethodRequest</c>, dispatches via the active session, and packs
+    ///     the response back into a <see cref="MethodCallResult"/>. Per-argument validation
+    ///     errors flow through <see cref="MethodCallResult.InputArgumentResults"/>; method-level
+    ///     errors (<c>BadMethodInvalid</c>, <c>BadUserAccessDenied</c>, etc.) flow through
+    ///     <see cref="MethodCallResult.StatusCode"/>.
+    /// </summary>
+    /// <param name="objectNodeId">
+    ///     Stringified NodeId of the OPC UA Object that owns the method (the <c>ObjectId</c>
+    ///     field of <c>CallMethodRequest</c>). Same serialization as <c>IReadable</c>'s
+    ///     <c>fullReference</c> — <c>ns=2;s=…</c> / <c>i=…</c> / <c>nsu=…;…</c>.
+    /// </param>
+    /// <param name="methodNodeId">
+    ///     Stringified NodeId of the Method node itself (the <c>MethodId</c> field).
+    /// </param>
+    /// <param name="inputs">
+    ///     Input arguments in declaration order. The driver wraps each value as a
+    ///     <c>Variant</c>; callers pass CLR primitives (plus arrays) — the wire-level
+    ///     encoding is the driver's concern.
+    /// </param>
+    /// <param name="cancellationToken">Per-call cancellation.</param>
+    /// <returns>
+    ///     Result of the call — see <see cref="MethodCallResult"/>. Never throws for a
+    ///     <c>Bad</c> upstream status; the bad code is surfaced via the result so the caller
+    ///     can map it onto an OPC UA service-result for downstream clients.
+    /// </returns>
+    Task<MethodCallResult> CallMethodAsync(
+        string objectNodeId,
+        string methodNodeId,
+        object[] inputs,
+        CancellationToken cancellationToken);
+}
+
+/// <summary>
+///     Result of a single OPC UA <c>Call</c> service invocation.
+/// </summary>
+/// <param name="StatusCode">
+///     Method-level status. <c>0</c> = Good. Bad codes pass through verbatim from the
+///     upstream so downstream clients see the canonical OPC UA error (e.g.
+///     <c>BadMethodInvalid</c>, <c>BadUserAccessDenied</c>, <c>BadArgumentsMissing</c>).
+/// </param>
+/// <param name="Outputs">
+///     Output argument values in declaration order. <c>null</c> when the upstream returned
+///     no output arguments (or returned a Bad status before producing any).
+/// </param>
+/// <param name="InputArgumentResults">
+///     Per-input-argument status codes. <c>null</c> when the upstream didn't surface
+///     per-argument validation results (typical for Good calls). Each entry is the OPC UA
+///     status code for the matching input argument — drivers can use this to surface
+///     <c>BadTypeMismatch</c>, <c>BadOutOfRange</c>, etc. on a specific argument.
+/// </param>
+public sealed record MethodCallResult(
+    uint StatusCode,
+    object[]? Outputs,
+    uint[]? InputArgumentResults);

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/ISubscribable.cs

@@ -20,7 +20,29 @@ public interface ISubscribable
         TimeSpan publishingInterval,
         CancellationToken cancellationToken);
 
-    /// <summary>Cancel a subscription returned by <see cref="SubscribeAsync"/>.</summary>
+    /// <summary>
+    ///     Subscribe to data changes with per-tag advanced tuning (sampling interval, queue
+    ///     size, monitoring mode, deadband filter). Drivers that don't have a native concept
+    ///     of these knobs (e.g. polled drivers like Modbus) MAY ignore the per-tag knobs and
+    ///     delegate to the simple
+    ///     <see cref="SubscribeAsync(IReadOnlyList{string}, TimeSpan, CancellationToken)"/>
+    ///     overload — the default implementation does exactly that, so existing implementers
+    ///     compile unchanged.
+    /// </summary>
+    /// <param name="tags">Per-tag subscription specs. <see cref="MonitoredTagSpec.TagName"/> is the driver-side full reference.</param>
+    /// <param name="publishingInterval">Subscription publishing interval, applied to the whole batch.</param>
+    /// <param name="cancellationToken">Cancellation.</param>
+    /// <returns>Opaque subscription handle for <see cref="UnsubscribeAsync"/>.</returns>
+    Task<ISubscriptionHandle> SubscribeAsync(
+        IReadOnlyList<MonitoredTagSpec> tags,
+        TimeSpan publishingInterval,
+        CancellationToken cancellationToken)
+        => SubscribeAsync(
+            tags.Select(t => t.TagName).ToList(),
+            publishingInterval,
+            cancellationToken);
+
+    /// <summary>Cancel a subscription returned by either <c>SubscribeAsync</c> overload.</summary>
     Task UnsubscribeAsync(ISubscriptionHandle handle, CancellationToken cancellationToken);
 
     /// <summary>
@@ -30,7 +52,7 @@ public interface ISubscribable
     event EventHandler<DataChangeEventArgs>? OnDataChange;
 }
 
-/// <summary>Opaque subscription identity returned by <see cref="ISubscribable.SubscribeAsync"/>.</summary>
+/// <summary>Opaque subscription identity returned by <see cref="ISubscribable.SubscribeAsync(IReadOnlyList{string}, TimeSpan, CancellationToken)"/>.</summary>
 public interface ISubscriptionHandle
 {
     /// <summary>Driver-internal subscription identifier (for diagnostics + post-mortem).</summary>
@@ -38,10 +60,99 @@ public interface ISubscriptionHandle
 }
 
 /// <summary>Event payload for <see cref="ISubscribable.OnDataChange"/>.</summary>
-/// <param name="SubscriptionHandle">The handle returned by the original <see cref="ISubscribable.SubscribeAsync"/> call.</param>
+/// <param name="SubscriptionHandle">The handle returned by the original <see cref="ISubscribable.SubscribeAsync(IReadOnlyList{string}, TimeSpan, CancellationToken)"/> call.</param>
 /// <param name="FullReference">Driver-side full reference of the changed attribute.</param>
 /// <param name="Snapshot">New value + quality + timestamps.</param>
 public sealed record DataChangeEventArgs(
     ISubscriptionHandle SubscriptionHandle,
     string FullReference,
     DataValueSnapshot Snapshot);
+
+/// <summary>
+///     Per-tag subscription tuning. Maps onto OPC UA <c>MonitoredItem</c> properties for the
+///     OpcUaClient driver; non-OPC-UA drivers either map a subset (e.g. ADS picks up
+///     <see cref="SamplingIntervalMs"/>) or ignore the knobs entirely and fall back to the
+///     simple <see cref="ISubscribable.SubscribeAsync(IReadOnlyList{string}, TimeSpan, CancellationToken)"/>.
+/// </summary>
+/// <param name="TagName">Driver-side full reference (e.g. <c>ns=2;s=Foo</c> for OPC UA).</param>
+/// <param name="SamplingIntervalMs">
+///     Server-side sampling rate in milliseconds. <c>null</c> = use the publishing interval.
+///     Sub-publish-interval values let a server sample faster than it publishes (queue +
+///     coalesce), useful for events that change between publish ticks.
+/// </param>
+/// <param name="QueueSize">Server-side notification queue depth. <c>null</c> = driver default (1).</param>
+/// <param name="DiscardOldest">
+///     When the server-side queue overflows: <c>true</c> drops oldest, <c>false</c> drops newest.
+///     <c>null</c> = driver default (true — preserve recency).
+/// </param>
+/// <param name="MonitoringMode">
+///     Per-item monitoring mode. <c>Reporting</c> = sample + publish, <c>Sampling</c> = sample
+///     but suppress publishing (useful with triggering), <c>Disabled</c> = neither.
+/// </param>
+/// <param name="DataChangeFilter">
+///     Optional data-change filter (deadband + trigger semantics). <c>null</c> = no filter
+///     (every change publishes regardless of magnitude).
+/// </param>
+public sealed record MonitoredTagSpec(
+    string TagName,
+    double? SamplingIntervalMs = null,
+    uint? QueueSize = null,
+    bool? DiscardOldest = null,
+    SubscriptionMonitoringMode? MonitoringMode = null,
+    DataChangeFilterSpec? DataChangeFilter = null);
+
+/// <summary>
+///     OPC UA <c>DataChangeFilter</c> spec. Mirrors the OPC UA Part 4 §7.17.2 structure but
+///     lives in Core.Abstractions so non-OpcUaClient drivers (e.g. Modbus, S7) can accept it
+///     as metadata even if they ignore the deadband mechanics.
+/// </summary>
+/// <param name="Trigger">When to fire: status only / status+value / status+value+timestamp.</param>
+/// <param name="DeadbandType">Deadband mode: none / absolute (engineering units) / percent of EURange.</param>
+/// <param name="DeadbandValue">
+///     Magnitude of the deadband. For <see cref="OtOpcUa.Core.Abstractions.DeadbandType.Absolute"/>
+///     this is in the variable's engineering units; for <see cref="OtOpcUa.Core.Abstractions.DeadbandType.Percent"/>
+///     it's a 0..100 percentage of EURange (server returns BadFilterNotAllowed if EURange isn't set).
+/// </param>
+public sealed record DataChangeFilterSpec(
+    DataChangeTrigger Trigger,
+    DeadbandType DeadbandType,
+    double DeadbandValue);
+
+/// <summary>
+///     OPC UA <c>DataChangeTrigger</c> values. Wraps the SDK enum so Core.Abstractions doesn't
+///     leak an OPC-UA-stack reference into every driver project.
+/// </summary>
+public enum DataChangeTrigger
+{
+    /// <summary>Fire only when StatusCode changes.</summary>
+    Status = 0,
+    /// <summary>Fire when StatusCode or Value changes (the OPC UA default).</summary>
+    StatusValue = 1,
+    /// <summary>Fire when StatusCode, Value, or SourceTimestamp changes.</summary>
+    StatusValueTimestamp = 2,
+}
+
+/// <summary>OPC UA deadband-filter modes.</summary>
+public enum DeadbandType
+{
+    /// <summary>No deadband — every value change publishes.</summary>
+    None = 0,
+    /// <summary>Deadband expressed in the variable's engineering units.</summary>
+    Absolute = 1,
+    /// <summary>Deadband expressed as 0..100 percent of the variable's EURange.</summary>
+    Percent = 2,
+}
+
+/// <summary>
+///     Per-item subscription monitoring mode. Wraps the OPC UA SDK's <c>MonitoringMode</c>
+///     so Core.Abstractions stays SDK-free.
+/// </summary>
+public enum SubscriptionMonitoringMode
+{
+    /// <summary>Item is created but neither sampling nor publishing.</summary>
+    Disabled = 0,
+    /// <summary>Item samples and queues but does not publish (useful with triggering).</summary>
+    Sampling = 1,
+    /// <summary>Item samples and publishes — the OPC UA default.</summary>
+    Reporting = 2,
+}

src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ScriptedAlarmEngine.cs

@@ -269,15 +269,6 @@ public sealed class ScriptedAlarmEngine : IDisposable
         AlarmState state, AlarmConditionState seed, DateTime nowUtc, CancellationToken ct)
     {
         var inputs = BuildReadCache(state.Inputs);
-
-        // Cold-start guard — skip the predicate when any referenced upstream tag has no
-        // cached value yet (the upstream subscription hasn't delivered its first push).
-        // Without this, predicates that cast `(double)ctx.GetTag(path).Value` throw NRE on
-        // every tick until the cache fills, spamming the log with identical stack traces.
-        // Bad quality is treated the same: the input isn't available at the predicate's
-        // expected type, so the only defensible move is to hold the prior condition state.
-        if (!AreInputsReady(inputs)) return seed;
-
         var context = new AlarmPredicateContext(inputs, state.Logger, _clock);
 
         bool predicateTrue;
@@ -314,27 +305,6 @@ public sealed class ScriptedAlarmEngine : IDisposable
         return d;
     }
 
-    /// <summary>
-    ///     Returns true when every entry in <paramref name="cache"/> has a non-null value
-    ///     and a Good-quality <see cref="DataValueSnapshot.StatusCode"/>. A false here lets
-    ///     callers short-circuit script evaluation — predicates that unconditionally cast
-    ///     <c>ctx.GetTag(path).Value</c> to a numeric type would otherwise throw
-    ///     <see cref="NullReferenceException"/> until the upstream subscription delivers
-    ///     its first push.
-    /// </summary>
-    private static bool AreInputsReady(IReadOnlyDictionary<string, DataValueSnapshot> cache)
-    {
-        foreach (var kv in cache)
-        {
-            if (kv.Value is null || kv.Value.Value is null) return false;
-            // OPC UA Part 4 StatusCode: bit 31 = severity 10 (Bad). Treat Good + Uncertain
-            // as "ready"; Uncertain carries a value the script can still inspect + make a
-            // qualified decision from. Only outright Bad is skipped.
-            if ((kv.Value.StatusCode & 0x80000000u) != 0) return false;
-        }
-        return true;
-    }
-
     private void EmitEvent(AlarmState state, AlarmConditionState condition, EmissionKind kind)
     {
         // Suppressed kind means shelving ate the emission — we don't fire for subscribers

src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagEngine.cs

@@ -228,14 +228,6 @@ public sealed class VirtualTagEngine : IDisposable
         try
         {
             var ctxCache = BuildReadCache(state.Reads);
-
-            // Cold-start guard — hold the prior value when any upstream input is still
-            // unset or Bad-quality. Evaluating with nulls would throw inside the script
-            // (scripts cast ctx.GetTag(path).Value directly) and produce a persistent
-            // BadInternalError result until the upstream cache fills. Keeping the prior
-            // snapshot is more honest: the virtual tag simply hasn't been computed yet.
-            if (!AreInputsReady(ctxCache)) return;
-
             var context = new VirtualTagContext(
                 ctxCache,
                 (p, v) => OnScriptSetVirtualTag(p, v),
@@ -286,23 +278,6 @@ public sealed class VirtualTagEngine : IDisposable
         return map;
     }
 
-    /// <summary>
-    ///     Returns true when every entry in <paramref name="cache"/> has a non-null value
-    ///     and a Good/Uncertain-quality <see cref="DataValueSnapshot.StatusCode"/>. Scripts
-    ///     cast <c>ctx.GetTag(path).Value</c> unconditionally; short-circuiting before the
-    ///     script runs keeps a not-yet-cached upstream from faulting the virtual tag with
-    ///     <c>BadInternalError</c>.
-    /// </summary>
-    private static bool AreInputsReady(IReadOnlyDictionary<string, DataValueSnapshot> cache)
-    {
-        foreach (var kv in cache)
-        {
-            if (kv.Value is null || kv.Value.Value is null) return false;
-            if ((kv.Value.StatusCode & 0x80000000u) != 0) return false;
-        }
-        return true;
-    }
-
     private void OnScriptSetVirtualTag(string path, object? value)
     {
         if (!_tags.ContainsKey(path))

src/ZB.MOM.WW.OtOpcUa.Core/Hosting/DriverFactoryRegistry.cs

@@ -19,8 +19,6 @@ public sealed class DriverFactoryRegistry
 {
     private readonly Dictionary<string, Func<string, string, IDriver>> _factories
         = new(StringComparer.OrdinalIgnoreCase);
-    private readonly Dictionary<string, DriverTier> _tiers
-        = new(StringComparer.OrdinalIgnoreCase);
     private readonly object _lock = new();
 
     /// <summary>
@@ -35,15 +33,7 @@ public sealed class DriverFactoryRegistry
     ///     itself — the bootstrapper calls it via <see cref="DriverHost.RegisterAsync"/>
     ///     so the host's per-driver retry semantics apply uniformly.
     /// </param>
-    /// <param name="tier">
+    public void Register(string driverType, Func<string, string, IDriver> factory)
-    ///     Stability tier per <c>docs/v2/driver-stability.md</c>. Defaults to
-    ///     <see cref="DriverTier.A"/> (in-process, lowest recycle footprint); Tier C
-    ///     drivers SHOULD pass this explicitly so the scheduled-recycle wiring in
-    ///     <c>DriverInstanceBootstrapper</c> can skip in-process drivers by tier check
-    ///     rather than by driver-type allow-list.
-    /// </param>
-    public void Register(string driverType, Func<string, string, IDriver> factory,
-        DriverTier tier = DriverTier.A)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(driverType);
         ArgumentNullException.ThrowIfNull(factory);
@@ -53,7 +43,6 @@ public sealed class DriverFactoryRegistry
                 throw new InvalidOperationException(
                     $"DriverType '{driverType}' factory already registered for this process");
             _factories[driverType] = factory;
-            _tiers[driverType] = tier;
         }
     }
 
@@ -68,17 +57,6 @@ public sealed class DriverFactoryRegistry
         lock (_lock) return _factories.GetValueOrDefault(driverType);
     }
 
-    /// <summary>
-    ///     Look up the tier recorded alongside the factory. Returns <see cref="DriverTier.A"/>
-    ///     for unknown driver types — a missing registration is already a skipped-bootstrap
-    ///     case upstream; we don't double-surface that failure here.
-    /// </summary>
-    public DriverTier GetTier(string driverType)
-    {
-        ArgumentException.ThrowIfNullOrWhiteSpace(driverType);
-        lock (_lock) return _tiers.GetValueOrDefault(driverType, DriverTier.A);
-    }
-
     public IReadOnlyCollection<string> RegisteredTypes
     {
         get { lock (_lock) return [.. _factories.Keys]; }

src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/EquipmentNodeWalker.cs

@@ -1,4 +1,3 @@
-using System.Text.Json;
 using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 
@@ -158,7 +157,7 @@ public static class EquipmentNodeWalker
     private static void AddTagVariable(IAddressSpaceBuilder equipmentBuilder, Tag tag)
     {
         var attr = new DriverAttributeInfo(
-            FullName: ExtractFullName(tag.TagConfig),
+            FullName: tag.TagConfig,
             DriverDataType: ParseDriverDataType(tag.DataType),
             IsArray: false,
             ArrayDim: null,
@@ -167,38 +166,6 @@ public static class EquipmentNodeWalker
         equipmentBuilder.Variable(tag.Name, tag.Name, attr);
     }
 
-    /// <summary>
-    ///     Cross-driver TagConfig convention — the Config DB's <c>CK_Tag_TagConfig_IsJson</c>
-    ///     check constraint requires TagConfig to be a JSON object, and every shipped driver
-    ///     (Galaxy / Modbus / AB CIP / S7 / FOCAS / TwinCAT / ABLegacy) stores the wire-level
-    ///     address in a top-level <c>FullName</c> field. Extracting it here keeps the walker
-    ///     driver-agnostic while giving the driver the plain address string its backend
-    ///     expects at read-time — the raw JSON would otherwise be passed verbatim to
-    ///     <c>IReadable.ReadAsync</c> and the driver would fail to resolve the tag.
-    /// </summary>
-    /// <remarks>
-    ///     Falls back to the raw <paramref name="tagConfig"/> if it doesn't parse as JSON or
-    ///     the <c>FullName</c> field is absent. This preserves the pre-refactor behaviour for
-    ///     any legacy row that slipped past the check constraint or any future driver that
-    ///     wants an opaque non-JSON reference.
-    /// </remarks>
-    internal static string ExtractFullName(string tagConfig)
-    {
-        if (string.IsNullOrWhiteSpace(tagConfig)) return tagConfig;
-        try
-        {
-            using var doc = JsonDocument.Parse(tagConfig);
-            if (doc.RootElement.ValueKind == JsonValueKind.Object
-                && doc.RootElement.TryGetProperty("FullName", out var fullName)
-                && fullName.ValueKind == JsonValueKind.String)
-            {
-                return fullName.GetString() ?? tagConfig;
-            }
-        }
-        catch (JsonException) { /* fall through */ }
-        return tagConfig;
-    }
-
     /// <summary>
     ///     Parse <see cref="Tag.DataType"/> (stored as the <see cref="DriverDataType"/> enum
     ///     name string, decision #138) into the enum value. Unknown names fall back to

src/ZB.MOM.WW.OtOpcUa.Core/Resilience/DriverResilienceOptions.cs

@@ -28,16 +28,6 @@ public sealed record DriverResilienceOptions
     /// </summary>
     public int BulkheadMaxQueue { get; init; } = 64;
 
-    /// <summary>
-    ///     Periodic scheduled recycle interval for Tier C out-of-process hosts, in seconds.
-    ///     Null (the default) = no scheduled recycle; the driver's Host process keeps running
-    ///     indefinitely unless a memory breach or operator action triggers a recycle. Only
-    ///     respected for <see cref="DriverTier.C"/>; Tier A/B recycle would tear down every
-    ///     OPC UA session, so the loader ignores non-null values for those tiers + logs a
-    ///     warning (per decisions #74 / #145).
-    /// </summary>
-    public int? RecycleIntervalSeconds { get; init; }
-
     /// <summary>
     ///     Look up the effective policy for a capability, falling back to tier defaults when no
     ///     override is configured. Never returns null.