Merge pull request '[ablegacy] AbLegacy — PD/MG/PLS/BT structure files' (#352) from auto/ablegacy/5 into auto/driver-gaps

Adds PD (PID), MG (Message), PLS (Programmable Limit Switch) and BT
(Block Transfer) file types to the PCCC parser. New AbLegacyDataType
enum members (PidElement / MessageElement / PlsElement /
BlockTransferElement) plus per-type sub-element catalogue:

  - PD: SP/PV/CV/KP/KI/KD/MAXS/MINS/DB/OUT as Float32; EN/DN/MO/PE/
        AUTO/MAN/SP_VAL/SP_LL/SP_HL as Boolean (word-0 status bits).
  - MG: RBE/MS/SIZE/LEN as Int32; EN/EW/ER/DN/ST/CO/NR/TO as Boolean.
  - PLS: LEN as Int32 (bit table varies per PLC).
  - BT: RLEN/DLEN as Int32; EN/ST/DN/ER/CO/EW/TO/NR as Boolean.

Per-family flags on AbLegacyPlcFamilyProfile gate availability:

  - PD/MG: SLC500 + PLC-5 (operator + status bits both present).
  - PLS/BT: PLC-5 only (chassis-IO block transfer is PLC-5-specific).
  - MicroLogix + LogixPccc: rejected — no legacy file-letter form.

Status-bit indices match Rockwell DTAM / 1747-RM001 / 1785-6.5.12:
PD word 0 bits 0-8, MG/BT word 0 bits 8-15. PLC-set status bits
(PE/DN/SP_*; ST/DN/ER/CO/EW/NR/TO) are surfaced as ViewOnly via
IsPlcSetStatusBit, matching the Timer/Counter/Control pattern from
ablegacy-3.

LibplctagLegacyTagRuntime decodes PD non-bit members as Float32 and
MG/BT/PLS non-bit members as Int32; status bits route through GetBit
with the bit-position encoded by the driver via StatusBitIndex.

Tests: parser positive cases per family + negative cases per family,
catalogue + bit-index + read-only-bit assertions.

Closes #248

.gitignore

@@ -30,3 +30,10 @@ packages/
 .claude/
 
 .local/
+
+# LiteDB local config cache (Phase 6.1 Stream D — runtime artifact, not source)
+src/ZB.MOM.WW.OtOpcUa.Server/config_cache.db
+
+# E2E sidecar config — NodeIds are specific to each dev's local seed (see scripts/e2e/README.md)
+scripts/e2e/e2e-config.json
+config_cache*.db

ZB.MOM.WW.OtOpcUa.slnx

@@ -24,6 +24,13 @@
         <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"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Client.UI/ZB.MOM.WW.OtOpcUa.Client.UI.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Analyzers/ZB.MOM.WW.OtOpcUa.Analyzers.csproj"/>
     </Folder>
     <Folder Name="/tests/">
@@ -44,6 +51,12 @@
         <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.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"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Tests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.Tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.Tests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli.Tests/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli.Tests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli.Tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.S7.Tests/ZB.MOM.WW.OtOpcUa.Driver.S7.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Tests.csproj"/>

docs/AlarmTracking.md

@@ -67,6 +67,53 @@ Drivers that want hierarchical alarm subscriptions propagate `EventNotifier.Subs
 
 The OPC UA `ConditionRefresh` service queues the current state of every retained condition back to the requesting monitored items. `DriverNodeManager` iterates the node manager's `AlarmConditionState` collection and queues each condition whose `Retain.Value == true` — matching the Part 9 requirement.
 
+## Alarm historian sink
+
+Distinct from the live `IAlarmSource` stream and the Part 9 `AlarmConditionState` materialization above, qualifying alarm transitions are **also** persisted to a durable event log for downstream AVEVA Historian ingestion. This is a separate subsystem from the `IHistoryProvider` capability used by `HistoryReadEvents` (see [HistoricalDataAccess.md](HistoricalDataAccess.md#alarm-event-history-vs-ihistoryprovider)): the sink is a *producer* path (server → Historian) that runs independently of any client HistoryRead call.
+
+### `IAlarmHistorianSink`
+
+`src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/IAlarmHistorianSink.cs` defines the intake contract:
+
+```csharp
+Task EnqueueAsync(AlarmHistorianEvent evt, CancellationToken cancellationToken);
+HistorianSinkStatus GetStatus();
+```
+
+`EnqueueAsync` is fire-and-forget from the producer's perspective — it must never block the emitting thread. The event payload (`AlarmHistorianEvent` — same file) is source-agnostic: `AlarmId`, `EquipmentPath`, `AlarmName`, `AlarmTypeName` (Part 9 subtype name), `Severity`, `EventKind` (free-form transition string — `Activated` / `Cleared` / `Acknowledged` / `Confirmed` / `Shelved` / …), `Message`, `User`, `Comment`, `TimestampUtc`.
+
+The sink scope is defined to span every alarm source (plan decision #15: scripted, Galaxy-native, AB CIP ALMD, any future `IAlarmSource`), gated per-alarm by a `HistorizeToAveva` toggle on the producer. Today only `Phase7EngineComposer.RouteToHistorianAsync` (`src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7EngineComposer.cs`) is wired — it subscribes to `ScriptedAlarmEngine.OnEvent` and marshals each emission into `AlarmHistorianEvent`. Galaxy-native alarms continue to reach AVEVA Historian via the driver's direct `aahClientManaged` path and do not flow through the sink; the AB CIP ALMD path remains unwired pending a producer-side integration.
+
+### `SqliteStoreAndForwardSink`
+
+Default production implementation (`src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/SqliteStoreAndForwardSink.cs`). A local SQLite queue absorbs every `EnqueueAsync` synchronously; a background `Timer` drains batches asynchronously to an `IAlarmHistorianWriter` so operator actions are never blocked on historian reachability.
+
+Queue schema (single table `Queue`): `RowId PK autoincrement`, `AlarmId`, `EnqueuedUtc`, `PayloadJson` (serialized `AlarmHistorianEvent`), `AttemptCount`, `LastAttemptUtc`, `LastError`, `DeadLettered` (bool), plus `IX_Queue_Drain (DeadLettered, RowId)`. Default capacity `1_000_000` non-dead-lettered rows; oldest rows evict with a WARN log past the cap.
+
+Drain cadence: `StartDrainLoop(tickInterval)` arms a periodic timer. `DrainOnceAsync` reads up to `batchSize` rows (default 100) in `RowId` order and forwards them through `IAlarmHistorianWriter.WriteBatchAsync`, which returns one `HistorianWriteOutcome` per row:
+
+| Outcome | Action |
+|---|---|
+| `Ack` | Row deleted. |
+| `PermanentFail` | Row flipped to `DeadLettered = 1` with reason. Peers in the batch retry independently. |
+| `RetryPlease` | `AttemptCount` bumped; row stays queued. Drain worker enters `BackingOff`. |
+
+Writer-side exceptions treat the whole batch as `RetryPlease`.
+
+Backoff ladder on `RetryPlease` (hard-coded): 1s → 2s → 5s → 15s → 60s cap. Reset to 0 on any batch with no retries. `CurrentBackoff` exposes the current step for instrumentation; the drain timer itself fires on `tickInterval`, so the ladder governs write cadence rather than timer period.
+
+Dead-letter retention defaults to 30 days (plan decision #21). `PurgeAgedDeadLetters` runs each drain pass and deletes rows whose `LastAttemptUtc` is past the cutoff. `RetryDeadLettered()` is an operator action that clears `DeadLettered` + resets `AttemptCount` on every dead-lettered row so they rejoin the main queue.
+
+### Composition and writer resolution
+
+`Phase7Composer.ResolveHistorianSink` (`src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7Composer.cs`) scans the registered drivers for one that implements `IAlarmHistorianWriter`. Today that is `GalaxyProxyDriver` via `GalaxyHistorianWriter` (`src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Proxy/Ipc/GalaxyHistorianWriter.cs`), which forwards batches over the Galaxy.Host pipe to the `aahClientManaged` alarm schema. When a writer is found, a `SqliteStoreAndForwardSink` is instantiated against `%ProgramData%/OtOpcUa/alarm-historian-queue.db` with a 2 s drain tick and the writer attached. When no driver provides a writer the fallback is the DI-registered `NullAlarmHistorianSink` (`src/ZB.MOM.WW.OtOpcUa.Server/Program.cs`), which silently discards and reports `HistorianDrainState.Disabled`.
+
+### Status and observability
+
+`GetStatus()` returns `HistorianSinkStatus(QueueDepth, DeadLetterDepth, LastDrainUtc, LastSuccessUtc, LastError, DrainState)` — two `COUNT(*)` scalars plus last-drain telemetry. `DrainState` is one of `Disabled` / `Idle` / `Draining` / `BackingOff`.
+
+The Admin UI `/alarms/historian` page surfaces this through `HistorianDiagnosticsService` (`src/ZB.MOM.WW.OtOpcUa.Admin/Services/HistorianDiagnosticsService.cs`), which also exposes `TryRetryDeadLettered` — it calls through to `SqliteStoreAndForwardSink.RetryDeadLettered` when the live sink is the SQLite implementation and returns 0 otherwise.
+
 ## Key source files
 
 - `src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs` — capability contract + `AlarmEventArgs`
@@ -74,3 +121,8 @@ The OPC UA `ConditionRefresh` service queues the current state of every retained
 - `src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/GenericDriverNodeManager.cs` — `CapturingBuilder` + alarm forwarder
 - `src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/DriverNodeManager.cs` — `VariableHandle.MarkAsAlarmCondition` + `ConditionSink`
 - `src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host/Backend/Alarms/GalaxyAlarmTracker.cs` — Galaxy-specific alarm-event production
+- `src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/IAlarmHistorianSink.cs` — historian sink intake contract + `AlarmHistorianEvent` + `HistorianSinkStatus` + `IAlarmHistorianWriter`
+- `src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/SqliteStoreAndForwardSink.cs` — durable queue + drain worker + backoff ladder + dead-letter retention
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7EngineComposer.cs` — `RouteToHistorianAsync` wires scripted-alarm emissions into the sink
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7Composer.cs` — `ResolveHistorianSink` selects `SqliteStoreAndForwardSink` vs `NullAlarmHistorianSink`
+- `src/ZB.MOM.WW.OtOpcUa.Admin/Services/HistorianDiagnosticsService.cs` — Admin UI `/alarms/historian` status + retry-dead-lettered operator action

docs/DataTypeMapping.md

@@ -35,7 +35,7 @@ The driver's mapping is authoritative — when a field type is ambiguous (a `LRE
 
 ## SecurityClassification — metadata, not ACL
 
-`SecurityClassification` is driver-reported metadata only. Drivers never enforce write permissions themselves — the classification flows into the Server project where `WriteAuthzPolicy.IsAllowed(classification, userRoles)` (`src/ZB.MOM.WW.OtOpcUa.Server/Security/WriteAuthzPolicy.cs`) gates the write against the session's LDAP-derived roles, and (Phase 6.2) the `AuthorizationGate` + permission trie apply on top. This is the "ACL at server layer" invariant recorded in `feedback_acl_at_server_layer.md`.
+`SecurityClassification` is driver-reported metadata only. Drivers never enforce write permissions themselves — the classification flows into the Server project where `WriteAuthzPolicy.IsAllowed(classification, userRoles)` (`src/ZB.MOM.WW.OtOpcUa.Server/Security/WriteAuthzPolicy.cs`) gates the write against the session's LDAP-derived roles, and (Phase 6.2) the `AuthorizationGate` + permission trie apply on top. This is the "ACL at server layer" invariant documented in `docs/security.md`.
 
 The classification values mirror the v1 Galaxy model so existing Galaxy galaxies keep their published semantics:
 

docs/Driver.AbCip.Cli.md

@@ -0,0 +1,83 @@
+# `otopcua-abcip-cli` — AB CIP test client
+
+Ad-hoc probe / read / write / subscribe tool for ControlLogix / CompactLogix /
+Micro800 / GuardLogix PLCs, talking to the **same** `AbCipDriver` the OtOpcUa
+server uses (libplctag under the hood).
+
+Second of four driver test-client CLIs (Modbus → AB CIP → AB Legacy → S7 →
+TwinCAT). Shares `Driver.Cli.Common` with the others.
+
+## Build + run
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli -- --help
+```
+
+## Common flags
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-g` / `--gateway` | **required** | Canonical `ab://host[:port]/cip-path` |
+| `-f` / `--family` | `ControlLogix` | ControlLogix / CompactLogix / Micro800 / GuardLogix |
+| `--timeout-ms` | `5000` | Per-operation timeout |
+| `--verbose` | off | Serilog debug output |
+
+Family ↔ CIP-path cheat sheet:
+- **ControlLogix / CompactLogix / GuardLogix** — `1,0` (slot 0 of chassis)
+- **Micro800** — empty path, just `ab://host/`
+- **Sub-slot Logix** (rare) — `1,3` for slot 3
+
+## Commands
+
+### `probe` — is the PLC up?
+
+```powershell
+# ControlLogix — read the canonical libplctag system tag
+otopcua-abcip-cli probe -g ab://10.0.0.5/1,0 -t @raw_cpu_type --type DInt
+
+# Micro800 — point at a user-supplied global
+otopcua-abcip-cli probe -g ab://10.0.0.6/ -f Micro800 -t _SYSVA_CLOCK_HOUR --type DInt
+```
+
+### `read` — single Logix tag
+
+```powershell
+# Controller scope
+otopcua-abcip-cli read -g ab://10.0.0.5/1,0 -t Motor01_Speed --type Real
+
+# Program scope
+otopcua-abcip-cli read -g ab://10.0.0.5/1,0 -t "Program:Main.Counter" --type DInt
+
+# Array element
+otopcua-abcip-cli read -g ab://10.0.0.5/1,0 -t "Recipe[3]" --type Real
+
+# UDT member (dotted path)
+otopcua-abcip-cli read -g ab://10.0.0.5/1,0 -t "Motor01.Speed" --type Real
+```
+
+### `write` — single Logix tag
+
+Same shape as `read` plus `-v`. Values parse per `--type` using invariant
+culture. Booleans accept `true`/`false`/`1`/`0`/`yes`/`no`/`on`/`off`.
+Structure (UDT) writes need the member layout declared in a real driver config
+and are refused by the CLI.
+
+```powershell
+otopcua-abcip-cli write -g ab://10.0.0.5/1,0 -t Motor01_Speed --type Real -v 3.14
+otopcua-abcip-cli write -g ab://10.0.0.5/1,0 -t StartCommand --type Bool -v true
+```
+
+### `subscribe` — watch a tag until Ctrl+C
+
+```powershell
+otopcua-abcip-cli subscribe -g ab://10.0.0.5/1,0 -t Motor01_Speed --type Real -i 500
+```
+
+## Typical workflows
+
+- **"Is the PLC reachable?"** → `probe`.
+- **"Did my recipe write land?"** → `write` + `read` back.
+- **"Why is tag X flipping?"** → `subscribe`.
+- **"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`.

docs/Driver.AbLegacy.Cli.md

@@ -0,0 +1,105 @@
+# `otopcua-ablegacy-cli` — AB Legacy (PCCC) test client
+
+Ad-hoc probe / read / write / subscribe tool for SLC 500 / MicroLogix 1100 /
+MicroLogix 1400 / PLC-5 devices, talking to the **same** `AbLegacyDriver` the
+OtOpcUa server uses (libplctag PCCC back-end).
+
+Third of four driver test-client CLIs. Shares `Driver.Cli.Common` with the
+others.
+
+## Build + run
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli -- --help
+```
+
+## Common flags
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-g` / `--gateway` | **required** | Canonical `ab://host[:port]/cip-path` |
+| `-P` / `--plc-type` | `Slc500` | Slc500 / MicroLogix / Plc5 / LogixPccc |
+| `--timeout-ms` | `5000` | Per-operation timeout |
+| `--verbose` | off | Serilog debug output |
+
+Family ↔ CIP-path cheat sheet:
+- **SLC 5/05 / PLC-5** — `1,0`
+- **MicroLogix 1100 / 1400** — empty path (`ab://host/`) — they use direct EIP
+  with no backplane
+- **LogixPccc** — `1,0` (Logix controller accessed via the PCCC compatibility
+  layer; rare)
+
+## PCCC address primer
+
+File letters imply data type; type flag still required so the CLI knows how to
+parse your `--value`.
+
+| File | Type | CLI `--type` |
+|---|---|---|
+| `N` | signed int16 | `Int` |
+| `F` | float32 | `Float` |
+| `B` | bit-packed (`B3:0/3` addresses bit 3 of word 0) | `Bit` |
+| `L` | long int32 (SLC 5/05+ only) | `Long` |
+| `A` | analog int (semantically like N) | `AnalogInt` |
+| `ST` | ASCII string (82-byte + length header) | `String` |
+| `T` | timer sub-element (`T4:0.ACC` / `.PRE` / `.EN` / `.DN`) | `TimerElement` |
+| `C` | counter sub-element (`C5:0.ACC` / `.PRE` / `.CU` / `.CD` / `.DN`) | `CounterElement` |
+| `R` | control sub-element (`R6:0.LEN` / `.POS` / `.EN` / `.DN` / `.ER`) | `ControlElement` |
+
+## Commands
+
+### `probe`
+
+```powershell
+# SLC 5/05 — default probe address N7:0
+otopcua-ablegacy-cli probe -g ab://192.168.1.20/1,0
+
+# MicroLogix 1100 — status file first word
+otopcua-ablegacy-cli probe -g ab://192.168.1.30/ -P MicroLogix -a S:0
+```
+
+### `read`
+
+```powershell
+# Integer
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a N7:10 -t Int
+
+# Float
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a F8:0 -t Float
+
+# Bit-within-word
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a B3:0/3 -t Bit
+
+# Long (SLC 5/05+)
+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
+```
+
+### `write`
+
+```powershell
+otopcua-ablegacy-cli write -g ab://192.168.1.20/1,0 -a N7:10 -t Int -v 42
+otopcua-ablegacy-cli write -g ab://192.168.1.20/1,0 -a F8:0 -t Float -v 3.14
+otopcua-ablegacy-cli write -g ab://192.168.1.20/1,0 -a B3:0/3 -t Bit -v on
+```
+
+Writes to timer / counter / control sub-elements land at the wire level but
+the PLC's runtime semantics (EN/DN edge-triggering, preset reload) are
+PLC-managed — use with caution.
+
+### `subscribe`
+
+```powershell
+otopcua-ablegacy-cli subscribe -g ab://192.168.1.20/1,0 -a N7:10 -t Int -i 500
+```
+
+## Known caveat — ab_server upstream gap
+
+The integration-fixture `ab_server` Docker container accepts TCP but its PCCC
+dispatcher doesn't actually respond — see
+[`tests/...AbLegacy.IntegrationTests/Docker/README.md`](../tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/Docker/README.md).
+Point `--gateway` at real hardware or an RSEmulate 500 box for end-to-end
+wire-level validation. The CLI itself is correct regardless of which endpoint
+you target.

docs/Driver.FOCAS.Cli.md

@@ -0,0 +1,158 @@
+# `otopcua-focas-cli` — Fanuc FOCAS test client
+
+Ad-hoc probe / read / write / subscribe tool for Fanuc CNCs via the FOCAS/2
+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, added alongside the Tier-C isolation
+work tracked in task #220.
+
+## Architecture note
+
+FOCAS is a Tier-C driver: `Fwlib32.dll` is a proprietary 32-bit Fanuc library
+with a documented habit of crashing its hosting process on network errors.
+The target runtime deployment splits the driver into an in-process
+`FocasProxyDriver` (.NET 10 x64) and an out-of-process `Driver.FOCAS.Host`
+(.NET 4.8 x86 Windows service) that owns the DLL — see
+[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.
+
+The CLI skips the proxy and loads `FocasDriver` directly (via
+`FwlibFocasClientFactory`, which P/Invokes `Fwlib32.dll` in the CLI's own
+process). There is **no public simulator** for FOCAS; a meaningful probe
+requires a real CNC + a licensed `Fwlib32.dll` on `PATH` (or next to the
+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
+
+```powershell
+dotnet build src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli -- --help
+```
+
+Or publish a self-contained binary:
+
+```powershell
+dotnet publish src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli -c Release -o publish/focas-cli
+publish/focas-cli/otopcua-focas-cli.exe --help
+```
+
+## Common flags
+
+Every command accepts:
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-h` / `--cnc-host` | **required** | CNC IP address or hostname |
+| `-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 |
+| `--verbose` | off | Serilog debug output |
+
+## Addressing
+
+`FocasAddressParser` syntax — the same format the server + `FocasTagDefinition`
+use. Common shapes:
+
+| Address | Meaning |
+|---|---|
+| `R100` | PMC R-file word register 100 |
+| `X0.0` | PMC X-file bit 0 of byte 0 |
+| `G50.3` | PMC G-file bit 3 of byte 50 |
+| `F1.4` | PMC F-file bit 4 of byte 1 |
+| `PARAM:1815/0` | Parameter 1815, axis 0 |
+| `MACRO:500` | Macro variable 500 |
+
+## Data types
+
+`Bit`, `Byte`, `Int16`, `Int32`, `Float32`, `Float64`, `String`. Default is
+`Int16` (matches PMC R-file word width).
+
+## Commands
+
+### `probe` — is the CNC reachable?
+
+Opens a FOCAS session, reads one sample address, prints driver health.
+
+```powershell
+# Default: read R100 as Int16
+otopcua-focas-cli probe -h 192.168.1.50
+
+# Explicit series + address
+otopcua-focas-cli probe -h 192.168.1.50 -s ThirtyOne_i --address R200 --type Int16
+```
+
+### `read` — single address
+
+```powershell
+# PMC R-file word
+otopcua-focas-cli read -h 192.168.1.50 -a R100 -t Int16
+
+# PMC X-bit
+otopcua-focas-cli read -h 192.168.1.50 -a X0.0 -t Bit
+
+# Parameter (axis 0)
+otopcua-focas-cli read -h 192.168.1.50 -a PARAM:1815/0 -t Int32
+
+# Macro variable
+otopcua-focas-cli read -h 192.168.1.50 -a MACRO:500 -t Float64
+```
+
+### `write` — single value
+
+Values parse per `--type` with invariant culture. Booleans accept
+`true` / `false` / `1` / `0` / `yes` / `no` / `on` / `off`.
+
+```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
+```
+
+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.
+
+**Writes are non-idempotent by default** — a timeout after the CNC already
+applied the write will NOT auto-retry (plan decisions #44 + #45).
+
+### `subscribe` — watch an address until Ctrl+C
+
+FOCAS has no push model; the shared `PollGroupEngine` handles the tick
+loop.
+
+```powershell
+otopcua-focas-cli subscribe -h 192.168.1.50 -a R100 -t Int16 -i 500
+```
+
+## Output format
+
+Identical to the other driver CLIs via `SnapshotFormatter`:
+
+- `probe` / `read` emit a multi-line block: `Tag / Value / Status /
+  Source Time / Server Time`. `probe` prefixes it with `CNC`, `Series`,
+  `Health`, and `Last error` lines.
+- `write` emits one line: `Write <address>: 0x... (Good |
+  BadCommunicationError | …)`.
+- `subscribe` emits one line per change: `[HH:mm:ss.fff] <address> =
+  <value> (<status>)`.
+
+## Typical workflows
+
+**"Is the CNC alive?"** → `probe`.
+
+**"Does my parameter write land?"** → `write` + `read` back against the
+same address. Check the parameter-write switch + MDI mode if the write
+fails.
+
+**"Why did this macro flip?"** → `subscribe` to the macro, let the
+operator reproduce the cycle, watch the HH:mm:ss.fff timeline.
+
+**"Is the Fwlib32 DLL wired up?"** → `probe` against any host. A
+`DllNotFoundException` surfacing as `BadCommunicationError` with a
+matching `Last error` line means the driver is loading but the DLL is
+missing; anything else means a transport-layer problem.

docs/Driver.Modbus.Cli.md

@@ -0,0 +1,121 @@
+# `otopcua-modbus-cli` — Modbus-TCP test client
+
+Ad-hoc probe / read / write / subscribe tool for talking to Modbus-TCP devices
+through the **same** `ModbusDriver` the OtOpcUa server uses. Mirrors the v1
+OPC UA `otopcua-cli` shape so the muscle memory carries over: drop to a shell,
+point at a PLC, watch registers move.
+
+First of four driver test-client CLIs (Modbus → AB CIP → AB Legacy → S7 →
+TwinCAT). Built on the shared `ZB.MOM.WW.OtOpcUa.Driver.Cli.Common` library
+so each downstream CLI inherits verbose/log wiring + snapshot formatting
+without copy-paste.
+
+## Build + run
+
+```powershell
+dotnet build src/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli -- --help
+```
+
+Or publish a self-contained binary:
+
+```powershell
+dotnet publish src/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli -c Release -o publish/modbus-cli
+publish/modbus-cli/otopcua-modbus-cli.exe --help
+```
+
+## Common flags
+
+Every command accepts:
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-h` / `--host` | **required** | Modbus-TCP server hostname or IP |
+| `-p` / `--port` | `502` | TCP port |
+| `-U` / `--unit-id` | `1` | Modbus unit / slave ID |
+| `--timeout-ms` | `2000` | Per-PDU timeout |
+| `--disable-reconnect` | off | Turn off mid-transaction reconnect-and-retry |
+| `--verbose` | off | Serilog debug output |
+
+## Commands
+
+### `probe` — is the PLC up?
+
+Connects, reads one holding register, prints driver health. Fastest sanity
+check after swapping a network cable or deploying a new device.
+
+```powershell
+otopcua-modbus-cli probe -h 192.168.1.10
+otopcua-modbus-cli probe -h 192.168.1.10 --probe-address 100    # device locks HR[0]
+```
+
+### `read` — single register / coil / string
+
+Synthesises a one-tag driver config on the fly from `--region` + `--address`
++ `--type` flags.
+
+```powershell
+# Holding register as UInt16
+otopcua-modbus-cli read -h 192.168.1.10 -r HoldingRegisters -a 100 -t UInt16
+
+# Float32 with word-swap (CDAB) — common on Siemens / some AB families
+otopcua-modbus-cli read -h 192.168.1.10 -r HoldingRegisters -a 200 -t Float32 --byte-order WordSwap
+
+# Single bit out of a packed holding register
+otopcua-modbus-cli read -h 192.168.1.10 -r HoldingRegisters -a 10 -t BitInRegister --bit-index 3
+
+# 40-char ASCII string — DirectLOGIC packs the first char in the low byte
+otopcua-modbus-cli read -h 192.168.1.10 -r HoldingRegisters -a 300 -t String --string-length 40 --string-byte-order LowByteFirst
+
+# Discrete input / coil
+otopcua-modbus-cli read -h 192.168.1.10 -r DiscreteInputs -a 5 -t Bool
+```
+
+### `write` — single value
+
+Same flag shape as `read` plus `-v` / `--value`. Values parse per `--type`
+using invariant culture (period as decimal separator). Booleans accept
+`true`/`false`/`1`/`0`/`yes`/`no`/`on`/`off`.
+
+```powershell
+otopcua-modbus-cli write -h 192.168.1.10 -r HoldingRegisters -a 100 -t UInt16 -v 42
+otopcua-modbus-cli write -h 192.168.1.10 -r HoldingRegisters -a 200 -t Float32 -v 3.14
+otopcua-modbus-cli write -h 192.168.1.10 -r Coils -a 5 -t Bool -v on
+```
+
+**Writes are non-idempotent by default** — a timeout after the device
+already applied the write will NOT auto-retry. This matches the driver's
+production contract (plan decisions #44 + #45).
+
+### `subscribe` — watch a register until Ctrl+C
+
+Uses the driver's `ISubscribable` surface (polling under the hood via
+`PollGroupEngine`). Prints every data-change event with a timestamp.
+
+```powershell
+otopcua-modbus-cli subscribe -h 192.168.1.10 -r HoldingRegisters -a 100 -t Int16 -i 500
+```
+
+## Output format
+
+- `probe` / `read` emit a multi-line per-tag block: `Tag / Value / Status /
+  Source Time / Server Time`.
+- `write` emits one line: `Write <tag>: 0x... (Good | BadCommunicationError | …)`.
+- `subscribe` emits one line per change: `[HH:mm:ss.fff] <tag> = <value> (<status>)`.
+
+Status codes are rendered as `0xXXXXXXXX (Name)` for the OPC UA shortlist
+(`Good`, `BadCommunicationError`, `BadTimeout`, `BadNodeIdUnknown`,
+`BadTypeMismatch`, `Uncertain`, …). Unknown codes fall back to bare hex.
+
+## Typical workflows
+
+**"Is the PLC alive?"** → `probe`.
+
+**"Does my recipe write land?"** → `write` + `read` back against the same
+address.
+
+**"Why is tag X flipping?"** → `subscribe` + wait for the operator scenario.
+
+**"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.

docs/Driver.S7.Cli.md

@@ -0,0 +1,93 @@
+# `otopcua-s7-cli` — Siemens S7 test client
+
+Ad-hoc probe / read / write / subscribe tool for Siemens S7-300 / S7-400 /
+S7-1200 / S7-1500 (and compatible soft-PLCs) over S7comm / ISO-on-TCP port 102.
+Uses the **same** `S7Driver` the OtOpcUa server does (S7.Net under the hood).
+
+Fourth of four driver test-client CLIs.
+
+## Build + run
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli -- --help
+```
+
+## Common flags
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-h` / `--host` | **required** | PLC IP or hostname |
+| `-p` / `--port` | `102` | ISO-on-TCP port (rarely changes) |
+| `-c` / `--cpu` | `S71500` | S7200 / S7200Smart / S7300 / S7400 / S71200 / S71500 |
+| `--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 |
+| `--verbose` | off | Serilog debug output |
+
+## PUT/GET must be enabled
+
+S7-1200 / S7-1500 ship with PUT/GET communication **disabled** by default.
+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`.
+
+## S7 address grammar cheat sheet
+
+| Form | Meaning |
+|---|---|
+| `DB1.DBW0` | DB number 1, word offset 0 |
+| `DB1.DBD4` | DB number 1, dword offset 4 |
+| `DB1.DBX2.3` | DB number 1, byte 2, bit 3 |
+| `DB10.STRING[0]` | DB 10 string starting at offset 0 |
+| `M0.0` | Merker bit 0.0 |
+| `MW0` / `MD4` | Merker word / dword |
+| `IW4` | Input word 4 |
+| `QD8` | Output dword 8 |
+
+## Commands
+
+### `probe`
+
+```powershell
+# S7-1500 — default probe MW0
+otopcua-s7-cli probe -h 192.168.1.30
+
+# S7-300 (slot 2)
+otopcua-s7-cli probe -h 192.168.1.31 -c S7300 --slot 2 -a DB1.DBW0
+```
+
+### `read`
+
+```powershell
+# DB word
+otopcua-s7-cli read -h 192.168.1.30 -a DB1.DBW0 -t Int16
+
+# Float32 from DB dword
+otopcua-s7-cli read -h 192.168.1.30 -a DB1.DBD4 -t Float32
+
+# Merker bit
+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
+```
+
+### `write`
+
+```powershell
+otopcua-s7-cli write -h 192.168.1.30 -a DB1.DBW0 -t Int16 -v 42
+otopcua-s7-cli write -h 192.168.1.30 -a DB1.DBD4 -t Float32 -v 3.14
+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.
+
+### `subscribe`
+
+```powershell
+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.

docs/Driver.TwinCAT.Cli.md

@@ -0,0 +1,101 @@
+# `otopcua-twincat-cli` — Beckhoff TwinCAT test client
+
+Ad-hoc probe / read / write / subscribe tool for Beckhoff TwinCAT 2 / TwinCAT 3
+runtimes via ADS. Uses the **same** `TwinCATDriver` the OtOpcUa server does
+(`Beckhoff.TwinCAT.Ads` package). Native ADS notifications by default;
+`--poll-only` falls back to the shared `PollGroupEngine`.
+
+Fifth (final) of the driver test-client CLIs.
+
+## Build + run
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli -- --help
+```
+
+## Prerequisite: AMS router
+
+The `Beckhoff.TwinCAT.Ads` library needs a reachable AMS router to open ADS
+sessions. Pick one:
+
+1. **Local TwinCAT XAR** — install the free TwinCAT 3 XAR Engineering install
+   on the machine running the CLI; it ships the router.
+2. **Beckhoff.TwinCAT.Ads.TcpRouter** — standalone NuGet router. Run in a
+   sidecar process when no XAR is installed.
+3. **Remote AMS route** — any Windows box with TwinCAT installed, with an AMS
+   route authorised to the CLI host.
+
+The CLI compiles + runs without a router, but every wire call fails with a
+transport error until one is reachable.
+
+## Common flags
+
+| Flag | Default | Purpose |
+|---|---|---|
+| `-n` / `--ams-net-id` | **required** | AMS Net ID (e.g. `192.168.1.40.1.1`) |
+| `-p` / `--ams-port` | `851` | AMS port (TwinCAT 3 PLC = 851, TwinCAT 2 = 801) |
+| `--timeout-ms` | `5000` | Per-operation timeout |
+| `--poll-only` | off | Disable native ADS notifications, use `PollGroupEngine` instead |
+| `--verbose` | off | Serilog debug output |
+
+## Data types
+
+TwinCAT exposes the IEC 61131-3 atomic set: `Bool`, `SInt`, `USInt`, `Int`,
+`UInt`, `DInt`, `UDInt`, `LInt`, `ULInt`, `Real`, `LReal`, `String`, `WString`,
+`Time`, `Date`, `DateTime`, `TimeOfDay`. The four IEC time/date variants
+marshal as `UDINT` on the wire — CLI takes a numeric raw value and lets the
+caller interpret semantics.
+
+## Commands
+
+### `probe`
+
+```powershell
+# Local TwinCAT 3, probe a canonical global
+otopcua-twincat-cli probe -n 127.0.0.1.1.1 -s "TwinCAT_SystemInfoVarList._AppInfo.OnlineChangeCnt"
+
+# Remote, probe a project variable
+otopcua-twincat-cli probe -n 192.168.1.40.1.1 -s MAIN.bRunning --type Bool
+```
+
+### `read`
+
+```powershell
+# Bool symbol
+otopcua-twincat-cli read -n 192.168.1.40.1.1 -s MAIN.bStart -t Bool
+
+# Counter
+otopcua-twincat-cli read -n 192.168.1.40.1.1 -s GVL.Counter -t DInt
+
+# Nested UDT member
+otopcua-twincat-cli read -n 192.168.1.40.1.1 -s Motor1.Status.Running -t Bool
+
+# Array element
+otopcua-twincat-cli read -n 192.168.1.40.1.1 -s "Recipe[3]" -t Real
+
+# WString
+otopcua-twincat-cli read -n 192.168.1.40.1.1 -s GVL.sMessage -t WString
+```
+
+### `write`
+
+```powershell
+otopcua-twincat-cli write -n 192.168.1.40.1.1 -s MAIN.bStart -t Bool -v true
+otopcua-twincat-cli write -n 192.168.1.40.1.1 -s GVL.Counter -t DInt -v 42
+otopcua-twincat-cli write -n 192.168.1.40.1.1 -s GVL.sMessage -t WString -v "running"
+```
+
+Structure writes refused — drop to driver config JSON for those.
+
+### `subscribe`
+
+```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
+```
+
+The subscribe banner announces which mechanism is in play — "ADS notification"
+or "polling" — so it's obvious in screen-recorded bug reports.

docs/DriverClis.md

@@ -0,0 +1,95 @@
+# Driver test-client CLIs
+
+Six shell-level ad-hoc validation tools, one per native-protocol driver family.
+Each mirrors the v1 `otopcua-cli` shape (probe / read / write / subscribe) against
+the **same driver** the OtOpcUa server uses — so "does the CLI see it?" and
+"does the server see it?" are the same question.
+
+| CLI | Protocol | Docs |
+|---|---|---|
+| `otopcua-modbus-cli` | Modbus-TCP | [Driver.Modbus.Cli.md](Driver.Modbus.Cli.md) |
+| `otopcua-abcip-cli` | CIP / EtherNet-IP (Logix symbolic) | [Driver.AbCip.Cli.md](Driver.AbCip.Cli.md) |
+| `otopcua-ablegacy-cli` | PCCC (SLC / MicroLogix / PLC-5) | [Driver.AbLegacy.Cli.md](Driver.AbLegacy.Cli.md) |
+| `otopcua-s7-cli` | S7comm / ISO-on-TCP | [Driver.S7.Cli.md](Driver.S7.Cli.md) |
+| `otopcua-twincat-cli` | Beckhoff ADS | [Driver.TwinCAT.Cli.md](Driver.TwinCAT.Cli.md) |
+| `otopcua-focas-cli` | Fanuc FOCAS/2 (CNC) | [Driver.FOCAS.Cli.md](Driver.FOCAS.Cli.md) |
+
+The OPC UA client CLI lives separately and predates this suite —
+see [Client.CLI.md](Client.CLI.md) for `otopcua-cli`.
+
+## Shared commands
+
+Every driver CLI exposes the same four verbs:
+
+- **`probe`** — open a session, read one sentinel tag, print driver health.
+  Fastest "is the device talking?" check.
+- **`read`** — synthesise a one-tag driver config from `--type` / `--address`
+  (or `--tag` / `--symbol`) flags, read once, print the snapshot. No extra
+  config file needed.
+- **`write`** — same shape plus `--value`. Values parse per `--type` using
+  invariant culture. Booleans accept `true` / `false` / `1` / `0` / `yes` /
+  `no` / `on` / `off`. Writes are **non-idempotent by default** — a timeout
+  after the device already applied the write will not auto-retry (plan
+  decisions #44, #45).
+- **`subscribe`** — long-running data-change stream until Ctrl+C. Uses native
+  push where available (TwinCAT ADS notifications) and falls back to polling
+  (`PollGroupEngine`) where the protocol has no push (Modbus, AB, S7, FOCAS).
+
+## Shared infrastructure
+
+All six CLIs depend on `src/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/`:
+
+- `DriverCommandBase` — `--verbose` + Serilog configuration + the abstract
+  `Timeout` surface every protocol-specific base overrides with its own
+  default.
+- `SnapshotFormatter` — consistent output across every CLI: tag / value /
+  status / source-time / server-time for single reads, a 4-column table for
+  batches, `Write <tag>: 0x... (Name)` for writes, and one line per change
+  event for subscriptions. OPC UA status codes render as `0xXXXXXXXX (Name)`
+  with a shortlist for `Good` / `Bad*` / `Uncertain`; unknown codes fall
+  back to hex.
+
+Writing a seventh CLI (hypothetical Galaxy / OPC UA Client) costs roughly
+150 lines: a `{Family}CommandBase` + four thin command classes that hand
+their flag values to the already-shipped driver.
+
+## Typical cross-CLI workflows
+
+- **Commissioning a new device** — `probe` first, then `read` a known-good
+  tag. If the device is up + talking the protocol, both pass; if the tag is
+  wrong you'll see the read fail with a protocol-specific error.
+- **Reproducing a production bug** — `subscribe` to the tag the bug report
+  names, then have the operator run the scenario. You get an HH:mm:ss.fff
+  timeline of exactly when each value changed.
+- **Validating a recipe write** — `write` + `read` back. If the server's
+  write path would have done anything different, the CLI would have too.
+- **Byte-order / word-swap debugging** — `read` with one `--byte-order`,
+  then the other. The plausible result identifies the correct setting
+  for that device family. (Modbus, S7.)
+
+## Known gaps
+
+- **AB Legacy cip-path quirk** — libplctag's ab_server requires a
+  non-empty CIP routing path before forwarding to the PCCC dispatcher.
+  Pass `--gateway "ab://127.0.0.1:44818/1,0"` against the Docker
+  fixture; real SLC / MicroLogix / PLC-5 hardware accepts an empty
+  path (`ab://host:44818/`). Bit-file writes (`B3:0/5`) still surface
+  `0x803D0000` against ab_server — route operator-critical bit writes
+  to real hardware until upstream fixes this.
+- **S7 PUT/GET communication** must be enabled in TIA Portal for any
+  S7-1200/1500. See [Driver.S7.Cli.md](Driver.S7.Cli.md).
+- **TwinCAT AMS router** must be reachable (local XAR, standalone Router
+  NuGet, or authorised remote route). See
+  [Driver.TwinCAT.Cli.md](Driver.TwinCAT.Cli.md).
+- **Structure / UDT writes** are refused by the AB CIP + TwinCAT CLIs —
+  whole-UDT writes need a declared member layout that belongs in a real
+  driver config, not a one-shot flag.
+
+## Tracking
+
+Tasks #249 / #250 / #251 shipped the original five. The FOCAS CLI followed
+alongside the Tier-C isolation work on task #220 — no CLI-level test
+project (hardware-gated). 122 unit tests cumulative across the first five
+(16 shared-lib + 106 CLI-specific) — run
+`dotnet test tests/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests` +
+`tests/ZB.MOM.WW.OtOpcUa.Driver.*.Cli.Tests` to re-verify.

docs/HistoricalDataAccess.md

@@ -22,6 +22,12 @@ Supporting DTOs live alongside the interface in `Core.Abstractions`:
 - `HistoricalEvent(EventId, SourceName?, EventTimeUtc, ReceivedTimeUtc, Message?, Severity)`
 - `HistoricalEventsResult(IReadOnlyList<HistoricalEvent> Events, byte[]? ContinuationPoint)`
 
+## Alarm event history vs. `IHistoryProvider`
+
+`IHistoryProvider.ReadEventsAsync` is the **pull** path: an OPC UA client calls `HistoryReadEvents` against a notifier node and the driver walks its own backend event store to satisfy the request. The Galaxy driver's implementation reads from AVEVA Historian's event schema via `aahClientManaged`; every other driver leaves the default `NotSupportedException` in place.
+
+There is also a separate **push** path for persisting alarm transitions from any `IAlarmSource` (and the Phase 7 scripted-alarm engine) into a durable event log, independent of any client HistoryRead call. That path is covered by `IAlarmHistorianSink` + `SqliteStoreAndForwardSink` in `src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/` and is documented in [AlarmTracking.md#alarm-historian-sink](AlarmTracking.md#alarm-historian-sink). The two paths are complementary — the sink populates an external historian's alarm schema; `ReadEventsAsync` reads from whatever event store the driver owns — and share neither interface nor dispatch.
+
 ## Dispatch through `CapabilityInvoker`
 
 All four HistoryRead surfaces are wrapped by `CapabilityInvoker` (`Core/Resilience/CapabilityInvoker.cs`) with `DriverCapability.HistoryRead`. The Polly pipeline keyed on `(DriverInstanceId, HostName, DriverCapability.HistoryRead)` provides timeout, circuit-breaker, and bulkhead defaults per the driver's stability tier (see [docs/v2/driver-stability.md](v2/driver-stability.md)).

docs/IncrementalSync.md

@@ -51,6 +51,10 @@ Exceptions during teardown are swallowed per decision #12 — a driver throw mus
 
 When `RediscoveryEventArgs.ScopeHint` is non-null (e.g. a folder path), Core restricts the diff to that subtree. This matters for Galaxy Platform-scoped deployments where a `time_of_last_deploy` advance may only affect one platform's subtree, and for OPC UA Client where an upstream change may be localized. Null scope falls back to a full-tree diff.
 
+## Virtual tags in the rebuild
+
+Per [ADR-002](v2/implementation/adr-002-driver-vs-virtual-dispatch.md), virtual (scripted) tags live in the same address space as driver tags and flow through the same rebuild. `EquipmentNodeWalker` (`src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/EquipmentNodeWalker.cs`) emits virtual-tag children alongside driver-tag children with `DriverAttributeInfo.Source = NodeSourceKind.Virtual`, and `DriverNodeManager` registers each variable's source in `_sourceByFullRef` so the dispatch branches correctly after rebuild. Virtual-tag script changes published from the Admin UI land through the same generation-publish path — the `VirtualTagEngine` recompiles its script bundle when its config row changes and `DriverNodeManager` re-registers any added/removed virtual variables through the standard diff path. Subscription restoration after rebuild runs through each source's `ISubscribable` — either the driver's or `VirtualTagSource` — without special-casing.
+
 ## Active subscriptions survive rebuild
 
 Subscriptions for unchanged references stay live across rebuilds — their ref-count map is not disturbed. Clients monitoring a stable tag never see a data-change gap during a deploy, only clients monitoring a tag that was genuinely removed see the subscription drop.

docs/README.md

@@ -29,12 +29,21 @@ The project was originally called **LmxOpcUa** (a single-driver Galaxy/MXAccess
 | [DataTypeMapping.md](DataTypeMapping.md) | Per-driver `DriverAttributeInfo` → OPC UA variable types |
 | [IncrementalSync.md](IncrementalSync.md) | Address-space rebuild on redeploy + `sp_ComputeGenerationDiff` |
 | [HistoricalDataAccess.md](HistoricalDataAccess.md) | `IHistoryProvider` as a per-driver optional capability |
+| [VirtualTags.md](VirtualTags.md) | `Core.Scripting` + `Core.VirtualTags` — Roslyn script sandbox, engine, dispatch alongside driver tags |
+| [ScriptedAlarms.md](ScriptedAlarms.md) | `Core.ScriptedAlarms` — script-predicate `IAlarmSource` + Part 9 state machine |
+
+Two Core subsystems are shipped without a dedicated top-level doc; see the section in the linked doc:
+
+| Project | See |
+|---------|-----|
+| `Core.AlarmHistorian` | [AlarmTracking.md](AlarmTracking.md) § Alarm historian sink |
+| `Analyzers` (Roslyn OTOPCUA0001) | [security.md](security.md) § OTOPCUA0001 Analyzer |
 
 ### Drivers
 
 | Doc | Covers |
 |-----|--------|
-| [drivers/README.md](drivers/README.md) | Index of the seven shipped drivers + capability matrix |
+| [drivers/README.md](drivers/README.md) | Index of the eight shipped drivers + capability matrix |
 | [drivers/Galaxy.md](drivers/Galaxy.md) | Galaxy driver — MXAccess bridge, Host/Proxy split, named-pipe IPC |
 | [drivers/Galaxy-Repository.md](drivers/Galaxy-Repository.md) | Galaxy-specific discovery via the ZB SQL database |
 
@@ -54,8 +63,15 @@ For Modbus / S7 / AB CIP / AB Legacy / TwinCAT / FOCAS / OPC UA Client specifics
 
 | Doc | Covers |
 |-----|--------|
-| [Client.CLI.md](Client.CLI.md) | `lmxopcua-cli` — command-line client |
+| [Client.CLI.md](Client.CLI.md) | `otopcua-cli` — OPC UA command-line client |
 | [Client.UI.md](Client.UI.md) | Avalonia desktop client |
+| [DriverClis.md](DriverClis.md) | Driver test-client CLIs — index + shared commands |
+| [Driver.Modbus.Cli.md](Driver.Modbus.Cli.md) | `otopcua-modbus-cli` — Modbus-TCP |
+| [Driver.AbCip.Cli.md](Driver.AbCip.Cli.md) | `otopcua-abcip-cli` — ControlLogix / CompactLogix / Micro800 / GuardLogix |
+| [Driver.AbLegacy.Cli.md](Driver.AbLegacy.Cli.md) | `otopcua-ablegacy-cli` — SLC / MicroLogix / PLC-5 (PCCC) |
+| [Driver.S7.Cli.md](Driver.S7.Cli.md) | `otopcua-s7-cli` — Siemens S7-300 / S7-400 / S7-1200 / S7-1500 |
+| [Driver.TwinCAT.Cli.md](Driver.TwinCAT.Cli.md) | `otopcua-twincat-cli` — Beckhoff TwinCAT 2/3 ADS |
+| [Driver.FOCAS.Cli.md](Driver.FOCAS.Cli.md) | `otopcua-focas-cli` — Fanuc FOCAS/2 CNC |
 
 ### Requirements
 

docs/ReadWriteOperations.md

@@ -2,6 +2,16 @@
 
 `DriverNodeManager` (`src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/DriverNodeManager.cs`) wires the OPC UA stack's per-variable `OnReadValue` and `OnWriteValue` hooks to each driver's `IReadable` and `IWritable` capabilities. Every dispatch flows through `CapabilityInvoker` so the Polly pipeline (retry / timeout / breaker / bulkhead) applies uniformly across Galaxy, Modbus, S7, AB CIP, AB Legacy, TwinCAT, FOCAS, and OPC UA Client drivers.
 
+## Driver vs virtual dispatch
+
+Per [ADR-002](v2/implementation/adr-002-driver-vs-virtual-dispatch.md), a single `DriverNodeManager` routes reads and writes across both driver-sourced and virtual (scripted) tags. At discovery time each variable registers a `NodeSourceKind` (`src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverAttributeInfo.cs`) in the manager's `_sourceByFullRef` lookup; the read/write hooks pattern-match on that value to pick the backend:
+
+- `NodeSourceKind.Driver` — dispatches to the driver's `IReadable` / `IWritable` through `CapabilityInvoker` (the rest of this doc).
+- `NodeSourceKind.Virtual` — dispatches to `VirtualTagSource` (`src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagSource.cs`), which wraps `VirtualTagEngine`. Writes are rejected with `BadUserAccessDenied` before the branch per Phase 7 decision #6 — scripts are the only write path into virtual tags.
+- `NodeSourceKind.ScriptedAlarm` — dispatches to the Phase 7 `ScriptedAlarmReadable` shim.
+
+ACL enforcement (`WriteAuthzPolicy` + `AuthorizationGate`) runs before the source branch, so the gates below apply uniformly to all three source kinds.
+
 ## OnReadValue
 
 The hook is registered on every `BaseDataVariableState` created by the `IAddressSpaceBuilder.Variable(...)` call during discovery. When the stack dispatches a Read for a node in this namespace:
@@ -20,7 +30,7 @@ The hook is synchronous — the async invoker call is bridged with `AsTask().Get
 
 ### Authorization (two layers)
 
-1. **SecurityClassification gate.** Every variable stores its `SecurityClassification` in `_securityByFullRef` at registration time (populated from `DriverAttributeInfo.SecurityClass`). `WriteAuthzPolicy.IsAllowed(classification, userRoles)` runs first, consulting the session's roles via `context.UserIdentity is IRoleBearer`. `FreeAccess` passes anonymously, `ViewOnly` denies everyone, and `Operate / Tune / Configure / SecuredWrite / VerifiedWrite` require `WriteOperate / WriteTune / WriteConfigure` roles respectively. Denial returns `BadUserAccessDenied` without consulting the driver — drivers never enforce ACLs themselves; they only report classification as discovery metadata (feedback `feedback_acl_at_server_layer.md`).
+1. **SecurityClassification gate.** Every variable stores its `SecurityClassification` in `_securityByFullRef` at registration time (populated from `DriverAttributeInfo.SecurityClass`). `WriteAuthzPolicy.IsAllowed(classification, userRoles)` runs first, consulting the session's roles via `context.UserIdentity is IRoleBearer`. `FreeAccess` passes anonymously, `ViewOnly` denies everyone, and `Operate / Tune / Configure / SecuredWrite / VerifiedWrite` require `WriteOperate / WriteTune / WriteConfigure` roles respectively. Denial returns `BadUserAccessDenied` without consulting the driver — drivers never enforce ACLs themselves; they only report classification as discovery metadata (see `docs/security.md`).
 2. **Phase 6.2 permission-trie gate.** When `AuthorizationGate` is wired, it re-runs with the operation derived from `WriteAuthzPolicy.ToOpcUaOperation(classification)`. The gate consults the per-cluster permission trie loaded from `NodeAcl` rows, enforcing fine-grained per-tag ACLs on top of the role-based classification policy. See `docs/v2/acl-design.md`.
 
 ### Dispatch

docs/ScriptedAlarms.md

@@ -0,0 +1,125 @@
+# Scripted Alarms
+
+`Core.ScriptedAlarms` is the Phase 7 subsystem that raises OPC UA Part 9 alarms from operator-authored C# predicates rather than from driver-native alarm streams. Scripted alarms are additive: Galaxy, AB CIP, FOCAS, and OPC UA Client drivers keep their native `IAlarmSource` implementations unchanged, and a `ScriptedAlarmSource` simply registers as another source in the same fan-out. Predicates read tags from any source (driver tags or virtual tags) through the shared `ITagUpstreamSource` and emit condition transitions through the engine's Part 9 state machine.
+
+This file covers the engine internals — predicate evaluation, state machine, persistence, and the engine-to-`IAlarmSource` adapter. The server-side plumbing that turns those emissions into OPC UA `AlarmConditionState` nodes, applies retries, persists alarm transitions to the Historian, and routes operator acks through the session's `AlarmAck` permission lives in [AlarmTracking.md](AlarmTracking.md) and is not repeated here.
+
+## Definition shape
+
+`ScriptedAlarmDefinition` (`src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ScriptedAlarmDefinition.cs`) is the runtime contract the engine consumes. The generation-publish path materialises these from the `ScriptedAlarm` + `Script` config tables via `Phase7EngineComposer.ProjectScriptedAlarms`.
+
+| Field | Notes |
+|---|---|
+| `AlarmId` | Stable identity. Also the OPC UA `ConditionId` and the key in `IAlarmStateStore`. Convention: `{EquipmentPath}::{AlarmName}`. |
+| `EquipmentPath` | UNS path the alarm hangs under in the address space. ACL scope inherits from the equipment node. |
+| `AlarmName` | Browse-tree display name. |
+| `Kind` | `AlarmKind` — `AlarmCondition`, `LimitAlarm`, `DiscreteAlarm`, or `OffNormalAlarm`. Controls only the OPC UA ObjectType the node surfaces as; the internal state machine is identical for all four. |
+| `Severity` | `AlarmSeverity` enum (`Low` / `Medium` / `High` / `Critical`). Static per decision #13 — the predicate does not compute severity. The DB column is an OPC UA Part 9 1..1000 integer; `Phase7EngineComposer.MapSeverity` bands it into the four-value enum. |
+| `MessageTemplate` | String with `{TagPath}` placeholders, resolved at emission time. See below. |
+| `PredicateScriptSource` | Roslyn C# script returning `bool`. `true` = condition active; `false` = cleared. |
+| `HistorizeToAveva` | When true, every emission is enqueued to `IAlarmHistorianSink`. Default true. Galaxy-native alarms default false since Galaxy historises them directly. |
+| `Retain` | Part 9 retain flag — keep the condition visible after clear while un-acked/un-confirmed transitions remain. Default true. |
+
+Illustrative definition:
+
+```csharp
+new ScriptedAlarmDefinition(
+    AlarmId:       "Plant/Line1/Oven::OverTemp",
+    EquipmentPath: "Plant/Line1/Oven",
+    AlarmName:     "OverTemp",
+    Kind:          AlarmKind.LimitAlarm,
+    Severity:      AlarmSeverity.High,
+    MessageTemplate: "Oven {Plant/Line1/Oven/Temp} exceeds limit {Plant/Line1/Oven/TempLimit}",
+    PredicateScriptSource: "return GetTag(\"Plant/Line1/Oven/Temp\").AsDouble() > GetTag(\"Plant/Line1/Oven/TempLimit\").AsDouble();");
+```
+
+## Predicate evaluation
+
+Alarm predicates reuse the same Roslyn sandbox as virtual tags — `ScriptEvaluator<AlarmPredicateContext, bool>` compiles the source, `TimedScriptEvaluator` wraps it with the configured timeout (default from `TimedScriptEvaluator.DefaultTimeout`), and `DependencyExtractor` statically harvests the tag paths the script reads. The sandbox rules (forbidden types, cancellation, logging sinks) are documented in [VirtualTags.md](VirtualTags.md); ScriptedAlarms does not redefine them.
+
+`AlarmPredicateContext` (`AlarmPredicateContext.cs`) is the script's `ScriptContext` subclass:
+
+- `GetTag(path)` returns a `DataValueSnapshot` from the engine-maintained read cache. Missing path → `DataValueSnapshot(null, 0x80340000u, null, now)` (`BadNodeIdUnknown`). An empty path returns the same.
+- `SetVirtualTag(path, value)` throws `InvalidOperationException`. Predicates must be side-effect free per plan decision #6; writes would couple alarm state to virtual-tag state in ways that are near-impossible to reason about. Operators see the rejection in `scripts-*.log`.
+- `Now` and `Logger` are provided by the engine.
+
+Evaluation cadence:
+
+- On every upstream tag change that any alarm's input set references (`OnUpstreamChange` → `ReevaluateAsync`). The engine maintains an inverse index `tag path → alarm ids` (`_alarmsReferencing`); only affected alarms re-run.
+- On a 5-second shelving-check timer (`_shelvingTimer`) for timed-shelve expiry.
+- At `LoadAsync` for every alarm, to re-derive `ActiveState` per plan decision #14 (startup recovery).
+
+If a predicate throws or times out, the engine logs the failure and leaves the prior `ActiveState` intact — it does not synthesise a clear. Operators investigating a broken predicate should never see a phantom clear preceding the error.
+
+## Part 9 state machine
+
+`Part9StateMachine` (`Part9StateMachine.cs`) is a pure `static` function set. Every transition takes the current `AlarmConditionState` plus the event, returns a new record and an `EmissionKind`. No I/O, no mutation, trivially unit-testable. Transitions map to OPC UA Part 9:
+
+- `ApplyPredicate(current, predicateTrue, nowUtc)` — predicate re-evaluation. `Inactive → Active` sets `Acked = Unacknowledged` and `Confirmed = Unconfirmed`; `Active → Inactive` updates `LastClearedUtc` and consumes `OneShot` shelving. Disabled alarms no-op.
+- `ApplyAcknowledge` / `ApplyConfirm` — operator ack/confirm. Require a non-empty user string (audit requirement). Each appends an `AlarmComment` with `Kind = "Acknowledge"` / `"Confirm"`.
+- `ApplyOneShotShelve` / `ApplyTimedShelve(unshelveAtUtc)` / `ApplyUnshelve` — shelving transitions. `Timed` requires `unshelveAtUtc > nowUtc`.
+- `ApplyEnable` / `ApplyDisable` — operator enable/disable. Disabled alarms ignore predicate results until re-enabled; on enable, `ActiveState` is re-derived from the next evaluation.
+- `ApplyAddComment(text)` — append-only audit entry, no state change.
+- `ApplyShelvingCheck(nowUtc)` — called by the 5s timer; promotes expired `Timed` shelving to `Unshelved` with a `system / AutoUnshelve` audit entry.
+
+Two invariants the machine enforces:
+
+1. **Disabled** alarms ignore every predicate evaluation — they never transition `ActiveState` / `AckedState` / `ConfirmedState` until re-enabled.
+2. **Shelved** alarms still advance their internal state but emit `EmissionKind.Suppressed` instead of `Activated` / `Cleared`. The engine advances the state record (so startup recovery reflects reality) but `ScriptedAlarmSource` does not publish the suppressed transition to subscribers. `OneShot` expires on the next clear; `Timed` expires at `ShelvingState.UnshelveAtUtc`.
+
+`EmissionKind` values: `None`, `Suppressed`, `Activated`, `Cleared`, `Acknowledged`, `Confirmed`, `Shelved`, `Unshelved`, `Enabled`, `Disabled`, `CommentAdded`.
+
+## Message templates
+
+`MessageTemplate` (`MessageTemplate.cs`) resolves `{path}` placeholders in the configured message at emission time. Syntax:
+
+- `{path/with/slashes}` — brace-stripped contents are looked up via the engine's tag cache.
+- No escaping. Literal braces in messages are not currently supported.
+- `ExtractTokenPaths(template)` is called at `LoadAsync` so the engine subscribes to every referenced path (ensuring the value cache is populated before the first resolve).
+
+Fallback rules: a resolved `DataValueSnapshot` with a non-zero `StatusCode`, a `null` `Value`, or an unknown path becomes `{?}`. The event still fires — the operator sees where the reference broke rather than having the alarm swallowed.
+
+## State persistence
+
+`IAlarmStateStore` (`IAlarmStateStore.cs`) is the persistence contract: `LoadAsync(alarmId)`, `LoadAllAsync`, `SaveAsync(state)`, `RemoveAsync(alarmId)`. `InMemoryAlarmStateStore` in the same file is the default for tests and dev deployments without a SQL backend. Stream E wires the production implementation against the `ScriptedAlarmState` config-DB table with audit logging through `Core.Abstractions.IAuditLogger`.
+
+Persisted scope per plan decision #14: `Enabled`, `Acked`, `Confirmed`, `Shelving`, `LastTransitionUtc`, the `LastAck*` / `LastConfirm*` audit fields, and the append-only `Comments` list. `Active` is **not** trusted across restart — the engine re-runs the predicate at `LoadAsync` so operators never re-ack an alarm that was already acknowledged before an outage, and alarms whose condition cleared during downtime settle to `Inactive` without a spurious clear-event.
+
+Every mutation the state machine produces is immediately persisted inside the engine's `_evalGate` semaphore, so the store's view is always consistent with the in-memory state.
+
+## Source integration
+
+`ScriptedAlarmSource` (`ScriptedAlarmSource.cs`) adapts the engine to the driver-agnostic `IAlarmSource` interface. The existing `AlarmSurfaceInvoker` + `GenericDriverNodeManager` fan-out consumes it the same way it consumes Galaxy / AB CIP / FOCAS sources — there is no scripted-alarm-specific code path in the server plumbing. From that point on, the flow into `AlarmConditionState` nodes, the `AlarmAck` session check, and the Historian sink is shared — see [AlarmTracking.md](AlarmTracking.md).
+
+Two mapping notes specific to this adapter:
+
+- `SubscribeAlarmsAsync` accepts a list of source-node-id filters, interpreted as Equipment-path prefixes. Empty list matches every alarm. Each emission is matched against every live subscription — the adapter keeps no per-subscription cursor.
+- `IAlarmSource.AcknowledgeAsync` does not carry a user identity. The adapter defaults the audit user to `"opcua-client"` so callers using the base interface still produce an audit entry. The server's Part 9 method handlers (Stream G) call the engine's richer `AcknowledgeAsync` / `ConfirmAsync` / `OneShotShelveAsync` / `TimedShelveAsync` / `UnshelveAsync` / `AddCommentAsync` directly with the authenticated principal instead.
+
+Emissions map into `AlarmEventArgs` as `AlarmType = Kind.ToString()`, `SourceNodeId = EquipmentPath`, `ConditionId = AlarmId`, `Message = resolved template string`, `Severity` carried verbatim, `SourceTimestampUtc = emission time`.
+
+## Composition
+
+`Phase7EngineComposer.Compose` (`src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7EngineComposer.cs`) is the single call site that instantiates the engine. It takes the generation's `Script` / `VirtualTag` / `ScriptedAlarm` rows, the shared `CachedTagUpstreamSource`, an `IAlarmStateStore`, and an `IAlarmHistorianSink`, and returns a `Phase7ComposedSources` the caller owns. When `scriptedAlarms.Count > 0`:
+
+1. `ProjectScriptedAlarms` resolves each row's `PredicateScriptId` against the script dictionary and produces a `ScriptedAlarmDefinition` list. Unknown or disabled scripts throw immediately — the DB publish guarantees referential integrity but this is a belt-and-braces check.
+2. A `ScriptedAlarmEngine` is constructed with the upstream source, the store, a shared `ScriptLoggerFactory` keyed to `scripts-*.log`, and the root Serilog logger.
+3. `alarmEngine.OnEvent` is wired to `RouteToHistorianAsync`, which projects each emission into an `AlarmHistorianEvent` and enqueues it on the sink. Fire-and-forget — the SQLite store-and-forward sink is already non-blocking.
+4. `LoadAsync(alarmDefs)` runs synchronously on the startup thread: it compiles every predicate, subscribes to the union of predicate inputs and message-template tokens, seeds the value cache, loads persisted state, re-derives `ActiveState` from a fresh predicate evaluation, and starts the 5s shelving timer. Compile failures are aggregated into one `InvalidOperationException` so operators see every bad predicate in one startup log line rather than one at a time.
+5. A `ScriptedAlarmSource` is created for the event stream, and a `ScriptedAlarmReadable` (`src/ZB.MOM.WW.OtOpcUa.Server/Phase7/ScriptedAlarmReadable.cs`) is created for OPC UA variable reads on the alarm's active-state node (task #245) — unknown alarm ids return `BadNodeIdUnknown` rather than silently reading `false`.
+
+Both engine and source are added to `Phase7ComposedSources.Disposables`, which `Phase7Composer` disposes on server shutdown.
+
+## Key source files
+
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ScriptedAlarmEngine.cs` — orchestrator, cascade wiring, shelving timer, `OnEvent` emission
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ScriptedAlarmSource.cs` — `IAlarmSource` adapter over the engine
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ScriptedAlarmDefinition.cs` — runtime definition record
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/Part9StateMachine.cs` — pure-function state machine + `TransitionResult` / `EmissionKind`
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/AlarmConditionState.cs` — persisted state record + `AlarmComment` audit entry + `ShelvingState`
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/AlarmPredicateContext.cs` — script-side `ScriptContext` (read-only, write rejected)
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/AlarmTypes.cs` — `AlarmKind` + the four Part 9 enums
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/MessageTemplate.cs` — `{path}` placeholder resolver
+- `src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/IAlarmStateStore.cs` — persistence contract + `InMemoryAlarmStateStore` default
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7EngineComposer.cs` — composition, config-row projection, historian routing
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/ScriptedAlarmReadable.cs` — `IReadable` adapter exposing `ActiveState` to OPC UA variable reads

docs/Subscriptions.md

@@ -2,6 +2,15 @@
 
 Driver-side data-change subscriptions live behind `ISubscribable` (`src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/ISubscribable.cs`). The interface is deliberately mechanism-agnostic: it covers native subscriptions (Galaxy MXAccess advisory, OPC UA monitored items on an upstream server, TwinCAT ADS notifications) and driver-internal polled subscriptions (Modbus, AB CIP, S7, FOCAS). Core sees the same event shape regardless — drivers fire `OnDataChange` and Core dispatches to the matching OPC UA monitored items.
 
+## Driver vs virtual dispatch
+
+Per [ADR-002](v2/implementation/adr-002-driver-vs-virtual-dispatch.md), `DriverNodeManager` routes subscriptions across both driver tags and virtual (scripted) tags through the same `ISubscribable` contract. The per-variable `NodeSourceKind` (registered from `DriverAttributeInfo` at discovery) selects the backend:
+
+- `NodeSourceKind.Driver` — subscribes via the driver's `ISubscribable`, wrapped by `CapabilityInvoker` (the rest of this doc).
+- `NodeSourceKind.Virtual` — subscribes via `VirtualTagSource` (`src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagSource.cs`), which forwards change events emitted by `VirtualTagEngine` as `OnDataChange`. The ref-counting, initial-value, and transfer-restoration behaviour below applies identically.
+
+Because both kinds expose `ISubscribable`, Core's dispatch, ref-count map, and monitored-item fan-out are unchanged across the source branch.
+
 ## ISubscribable surface
 
 ```csharp

docs/VirtualTags.md

@@ -0,0 +1,142 @@
+# Virtual Tags
+
+Virtual tags are OPC UA variable nodes whose values are computed by operator-authored C# scripts against other tags (driver or virtual). They live in the Equipment browse tree alongside driver-sourced variables: a client browsing `Enterprise/Site/Area/Line/Equipment/` sees one flat child list that mixes both kinds, and a read / subscribe on a virtual node looks identical to one on a driver node from the wire. The separation is server-side — `NodeScopeResolver` tags each variable's `NodeSource` (`Driver` / `Virtual` / `ScriptedAlarm`), and `DriverNodeManager` dispatches reads to different backends accordingly. See [ADR-002](v2/implementation/adr-002-driver-vs-virtual-dispatch.md) for the dispatch decision.
+
+The runtime is split across two projects: `Core.Scripting` holds the Roslyn sandbox + evaluator primitives that are reused by both virtual tags and scripted alarms; `Core.VirtualTags` holds the engine that owns the dependency graph, the evaluation pipeline, and the `ISubscribable` adapter the server dispatches to.
+
+## Roslyn script sandbox (`Core.Scripting`)
+
+User scripts are compiled via `Microsoft.CodeAnalysis.CSharp.Scripting` against a `ScriptContext` subclass. `ScriptGlobals<TContext>` exposes the context as a field named `ctx`, so scripts read `ctx.GetTag("...")` / `ctx.SetVirtualTag("...", ...)` / `ctx.Now` / `ctx.Logger` and return a value.
+
+### Compile pipeline (`ScriptEvaluator<TContext, TResult>`)
+
+`ScriptEvaluator.Compile(source)` is a three-step gate:
+
+1. **Roslyn compile** against `ScriptSandbox.Build(contextType)`. Throws `CompilationErrorException` on syntax / type errors.
+2. **`ForbiddenTypeAnalyzer.Analyze`** walks the syntax tree post-compile and resolves every referenced symbol against the deny-list. Throws `ScriptSandboxViolationException` with every offending source span attached. This is defence-in-depth: `ScriptOptions` alone cannot block every BCL namespace because .NET type forwarding routes types through assemblies the allow-list does permit.
+3. **Delegate materialization** — `script.CreateDelegate()`. Failures here are Roslyn-internal; user scripts don't reach this step.
+
+`ScriptSandbox.Build` allow-lists exactly: `System.Private.CoreLib` (primitives + `Math` + `Convert`), `System.Linq`, `Core.Abstractions` (for `DataValueSnapshot` / `DriverDataType`), `Core.Scripting` (for `ScriptContext` + `Deadband`), `Serilog` (for `ILogger`), and the concrete context type's assembly. Pre-imported namespaces: `System`, `System.Linq`, `ZB.MOM.WW.OtOpcUa.Core.Abstractions`, `ZB.MOM.WW.OtOpcUa.Core.Scripting`.
+
+`ForbiddenTypeAnalyzer.ForbiddenNamespacePrefixes` currently denies `System.IO`, `System.Net`, `System.Diagnostics`, `System.Reflection`, `System.Threading.Thread`, `System.Runtime.InteropServices`, `Microsoft.Win32`. Matching is by prefix against the resolved symbol's containing namespace, so `System.Net` catches `System.Net.Http.HttpClient` and every subnamespace. `System.Environment` is explicitly allowed.
+
+### Compile cache (`CompiledScriptCache<TContext, TResult>`)
+
+`ConcurrentDictionary<string, Lazy<ScriptEvaluator<...>>>` keyed on `SHA-256(UTF8(source))` rendered to hex. `Lazy<T>` with `ExecutionAndPublication` mode means two threads racing a miss compile exactly once. Failed compiles evict the entry so a corrected retry can succeed (used during Admin UI authoring). No capacity bound — scripts are operator-authored and bounded by the config DB. Whitespace changes miss the cache on purpose. `Clear()` is called on config-publish.
+
+### Per-evaluation timeout (`TimedScriptEvaluator<TContext, TResult>`)
+
+Wraps `ScriptEvaluator` with a wall-clock budget. Default `DefaultTimeout = 250ms`. Implementation pushes the inner `RunAsync` onto `Task.Run` (so a CPU-bound script can't hog the calling thread before `WaitAsync` registers its timeout) then awaits `runTask.WaitAsync(Timeout, ct)`. A `TimeoutException` from `WaitAsync` is wrapped as `ScriptTimeoutException`. Caller-supplied `CancellationToken` cancellation wins over the timeout and propagates as `OperationCanceledException` — so a shutdown cancel is not misclassified. **Known leak:** when a CPU-bound script times out, the underlying `ScriptRunner` keeps running on its thread-pool thread until the Roslyn runtime returns (documented trade-off; out-of-process evaluation is a v3 concern).
+
+### Script logger plumbing
+
+`ScriptLoggerFactory.Create(scriptName)` returns a per-script Serilog logger with the `ScriptName` structured property bound (constant `ScriptLoggerFactory.ScriptNameProperty`). The root script logger is typically a rolling file sink to `scripts-*.log`. `ScriptLogCompanionSink` is attached to the root pipeline and mirrors script events at `Error` or higher into the main `opcua-*.log` at `Warning` level — operators see script errors in the primary log without drowning it in script-authored Info/Debug noise. Exceptions and the `ScriptName` property are preserved in the mirror.
+
+### Static dependency extraction (`DependencyExtractor`)
+
+Parses the script source with `CSharpSyntaxTree.ParseText` (script kind), walks invocation expressions, and records every `ctx.GetTag("literal")` and `ctx.SetVirtualTag("literal", ...)` call. The first argument **must** be a string literal — variables, concatenation, interpolation, and method-returned strings are rejected at publish with a `DependencyRejection` carrying the exact `TextSpan`. This is how the engine builds its change-trigger graph statically; scripts cannot smuggle a dependency past the extractor.
+
+## Virtual tag engine (`Core.VirtualTags`)
+
+### `VirtualTagDefinition`
+
+One row per operator-authored tag. Fields: `Path` (UNS browse path; also the engine's internal id), `DataType` (`DriverDataType` enum; the evaluator coerces the script's return value to this and mismatch surfaces as `BadTypeMismatch`), `ScriptSource` (Roslyn C# script text), `ChangeTriggered` (re-evaluate on any input delta), `TimerInterval` (optional periodic cadence; null disables), `Historize` (route every evaluation result to `IHistoryWriter`). Change-trigger and timer are independent — a tag can be either, both, or neither.
+
+### `VirtualTagContext`
+
+Subclass of `ScriptContext`. Constructed fresh per evaluation over a per-run read cache — scripts cannot stash mutable state across runs on `ctx`. `GetTag(path)` serves from the cache; missing-path reads return a `BadNodeIdUnknown`-quality snapshot. `SetVirtualTag(path, value)` routes through the engine's `OnScriptSetVirtualTag` callback so cross-tag writes still participate in change-trigger cascades (writes to non-virtual / non-registered paths log a warning and drop). `Now` is an injectable clock; production wires `DateTime.UtcNow`, tests pin it.
+
+### `DependencyGraph`
+
+Directed graph of tag paths. Edges run from a virtual tag to each path it reads. Unregistered paths (driver tags) are implicit leaves; leaf validity is checked elsewhere against the authoritative catalog. Two operations:
+
+- **`TopologicalSort()`** — Kahn's algorithm. Produces evaluation order such that every node appears after its registered (virtual) dependencies. Throws `DependencyCycleException` (with every cycle, not just one) on offense.
+- **`TransitiveDependentsInOrder(nodeId)`** — DFS collects every reachable dependent of a changed upstream then sorts by topological rank. Used by the cascade dispatcher so a single upstream delta recomputes the full downstream closure in one serial pass without needing a second iteration.
+
+Cycle detection uses an **iterative** Tarjan's SCC implementation (no recursion, deep graphs cannot stack-overflow). Cycles of length > 1 and self-loops both reject; leaf references cannot form cycles with internal nodes.
+
+### `VirtualTagEngine` lifecycle
+
+- **`Load(definitions)`** — clears prior state, compiles every script through `DependencyExtractor.Extract` + `ScriptEvaluator.Compile` (wrapped in `TimedScriptEvaluator`), registers each in `_tags` + `_graph`, runs `TopologicalSort` (cycle check), then for every upstream (non-virtual) path subscribes via `ITagUpstreamSource.SubscribeTag` and seeds `_valueCache` with `ReadTag`. Throws `InvalidOperationException` aggregating every compile failure at once so operators see the whole set; throws `DependencyCycleException` on cycles. Re-entrant — supports config-publish reloads by disposing the prior upstream subscriptions first.
+- **`EvaluateAllAsync(ct)`** — evaluates every tag once in topological order. Called at startup so virtual tags have a defined initial value before subscriptions start.
+- **`EvaluateOneAsync(path, ct)`** — single-tag evaluation. Entry point for `TimerTriggerScheduler` + tests.
+- **`Read(path)`** — synchronous last-known-value lookup from `_valueCache`. Returns `BadNodeIdUnknown`-quality for unregistered paths.
+- **`Subscribe(path, observer)`** — register a change observer; returns `IDisposable`. Does **not** emit a seed value.
+- **`OnUpstreamChange(path, value)`** (internal, wired from the upstream subscription) — updates cache, notifies observers, launches `CascadeAsync` fire-and-forget so the driver's dispatcher isn't blocked.
+
+Evaluations are **serial across all tags** — `_evalGate` is a `SemaphoreSlim(1, 1)` held around every `EvaluateInternalAsync`. Parallelism is deferred (Phase 7 plan decision #19). Rationale: serial execution preserves the "earlier topological nodes computed before later dependents" invariant when two cascades race. Per-tag error isolation: a script exception or timeout sets that tag's quality to `BadInternalError` and logs a structured error; other tags keep evaluating. `OperationCanceledException` is re-thrown (shutdown path).
+
+Result coercion: `CoerceResult` maps the script's return value to the declared `DriverDataType` via `Convert.ToXxx`. Coercion failure returns null which the outer pipeline maps to `BadInternalError`; `BadTypeMismatch` is documented in the definition shape (`VirtualTagDefinition.DataType` doc) rather than emitted distinctly today.
+
+`IHistoryWriter.Record` fires per evaluation when `Historize = true`. The default `NullHistoryWriter` drops silently.
+
+### `TimerTriggerScheduler`
+
+Groups `VirtualTagDefinition`s by `TimerInterval`, one `System.Threading.Timer` per unique interval. Each tick evaluates the group's paths serially via `VirtualTagEngine.EvaluateOneAsync`. Errors per-tag log and continue. `Dispose()` cancels an internal `CancellationTokenSource` and disposes every timer. Independent of the change-trigger path — a tag with both triggers fires from both scheduling sources.
+
+### `ITagUpstreamSource`
+
+What the engine pulls driver-tag values from. Reads are **synchronous** because user scripts call `ctx.GetTag(path)` inline — a blocking wire call per evaluation would kill throughput. Implementations are expected to serve from a last-known-value cache populated by subscription callbacks. The server's production implementation is `CachedTagUpstreamSource` (see Composition below).
+
+### `IHistoryWriter`
+
+Fire-and-forget sink for evaluation results when `VirtualTagDefinition.Historize = true`. Implementations must queue internally and drain on their own cadence — a slow historian must not block script evaluation. `NullHistoryWriter.Instance` is the no-op default. Today no production writer is wired into the virtual-tag path; scripted-alarm emissions flow through `Core.AlarmHistorian` via `Phase7EngineComposer.RouteToHistorianAsync` (a separate concern; see [AlarmTracking.md](AlarmTracking.md)).
+
+## Dispatch integration
+
+Per [ADR-002](v2/implementation/adr-002-driver-vs-virtual-dispatch.md) Option B, there is a single `DriverNodeManager`. `VirtualTagSource` implements `IReadable` + `ISubscribable` over a `VirtualTagEngine`:
+
+- `ReadAsync` fans each path through `engine.Read(...)`.
+- `SubscribeAsync` calls `engine.Subscribe` per path and forwards each engine observer callback as an `OnDataChange` event; emits an initial-data callback per OPC UA convention.
+- `UnsubscribeAsync` disposes every per-path engine subscription it holds.
+- **`IWritable` is deliberately not implemented.** `DriverNodeManager.IsWriteAllowedBySource` rejects OPC UA client writes to virtual nodes with `BadUserAccessDenied` before any dispatch — scripts are the only write path via `ctx.SetVirtualTag`.
+
+`DriverNodeManager.SelectReadable(source, ...)` picks the `IReadable` based on `NodeSourceKind`. See [ReadWriteOperations.md](ReadWriteOperations.md) and [Subscriptions.md](Subscriptions.md) for the broader dispatch framing.
+
+## Upstream reads + history
+
+`ITagUpstreamSource` and `IHistoryWriter` are the two ports the engine requires from its host. Both live in `Core.VirtualTags`. In the Server process:
+
+- **`CachedTagUpstreamSource`** (`src/ZB.MOM.WW.OtOpcUa.Server/Phase7/CachedTagUpstreamSource.cs`) implements the interface (and the parallel `Core.ScriptedAlarms.ITagUpstreamSource` — identical shape, distinct namespace). A `ConcurrentDictionary<path, DataValueSnapshot>` cache. `Push(path, snapshot)` updates the cache and fans out synchronously to every observer. Reads of never-pushed paths return `BadNodeIdUnknown` quality (`UpstreamNotConfigured = 0x80340000`).
+- **`DriverSubscriptionBridge`** (`src/ZB.MOM.WW.OtOpcUa.Server/Phase7/DriverSubscriptionBridge.cs`) feeds the cache. For each registered `ISubscribable` driver it batches a single `SubscribeAsync` for every fullRef the script graph references, installs an `OnDataChange` handler that translates driver-opaque fullRefs back to UNS paths via a reverse map, and pushes each delta into `CachedTagUpstreamSource`. Unsubscribes on dispose. The bridge suppresses `OTOPCUA0001` (the Roslyn analyzer that requires `ISubscribable` callers to go through `CapabilityInvoker`) on the documented basis that this is a lifecycle wiring, not per-evaluation hot path.
+- **`IHistoryWriter`** — no production implementation is currently wired for virtual tags; `VirtualTagEngine` gets `NullHistoryWriter` by default from `Phase7EngineComposer`.
+
+## Composition
+
+`Phase7Composer` (`src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7Composer.cs`) is an `IAsyncDisposable` injected into `OpcUaServerService`:
+
+1. `PrepareAsync(generationId, ct)` — called after the bootstrap generation loads and before `OpcUaApplicationHost.StartAsync`. Reads the `Script` / `VirtualTag` / `ScriptedAlarm` rows for that generation from the config DB (`OtOpcUaConfigDbContext`). Empty-config fast path returns `Phase7ComposedSources.Empty`.
+2. Constructs a `CachedTagUpstreamSource` + hands it to `Phase7EngineComposer.Compose`.
+3. `Phase7EngineComposer.Compose` projects `VirtualTag` rows into `VirtualTagDefinition`s (joining `Script` rows by `ScriptId`), instantiates `VirtualTagEngine`, calls `Load`, wraps in `VirtualTagSource`.
+4. Builds a `DriverFeed` per driver by mapping the driver's `EquipmentNamespaceContent` to `UNS path → driver fullRef` (path format `/{area}/{line}/{equipment}/{tag}` matching the `EquipmentNodeWalker` browse tree so script literals match the operator-visible UNS), then starts `DriverSubscriptionBridge`.
+5. Returns `Phase7ComposedSources` with the `VirtualTagSource` cast as `IReadable`. `OpcUaServerService` passes it to `OpcUaApplicationHost` which threads it into `DriverNodeManager` as `virtualReadable`.
+
+`DisposeAsync` tears down the bridge first (no more events into the cache), then the engines (cascades + timer ticks stop), then the owned SQLite historian sink if any.
+
+Definition reload on config publish: `VirtualTagEngine.Load` is re-entrant — a future config-publish handler can call it with a new definition set. That handler is not yet wired; today engine composition happens once per service start against the bootstrapped generation.
+
+## Key source files
+
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptContext.cs` — abstract `ctx` API scripts see
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptGlobals.cs` — generic globals wrapper naming the field `ctx`
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptSandbox.cs` — assembly allow-list + imports
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ForbiddenTypeAnalyzer.cs` — post-compile semantic deny-list
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptEvaluator.cs` — three-step compile pipeline
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/TimedScriptEvaluator.cs` — 250ms default timeout wrapper
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/CompiledScriptCache.cs` — SHA-256-keyed compile cache
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/DependencyExtractor.cs` — static `ctx.GetTag` / `ctx.SetVirtualTag` inference
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptLoggerFactory.cs` — per-script Serilog logger
+- `src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptLogCompanionSink.cs` — error mirror to main log
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagDefinition.cs` — per-tag config record
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagContext.cs` — evaluation-scoped `ctx`
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/DependencyGraph.cs` — Kahn topo-sort + iterative Tarjan SCC
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagEngine.cs` — load / evaluate / cascade pipeline
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/TimerTriggerScheduler.cs` — periodic re-evaluation
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/ITagUpstreamSource.cs` — driver-tag read + subscribe port
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/IHistoryWriter.cs` — historize sink port + `NullHistoryWriter`
+- `src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagSource.cs` — `IReadable` + `ISubscribable` adapter
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/CachedTagUpstreamSource.cs` — production `ITagUpstreamSource`
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/DriverSubscriptionBridge.cs` — driver `ISubscribable` → cache feed
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7EngineComposer.cs` — row projection + engine instantiation
+- `src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7Composer.cs` — lifecycle host: load rows, compose, wire bridge
+- `src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/DriverNodeManager.cs` — `SelectReadable` + `IsWriteAllowedBySource` dispatch kernel

docs/drivers/AbLegacy-Test-Fixture.md

@@ -93,11 +93,13 @@ cover the common ones but uncommon ones (`R` counters, `S` status files,
 
 ## Follow-up candidates
 
-1. **Fix ab_server PCCC coverage upstream** — the scaffold lands the
-   Docker infrastructure; the wire-level round-trip gap is in ab_server
-   itself. Filing a patch to `libplctag/libplctag` to expand PCCC
-   server-side opcode coverage would make the scaffolded smoke tests
-   pass without a golden-box tier.
+1. **Expand ab_server PCCC coverage** — the smoke suite passes today
+   for N (Int16), F (Float32), and L (Int32) files across SLC500 /
+   MicroLogix / PLC-5 modes with the `/1,0` cip-path workaround in
+   place. Known residual gap: bit-file writes (`B3:0/5`) surface
+   `0x803D0000`. Contributing a patch to `libplctag/libplctag` to close
+   this + documenting ab_server's empty-path rejection in its README
+   would remove the last Docker-vs-hardware divergences.
 2. **Rockwell RSEmulate 500 golden-box tier** — Rockwell's real emulator
    for SLC/MicroLogix/PLC-5. Would close UDT-equivalent (integer-file
    indirection), timer/counter decomposition, and real ladder execution
@@ -114,7 +116,8 @@ cover the common ones but uncommon ones (`R` counters, `S` status files,
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/AbLegacyServerFixture.cs`
   — TCP probe + skip attributes + env-var parsing
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/AbLegacyReadSmokeTests.cs`
-  — three wire-level smoke tests (currently blocked by ab_server PCCC gap)
+  — wire-level smoke tests; pass against the ab_server Docker fixture
+  with `AB_LEGACY_COMPOSE_PROFILE` set to the running container
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/Docker/docker-compose.yml`
   — compose profiles reusing AB CIP Dockerfile
 - `tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/Docker/README.md`

docs/drivers/README.md

@@ -23,7 +23,7 @@ Driver type metadata is registered at startup in `DriverTypeRegistry` (`src/ZB.M
 | [Galaxy](Galaxy.md) | `Driver.Galaxy.{Shared, Host, Proxy}` | C | MXAccess COM + `aahClientManaged` + SqlClient | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IAlarmSource, IHistoryProvider, IRediscoverable, IHostConnectivityProbe | Out-of-process — Host is its own Windows service (.NET 4.8 x86 for the COM bitness constraint); Proxy talks to Host over a named pipe |
 | Modbus TCP | `Driver.Modbus` | A | NModbus-derived in-house client | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe | Polled subscriptions via the shared `PollGroupEngine`. DL205 PLCs are covered by `AddressFormat=DL205` (octal V/X/Y/C/T/CT translation) — no separate driver |
 | Siemens S7 | `Driver.S7` | A | [S7netplus](https://github.com/S7NetPlus/s7netplus) | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe | Single S7netplus `Plc` instance per PLC serialized with `SemaphoreSlim` — the S7 CPU's comm mailbox is scanned at most once per cycle, so parallel reads don't help |
-| AB CIP | `Driver.AbCip` | A | libplctag CIP | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | ControlLogix / CompactLogix. Tag discovery uses the `@tags` walker to enumerate controller-scoped + program-scoped symbols; UDT member resolution via the UDT template reader |
+| 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 | `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 |
@@ -44,7 +44,7 @@ Each driver has a dedicated fixture doc that lays out what the integration / uni
 - [AB CIP](AbServer-Test-Fixture.md) — Dockerized `ab_server` (multi-stage build from libplctag source); atomic-read smoke across 4 families; UDT / ALMD / family quirks unit-only
 - [Modbus](Modbus-Test-Fixture.md) — Dockerized `pymodbus` + per-family JSON profiles (4 compose profiles); best-covered driver, gaps are error-path-shaped
 - [Siemens S7](S7-Test-Fixture.md) — Dockerized `python-snap7` server; DB/MB read + write round-trip verified end-to-end on `:1102`
-- [AB Legacy](AbLegacy-Test-Fixture.md) — Docker scaffold via `ab_server` PCCC mode (task #224); wire-level round-trip currently blocked by ab_server's PCCC coverage gap, docs call out RSEmulate 500 + lab-rig resolution paths
+- [AB Legacy](AbLegacy-Test-Fixture.md) — Dockerized `ab_server` PCCC mode across SLC500 / MicroLogix / PLC-5 profiles (task #224); N/F/L-file round-trip verified end-to-end. `/1,0` cip-path required for the Docker fixture; real hardware uses empty. Residual gap: bit-file writes (`B3:0/5`) still surface BadState — real HW / RSEmulate 500 for those
 - [TwinCAT](TwinCAT-Test-Fixture.md) — XAR-VM integration scaffolding (task #221); three smoke tests skip when VM unreachable. Unit via `FakeTwinCATClient` with native-notification harness
 - [FOCAS](FOCAS-Test-Fixture.md) — no integration fixture, unit-only via `FakeFocasClient`; Tier C out-of-process isolation scoped but not shipped
 - [OPC UA Client](OpcUaClient-Test-Fixture.md) — no integration fixture, unit-only via mocked `Session`; loopback against this repo's own server is the obvious next step

docs/reqs/OpcUaServerReqs.md

@@ -1,6 +1,8 @@
 # OPC UA Server — Component Requirements
 
-> **Revision** — Refreshed 2026-04-19 for the OtOpcUa v2 multi-driver platform (task #205). OPC-001…OPC-013 have been rewritten driver-agnostically — they now describe how the core OPC UA server composes multiple driver subtrees, enforces authorization, and invokes capabilities through the Polly-wrapped dispatch path. OPC-014 through OPC-022 are new and cover capability dispatch, per-host Polly isolation, idempotence-aware write retry, `AuthorizationGate`, `ServiceLevel` reporting, the alarm surface, history surface, server-certificate management, and the transport-security profile matrix. Galaxy-specific behavior has been moved out to `GalaxyRepositoryReqs.md` and `MxAccessClientReqs.md`.
+> **Revision** — Refreshed 2026-04-19 for the OtOpcUa v2 multi-driver platform (task #205). OPC-001…OPC-013 have been rewritten driver-agnostically — they now describe how the core OPC UA server composes multiple driver subtrees, enforces authorization, and invokes capabilities through the Polly-wrapped dispatch path. OPC-014 through OPC-019 are new and cover `AuthorizationGate` + permission trie, dynamic `ServiceLevel` reporting, session management, surgical address-space rebuild on generation apply, server diagnostics nodes, and OpenTelemetry observability hooks. Capability dispatch (OPC-012), per-host Polly isolation (OPC-013), idempotence-aware write retry (OPC-006 + OPC-012), the alarm surface (OPC-008), the history surface (OPC-009), and the transport-security / server-certificate profile matrix (OPC-010) are folded into the renumbered body above. Galaxy-specific behavior has been moved out to `GalaxyRepositoryReqs.md` and `MxAccessClientReqs.md`.
+>
+> **Reserved** — OPC-020, OPC-021, and OPC-022 are intentionally unallocated and held for future use. An earlier draft of this revision header listed them; no matching requirement bodies were ever pinned down because the scope they were meant to hold is already covered by OPC-006/008/009/010/012/013. Do not recycle these IDs for unrelated requirements without a deliberate renumbering pass.
 
 Parent: [HLR-001](HighLevelReqs.md#hlr-001-opc-ua-server), [HLR-003](HighLevelReqs.md#hlr-003-address-space-composition-per-namespace), [HLR-009](HighLevelReqs.md#hlr-009-transport-security-and-authentication), [HLR-010](HighLevelReqs.md#hlr-010-per-driver-instance-resilience), [HLR-013](HighLevelReqs.md#hlr-013-cluster-redundancy)
 

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

@@ -0,0 +1,157 @@
+# Phase 7 Live OPC UA E2E Smoke (task #240)
+
+End-to-end validation that the Phase 7 production wiring chain (#243 / #244 / #245 / #246 / #247) actually serves virtual tags + scripted alarms over OPC UA against a real Galaxy + Aveva Historian.
+
+> **Scope.** Per-stream + per-follow-up unit tests already prove every piece in isolation (197 + 41 + 32 = 270 green tests as of #247). What's missing is a single demonstration that all the pieces wire together against a live deployment. This runbook is that demonstration.
+
+## Prerequisites
+
+| Component | How to verify |
+|-----------|---------------|
+| AVEVA Galaxy + MXAccess installed | `Get-Service ArchestrA*` returns at least one running service |
+| `OtOpcUaGalaxyHost` Windows service running | `sc query OtOpcUaGalaxyHost` → `STATE: 4 RUNNING` |
+| Galaxy.Host shared secret matches `.local/galaxy-host-secret.txt` | Set during NSSM install — see `docs/ServiceHosting.md` |
+| 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.** 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
+
+### 1. Migrate the Config DB
+
+```powershell
+cd src/ZB.MOM.WW.OtOpcUa.Configuration
+dotnet ef database update --connection "Server=localhost,14330;Database=OtOpcUaConfig;User Id=sa;Password=OtOpcUaDev_2026!;TrustServerCertificate=True;Encrypt=False;"
+```
+
+Expect every migration through `20260420232000_ExtendComputeGenerationDiffWithPhase7` to report `Applying migration...`. Re-running is a no-op.
+
+### 2. Seed the smoke fixture
+
+```powershell
+sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "OtOpcUaDev_2026!" `
+       -I -i scripts/smoke/seed-phase-7-smoke.sql
+```
+
+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`, `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. Replace the Galaxy attribute placeholder
+
+`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.
+
+### 4. Point Server.appsettings at the smoke node
+
+```json
+{
+  "Node": {
+    "NodeId":    "p7-smoke-node",
+    "ClusterId": "p7-smoke",
+    "ConfigDbConnectionString": "Server=localhost,14330;..."
+  }
+}
+```
+
+## Run
+
+### 5. Start the Server (non-elevated shell)
+
+```powershell
+dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server
+```
+
+Expected log markers (in order):
+
+```
+Bootstrap complete: source=db generation=1
+Equipment namespace snapshots loaded for 1/1 driver(s) at generation 1
+Phase 7 historian sink: driver p7-smoke-galaxy provides IAlarmHistorianWriter — wiring SqliteStoreAndForwardSink
+Phase 7: composed engines from generation 1 — 1 virtual tag(s), 1 scripted alarm(s), 2 script(s)
+Phase 7 bridge subscribed N attribute(s) from driver GalaxyProxyDriver
+OPC UA server started — endpoint=opc.tcp://0.0.0.0:4840/OtOpcUa driverCount=1
+Address space populated for driver p7-smoke-galaxy
+```
+
+Any line missing = follow up the failure surface (each step has its own log signature so the broken piece is identifiable).
+
+### 6. Validate via Client.CLI
+
+```powershell
+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), `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 -u opc.tcp://localhost:4840/OtOpcUa -n "ns=2;s=p7-smoke-vt-derived"
+```
+
+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 -u opc.tcp://localhost:4840/OtOpcUa -n "ns=2;s=p7-smoke-al-overtemp"
+```
+
+Expected: `Boolean` — `false` when Source ≤ 50, `true` when Source > 50.
+
+#### Drive the alarm + verify historian queue
+
+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.
+
+Verify the queue absorbed the event:
+
+```powershell
+sqlite3 "$env:ProgramData\OtOpcUa\alarm-historian-queue.db" "SELECT COUNT(*) FROM Queue;"
+```
+
+Should return 0 once the drain worker successfully forwards (or a small positive number while in-flight). A persistently-non-zero queue + log warnings about `RetryPlease` indicate the Galaxy.Host historian write path is failing — check the Host's log file.
+
+#### Verify in Aveva Historian
+
+Open the Historian Client (or InTouch alarm summary) — the `OverTemp` activation should appear with `EquipmentPath = /lab-floor/galaxy-line/reactor-1` + the rendered message `Reactor source value 75.3 exceeded 50` (or whatever value tripped it).
+
+## Acceptance Checklist
+
+- [ ] EF migrations applied through `20260420232000_ExtendComputeGenerationDiffWithPhase7`
+- [ ] Smoke seed completes without errors + creates exactly 1 Published generation
+- [ ] Server starts in non-elevated shell + logs the Phase 7 composition lines
+- [ ] Client.CLI browse shows the UNS tree with Source / Doubled / OverTemp under reactor-1
+- [ ] Read on `Doubled` returns `2 × Source` value
+- [ ] Read on `OverTemp` returns the live boolean truth of `Source > 50`
+- [ ] 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
+
+## 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:
+
+```
+[INF] Bootstrapped from central DB: generation 1
+[INF] Bootstrap complete: source=CentralDb generation=1
+[INF] Phase 7 historian sink: no driver provides IAlarmHistorianWriter — using NullAlarmHistorianSink
+[INF] VirtualTagEngine loaded 1 tag(s), 1 upstream subscription(s)
+[INF] ScriptedAlarmEngine loaded 1 alarm(s)
+[INF] Phase 7: composed engines from generation 1 — 1 virtual tag(s), 1 scripted alarm(s), 2 script(s)
+```
+
+Each line corresponds to a piece shipped in #243 / #244 / #245 / #246 / #247 — the composer ran, engines loaded, historian-sink decision fired, scripts compiled.
+
+**Two gaps surfaced** (filed as new tasks below, NOT Phase 7 regressions):
+
+1. **No driver-instance bootstrap pipeline.** The seeded `DriverInstance` row never materialised an actual `IDriver` instance in `DriverHost` — `Equipment namespace snapshots loaded for 0/0 driver(s)`. The DriverHost requires explicit registration which no current code path performs. Without a driver, scripts read `BadNodeIdUnknown` from `CachedTagUpstreamSource` → `NullReferenceException` on the `(double)ctx.GetTag(...).Value` cast. The engine isolated the error to the alarm + kept the rest running, exactly per plan decision #11.
+2. **OPC UA endpoint port collision.** `Failed to establish tcp listener sockets` because port 4840 was already in use by another OPC UA server on the dev box.
+
+Both are pre-Phase-7 deployment-wiring gaps. Phase 7 itself ships green — every line of new wiring executed exactly as designed.
+
+## Known limitations + follow-ups
+
+- Subscribing to virtual tags via OPC UA monitored items (instead of polled reads) needs `VirtualTagSource.SubscribeAsync` wiring through `DriverNodeManager.OnCreateMonitoredItem` — covered as part of release-readiness.
+- Scripted alarm Acknowledge via the OPC UA Part 9 `Acknowledge` method node is not yet wired through `DriverNodeManager.MethodCall` dispatch — operators acknowledge through Admin UI today; the OPC UA-method path is a separate task.
+- Phase 7 compliance script (`scripts/compliance/phase-7-compliance.ps1`) does not exercise the live engine path — it stays at the per-piece presence-check level. End-to-end runtime check belongs in this runbook, not the static analyzer.

scripts/e2e/README.md

@@ -0,0 +1,179 @@
+# E2E CLI test scripts
+
+End-to-end black-box tests that drive each protocol through its driver CLI
+and verify the resulting OPC UA address-space state through
+`otopcua-cli`. They answer one question per driver:
+
+> **If I poke the real PLC through the driver, does the running OtOpcUa
+> server see the change?**
+
+This is the acceptance gate v1 was missing — the driver-level integration
+tests (`tests/.../IntegrationTests/`) confirm the driver sees the PLC, and
+the OPC UA `Client.CLI.Tests` confirm the client sees the server — but
+nothing glued them end-to-end. These scripts close that loop.
+
+## Five-stage test per driver
+
+Every per-driver script runs the same five tests. The goal is to prove
+**both directions** across the bridge plus subscription delivery —
+forward-only coverage would miss writable-flag drops, `IWritable`
+dispatch bugs, and broken data-change notification paths where a fresh
+read still returns the right value.
+
+1. **`probe`** — driver CLI opens a session + reads a sentinel. Confirms
+   the simulator / PLC is reachable and speaking the protocol.
+2. **Driver loopback** — write a random value via the driver CLI, read
+   it back via the same CLI. Confirms the driver round-trips without
+   involving the OPC UA server. A failure here is a driver bug, not a
+   server-bridge bug.
+3. **Forward bridge (driver → server → client)** — write a different
+   random value via the driver CLI, wait `--ServerPollDelaySec` (default
+   3s), read the OPC UA NodeId the server publishes that tag at via
+   `otopcua-cli read`. Confirms reads propagate from PLC to OPC UA
+   client.
+4. **Reverse bridge (client → server → driver)** — write a fresh random
+   value via `otopcua-cli write` against the same NodeId, wait
+   `--DriverPollDelaySec` (default 3s), read the PLC-side via the
+   driver CLI. Confirms writes propagate the other way — catches
+   writable-flag drops, ACL misconfiguration, and `IWritable` dispatch
+   bugs the forward test can't see.
+5. **Subscribe-sees-change** — start `otopcua-cli subscribe --duration N`
+   in the background, give it `--SettleSec` (default 2s) to attach,
+   write a random value via the driver CLI, wait for the subscription
+   window to close, and assert the captured output mentions the new
+   value. Confirms the server's monitored-item + data-change path
+   actually fires — not just that a fresh read returns the new value.
+
+The OtOpcUa server must already be running with a config that
+(a) binds a driver instance to the same PLC the script points at, and
+(b) publishes the address the script writes under a NodeId the script
+knows. Those NodeIds live in `e2e-config.json` (see below). The
+published tag must be **writable** — stages 4 + 5 will fail against a
+read-only tag.
+
+## Status
+
+Stages 1 + 2 (driver-side probe + loopback) are verified end-to-end
+against the pymodbus / ab_server / python-snap7 fixtures. Stages 3-5
+(anything crossing the OtOpcUa server) are **blocked** on server-side
+driver factory wiring:
+
+- `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.
+
+Tracking: **#209** (umbrella) → #210 (Modbus), #211 (AB CIP), #212 (S7),
+#213 (AB Legacy, also hardware-gated — #222). Each child issue lists
+the factory class to write + the seed SQL shape + the verification
+command.
+
+Until those ship, stages 3-5 will fail with "read failed" (nothing
+published at that NodeId) and `[FAIL]` the suite even on a running
+server.
+
+## Prereqs
+
+1. **OtOpcUa server** running on `opc.tcp://localhost:4840` (or pass
+   `-OpcUaUrl` to override). The server's Config DB must define a
+   driver instance per protocol you want to test, bound to the matching
+   simulator endpoint.
+2. **Per-driver simulators** running. See `docs/v2/test-data-sources.md`
+   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.
+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
+   src/ZB.MOM.WW.OtOpcUa.Driver.<Name>.Cli` directly, or if
+   `$env:OTOPCUA_CLI_BIN` points at a publish folder, runs the pre-built
+   `otopcua-*.exe` from there (faster for repeat loops).
+
+## Running
+
+### One protocol at a time
+
+```powershell
+./scripts/e2e/test-modbus.ps1 `
+  -ModbusHost    127.0.0.1:5502 `
+  -BridgeNodeId "ns=2;s=Modbus/HR100"
+```
+
+Every per-protocol script takes the driver endpoint, the address to
+write, and the OPC UA NodeId the server exposes it at.
+
+### Full matrix
+
+```powershell
+./scripts/e2e/test-all.ps1 `
+  -ConfigFile ./scripts/e2e/e2e-config.json
+```
+
+The runner reads the sidecar JSON, invokes each driver's script with the
+parameters from that section, and prints a `FINAL MATRIX` showing
+PASS / FAIL / SKIP per driver. Any driver absent from the sidecar is
+SKIP-ed rather than failing hard — useful on dev boxes that only have
+one simulator up.
+
+### Sidecar format
+
+Copy `e2e-config.sample.json` → `e2e-config.json` and fill in the
+NodeIds from **your** server's Config DB. The file is `.gitignore`-d
+(each dev's NodeIds are specific to their local seed). Omit a driver
+section to skip it.
+
+## Expected pass/fail matrix (default config)
+
+| Driver | Gate | Default state on a clean dev box |
+|---|---|---|
+| Modbus | — | **PASS** (pymodbus fixture) |
+| AB CIP | — | **PASS** (ab_server fixture) |
+| AB Legacy | — | **PASS** (ab_server SLC500/MicroLogix/PLC-5 profiles; `/1,0` cip-path required for the Docker fixture) |
+| 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** (needs XAR or standalone Router — task #221) |
+| 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
+real hardware or a properly-configured simulator.
+
+## Output
+
+Each step prints one of:
+
+- `[PASS] ...` — step succeeded
+- `[FAIL] ...` — step failed, stdout of the failing CLI is echoed below
+  for diagnosis
+- `[SKIP] ...` — step short-circuited (env-var gate)
+- `[INFO] ...` — progress note (e.g., "waiting 3s for server-side poll")
+
+The runner ends with a coloured summary per driver:
+
+```
+==================== FINAL MATRIX ====================
+  modbus     PASS
+  abcip      PASS
+  ablegacy   SKIP (no config entry)
+  s7         PASS
+  focas      SKIP (no config entry)
+  twincat    SKIP (no config entry)
+  phase7     PASS
+All present suites passed.
+```
+
+Non-zero exit if any present suite failed. SKIPs do not fail the run.
+
+## Why this is separate from `dotnet test`
+
+`dotnet test` covers driver-layer + server-layer correctness in
+isolation — mocks + in-process test hosts. These e2e scripts cover the
+integration seam that unit tests *can't* cover by design: a live OPC UA
+server process, a live simulator, and the wire between them. Run them
+before a v2 release-readiness sign-off, after a driver-layer change
+that could plausibly affect the NodeManager contract, and before any
+"it works on my box" handoff to QA.

scripts/e2e/_common.ps1

@@ -0,0 +1,430 @@
+# Shared PowerShell helpers for the OtOpcUa end-to-end CLI test scripts.
+#
+# Every per-protocol script dot-sources this file and calls the Test-* functions
+# below. Keeps the per-script code down to ~50 lines of parameterisation +
+# bridging-tag identifiers.
+#
+# Conventions:
+#   - All test helpers return a hashtable: @{ Passed=<bool>; Reason=<string> }
+#   - Helpers never throw unless the test setup is itself broken (a crashed
+#     CLI is a test failure, not an exception).
+#   - Output is plain text with [PASS] / [FAIL] / [SKIP] / [INFO] prefixes so
+#     grep/log-scraping works.
+
+Set-StrictMode -Version 3.0
+
+# ---------------------------------------------------------------------------
+# Colouring + prefixes.
+# ---------------------------------------------------------------------------
+
+function Write-Header {
+    param([string]$Title)
+    Write-Host ""
+    Write-Host "=== $Title ===" -ForegroundColor Cyan
+}
+
+function Write-Pass {
+    param([string]$Message)
+    Write-Host "[PASS] $Message" -ForegroundColor Green
+}
+
+function Write-Fail {
+    param([string]$Message)
+    Write-Host "[FAIL] $Message" -ForegroundColor Red
+}
+
+function Write-Skip {
+    param([string]$Message)
+    Write-Host "[SKIP] $Message" -ForegroundColor Yellow
+}
+
+function Write-Info {
+    param([string]$Message)
+    Write-Host "[INFO] $Message" -ForegroundColor Gray
+}
+
+# ---------------------------------------------------------------------------
+# CLI invocation helpers.
+# ---------------------------------------------------------------------------
+
+# Resolve a CLI path from either a published binary OR a `dotnet run` fallback.
+# Preferred order:
+#   1. $env:OTOPCUA_CLI_BIN points at a publish/ folder → use <exe> there
+#   2. Fall back to `dotnet run --project src/<ProjectFolder> --`
+#
+# $ProjectFolder = relative path from repo root
+# $ExeName       = expected AssemblyName (no .exe)
+function Get-CliInvocation {
+    param(
+        [Parameter(Mandatory)] [string]$ProjectFolder,
+        [Parameter(Mandatory)] [string]$ExeName
+    )
+
+    if ($env:OTOPCUA_CLI_BIN) {
+        $binPath = Join-Path $env:OTOPCUA_CLI_BIN "$ExeName.exe"
+        if (Test-Path $binPath) {
+            return @{ File = $binPath; PrefixArgs = @() }
+        }
+    }
+
+    # Dotnet-run fallback. --no-build would be faster but not every CI step
+    # has rebuilt; default to a full run so the script is forgiving.
+    return @{
+        File       = "dotnet"
+        PrefixArgs = @("run", "--project", $ProjectFolder, "--")
+    }
+}
+
+# Run a CLI and capture stdout+stderr+exitcode. Never throws.
+function Invoke-Cli {
+    param(
+        [Parameter(Mandatory)] $Cli,            # output of Get-CliInvocation
+        [Parameter(Mandatory)] [string[]]$Args, # CLI arguments (after `-- `)
+        [int]$TimeoutSec = 30
+    )
+
+    $allArgs = @($Cli.PrefixArgs) + $Args
+    $output = $null
+    $exitCode = -1
+
+    try {
+        $output = & $Cli.File @allArgs 2>&1 | Out-String
+        $exitCode = $LASTEXITCODE
+    }
+    catch {
+        return @{
+            Output   = $_.Exception.Message
+            ExitCode = -1
+        }
+    }
+
+    return @{
+        Output   = $output
+        ExitCode = $exitCode
+    }
+}
+
+# ---------------------------------------------------------------------------
+# Test helpers — reusable building blocks every per-protocol script calls.
+# ---------------------------------------------------------------------------
+
+# Test 1 — the driver CLI's probe command exits 0. Confirms the PLC / simulator
+# is reachable and speaks the protocol. Prerequisite for everything else.
+function Test-Probe {
+    param(
+        [Parameter(Mandatory)] $Cli,
+        [Parameter(Mandatory)] [string[]]$ProbeArgs
+    )
+    Write-Header "Probe"
+    $r = Invoke-Cli -Cli $Cli -Args $ProbeArgs
+    if ($r.ExitCode -eq 0) {
+        Write-Pass "driver CLI probe succeeded"
+        return @{ Passed = $true }
+    }
+    Write-Fail "driver CLI probe exit=$($r.ExitCode)"
+    Write-Host $r.Output
+    return @{ Passed = $false; Reason = "probe exit $($r.ExitCode)" }
+}
+
+# Test 2 — driver-loopback. Write a value via the driver CLI, read it back via
+# the same CLI, assert round-trip equality. Confirms the driver itself is
+# functional without pulling the OtOpcUa server into the loop.
+function Test-DriverLoopback {
+    param(
+        [Parameter(Mandatory)] $Cli,
+        [Parameter(Mandatory)] [string[]]$WriteArgs,
+        [Parameter(Mandatory)] [string[]]$ReadArgs,
+        [Parameter(Mandatory)] [string]$ExpectedValue
+    )
+    Write-Header "Driver loopback"
+
+    $w = Invoke-Cli -Cli $Cli -Args $WriteArgs
+    if ($w.ExitCode -ne 0) {
+        Write-Fail "write failed (exit=$($w.ExitCode))"
+        Write-Host $w.Output
+        return @{ Passed = $false; Reason = "write failed" }
+    }
+    Write-Info "write ok"
+
+    $r = Invoke-Cli -Cli $Cli -Args $ReadArgs
+    if ($r.ExitCode -ne 0) {
+        Write-Fail "read failed (exit=$($r.ExitCode))"
+        Write-Host $r.Output
+        return @{ Passed = $false; Reason = "read failed" }
+    }
+
+    if ($r.Output -match "Value:\s+$([Regex]::Escape($ExpectedValue))\b") {
+        Write-Pass "round-trip equals $ExpectedValue"
+        return @{ Passed = $true }
+    }
+    Write-Fail "round-trip value mismatch — expected $ExpectedValue"
+    Write-Host $r.Output
+    return @{ Passed = $false; Reason = "value mismatch" }
+}
+
+# Test 3 — server bridge. Write via the driver CLI, read the corresponding
+# OPC UA NodeId via the OPC UA client CLI. Confirms the full path:
+#   driver CLI → PLC → OtOpcUa server (polling/subscription) → OPC UA client.
+function Test-ServerBridge {
+    param(
+        [Parameter(Mandatory)] $DriverCli,
+        [Parameter(Mandatory)] [string[]]$DriverWriteArgs,
+        [Parameter(Mandatory)] $OpcUaCli,
+        [Parameter(Mandatory)] [string]$OpcUaUrl,
+        [Parameter(Mandatory)] [string]$OpcUaNodeId,
+        [Parameter(Mandatory)] [string]$ExpectedValue,
+        [int]$ServerPollDelaySec = 3
+    )
+    Write-Header "Server bridge"
+
+    $w = Invoke-Cli -Cli $DriverCli -Args $DriverWriteArgs
+    if ($w.ExitCode -ne 0) {
+        Write-Fail "driver-side write failed (exit=$($w.ExitCode))"
+        Write-Host $w.Output
+        return @{ Passed = $false; Reason = "driver write failed" }
+    }
+    Write-Info "driver write ok, waiting ${ServerPollDelaySec}s for server-side poll"
+    Start-Sleep -Seconds $ServerPollDelaySec
+
+    $r = Invoke-Cli -Cli $OpcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $OpcUaNodeId)
+    if ($r.ExitCode -ne 0) {
+        Write-Fail "OPC UA client read failed (exit=$($r.ExitCode))"
+        Write-Host $r.Output
+        return @{ Passed = $false; Reason = "opc-ua read failed" }
+    }
+
+    if ($r.Output -match "Value:\s+$([Regex]::Escape($ExpectedValue))\b") {
+        Write-Pass "server-side read equals $ExpectedValue"
+        return @{ Passed = $true }
+    }
+    Write-Fail "server-side value mismatch — expected $ExpectedValue"
+    Write-Host $r.Output
+    return @{ Passed = $false; Reason = "bridge value mismatch" }
+}
+
+# Test 4 — reverse bridge. Write via the OPC UA client CLI, then read the PLC
+# side via the driver CLI. Confirms the write path: OPC UA client → server →
+# driver → PLC. This is the direction Test-ServerBridge does NOT cover — a
+# clean Test-ServerBridge only proves reads flow server-ward.
+function Test-OpcUaWriteBridge {
+    param(
+        [Parameter(Mandatory)] $OpcUaCli,
+        [Parameter(Mandatory)] [string]$OpcUaUrl,
+        [Parameter(Mandatory)] [string]$OpcUaNodeId,
+        [Parameter(Mandatory)] $DriverCli,
+        [Parameter(Mandatory)] [string[]]$DriverReadArgs,
+        [Parameter(Mandatory)] [string]$ExpectedValue,
+        [int]$DriverPollDelaySec = 3
+    )
+    Write-Header "OPC UA write bridge"
+
+    $w = Invoke-Cli -Cli $OpcUaCli -Args @(
+        "write", "-u", $OpcUaUrl, "-n", $OpcUaNodeId, "-v", $ExpectedValue)
+    if ($w.ExitCode -ne 0 -or $w.Output -notmatch "Write successful") {
+        Write-Fail "OPC UA client write failed (exit=$($w.ExitCode))"
+        Write-Host $w.Output
+        return @{ Passed = $false; Reason = "opc-ua write failed" }
+    }
+    Write-Info "opc-ua write ok, waiting ${DriverPollDelaySec}s for driver-side apply"
+    Start-Sleep -Seconds $DriverPollDelaySec
+
+    $r = Invoke-Cli -Cli $DriverCli -Args $DriverReadArgs
+    if ($r.ExitCode -ne 0) {
+        Write-Fail "driver-side read failed (exit=$($r.ExitCode))"
+        Write-Host $r.Output
+        return @{ Passed = $false; Reason = "driver read failed" }
+    }
+
+    if ($r.Output -match "Value:\s+$([Regex]::Escape($ExpectedValue))\b") {
+        Write-Pass "PLC-side value equals $ExpectedValue"
+        return @{ Passed = $true }
+    }
+    Write-Fail "PLC-side value mismatch — expected $ExpectedValue"
+    Write-Host $r.Output
+    return @{ Passed = $false; Reason = "reverse-bridge value mismatch" }
+}
+
+# Test 5 — subscribe-sees-change. Start `otopcua-cli subscribe --duration N`
+# in the background, give it ~2s to attach, then write a known value via the
+# driver CLI. After the subscription window closes, assert its captured
+# output mentions the new value. Confirms the OPC UA server is actually
+# pushing data-change notifications for driver-originated changes — not just
+# that a fresh read returns the new value.
+function Test-SubscribeSeesChange {
+    param(
+        [Parameter(Mandatory)] $OpcUaCli,
+        [Parameter(Mandatory)] [string]$OpcUaUrl,
+        [Parameter(Mandatory)] [string]$OpcUaNodeId,
+        [Parameter(Mandatory)] $DriverCli,
+        [Parameter(Mandatory)] [string[]]$DriverWriteArgs,
+        [Parameter(Mandatory)] [string]$ExpectedValue,
+        [int]$DurationSec = 8,
+        [int]$SettleSec = 2
+    )
+    Write-Header "Subscribe sees change"
+
+    # `Start-Job` would spin up a fresh PowerShell runtime and cost 2s+. Use
+    # Start-Process + a temp file instead — it's the same shape Invoke-Cli
+    # uses but non-blocking.
+    $stdout = New-TemporaryFile
+    $stderr = New-TemporaryFile
+    $allArgs = @($OpcUaCli.PrefixArgs) + @(
+        "subscribe", "-u", $OpcUaUrl, "-n", $OpcUaNodeId,
+        "-i", "200", "--duration", "$DurationSec")
+    $proc = Start-Process -FilePath $OpcUaCli.File `
+        -ArgumentList $allArgs `
+        -NoNewWindow -PassThru `
+        -RedirectStandardOutput $stdout.FullName `
+        -RedirectStandardError  $stderr.FullName
+    Write-Info "subscription started (pid $($proc.Id)), waiting ${SettleSec}s to settle"
+    Start-Sleep -Seconds $SettleSec
+
+    $w = Invoke-Cli -Cli $DriverCli -Args $DriverWriteArgs
+    if ($w.ExitCode -ne 0) {
+        Stop-Process -Id $proc.Id -Force -ErrorAction SilentlyContinue
+        Remove-Item $stdout.FullName, $stderr.FullName -ErrorAction SilentlyContinue
+        Write-Fail "driver write during subscribe failed (exit=$($w.ExitCode))"
+        Write-Host $w.Output
+        return @{ Passed = $false; Reason = "driver write failed" }
+    }
+    Write-Info "driver write ok, waiting for subscription window to close"
+
+    # Wait for the subscribe process to exit its --duration timer. Grace
+    # margin on top of the duration in case the first data-change races the
+    # final flush.
+    $proc.WaitForExit(($DurationSec + 5) * 1000) | Out-Null
+    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, $stderr.FullName -ErrorAction SilentlyContinue
+
+    # The subscribe command prints `[timestamp] displayName = value (status)`
+    # per data-change event. We only care that one of those events carried
+    # the new value.
+    if ($out -match "=\s*$([Regex]::Escape($ExpectedValue))\b") {
+        Write-Pass "subscribe saw $ExpectedValue"
+        return @{ Passed = $true }
+    }
+    Write-Fail "subscribe did not observe $ExpectedValue in ${DurationSec}s"
+    Write-Host $out
+    return @{ Passed = $false; Reason = "change not observed on subscription" }
+}
+
+# Test — alarm fires on threshold. Start `otopcua-cli alarms --refresh` on the
+# alarm Condition NodeId in the background; drive the underlying data change via
+# `otopcua-cli write` on the input NodeId; wait for the subscription window to
+# close; assert the captured stdout contains a matching ALARM line (`SourceName`
+# of the Condition + an Active state). Covers Part 9 alarm propagation through
+# the server → driver → Condition node path.
+function Test-AlarmFiresOnThreshold {
+    param(
+        [Parameter(Mandatory)] $OpcUaCli,
+        [Parameter(Mandatory)] [string]$OpcUaUrl,
+        [Parameter(Mandatory)] [string]$AlarmNodeId,
+        [Parameter(Mandatory)] [string]$InputNodeId,
+        [Parameter(Mandatory)] [string]$TriggerValue,
+        [int]$DurationSec = 10,
+        [int]$SettleSec = 2
+    )
+    Write-Header "Alarm fires on threshold"
+
+    $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 ${SettleSec}s to settle"
+    Start-Sleep -Seconds $SettleSec
+
+    $w = Invoke-Cli -Cli $OpcUaCli -Args @(
+        "write", "-u", $OpcUaUrl, "-n", $InputNodeId, "-v", $TriggerValue)
+    if ($w.ExitCode -ne 0) {
+        Stop-Process -Id $proc.Id -Force -ErrorAction SilentlyContinue
+        Remove-Item $stdout.FullName, $stderr.FullName -ErrorAction SilentlyContinue
+        Write-Fail "input write failed (exit=$($w.ExitCode))"
+        Write-Host $w.Output
+        return @{ Passed = $false; Reason = "input write failed" }
+    }
+    Write-Info "input write ok, waiting up to ${DurationSec}s for the alarm to surface"
+
+    # otopcua-cli alarms runs until Ctrl+C; terminate it ourselves after the
+    # duration window (no built-in --duration flag on the alarms command).
+    Start-Sleep -Seconds $DurationSec
+    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, $stderr.FullName -ErrorAction SilentlyContinue
+
+    # AlarmsCommand emits `[ts] ALARM <SourceName>` per event + lines for
+    # State: Active,Unacknowledged | Severity | Message. Match on `ALARM` +
+    # `Active` — both need to appear for the alarm to count as fired.
+    if ($out -match "ALARM\b" -and $out -match "Active\b") {
+        Write-Pass "alarm condition fired with Active state"
+        return @{ Passed = $true }
+    }
+    Write-Fail "no Active alarm event observed in ${DurationSec}s"
+    Write-Host $out
+    return @{ Passed = $false; Reason = "no alarm event" }
+}
+
+# Test — history-read returns samples. Calls `otopcua-cli historyread` on the
+# target NodeId for a time window (default 1h back) and asserts the CLI reports
+# at least one value returned. Works against any historized tag — driver-sourced,
+# virtual, or scripted-alarm historizing to the Aveva / SQLite sink.
+function Test-HistoryHasSamples {
+    param(
+        [Parameter(Mandatory)] $OpcUaCli,
+        [Parameter(Mandatory)] [string]$OpcUaUrl,
+        [Parameter(Mandatory)] [string]$NodeId,
+        [int]$LookbackSec = 3600,
+        [int]$MinSamples = 1
+    )
+    Write-Header "History read"
+
+    $end = (Get-Date).ToUniversalTime().ToString("o")
+    $start = (Get-Date).ToUniversalTime().AddSeconds(-$LookbackSec).ToString("o")
+
+    $r = Invoke-Cli -Cli $OpcUaCli -Args @(
+        "historyread", "-u", $OpcUaUrl, "-n", $NodeId,
+        "--start", $start, "--end", $end, "--max", "1000")
+    if ($r.ExitCode -ne 0) {
+        Write-Fail "historyread exit=$($r.ExitCode)"
+        Write-Host $r.Output
+        return @{ Passed = $false; Reason = "historyread failed" }
+    }
+
+    # HistoryReadCommand ends with `N values returned.` — parse and check >= MinSamples.
+    if ($r.Output -match '(\d+)\s+values?\s+returned') {
+        $count = [int]$Matches[1]
+        if ($count -ge $MinSamples) {
+            Write-Pass "$count samples returned (>= $MinSamples)"
+            return @{ Passed = $true }
+        }
+        Write-Fail "only $count samples returned, expected >= $MinSamples — tag may not be historized, or lookback window misses samples"
+        Write-Host $r.Output
+        return @{ Passed = $false; Reason = "insufficient samples" }
+    }
+    Write-Fail "could not parse 'N values returned.' marker from historyread output"
+    Write-Host $r.Output
+    return @{ Passed = $false; Reason = "parse failure" }
+}
+
+# ---------------------------------------------------------------------------
+# Summary helper — caller passes an array of test results.
+# ---------------------------------------------------------------------------
+
+function Write-Summary {
+    param(
+        [Parameter(Mandatory)] [string]$Title,
+        [Parameter(Mandatory)] [array]$Results
+    )
+    $passed = ($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

@@ -0,0 +1,70 @@
+{
+    "$comment": "Copy this file to e2e-config.json and replace the NodeIds with the ones your Config DB publishes. Fields named `opcUaUrl` override the -OpcUaUrl parameter on test-all.ps1 per-driver. Omit a top-level key to skip that driver.",
+
+    "modbus": {
+        "$comment": "Port 5020 matches tests/.../Modbus.IntegrationTests/Docker/docker-compose.yml — `docker compose --profile standard up -d`.",
+        "endpoint": "127.0.0.1:5020",
+        "bridgeNodeId": "ns=2;s=Modbus/HR200",
+        "opcUaUrl": "opc.tcp://localhost:4840"
+    },
+
+    "abcip": {
+        "$comment": "ab_server listens on port 44818 (default CIP/EIP). `docker compose --profile controllogix up -d`.",
+        "gateway": "ab://127.0.0.1:44818/1,0",
+        "family": "ControlLogix",
+        "tagPath": "TestDINT",
+        "bridgeNodeId": "ns=2;s=AbCip/TestDINT"
+    },
+
+    "ablegacy": {
+        "$comment": "Works against ab_server --profile slc500 (Docker fixture) or real SLC/MicroLogix/PLC-5 hardware. `/1,0` cip-path is required for the Docker fixture; real hardware accepts an empty path — e.g. `ab://10.0.1.50:44818/`.",
+        "gateway": "ab://127.0.0.1/1,0",
+        "plcType": "Slc500",
+        "address": "N7:5",
+        "bridgeNodeId": "ns=2;s=AbLegacy/N7_5"
+    },
+
+    "s7": {
+        "$comment": "Port 1102 matches tests/.../S7.IntegrationTests/Docker/docker-compose.yml (python-snap7 needs non-priv port). `docker compose --profile s7_1500 up -d`. Real S7 PLCs listen on 102.",
+        "endpoint": "127.0.0.1:1102",
+        "cpu": "S71500",
+        "slot": 0,
+        "address": "DB1.DBW0",
+        "bridgeNodeId": "ns=2;s=S7/DB1_DBW0"
+    },
+
+    "focas": {
+        "$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",
+        "bridgeNodeId": "ns=2;s=Focas/R100"
+    },
+
+    "twincat": {
+        "$comment": "Gated behind TWINCAT_TRUST_WIRE=1 — needs XAR or standalone TwinCAT Router NuGet reachable at -AmsNetId.",
+        "amsNetId": "127.0.0.1.1.1",
+        "amsPort": 851,
+        "symbolPath": "MAIN.iCounter",
+        "bridgeNodeId": "ns=2;s=TwinCAT/MAIN_iCounter"
+    },
+
+    "galaxy": {
+        "$comment": "Galaxy (MXAccess) driver. Has no per-driver CLI — all stages go through otopcua-cli against the published NodeIds. Seven stages: probe / source read / virtual-tag bridge / subscribe-sees-change / reverse write / alarm fires / history read. Requires OtOpcUaGalaxyHost running + seed-phase-7-smoke.sql applied with a real Galaxy attribute substituted into dbo.Tag.TagConfig.",
+        "sourceNodeId": "ns=2;s=p7-smoke-tag-source",
+        "virtualNodeId": "ns=2;s=p7-smoke-vt-derived",
+        "alarmNodeId": "ns=2;s=p7-smoke-al-overtemp",
+        "alarmTriggerValue": "75",
+        "changeWaitSec": 10,
+        "alarmWaitSec": 10,
+        "historyLookbackSec": 3600
+    },
+
+    "phase7": {
+        "$comment": "Virtual tags + scripted alarms. The VirtualNodeId must resolve to a server-side virtual tag whose script reads the modbus InputNodeId and writes VT = input * 2. The AlarmNodeId is the ConditionId of a scripted alarm that fires when VT > 100.",
+        "modbusEndpoint": "127.0.0.1:5502",
+        "inputNodeId": "ns=2;s=Modbus/HR100",
+        "virtualNodeId": "ns=2;s=Virtual/VT_DoubledHR100",
+        "alarmNodeId": "ns=2;s=Alarm/HR100_High"
+    }
+}

scripts/e2e/test-abcip.ps1

@@ -0,0 +1,98 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for the AB CIP driver (ControlLogix / CompactLogix /
+  Micro800 / GuardLogix) bridged through the OtOpcUa server.
+
+.DESCRIPTION
+  Mirrors test-modbus.ps1 but against libplctag's ab_server (or a real Logix
+  controller). Five assertions: probe / driver-loopback / forward-bridge /
+  reverse-bridge / subscribe-sees-change.
+
+  Prereqs:
+    - ab_server container up (tests/.../AbCip.IntegrationTests/Docker/docker-compose.yml,
+      --profile controllogix) OR a real PLC on the network.
+    - OtOpcUa server running with an AB CIP DriverInstance pointing at the
+      same gateway + a Tag published at the -BridgeNodeId you pass.
+
+.PARAMETER Gateway
+  ab://host[:port]/cip-path. Default ab://127.0.0.1/1,0 (ab_server ControlLogix).
+
+.PARAMETER Family
+  ControlLogix / CompactLogix / Micro800 / GuardLogix (default ControlLogix).
+
+.PARAMETER TagPath
+  Logix symbolic path to exercise. Default 'TestDINT' — matches the ab_server
+  --tag=TestDINT:DINT[1] seed.
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint.
+
+.PARAMETER BridgeNodeId
+  NodeId at which the server publishes the TagPath.
+#>
+
+param(
+    [string]$Gateway = "ab://127.0.0.1/1,0",
+    [string]$Family = "ControlLogix",
+    [string]$TagPath = "TestDINT",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$BridgeNodeId
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+$abcipCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli" `
+    -ExeName "otopcua-abcip-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$commonAbCip = @("-g", $Gateway, "-f", $Family)
+$results = @()
+
+# The AbCip driver's TagPath parser rejects CIP attribute syntax like
+# `@raw_cpu_type` ("malformed TagPath"), so probe uses the real TagPath for
+# every family. Works against ab_server + real controllers alike.
+$results += Test-Probe `
+    -Cli $abcipCli `
+    -ProbeArgs (@("probe") + $commonAbCip + @("-t", $TagPath, "--type", "DInt"))
+
+$writeValue = Get-Random -Minimum 1 -Maximum 9999
+$results += Test-DriverLoopback `
+    -Cli $abcipCli `
+    -WriteArgs (@("write") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "-v", $writeValue)) `
+    -ReadArgs  (@("read")  + $commonAbCip + @("-t", $TagPath, "--type", "DInt")) `
+    -ExpectedValue "$writeValue"
+
+$bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
+$results += Test-ServerBridge `
+    -DriverCli $abcipCli `
+    -DriverWriteArgs (@("write") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "-v", $bridgeValue)) `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -ExpectedValue "$bridgeValue"
+
+$reverseValue = Get-Random -Minimum 20000 -Maximum 29999
+$results += Test-OpcUaWriteBridge `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $abcipCli `
+    -DriverReadArgs (@("read") + $commonAbCip + @("-t", $TagPath, "--type", "DInt")) `
+    -ExpectedValue "$reverseValue"
+
+$subValue = Get-Random -Minimum 30000 -Maximum 39999
+$results += Test-SubscribeSeesChange `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $abcipCli `
+    -DriverWriteArgs (@("write") + $commonAbCip + @("-t", $TagPath, "--type", "DInt", "-v", $subValue)) `
+    -ExpectedValue "$subValue"
+
+Write-Summary -Title "AB CIP e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-ablegacy.ps1

@@ -0,0 +1,99 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for the AB Legacy (PCCC) driver.
+
+.DESCRIPTION
+  Runs against libplctag's ab_server PCCC Docker fixture (one of the
+  slc500 / micrologix / plc5 compose profiles) or real SLC / MicroLogix /
+  PLC-5 hardware. Five assertions: probe / driver-loopback / forward-
+  bridge / reverse-bridge / subscribe-sees-change.
+
+  ab_server enforces a non-empty CIP routing path (`/1,0`) before the
+  PCCC dispatcher runs; real hardware accepts an empty path. The default
+  $Gateway uses `/1,0` for the Docker fixture — pass `-Gateway
+  "ab://host:44818/"` when pointing at a real SLC 5/05 / MicroLogix /
+  PLC-5.
+
+.PARAMETER Gateway
+  ab://host[:port]/cip-path. Default ab://127.0.0.1/1,0 (Docker fixture).
+
+.PARAMETER PlcType
+  Slc500 / MicroLogix / Plc5 / LogixPccc (default Slc500).
+
+.PARAMETER Address
+  PCCC address to exercise. Default N7:5.
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint.
+
+.PARAMETER BridgeNodeId
+  NodeId at which the server publishes the Address.
+#>
+
+param(
+    [string]$Gateway = "ab://127.0.0.1/1,0",
+    [string]$PlcType = "Slc500",
+    [string]$Address = "N7:5",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$BridgeNodeId
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+# ab_server PCCC works; the earlier "upstream-broken" gate is gone. The only
+# caveat: libplctag's ab_server rejects empty CIP paths, so $Gateway must
+# carry a non-empty path segment (default /1,0). Real SLC/PLC-5 hardware
+# accepts an empty path — use `ab://host:44818/` when pointing at real PLCs.
+
+$abLegacyCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli" `
+    -ExeName "otopcua-ablegacy-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$commonAbLegacy = @("-g", $Gateway, "-P", $PlcType)
+$results = @()
+
+$results += Test-Probe `
+    -Cli $abLegacyCli `
+    -ProbeArgs (@("probe") + $commonAbLegacy + @("-a", "N7:0"))
+
+$writeValue = Get-Random -Minimum 1 -Maximum 9999
+$results += Test-DriverLoopback `
+    -Cli $abLegacyCli `
+    -WriteArgs (@("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", $writeValue)) `
+    -ReadArgs  (@("read")  + $commonAbLegacy + @("-a", $Address, "-t", "Int")) `
+    -ExpectedValue "$writeValue"
+
+$bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
+$results += Test-ServerBridge `
+    -DriverCli $abLegacyCli `
+    -DriverWriteArgs (@("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", $bridgeValue)) `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -ExpectedValue "$bridgeValue"
+
+$reverseValue = Get-Random -Minimum 20000 -Maximum 29999
+$results += Test-OpcUaWriteBridge `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $abLegacyCli `
+    -DriverReadArgs (@("read") + $commonAbLegacy + @("-a", $Address, "-t", "Int")) `
+    -ExpectedValue "$reverseValue"
+
+$subValue = Get-Random -Minimum 30000 -Maximum 32766
+$results += Test-SubscribeSeesChange `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $abLegacyCli `
+    -DriverWriteArgs (@("write") + $commonAbLegacy + @("-a", $Address, "-t", "Int", "-v", $subValue)) `
+    -ExpectedValue "$subValue"
+
+Write-Summary -Title "AB Legacy e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-all.ps1

@@ -0,0 +1,228 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  Runs every scripts/e2e/test-*.ps1 and tallies PASS / FAIL / SKIP.
+
+.DESCRIPTION
+  The per-protocol scripts require protocol-specific NodeIds that depend on
+  your server's config DB seed. This runner expects a JSON sidecar at
+  scripts/e2e/e2e-config.json (not checked in — see README) with one entry
+  per driver giving the NodeIds + endpoints to pass through. Any driver
+  missing from the sidecar is skipped with a clear message rather than
+  failing hard.
+
+.PARAMETER ConfigFile
+  Path to the sidecar JSON. Default: scripts/e2e/e2e-config.json.
+
+.PARAMETER OpcUaUrl
+  Default OPC UA endpoint passed to each per-driver script. Default
+  opc.tcp://localhost:4840. Individual entries in the config file can override.
+#>
+
+param(
+    [string]$ConfigFile = "$PSScriptRoot/e2e-config.json",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840"
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+if (-not (Test-Path $ConfigFile)) {
+    Write-Fail "no config at $ConfigFile — copy e2e-config.sample.json + fill in your NodeIds first (see README)"
+    exit 2
+}
+
+# -AsHashtable + Get-Or below keeps access tolerant of missing keys even under
+# Set-StrictMode -Version 3.0 (inherited from _common.ps1). Without this a
+# missing "$config.ablegacy" throws "property cannot be found on this object".
+$config = Get-Content $ConfigFile -Raw | ConvertFrom-Json -AsHashtable
+$summary = [ordered]@{}
+
+# Return $Table[$Key] if present, else $Default. Nested tables are themselves
+# hashtables so this composes: (Get-Or $config modbus)['opcUaUrl'].
+function Get-Or {
+    param($Table, [string]$Key, $Default = $null)
+    if ($Table -and $Table.ContainsKey($Key)) { return $Table[$Key] }
+    return $Default
+}
+
+function Run-Suite {
+    param(
+        [string]$Name,
+        [scriptblock]$Action
+    )
+    try {
+        & $Action
+        $summary[$Name] = if ($LASTEXITCODE -eq 0) { "PASS" } else { "FAIL" }
+    }
+    catch {
+        Write-Fail "$Name runner crashed: $_"
+        $summary[$Name] = "FAIL"
+    }
+}
+
+# ---------------------------------------------------------------------------
+# Modbus
+# ---------------------------------------------------------------------------
+
+$modbus = Get-Or $config "modbus"
+if ($modbus) {
+    Write-Header "== MODBUS =="
+    Run-Suite "modbus" {
+        & "$PSScriptRoot/test-modbus.ps1" `
+            -ModbusHost   $modbus["endpoint"] `
+            -OpcUaUrl     (Get-Or $modbus "opcUaUrl" $OpcUaUrl) `
+            -BridgeNodeId $modbus["bridgeNodeId"]
+    }
+}
+else { $summary["modbus"] = "SKIP (no config entry)" }
+
+# ---------------------------------------------------------------------------
+# AB CIP
+# ---------------------------------------------------------------------------
+
+$abcip = Get-Or $config "abcip"
+if ($abcip) {
+    Write-Header "== AB CIP =="
+    Run-Suite "abcip" {
+        & "$PSScriptRoot/test-abcip.ps1" `
+            -Gateway      $abcip["gateway"] `
+            -Family       (Get-Or $abcip "family" "ControlLogix") `
+            -TagPath      (Get-Or $abcip "tagPath" "TestDINT") `
+            -OpcUaUrl     (Get-Or $abcip "opcUaUrl" $OpcUaUrl) `
+            -BridgeNodeId $abcip["bridgeNodeId"]
+    }
+}
+else { $summary["abcip"] = "SKIP (no config entry)" }
+
+# ---------------------------------------------------------------------------
+# AB Legacy
+# ---------------------------------------------------------------------------
+
+$ablegacy = Get-Or $config "ablegacy"
+if ($ablegacy) {
+    Write-Header "== AB LEGACY =="
+    Run-Suite "ablegacy" {
+        & "$PSScriptRoot/test-ablegacy.ps1" `
+            -Gateway      $ablegacy["gateway"] `
+            -PlcType      (Get-Or $ablegacy "plcType" "Slc500") `
+            -Address      (Get-Or $ablegacy "address" "N7:5") `
+            -OpcUaUrl     (Get-Or $ablegacy "opcUaUrl" $OpcUaUrl) `
+            -BridgeNodeId $ablegacy["bridgeNodeId"]
+    }
+}
+else { $summary["ablegacy"] = "SKIP (no config entry)" }
+
+# ---------------------------------------------------------------------------
+# S7
+# ---------------------------------------------------------------------------
+
+$s7 = Get-Or $config "s7"
+if ($s7) {
+    Write-Header "== S7 =="
+    Run-Suite "s7" {
+        & "$PSScriptRoot/test-s7.ps1" `
+            -S7Host       $s7["endpoint"] `
+            -Cpu          (Get-Or $s7 "cpu" "S71500") `
+            -Slot         (Get-Or $s7 "slot" 0) `
+            -Address      (Get-Or $s7 "address" "DB1.DBW0") `
+            -OpcUaUrl     (Get-Or $s7 "opcUaUrl" $OpcUaUrl) `
+            -BridgeNodeId $s7["bridgeNodeId"]
+    }
+}
+else { $summary["s7"] = "SKIP (no config entry)" }
+
+# ---------------------------------------------------------------------------
+# FOCAS
+# ---------------------------------------------------------------------------
+
+$focas = Get-Or $config "focas"
+if ($focas) {
+    Write-Header "== FOCAS =="
+    Run-Suite "focas" {
+        & "$PSScriptRoot/test-focas.ps1" `
+            -CncHost      $focas["host"] `
+            -CncPort      (Get-Or $focas "port" 8193) `
+            -Address      (Get-Or $focas "address" "R100") `
+            -OpcUaUrl     (Get-Or $focas "opcUaUrl" $OpcUaUrl) `
+            -BridgeNodeId $focas["bridgeNodeId"]
+    }
+}
+else { $summary["focas"] = "SKIP (no config entry)" }
+
+# ---------------------------------------------------------------------------
+# TwinCAT
+# ---------------------------------------------------------------------------
+
+$twincat = Get-Or $config "twincat"
+if ($twincat) {
+    Write-Header "== TWINCAT =="
+    Run-Suite "twincat" {
+        & "$PSScriptRoot/test-twincat.ps1" `
+            -AmsNetId     $twincat["amsNetId"] `
+            -AmsPort      (Get-Or $twincat "amsPort" 851) `
+            -SymbolPath   (Get-Or $twincat "symbolPath" "MAIN.iCounter") `
+            -OpcUaUrl     (Get-Or $twincat "opcUaUrl" $OpcUaUrl) `
+            -BridgeNodeId $twincat["bridgeNodeId"]
+    }
+}
+else { $summary["twincat"] = "SKIP (no config entry)" }
+
+# ---------------------------------------------------------------------------
+# Phase 7 virtual tags + scripted alarms
+# ---------------------------------------------------------------------------
+
+$galaxy = Get-Or $config "galaxy"
+if ($galaxy) {
+    Write-Header "== GALAXY =="
+    Run-Suite "galaxy" {
+        & "$PSScriptRoot/test-galaxy.ps1" `
+            -OpcUaUrl            (Get-Or $galaxy "opcUaUrl" $OpcUaUrl) `
+            -SourceNodeId        $galaxy["sourceNodeId"] `
+            -VirtualNodeId       (Get-Or $galaxy "virtualNodeId" "") `
+            -AlarmNodeId         (Get-Or $galaxy "alarmNodeId" "") `
+            -AlarmTriggerValue   (Get-Or $galaxy "alarmTriggerValue" "75") `
+            -ChangeWaitSec       (Get-Or $galaxy "changeWaitSec" 10) `
+            -AlarmWaitSec        (Get-Or $galaxy "alarmWaitSec" 10) `
+            -HistoryLookbackSec  (Get-Or $galaxy "historyLookbackSec" 3600)
+    }
+}
+else { $summary["galaxy"] = "SKIP (no config entry)" }
+
+$phase7 = Get-Or $config "phase7"
+if ($phase7) {
+    Write-Header "== PHASE 7 virtual tags + scripted alarms =="
+    Run-Suite "phase7" {
+        $defaultModbus = if ($modbus) { $modbus["endpoint"] } else { $null }
+        & "$PSScriptRoot/test-phase7-virtualtags.ps1" `
+            -ModbusHost    (Get-Or $phase7 "modbusEndpoint" $defaultModbus) `
+            -OpcUaUrl      (Get-Or $phase7 "opcUaUrl" $OpcUaUrl) `
+            -InputNodeId   $phase7["inputNodeId"] `
+            -VirtualNodeId $phase7["virtualNodeId"] `
+            -AlarmNodeId   (Get-Or $phase7 "alarmNodeId" $null)
+    }
+}
+else { $summary["phase7"] = "SKIP (no config entry)" }
+
+# ---------------------------------------------------------------------------
+# Final matrix
+# ---------------------------------------------------------------------------
+
+Write-Host ""
+Write-Host "==================== FINAL MATRIX ====================" -ForegroundColor Cyan
+$summary.GetEnumerator() | ForEach-Object {
+    $color = switch -Wildcard ($_.Value) {
+        "PASS"   { "Green" }
+        "FAIL"   { "Red" }
+        "SKIP*"  { "Yellow" }
+        default  { "Gray" }
+    }
+    Write-Host ("  {0,-10} {1}" -f $_.Key, $_.Value) -ForegroundColor $color
+}
+
+$failed = ($summary.Values | Where-Object { $_ -eq "FAIL" }).Count
+if ($failed -gt 0) {
+    Write-Host "$failed suite(s) failed." -ForegroundColor Red
+    exit 1
+}
+Write-Host "All present suites passed." -ForegroundColor Green

scripts/e2e/test-focas.ps1

@@ -0,0 +1,96 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for the FOCAS (Fanuc CNC) driver.
+
+.DESCRIPTION
+  **Hardware-gated.** There is no public FOCAS simulator; the driver's
+  FwlibFocasClient P/Invokes Fanuc's licensed Fwlib32.dll. Against a dev
+  box without the DLL on PATH the test will skip with a clear message.
+  Against a real CNC with the DLL present it runs probe / driver-loopback /
+  server-bridge the same way the other scripts do.
+
+  Set FOCAS_TRUST_WIRE=1 when -CncHost points at a real CNC to un-gate.
+
+.PARAMETER CncHost
+  IP or hostname of the CNC. Default 127.0.0.1 — override for real runs.
+
+.PARAMETER CncPort
+  FOCAS TCP port. Default 8193.
+
+.PARAMETER Address
+  FOCAS address to exercise. Default R100 (PMC R-file register).
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint.
+
+.PARAMETER BridgeNodeId
+  NodeId at which the server publishes the Address.
+#>
+
+param(
+    [string]$CncHost = "127.0.0.1",
+    [int]$CncPort = 8193,
+    [string]$Address = "R100",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$BridgeNodeId
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+if (-not ($env:FOCAS_TRUST_WIRE -eq "1" -or $env:FOCAS_TRUST_WIRE -eq "true")) {
+    Write-Skip "FOCAS_TRUST_WIRE not set — no public simulator exists (task #222 tracks the lab rig). Set =1 when -CncHost points at a real CNC with Fwlib32.dll on PATH."
+    exit 0
+}
+
+$focasCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli" `
+    -ExeName "otopcua-focas-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$commonFocas = @("-h", $CncHost, "-p", $CncPort)
+$results = @()
+
+$results += Test-Probe `
+    -Cli $focasCli `
+    -ProbeArgs (@("probe") + $commonFocas + @("-a", $Address, "--type", "Int16"))
+
+$writeValue = Get-Random -Minimum 1 -Maximum 9999
+$results += Test-DriverLoopback `
+    -Cli $focasCli `
+    -WriteArgs (@("write") + $commonFocas + @("-a", $Address, "-t", "Int16", "-v", $writeValue)) `
+    -ReadArgs  (@("read")  + $commonFocas + @("-a", $Address, "-t", "Int16")) `
+    -ExpectedValue "$writeValue"
+
+$bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
+$results += Test-ServerBridge `
+    -DriverCli $focasCli `
+    -DriverWriteArgs (@("write") + $commonFocas + @("-a", $Address, "-t", "Int16", "-v", $bridgeValue)) `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -ExpectedValue "$bridgeValue"
+
+$reverseValue = Get-Random -Minimum 20000 -Maximum 29999
+$results += Test-OpcUaWriteBridge `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $focasCli `
+    -DriverReadArgs (@("read") + $commonFocas + @("-a", $Address, "-t", "Int16")) `
+    -ExpectedValue "$reverseValue"
+
+$subValue = Get-Random -Minimum 30000 -Maximum 32766
+$results += Test-SubscribeSeesChange `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $focasCli `
+    -DriverWriteArgs (@("write") + $commonFocas + @("-a", $Address, "-t", "Int16", "-v", $subValue)) `
+    -ExpectedValue "$subValue"
+
+Write-Summary -Title "FOCAS e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-galaxy.ps1

@@ -0,0 +1,278 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for the Galaxy (MXAccess) driver — read, write, subscribe,
+  alarms, and history through a running OtOpcUa server.
+
+.DESCRIPTION
+  Unlike the other e2e scripts there is no `otopcua-galaxy-cli` — the Galaxy
+  driver proxy lives in-process with the server + talks to `OtOpcUaGalaxyHost`
+  over a named pipe (MXAccess is 32-bit COM, can't ship in the .NET 10 process).
+  Every stage therefore goes through `otopcua-cli` against the published OPC UA
+  address space.
+
+  Seven stages:
+
+    1. Probe             — otopcua-cli connect + read the source NodeId; confirms
+                           the whole Galaxy.Host → Proxy → server → client chain is
+                           up
+    2. Source read       — otopcua-cli read returns a Good value for the source
+                           attribute; proves IReadable.ReadAsync is dispatching
+                           through the IPC bridge
+    3. Virtual-tag bridge — `otopcua-cli read` on the VirtualTag NodeId; confirms
+                           the Phase 7 CachedTagUpstreamSource is bridging the
+                           driver-sourced input into the scripting engine
+    4. Subscribe-sees-change — subscribe to the source NodeId in the background;
+                           Galaxy pushes a data-change event within N seconds
+                           (Galaxy's underlying attribute must be actively
+                           changing — production Galaxies typically have
+                           scan-driven updates; for idle galaxies, widen
+                           -ChangeWaitSec or drive the write stage below first)
+    5. Reverse bridge    — `otopcua-cli write` to a writable Galaxy attribute;
+                           read it back. Gracefully becomes INFO-only if the
+                           attribute's Galaxy-side AccessLevel forbids writes
+                           (BadUserAccessDenied / BadNotWritable)
+    6. Alarm fires       — subscribe to the scripted-alarm Condition NodeId,
+                           drive the source tag above its threshold, confirm an
+                           Active alarm event surfaces. Exercises the Part 9
+                           alarm-condition propagation path
+    7. History read      — historyread on the source tag over the last hour;
+                           confirms Aveva Historian → IHistoryProvider dispatch
+                           returns samples
+
+  The Phase 7 seed (`scripts/smoke/seed-phase-7-smoke.sql`) already plants the
+  right shape — one Galaxy DriverInstance, one source Tag, one VirtualTag
+  (source × 2), one ScriptedAlarm (source > 50). Substitute the real Galaxy
+  attribute FullName into `dbo.Tag.TagConfig` before running.
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint. Default opc.tcp://localhost:4840.
+
+.PARAMETER SourceNodeId
+  NodeId of the driver-sourced Galaxy tag (numeric, writable preferred).
+  Default matches the Phase 7 seed — `ns=2;s=p7-smoke-tag-source`.
+
+.PARAMETER VirtualNodeId
+  NodeId of the VirtualTag computed as Source × 2 (Phase 7 scripting).
+  Default matches the Phase 7 seed — `ns=2;s=p7-smoke-vt-derived`.
+
+.PARAMETER AlarmNodeId
+  NodeId of the scripted-alarm Condition (fires when Source > 50).
+  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.
+  Default 75 (well above the seeded 50-threshold).
+
+.PARAMETER ChangeWaitSec
+  Seconds the subscribe-sees-change stage waits for a natural data change.
+  Default 10. Idle galaxies may need this extended or the stage will fail
+  with "subscribe did not observe...".
+
+.PARAMETER AlarmWaitSec
+  Seconds the alarm-fires stage waits after triggering the write. Default 10.
+
+.PARAMETER HistoryLookbackSec
+  Seconds back from now to query history. Default 3600 (1 h).
+
+.EXAMPLE
+  # Against the default Phase-7 smoke seed + live Galaxy + OtOpcUa server
+  ./scripts/e2e/test-galaxy.ps1
+
+.EXAMPLE
+  # Custom NodeIds from a non-smoke cluster
+  ./scripts/e2e/test-galaxy.ps1 `
+    -SourceNodeId "ns=2;s=Reactor1.Temperature" `
+    -VirtualNodeId "ns=2;s=Reactor1.TempDoubled" `
+    -AlarmNodeId   "ns=2;s=Reactor1.OverTemp" `
+    -AlarmTriggerValue 120
+#>
+
+param(
+    [string]$OpcUaUrl           = "opc.tcp://localhost:4840",
+    [string]$SourceNodeId       = "ns=2;s=p7-smoke-tag-source",
+    [string]$VirtualNodeId      = "ns=2;s=p7-smoke-vt-derived",
+    [string]$AlarmNodeId        = "ns=2;s=p7-smoke-al-overtemp",
+    [string]$AlarmTriggerValue  = "75",
+    [int]$ChangeWaitSec         = 10,
+    [int]$AlarmWaitSec          = 10,
+    [int]$HistoryLookbackSec    = 3600
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$results = @()
+
+# ---------------------------------------------------------------------------
+# Stage 1 — Probe. The probe is an otopcua-cli read against the source NodeId;
+# success implies Galaxy.Host is up + the pipe ACL lets the server connect +
+# the Proxy is tracking the tag + the server published it.
+# ---------------------------------------------------------------------------
+
+Write-Header "Probe"
+$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 = $true }
+} else {
+    Write-Fail "probe read failed (exit=$($probe.ExitCode))"
+    Write-Host $probe.Output
+    $results += @{ Passed = $false; Reason = "probe failed" }
+}
+
+# ---------------------------------------------------------------------------
+# Stage 2 — Source read. Captures the current value for the later virtual-tag
+# comparison + confirms read dispatch works end-to-end. Failure here without a
+# stage-1 failure would be unusual — probe already reads.
+# ---------------------------------------------------------------------------
+
+Write-Header "Source read"
+$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()
+    Write-Pass "source value = $sourceValue"
+    $results += @{ Passed = $true }
+} else {
+    Write-Fail "source read failed"
+    Write-Host $sourceRead.Output
+    $results += @{ Passed = $false; Reason = "source read failed" }
+}
+
+# ---------------------------------------------------------------------------
+# Stage 3 — Virtual-tag bridge. Reads the Phase 7 VirtualTag (source × 2). Not
+# strictly driver-specific, but exercises the CachedTagUpstreamSource bridge
+# (the seam most likely to silently stop working after a Galaxy-side change).
+# Skip if the VirtualNodeId param is empty (non-Phase-7 clusters).
+# ---------------------------------------------------------------------------
+
+if ([string]::IsNullOrEmpty($VirtualNodeId)) {
+    Write-Header "Virtual-tag bridge"
+    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", $VirtualNodeId)
+    if ($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)"
+        $results += @{ Passed = $true }
+    } else {
+        Write-Fail "virtual-tag read failed"
+        Write-Host $vtRead.Output
+        $results += @{ Passed = $false; Reason = "virtual-tag read failed" }
+    }
+}
+
+# ---------------------------------------------------------------------------
+# Stage 4 — Subscribe-sees-change. otopcua-cli subscribe in the background;
+# wait N seconds for Galaxy to push any data-change event on the source node.
+# This is optimistic — if the Galaxy attribute is idle, widen -ChangeWaitSec.
+# ---------------------------------------------------------------------------
+
+Write-Header "Subscribe sees change"
+$stdout = New-TemporaryFile
+$stderr = New-TemporaryFile
+$subArgs = @($opcUaCli.PrefixArgs) + @(
+    "subscribe", "-u", $OpcUaUrl, "-n", $SourceNodeId,
+    "-i", "500", "--duration", "$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, $stderr.FullName -ErrorAction SilentlyContinue
+
+# Any `=` followed by `(Good)` line after the initial subscribe-confirmation
+# indicates at least one data-change tick arrived.
+$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 }
+} else {
+    Write-Fail "no data-change events in ${ChangeWaitSec}s — Galaxy attribute may be idle; rerun with -ChangeWaitSec larger, or trigger a change first"
+    Write-Host $subOut
+    $results += @{ Passed = $false; Reason = "no data-change" }
+}
+
+# ---------------------------------------------------------------------------
+# Stage 5 — Reverse bridge (OPC UA write → Galaxy). Galaxy attributes with
+# AccessLevel > FreeAccess often reject anonymous writes; record as INFO when
+# that's the case rather than failing the whole script.
+# ---------------------------------------------------------------------------
+
+Write-Header "Reverse bridge (OPC UA write)"
+$writeValue = [int]$AlarmTriggerValue   # reuse the alarm trigger value — two stages for one write
+$w = Invoke-Cli -Cli $opcUaCli -Args @(
+    "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)"
+    Write-Host $w.Output
+    $results += @{ Passed = $false; Reason = "write failed" }
+} elseif ($w.Output -match "Write failed:\s*0x801F0000") {
+    Write-Info "BadUserAccessDenied — attribute's Galaxy-side ACL blocks writes for this session. Not a bug; grant WriteOperate or run against a writable attribute."
+    $results += @{ Passed = $true; Reason = "acl-expected" }
+} elseif ($w.Output -match "Write failed:\s*0x80390000|BadNotWritable") {
+    Write-Info "BadNotWritable — attribute is read-only at the Galaxy layer (status attributes, @-prefixed meta, etc)."
+    $results += @{ Passed = $true; Reason = "readonly-expected" }
+} elseif ($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", $SourceNodeId)
+    if ($r.Output -match "Value:\s+$([Regex]::Escape("$writeValue"))\b") {
+        Write-Pass "write propagated — source reads back $writeValue"
+        $results += @{ Passed = $true }
+    } else {
+        Write-Fail "write reported success but read-back did not reflect $writeValue"
+        Write-Host $r.Output
+        $results += @{ Passed = $false; Reason = "write-readback mismatch" }
+    }
+} else {
+    Write-Fail "unexpected write response"
+    Write-Host $w.Output
+    $results += @{ Passed = $false; Reason = "unexpected write response" }
+}
+
+# ---------------------------------------------------------------------------
+# Stage 6 — Alarm fires. Uses the helper from _common.ps1. If stage 5 already
+# wrote the trigger value the alarm may already be active; that's fine — the
+# Part 9 ConditionRefresh in the alarms CLI replays the current state so the
+# subscribe window still captures the Active event.
+# ---------------------------------------------------------------------------
+
+if ([string]::IsNullOrEmpty($AlarmNodeId)) {
+    Write-Header "Alarm fires on threshold"
+    Write-Skip "AlarmNodeId not supplied — skipping alarm check"
+} else {
+    $results += Test-AlarmFiresOnThreshold `
+        -OpcUaCli $opcUaCli `
+        -OpcUaUrl $OpcUaUrl `
+        -AlarmNodeId $AlarmNodeId `
+        -InputNodeId $SourceNodeId `
+        -TriggerValue $AlarmTriggerValue `
+        -DurationSec $AlarmWaitSec
+}
+
+# ---------------------------------------------------------------------------
+# Stage 7 — History read. historyread against the source tag over the last N
+# seconds. Failure modes the skip pattern catches: tag not historized in the
+# Galaxy attribute's historization profile, or the lookback window misses the
+# sample cadence.
+# ---------------------------------------------------------------------------
+
+$results += Test-HistoryHasSamples `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -NodeId $SourceNodeId `
+    -LookbackSec $HistoryLookbackSec
+
+Write-Summary -Title "Galaxy e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-modbus.ps1

@@ -0,0 +1,99 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for the Modbus-TCP driver bridged through the OtOpcUa server.
+
+.DESCRIPTION
+  Five assertions:
+    1. `otopcua-modbus-cli probe` hits the simulator
+    2. Driver-loopback write + read-back via modbus-cli
+    3. Forward bridge: modbus-cli writes HR[200], OPC UA client reads the bridged NodeId
+    4. Reverse bridge: OPC UA client writes the NodeId, modbus-cli reads HR[200]
+    5. Subscribe-sees-change: OPC UA subscription observes a modbus-cli write
+
+  Requires a running Modbus simulator on localhost:5020 (the pymodbus fixture
+  default — see tests/.../Modbus.IntegrationTests/Docker/docker-compose.yml)
+  and a running OtOpcUa server whose config DB has a Modbus DriverInstance
+  bound to that simulator + a Tag at HR[200] UInt16 published under the
+  NodeId passed via -BridgeNodeId.
+
+  NOTE: HR[200] (not HR[100]) — pymodbus standard.json makes HR[100] an
+  auto-incrementing register that mutates every poll, so loopback writes
+  can't be verified there.
+
+.PARAMETER ModbusHost
+  Host:port of the Modbus simulator. Default 127.0.0.1:5020.
+
+.PARAMETER OpcUaUrl
+  Endpoint URL of the OtOpcUa server. Default opc.tcp://localhost:4840.
+
+.PARAMETER BridgeNodeId
+  OPC UA NodeId the OtOpcUa server publishes the HR[100] tag at. Set per your
+  server config — e.g. 'ns=2;s=/warsaw/modbus-sim/HR_100'. Required.
+
+.EXAMPLE
+  .\test-modbus.ps1 -BridgeNodeId "ns=2;s=/warsaw/modbus-sim/HR_100"
+#>
+
+param(
+    [string]$ModbusHost = "127.0.0.1:5020",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$BridgeNodeId
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+$hostPart, $portPart = $ModbusHost.Split(":")
+$port = [int]$portPart
+
+$modbusCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli" `
+    -ExeName "otopcua-modbus-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$commonModbus = @("-h", $hostPart, "-p", $port)
+$results = @()
+
+$results += Test-Probe `
+    -Cli $modbusCli `
+    -ProbeArgs (@("probe") + $commonModbus)
+
+$writeValue = Get-Random -Minimum 1 -Maximum 9999
+$results += Test-DriverLoopback `
+    -Cli $modbusCli `
+    -WriteArgs (@("write") + $commonModbus + @("-r", "HoldingRegisters", "-a", "200", "-t", "UInt16", "-v", $writeValue)) `
+    -ReadArgs  (@("read")  + $commonModbus + @("-r", "HoldingRegisters", "-a", "200", "-t", "UInt16")) `
+    -ExpectedValue "$writeValue"
+
+$bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
+$results += Test-ServerBridge `
+    -DriverCli $modbusCli `
+    -DriverWriteArgs (@("write") + $commonModbus + @("-r", "HoldingRegisters", "-a", "200", "-t", "UInt16", "-v", $bridgeValue)) `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -ExpectedValue "$bridgeValue"
+
+$reverseValue = Get-Random -Minimum 20000 -Maximum 29999
+$results += Test-OpcUaWriteBridge `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $modbusCli `
+    -DriverReadArgs (@("read") + $commonModbus + @("-r", "HoldingRegisters", "-a", "200", "-t", "UInt16")) `
+    -ExpectedValue "$reverseValue"
+
+$subValue = Get-Random -Minimum 30000 -Maximum 39999
+$results += Test-SubscribeSeesChange `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $modbusCli `
+    -DriverWriteArgs (@("write") + $commonModbus + @("-r", "HoldingRegisters", "-a", "200", "-t", "UInt16", "-v", $subValue)) `
+    -ExpectedValue "$subValue"
+
+Write-Summary -Title "Modbus e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-phase7-virtualtags.ps1

@@ -0,0 +1,156 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end test for Phase 7 virtual tags + scripted alarms, driven via the
+  Modbus CLI.
+
+.DESCRIPTION
+  Assumes the OtOpcUa server's config DB has this Phase 7 scaffolding:
+
+    1. A Modbus DriverInstance bound to -ModbusHost, with a Tag at HR[100]
+       as UInt16 published under -InputNodeId.
+    2. A VirtualTag `VT_DoubledHR100` = `double(input)` where input is
+       HR[100], published under -VirtualNodeId.
+    3. A ScriptedAlarm `Alarm_HighHR100` that fires when VT_DoubledHR100 > 100,
+       published so the client can subscribe to AlarmConditionType events.
+
+  Three assertions:
+    1. Virtual-tag bridge — modbus-cli writes HR[100]=21, OPC UA client reads
+       VirtualNodeId + expects 42.
+    2. Alarm fire — modbus-cli writes HR[100]=60 (VT=120, above threshold),
+       OPC UA client alarms subscribe sees the condition go Active.
+    3. Alarm clear — modbus-cli writes HR[100]=10 (VT=20, below threshold),
+       OPC UA client sees the condition go back to Inactive.
+
+  See scripts/smoke/seed-phase-7-smoke.sql for the seed shape. This script
+  doesn't seed; it verifies the running state.
+
+.PARAMETER ModbusHost
+  Modbus simulator endpoint. Default 127.0.0.1:5502.
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint.
+
+.PARAMETER InputNodeId
+  NodeId at which the server publishes HR[100] (the input tag).
+
+.PARAMETER VirtualNodeId
+  NodeId at which the server publishes VT_DoubledHR100.
+
+.PARAMETER AlarmNodeId
+  NodeId of the AlarmConditionType (or its source) the server publishes for
+  Alarm_HighHR100. Alarms subscribe filters by SourceNode = this NodeId.
+#>
+
+param(
+    [string]$ModbusHost = "127.0.0.1:5502",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$InputNodeId,
+    [Parameter(Mandatory)] [string]$VirtualNodeId,
+    [string]$AlarmNodeId
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+$hostPart, $portPart = $ModbusHost.Split(":")
+$port = [int]$portPart
+
+$modbusCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Cli" `
+    -ExeName "otopcua-modbus-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$commonModbus = @("-h", $hostPart, "-p", $port)
+$results = @()
+
+# --- Assertion 1: virtual-tag bridge ------------------------------------------
+Write-Header "Virtual tag — VT_DoubledHR100 = HR[100] * 2"
+$inputValue = 21
+$expectedVirtual = $inputValue * 2
+
+$w = Invoke-Cli -Cli $modbusCli -Args (@("write") + $commonModbus + `
+    @("-r", "HoldingRegisters", "-a", "100", "-t", "UInt16", "-v", $inputValue))
+if ($w.ExitCode -ne 0) {
+    Write-Fail "modbus write failed (exit=$($w.ExitCode))"
+    $results += @{ Passed = $false; Reason = "seed write failed" }
+}
+else {
+    Write-Info "wrote HR[100]=$inputValue, waiting 3s for virtual-tag engine to re-evaluate"
+    Start-Sleep -Seconds 3
+    $r = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $VirtualNodeId)
+    if ($r.ExitCode -eq 0 -and $r.Output -match "Value:\s+$expectedVirtual\b") {
+        Write-Pass "virtual tag = $expectedVirtual (input * 2)"
+        $results += @{ Passed = $true }
+    }
+    else {
+        Write-Fail "expected VT = $expectedVirtual; got:"
+        Write-Host $r.Output
+        $results += @{ Passed = $false; Reason = "virtual tag mismatch" }
+    }
+}
+
+# --- Assertion 2: scripted alarm fires ---------------------------------------
+if ([string]::IsNullOrWhiteSpace($AlarmNodeId)) {
+    Write-Skip "AlarmNodeId not provided — skipping alarm fire/clear assertions"
+}
+else {
+    Write-Header "Scripted alarm — fires when VT > 100"
+    $fireValue = 60   # VT = 120, above threshold
+    $w = Invoke-Cli -Cli $modbusCli -Args (@("write") + $commonModbus + `
+        @("-r", "HoldingRegisters", "-a", "100", "-t", "UInt16", "-v", $fireValue))
+    if ($w.ExitCode -ne 0) {
+        Write-Fail "modbus write failed"
+        $results += @{ Passed = $false }
+    }
+    else {
+        Write-Info "wrote HR[100]=$fireValue (VT=$($fireValue*2)); subscribing alarms for 5s"
+        # otopcua-cli's `alarms` command subscribes + prints events until an
+        # interrupt or timeout. We capture ~5s worth then parse for ActiveState.
+        $job = Start-Job -ScriptBlock {
+            param($file, $prefix, $url, $source)
+            $cmdArgs = $prefix + @("alarms", "-u", $url, "-n", $source, "--duration-seconds", "5")
+            & $file @cmdArgs 2>&1
+        } -ArgumentList $opcUaCli.File, $opcUaCli.PrefixArgs, $OpcUaUrl, $AlarmNodeId
+
+        $alarmOutput = Receive-Job -Job $job -Wait -AutoRemoveJob
+        $alarmText = ($alarmOutput | Out-String)
+        if ($alarmText -match "Active" -or $alarmText -match "HighAlarm" -or $alarmText -match "Severity") {
+            Write-Pass "alarm subscription received an event"
+            $results += @{ Passed = $true }
+        }
+        else {
+            Write-Fail "expected alarm event in subscription output"
+            Write-Host $alarmText
+            $results += @{ Passed = $false; Reason = "alarm did not fire" }
+        }
+    }
+
+    # --- Assertion 3: alarm clears ---
+    Write-Header "Scripted alarm — clears when VT falls below threshold"
+    $clearValue = 10  # VT = 20, below threshold
+    $w = Invoke-Cli -Cli $modbusCli -Args (@("write") + $commonModbus + `
+        @("-r", "HoldingRegisters", "-a", "100", "-t", "UInt16", "-v", $clearValue))
+    if ($w.ExitCode -eq 0) {
+        Write-Info "wrote HR[100]=$clearValue (VT=$($clearValue*2)); alarm should clear"
+        # We don't re-subscribe here — the clear is asserted via the virtual
+        # tag's current value (the Phase 7 engine's commitment is that state
+        # propagates on the next tick; the OPC UA alarm transition follows).
+        Start-Sleep -Seconds 3
+        $r = Invoke-Cli -Cli $opcUaCli -Args @("read", "-u", $OpcUaUrl, "-n", $VirtualNodeId)
+        if ($r.Output -match "Value:\s+$($clearValue*2)\b") {
+            Write-Pass "virtual tag returned to below-threshold ($($clearValue*2))"
+            $results += @{ Passed = $true }
+        }
+        else {
+            Write-Fail "virtual tag did not reflect cleared state"
+            Write-Host $r.Output
+            $results += @{ Passed = $false; Reason = "clear state mismatch" }
+        }
+    }
+}
+
+Write-Summary -Title "Phase 7 virtual tags + scripted alarms" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-s7.ps1

@@ -0,0 +1,100 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for the Siemens S7 driver bridged through the OtOpcUa server.
+
+.DESCRIPTION
+  Five assertions (probe / driver-loopback / forward-bridge / reverse-bridge /
+  subscribe-sees-change) against a Siemens S7-300/400/1200/1500 or compatible
+  soft-PLC. python-snap7 simulator (task #216) or real hardware both work.
+
+  Prereqs:
+    - S7 simulator / PLC on $S7Host:$S7Port
+    - On real S7-1200/1500: PUT/GET communication enabled in TIA Portal.
+    - OtOpcUa server running with an S7 DriverInstance bound to the same
+      endpoint + a Tag at DB1.DBW0 Int16 published under -BridgeNodeId.
+
+.PARAMETER S7Host
+  Host:port of the S7 simulator / PLC. Default 127.0.0.1:102.
+
+.PARAMETER Cpu
+  S7200 / S7200Smart / S7300 / S7400 / S71200 / S71500 (default S71500).
+
+.PARAMETER Slot
+  CPU slot. Default 0 (S7-1200/1500). S7-300 uses 2.
+
+.PARAMETER Address
+  S7 address to exercise. Default DB1.DBW0.
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint.
+
+.PARAMETER BridgeNodeId
+  NodeId at which the server publishes the Address.
+#>
+
+param(
+    [string]$S7Host = "127.0.0.1:102",
+    [string]$Cpu = "S71500",
+    [int]$Slot = 0,
+    [string]$Address = "DB1.DBW0",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$BridgeNodeId
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+$hostPart, $portPart = $S7Host.Split(":")
+$port = [int]$portPart
+
+$s7Cli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli" `
+    -ExeName "otopcua-s7-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$commonS7 = @("-h", $hostPart, "-p", $port, "-c", $Cpu, "--slot", $Slot)
+$results = @()
+
+$results += Test-Probe `
+    -Cli $s7Cli `
+    -ProbeArgs (@("probe") + $commonS7)
+
+$writeValue = Get-Random -Minimum 1 -Maximum 9999
+$results += Test-DriverLoopback `
+    -Cli $s7Cli `
+    -WriteArgs (@("write") + $commonS7 + @("-a", $Address, "-t", "Int16", "-v", $writeValue)) `
+    -ReadArgs  (@("read")  + $commonS7 + @("-a", $Address, "-t", "Int16")) `
+    -ExpectedValue "$writeValue"
+
+$bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
+$results += Test-ServerBridge `
+    -DriverCli $s7Cli `
+    -DriverWriteArgs (@("write") + $commonS7 + @("-a", $Address, "-t", "Int16", "-v", $bridgeValue)) `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -ExpectedValue "$bridgeValue"
+
+$reverseValue = Get-Random -Minimum 20000 -Maximum 29999
+$results += Test-OpcUaWriteBridge `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $s7Cli `
+    -DriverReadArgs (@("read") + $commonS7 + @("-a", $Address, "-t", "Int16")) `
+    -ExpectedValue "$reverseValue"
+
+$subValue = Get-Random -Minimum 30000 -Maximum 32766
+$results += Test-SubscribeSeesChange `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $s7Cli `
+    -DriverWriteArgs (@("write") + $commonS7 + @("-a", $Address, "-t", "Int16", "-v", $subValue)) `
+    -ExpectedValue "$subValue"
+
+Write-Summary -Title "S7 e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/e2e/test-twincat.ps1

@@ -0,0 +1,99 @@
+#Requires -Version 7.0
+<#
+.SYNOPSIS
+  End-to-end CLI test for the TwinCAT (Beckhoff ADS) driver.
+
+.DESCRIPTION
+  Requires a reachable AMS router (local TwinCAT XAR, Beckhoff.TwinCAT.Ads.
+  TcpRouter NuGet, or an authorised remote AMS route) + a live TwinCAT
+  runtime on -AmsNetId. Without one the driver surfaces a transport error
+  on InitializeAsync + the script's probe fails.
+
+  Set TWINCAT_TRUST_WIRE=1 to promise the endpoint is live. Without it the
+  script skips (task #221 tracks the 7-day-trial CI fixture — until that
+  lands, TwinCAT testing is a manual operator task).
+
+.PARAMETER AmsNetId
+  AMS Net ID of the target (e.g. 127.0.0.1.1.1 for local XAR,
+  192.168.1.40.1.1 for a remote PLC).
+
+.PARAMETER AmsPort
+  AMS port. Default 851 (TC3 PLC runtime). TC2 uses 801.
+
+.PARAMETER SymbolPath
+  TwinCAT symbol to exercise. Default 'MAIN.iCounter' — substitute with
+  whatever your project actually declares.
+
+.PARAMETER OpcUaUrl
+  OtOpcUa server endpoint.
+
+.PARAMETER BridgeNodeId
+  NodeId at which the server publishes the Symbol.
+#>
+
+param(
+    [string]$AmsNetId = "127.0.0.1.1.1",
+    [int]$AmsPort = 851,
+    [string]$SymbolPath = "MAIN.iCounter",
+    [string]$OpcUaUrl = "opc.tcp://localhost:4840",
+    [Parameter(Mandatory)] [string]$BridgeNodeId
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot/_common.ps1"
+
+if (-not ($env:TWINCAT_TRUST_WIRE -eq "1" -or $env:TWINCAT_TRUST_WIRE -eq "true")) {
+    Write-Skip "TWINCAT_TRUST_WIRE not set — requires reachable AMS router + live TC runtime (task #221 tracks the CI fixture). Set =1 once the router is up."
+    exit 0
+}
+
+$twinCatCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli" `
+    -ExeName "otopcua-twincat-cli"
+$opcUaCli = Get-CliInvocation `
+    -ProjectFolder "src/ZB.MOM.WW.OtOpcUa.Client.CLI" `
+    -ExeName "otopcua-cli"
+
+$commonTc = @("-n", $AmsNetId, "-p", $AmsPort)
+$results = @()
+
+$results += Test-Probe `
+    -Cli $twinCatCli `
+    -ProbeArgs (@("probe") + $commonTc + @("-s", $SymbolPath, "--type", "DInt"))
+
+$writeValue = Get-Random -Minimum 1 -Maximum 9999
+$results += Test-DriverLoopback `
+    -Cli $twinCatCli `
+    -WriteArgs (@("write") + $commonTc + @("-s", $SymbolPath, "-t", "DInt", "-v", $writeValue)) `
+    -ReadArgs  (@("read")  + $commonTc + @("-s", $SymbolPath, "-t", "DInt")) `
+    -ExpectedValue "$writeValue"
+
+$bridgeValue = Get-Random -Minimum 10000 -Maximum 19999
+$results += Test-ServerBridge `
+    -DriverCli $twinCatCli `
+    -DriverWriteArgs (@("write") + $commonTc + @("-s", $SymbolPath, "-t", "DInt", "-v", $bridgeValue)) `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -ExpectedValue "$bridgeValue"
+
+$reverseValue = Get-Random -Minimum 20000 -Maximum 29999
+$results += Test-OpcUaWriteBridge `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $twinCatCli `
+    -DriverReadArgs (@("read") + $commonTc + @("-s", $SymbolPath, "-t", "DInt")) `
+    -ExpectedValue "$reverseValue"
+
+$subValue = Get-Random -Minimum 30000 -Maximum 39999
+$results += Test-SubscribeSeesChange `
+    -OpcUaCli $opcUaCli `
+    -OpcUaUrl $OpcUaUrl `
+    -OpcUaNodeId $BridgeNodeId `
+    -DriverCli $twinCatCli `
+    -DriverWriteArgs (@("write") + $commonTc + @("-s", $SymbolPath, "-t", "DInt", "-v", $subValue)) `
+    -ExpectedValue "$subValue"
+
+Write-Summary -Title "TwinCAT e2e" -Results $results
+if ($results | Where-Object { -not $_.Passed }) { exit 1 }

scripts/smoke/seed-abcip-smoke.sql

@@ -0,0 +1,128 @@
+-- AB CIP e2e smoke seed — closes #211 (umbrella #209).
+--
+-- One-cluster seed pointing at the ab_server ControlLogix fixture
+-- (`docker compose -f tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/Docker/docker-compose.yml --profile controllogix up -d`).
+-- Publishes a single `TestDINT:DInt` tag under NodeId `ns=<N>;s=TestDINT`
+-- (ab_server seeds this tag by default).
+--
+-- Usage:
+--   sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "OtOpcUaDev_2026!" \
+--          -i scripts/smoke/seed-abcip-smoke.sql
+--
+-- After seeding, point appsettings at this cluster:
+--     Node:NodeId    = "abcip-smoke-node"
+--     Node:ClusterId = "abcip-smoke"
+-- Then start server + run `./scripts/e2e/test-abcip.ps1 -BridgeNodeId "ns=2;s=TestDINT"`.
+
+SET NOCOUNT ON;
+SET XACT_ABORT ON;
+SET QUOTED_IDENTIFIER ON;
+SET ANSI_NULLS ON;
+SET ANSI_PADDING ON;
+SET ANSI_WARNINGS ON;
+SET ARITHABORT ON;
+SET CONCAT_NULL_YIELDS_NULL ON;
+
+DECLARE @ClusterId nvarchar(64) = 'abcip-smoke';
+DECLARE @NodeId    nvarchar(64) = 'abcip-smoke-node';
+DECLARE @DrvId     nvarchar(64) = 'abcip-smoke-drv';
+DECLARE @NsId      nvarchar(64) = 'abcip-smoke-ns';
+DECLARE @AreaId    nvarchar(64) = 'abcip-smoke-area';
+DECLARE @LineId    nvarchar(64) = 'abcip-smoke-line';
+DECLARE @EqId      nvarchar(64) = 'abcip-smoke-eq';
+DECLARE @EqUuid    uniqueidentifier = '41BC12E0-41BC-412E-841B-C12E041BC12E';
+DECLARE @TagId     nvarchar(64) = 'abcip-smoke-tag-testdint';
+
+BEGIN TRAN;
+
+DELETE FROM dbo.Tag                        WHERE TagId IN (@TagId);
+DELETE FROM dbo.Equipment                  WHERE EquipmentId = @EqId;
+DELETE FROM dbo.UnsLine                    WHERE UnsLineId = @LineId;
+DELETE FROM dbo.UnsArea                    WHERE UnsAreaId = @AreaId;
+DELETE FROM dbo.DriverInstance             WHERE DriverInstanceId = @DrvId;
+DELETE FROM dbo.Namespace                  WHERE NamespaceId = @NsId;
+DELETE FROM dbo.ConfigGeneration           WHERE ClusterId = @ClusterId;
+DELETE FROM dbo.ClusterNodeCredential      WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNodeGenerationState WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNode                WHERE NodeId = @NodeId;
+DELETE FROM dbo.ServerCluster              WHERE ClusterId = @ClusterId;
+
+DELETE FROM dbo.ClusterNodeCredential WHERE Kind = 'SqlLogin' AND Value = 'sa';
+
+INSERT dbo.ServerCluster(ClusterId, Name, Enterprise, Site, NodeCount, RedundancyMode, Enabled, CreatedBy)
+VALUES (@ClusterId, 'AB CIP Smoke', 'zb', 'lab', 1, 'None', 1, 'abcip-smoke');
+
+INSERT dbo.ClusterNode(NodeId, ClusterId, RedundancyRole, Host, OpcUaPort, DashboardPort,
+                       ApplicationUri, ServiceLevelBase, Enabled, CreatedBy)
+VALUES (@NodeId, @ClusterId, 'Primary', 'localhost', 4840, 15050,
+        'urn:OtOpcUa:abcip-smoke-node', 200, 1, 'abcip-smoke');
+
+INSERT dbo.ClusterNodeCredential(NodeId, Kind, Value, Enabled, CreatedBy)
+VALUES (@NodeId, 'SqlLogin', 'sa', 1, 'abcip-smoke');
+
+DECLARE @Gen bigint;
+INSERT dbo.ConfigGeneration(ClusterId, Status, CreatedBy)
+VALUES (@ClusterId, 'Draft', 'abcip-smoke');
+SET @Gen = SCOPE_IDENTITY();
+
+INSERT dbo.Namespace(GenerationId, NamespaceId, ClusterId, Kind, NamespaceUri, Enabled)
+VALUES (@Gen, @NsId, @ClusterId, 'Equipment', 'urn:abcip-smoke:eq', 1);
+
+INSERT dbo.UnsArea(GenerationId, UnsAreaId, ClusterId, Name)
+VALUES (@Gen, @AreaId, @ClusterId, 'lab-floor');
+
+INSERT dbo.UnsLine(GenerationId, UnsLineId, UnsAreaId, Name)
+VALUES (@Gen, @LineId, @AreaId, 'abcip-line');
+
+INSERT dbo.Equipment(GenerationId, EquipmentId, EquipmentUuid, DriverInstanceId, UnsLineId,
+                     Name, MachineCode, Enabled)
+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.
+INSERT dbo.DriverInstance(GenerationId, DriverInstanceId, ClusterId, NamespaceId,
+                          Name, DriverType, DriverConfig, Enabled)
+VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'ab-server-smoke', 'AbCip', N'{
+  "TimeoutMs": 2000,
+  "Devices": [
+    {
+      "HostAddress": "ab://127.0.0.1:44818/1,0",
+      "PlcFamily": "ControlLogix",
+      "DeviceName": "ab-server"
+    }
+  ],
+  "Probe": { "Enabled": true, "IntervalMs": 5000, "TimeoutMs": 2000 },
+  "Tags": [
+    {
+      "Name": "TestDINT",
+      "DeviceHostAddress": "ab://127.0.0.1:44818/1,0",
+      "TagPath": "TestDINT",
+      "DataType": "DInt",
+      "Writable": true,
+      "WriteIdempotent": true
+    }
+  ]
+}', 1);
+
+INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataType,
+               AccessLevel, TagConfig, WriteIdempotent)
+VALUES (@Gen, @TagId, @DrvId, @EqId, 'TestDINT', 'Int32', 'ReadWrite',
+        N'{"FullName":"TestDINT","DataType":"DInt"}', 1);
+
+EXEC dbo.sp_PublishGeneration @ClusterId = @ClusterId, @DraftGenerationId = @Gen,
+                              @Notes = N'AB CIP smoke — task #211';
+
+COMMIT;
+
+PRINT '';
+PRINT 'AB CIP smoke seed complete.';
+PRINT '  Cluster:    ' + @ClusterId;
+PRINT '  Node:       ' + @NodeId;
+PRINT '  Generation: ' + CONVERT(nvarchar(20), @Gen);
+PRINT '';
+PRINT 'Next steps:';
+PRINT '  1. Set src/.../Server/appsettings.json Node:NodeId = "abcip-smoke-node"';
+PRINT '                                          Node:ClusterId = "abcip-smoke"';
+PRINT '  2. docker compose -f tests/.../AbCip.IntegrationTests/Docker/docker-compose.yml --profile controllogix up -d';
+PRINT '  3. dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server';
+PRINT '  4. ./scripts/e2e/test-abcip.ps1 -BridgeNodeId "ns=2;s=TestDINT"';

scripts/smoke/seed-ablegacy-smoke.sql

@@ -0,0 +1,125 @@
+-- AB Legacy e2e smoke seed — closes #213 (umbrella #209).
+--
+-- Works against the ab_server PCCC Docker fixture (one of the slc500 /
+-- micrologix / plc5 compose profiles) or real SLC 500 / MicroLogix / PLC-5
+-- hardware. Default HostAddress below points at the Docker fixture with a
+-- `/1,0` cip-path; libplctag's ab_server rejects empty paths before routing
+-- to the PCCC dispatcher. Real hardware uses an empty path — change the
+-- HostAddress to `ab://<plc-ip>:44818/` (note the trailing slash with nothing
+-- after) before running the seed for that setup.
+--
+-- Usage:
+--   docker compose -f tests/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.IntegrationTests/Docker/docker-compose.yml --profile slc500 up -d
+--   sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "OtOpcUaDev_2026!" \
+--          -i scripts/smoke/seed-ablegacy-smoke.sql
+
+SET NOCOUNT ON;
+SET XACT_ABORT ON;
+SET QUOTED_IDENTIFIER ON;
+SET ANSI_NULLS ON;
+SET ANSI_PADDING ON;
+SET ANSI_WARNINGS ON;
+SET ARITHABORT ON;
+SET CONCAT_NULL_YIELDS_NULL ON;
+
+DECLARE @ClusterId nvarchar(64) = 'ablegacy-smoke';
+DECLARE @NodeId    nvarchar(64) = 'ablegacy-smoke-node';
+DECLARE @DrvId     nvarchar(64) = 'ablegacy-smoke-drv';
+DECLARE @NsId      nvarchar(64) = 'ablegacy-smoke-ns';
+DECLARE @AreaId    nvarchar(64) = 'ablegacy-smoke-area';
+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';
+
+BEGIN TRAN;
+
+DELETE FROM dbo.Tag                        WHERE TagId IN (@TagId);
+DELETE FROM dbo.Equipment                  WHERE EquipmentId = @EqId;
+DELETE FROM dbo.UnsLine                    WHERE UnsLineId = @LineId;
+DELETE FROM dbo.UnsArea                    WHERE UnsAreaId = @AreaId;
+DELETE FROM dbo.DriverInstance             WHERE DriverInstanceId = @DrvId;
+DELETE FROM dbo.Namespace                  WHERE NamespaceId = @NsId;
+DELETE FROM dbo.ConfigGeneration           WHERE ClusterId = @ClusterId;
+DELETE FROM dbo.ClusterNodeCredential      WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNodeGenerationState WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNode                WHERE NodeId = @NodeId;
+DELETE FROM dbo.ServerCluster              WHERE ClusterId = @ClusterId;
+
+DELETE FROM dbo.ClusterNodeCredential WHERE Kind = 'SqlLogin' AND Value = 'sa';
+
+INSERT dbo.ServerCluster(ClusterId, Name, Enterprise, Site, NodeCount, RedundancyMode, Enabled, CreatedBy)
+VALUES (@ClusterId, 'AB Legacy Smoke', 'zb', 'lab', 1, 'None', 1, 'ablegacy-smoke');
+
+INSERT dbo.ClusterNode(NodeId, ClusterId, RedundancyRole, Host, OpcUaPort, DashboardPort,
+                       ApplicationUri, ServiceLevelBase, Enabled, CreatedBy)
+VALUES (@NodeId, @ClusterId, 'Primary', 'localhost', 4840, 15050,
+        'urn:OtOpcUa:ablegacy-smoke-node', 200, 1, 'ablegacy-smoke');
+
+INSERT dbo.ClusterNodeCredential(NodeId, Kind, Value, Enabled, CreatedBy)
+VALUES (@NodeId, 'SqlLogin', 'sa', 1, 'ablegacy-smoke');
+
+DECLARE @Gen bigint;
+INSERT dbo.ConfigGeneration(ClusterId, Status, CreatedBy)
+VALUES (@ClusterId, 'Draft', 'ablegacy-smoke');
+SET @Gen = SCOPE_IDENTITY();
+
+INSERT dbo.Namespace(GenerationId, NamespaceId, ClusterId, Kind, NamespaceUri, Enabled)
+VALUES (@Gen, @NsId, @ClusterId, 'Equipment', 'urn:ablegacy-smoke:eq', 1);
+
+INSERT dbo.UnsArea(GenerationId, UnsAreaId, ClusterId, Name)
+VALUES (@Gen, @AreaId, @ClusterId, 'lab-floor');
+
+INSERT dbo.UnsLine(GenerationId, UnsLineId, UnsAreaId, Name)
+VALUES (@Gen, @LineId, @AreaId, 'ablegacy-line');
+
+INSERT dbo.Equipment(GenerationId, EquipmentId, EquipmentUuid, DriverInstanceId, UnsLineId,
+                     Name, MachineCode, Enabled)
+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.
+INSERT dbo.DriverInstance(GenerationId, DriverInstanceId, ClusterId, NamespaceId,
+                          Name, DriverType, DriverConfig, Enabled)
+VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'ablegacy-smoke', 'AbLegacy', N'{
+  "TimeoutMs": 2000,
+  "Devices": [
+    {
+      "HostAddress": "ab://127.0.0.1:44818/1,0",
+      "PlcFamily": "Slc500",
+      "DeviceName": "slc-500"
+    }
+  ],
+  "Probe": { "Enabled": true, "IntervalMs": 5000, "TimeoutMs": 2000, "ProbeAddress": "S:0" },
+  "Tags": [
+    {
+      "Name": "N7_5",
+      "DeviceHostAddress": "ab://127.0.0.1:44818/1,0",
+      "Address": "N7:5",
+      "DataType": "Int",
+      "Writable": true,
+      "WriteIdempotent": true
+    }
+  ]
+}', 1);
+
+INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataType,
+               AccessLevel, TagConfig, WriteIdempotent)
+VALUES (@Gen, @TagId, @DrvId, @EqId, 'N7_5', 'Int16', 'ReadWrite',
+        N'{"FullName":"N7_5","Address":"N7:5","DataType":"Int"}', 1);
+
+EXEC dbo.sp_PublishGeneration @ClusterId = @ClusterId, @DraftGenerationId = @Gen,
+                              @Notes = N'AB Legacy smoke — task #213';
+
+COMMIT;
+
+PRINT '';
+PRINT 'AB Legacy smoke seed complete.';
+PRINT '  Cluster:    ' + @ClusterId;
+PRINT '  Node:       ' + @NodeId;
+PRINT '  Generation: ' + CONVERT(nvarchar(20), @Gen);
+PRINT '';
+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.';

scripts/smoke/seed-modbus-smoke.sql

@@ -0,0 +1,156 @@
+-- Modbus e2e smoke seed — closes #210 (umbrella #209).
+--
+-- Idempotent — DROP-and-recreate of one cluster's worth of Modbus test config:
+--   * 1 ServerCluster ('modbus-smoke') + ClusterNode ('modbus-smoke-node')
+--   * 1 ConfigGeneration (Draft → Published at the end)
+--   * 1 Namespace + UnsArea + UnsLine + Equipment
+--   * 1 Modbus DriverInstance pointing at the pymodbus standard fixture
+--     (127.0.0.1:5020 per tests/.../Modbus.IntegrationTests/Docker)
+--   * 1 Tag at HR[200]:UInt16 (HR[100] is auto-increment in standard.json,
+--     unusable as a write target — the e2e script uses HR[200] for that reason)
+--
+-- Usage:
+--   sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "OtOpcUaDev_2026!" \
+--          -i scripts/smoke/seed-modbus-smoke.sql
+--
+-- After seeding, update src/.../Server/appsettings.json:
+--     Node:NodeId    = "modbus-smoke-node"
+--     Node:ClusterId = "modbus-smoke"
+--
+-- Then start the simulator + server + run the e2e script:
+--   docker compose -f tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/Docker/docker-compose.yml --profile standard up -d
+--   dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server
+--   ./scripts/e2e/test-modbus.ps1 -BridgeNodeId "ns=2;s=HR200"
+
+SET NOCOUNT ON;
+SET XACT_ABORT ON;
+SET QUOTED_IDENTIFIER ON;
+SET ANSI_NULLS ON;
+SET ANSI_PADDING ON;
+SET ANSI_WARNINGS ON;
+SET ARITHABORT ON;
+SET CONCAT_NULL_YIELDS_NULL ON;
+
+DECLARE @ClusterId nvarchar(64) = 'modbus-smoke';
+DECLARE @NodeId    nvarchar(64) = 'modbus-smoke-node';
+DECLARE @DrvId     nvarchar(64) = 'modbus-smoke-drv';
+DECLARE @NsId      nvarchar(64) = 'modbus-smoke-ns';
+DECLARE @AreaId    nvarchar(64) = 'modbus-smoke-area';
+DECLARE @LineId    nvarchar(64) = 'modbus-smoke-line';
+DECLARE @EqId      nvarchar(64) = 'modbus-smoke-eq';
+DECLARE @EqUuid    uniqueidentifier = '72BD5A10-72BD-45A1-B72B-D5A1072BD5A1';
+DECLARE @TagHr200  nvarchar(64) = 'modbus-smoke-tag-hr200';
+
+BEGIN TRAN;
+
+-- Clean prior smoke state (child rows first).
+DELETE FROM dbo.Tag                        WHERE TagId IN (@TagHr200);
+DELETE FROM dbo.Equipment                  WHERE EquipmentId = @EqId;
+DELETE FROM dbo.UnsLine                    WHERE UnsLineId = @LineId;
+DELETE FROM dbo.UnsArea                    WHERE UnsAreaId = @AreaId;
+DELETE FROM dbo.DriverInstance             WHERE DriverInstanceId = @DrvId;
+DELETE FROM dbo.Namespace                  WHERE NamespaceId = @NsId;
+DELETE FROM dbo.ConfigGeneration           WHERE ClusterId = @ClusterId;
+DELETE FROM dbo.ClusterNodeCredential      WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNodeGenerationState WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNode                WHERE NodeId = @NodeId;
+DELETE FROM dbo.ServerCluster              WHERE ClusterId = @ClusterId;
+
+-- `UX_ClusterNodeCredential_Value` is a unique index on (Kind, Value) WHERE
+-- Enabled=1, so a `sa` login can only bind to one node at a time. Drop any
+-- prior smoke cluster's binding before we claim the login for this one.
+DELETE FROM dbo.ClusterNodeCredential WHERE Kind = 'SqlLogin' AND Value = 'sa';
+
+-- 1. Cluster + Node.
+INSERT dbo.ServerCluster(ClusterId, Name, Enterprise, Site, NodeCount, RedundancyMode, Enabled, CreatedBy)
+VALUES (@ClusterId, 'Modbus Smoke', 'zb', 'lab', 1, 'None', 1, 'modbus-smoke');
+
+-- DashboardPort 15050 rather than 5000 — HttpListener on :5000 requires
+-- URL-ACL reservation or admin rights on Windows (HttpListenerException 32).
+-- 15000+ ports are unreserved by default. Safe to change back when deploying
+-- with a netsh urlacl grant or reverse-proxy fronting :5000.
+INSERT dbo.ClusterNode(NodeId, ClusterId, RedundancyRole, Host, OpcUaPort, DashboardPort,
+                       ApplicationUri, ServiceLevelBase, Enabled, CreatedBy)
+VALUES (@NodeId, @ClusterId, 'Primary', 'localhost', 4840, 15050,
+        'urn:OtOpcUa:modbus-smoke-node', 200, 1, 'modbus-smoke');
+
+-- Bind the SQL login this smoke test connects as to the node identity. The
+-- sp_GetCurrentGenerationForCluster + sp_UpdateClusterNodeGenerationState
+-- sprocs raise RAISERROR('Unauthorized: caller %s is not bound to NodeId %s')
+-- when this row is missing. `Kind='SqlLogin'` / `Value='sa'` matches the
+-- container's SA user; rotate Value for real deployments using a non-SA login.
+INSERT dbo.ClusterNodeCredential(NodeId, Kind, Value, Enabled, CreatedBy)
+VALUES (@NodeId, 'SqlLogin', 'sa', 1, 'modbus-smoke');
+
+-- 2. Draft generation.
+DECLARE @Gen bigint;
+INSERT dbo.ConfigGeneration(ClusterId, Status, CreatedBy)
+VALUES (@ClusterId, 'Draft', 'modbus-smoke');
+SET @Gen = SCOPE_IDENTITY();
+
+-- 3. Namespace.
+INSERT dbo.Namespace(GenerationId, NamespaceId, ClusterId, Kind, NamespaceUri, Enabled)
+VALUES (@Gen, @NsId, @ClusterId, 'Equipment', 'urn:modbus-smoke:eq', 1);
+
+-- 4. UNS hierarchy.
+INSERT dbo.UnsArea(GenerationId, UnsAreaId, ClusterId, Name)
+VALUES (@Gen, @AreaId, @ClusterId, 'lab-floor');
+
+INSERT dbo.UnsLine(GenerationId, UnsLineId, UnsAreaId, Name)
+VALUES (@Gen, @LineId, @AreaId, 'modbus-line');
+
+INSERT dbo.Equipment(GenerationId, EquipmentId, EquipmentUuid, DriverInstanceId, UnsLineId,
+                     Name, MachineCode, Enabled)
+VALUES (@Gen, @EqId, @EqUuid, @DrvId, @LineId, 'modbus-sim', 'modbus-001', 1);
+
+-- 5. Modbus DriverInstance. DriverConfig mirrors ModbusDriverConfigDto
+--    (mapped to ModbusDriverOptions by ModbusDriverFactoryExtensions).
+INSERT dbo.DriverInstance(GenerationId, DriverInstanceId, ClusterId, NamespaceId,
+                          Name, DriverType, DriverConfig, Enabled)
+VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'pymodbus-smoke', 'Modbus', N'{
+  "Host": "127.0.0.1",
+  "Port": 5020,
+  "UnitId": 1,
+  "TimeoutMs": 2000,
+  "AutoReconnect": true,
+  "Probe": { "Enabled": true, "IntervalMs": 5000, "TimeoutMs": 2000, "ProbeAddress": 0 },
+  "Tags": [
+    {
+      "Name": "HR200",
+      "Region": "HoldingRegisters",
+      "Address": 200,
+      "DataType": "UInt16",
+      "Writable": true,
+      "WriteIdempotent": true
+    }
+  ]
+}', 1);
+
+-- 6. Tag row bound to the Equipment. Driver reports the same tag via
+--    DiscoverAsync + the walker maps the UnsArea/Line/Equipment/Tag path to the
+--    driver's folder/variable (NodeId ends up ns=<driver-ns>;s=HR200 per
+--    ModbusDriver.DiscoverAsync using FullName = tag.Name).
+INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataType,
+               AccessLevel, TagConfig, WriteIdempotent)
+VALUES (@Gen, @TagHr200, @DrvId, @EqId, 'HR200', 'UInt16', 'ReadWrite',
+        N'{"FullName":"HR200","DataType":"UInt16"}', 1);
+
+-- 7. Publish the generation — flips Status Draft → Published, merges
+--    ExternalIdReservation, claims cluster write lock.
+EXEC dbo.sp_PublishGeneration @ClusterId = @ClusterId, @DraftGenerationId = @Gen,
+                              @Notes = N'Modbus smoke — task #210';
+
+COMMIT;
+
+PRINT '';
+PRINT 'Modbus smoke seed complete.';
+PRINT '  Cluster:    ' + @ClusterId;
+PRINT '  Node:       ' + @NodeId;
+PRINT '  Generation: ' + CONVERT(nvarchar(20), @Gen);
+PRINT '';
+PRINT 'Next steps:';
+PRINT '  1. Set src/.../Server/appsettings.json Node:NodeId = "modbus-smoke-node"';
+PRINT '                                          Node:ClusterId = "modbus-smoke"';
+PRINT '  2. docker compose -f tests/.../Modbus.IntegrationTests/Docker/docker-compose.yml --profile standard up -d';
+PRINT '  3. dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server';
+PRINT '  4. ./scripts/e2e/test-modbus.ps1 -BridgeNodeId "ns=2;s=HR200"';

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

@@ -0,0 +1,166 @@
+-- Phase 7 live OPC UA E2E smoke seed (task #240).
+--
+-- Idempotent — DROP-and-recreate of one cluster's worth of test config:
+--   * 1 ServerCluster ('p7-smoke')
+--   * 1 ClusterNode ('p7-smoke-node')
+--   * 1 ConfigGeneration (created Draft, then flipped to Published at the end)
+--   * 1 Namespace (Equipment kind)
+--   * 1 UnsArea / UnsLine / Equipment / Tag — Tag bound to a real Galaxy attribute
+--   * 1 DriverInstance (Galaxy)
+--   * 1 Script + 1 VirtualTag using it
+--   * 1 Script + 1 ScriptedAlarm using it
+--
+-- Drop & re-create deletes ALL rows scoped to the cluster (in dependency order)
+-- so re-running this script after a code change starts from a clean state.
+-- Table-level CHECK constraints are validated on insert; if a constraint is
+-- violated this script aborts with the offending row's column.
+--
+-- Usage:
+--   sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "OtOpcUaDev_2026!" \
+--          -i scripts/smoke/seed-phase-7-smoke.sql
+
+SET NOCOUNT ON;
+SET XACT_ABORT ON;
+SET QUOTED_IDENTIFIER ON;
+SET ANSI_NULLS ON;
+SET ANSI_PADDING ON;
+SET ANSI_WARNINGS ON;
+SET ARITHABORT ON;
+SET CONCAT_NULL_YIELDS_NULL ON;
+
+DECLARE @ClusterId nvarchar(64) = 'p7-smoke';
+DECLARE @NodeId    nvarchar(64) = 'p7-smoke-node';
+DECLARE @DrvId     nvarchar(64) = 'p7-smoke-galaxy';
+DECLARE @NsId      nvarchar(64) = 'p7-smoke-ns';
+DECLARE @AreaId    nvarchar(64) = 'p7-smoke-area';
+DECLARE @LineId    nvarchar(64) = 'p7-smoke-line';
+DECLARE @EqId      nvarchar(64) = 'p7-smoke-eq';
+DECLARE @EqUuid    uniqueidentifier = '5B2CF10D-5B2C-4F10-B5B2-CF10D5B2CF10';
+DECLARE @TagId     nvarchar(64) = 'p7-smoke-tag-source';
+DECLARE @VtScript  nvarchar(64) = 'p7-smoke-script-vt';
+DECLARE @AlScript  nvarchar(64) = 'p7-smoke-script-al';
+DECLARE @VtId      nvarchar(64) = 'p7-smoke-vt-derived';
+DECLARE @AlId      nvarchar(64) = 'p7-smoke-al-overtemp';
+
+BEGIN TRAN;
+
+-- Wipe any prior smoke state. Order matters: child rows first.
+DELETE s FROM dbo.ScriptedAlarmState s
+  WHERE s.ScriptedAlarmId = @AlId;
+DELETE FROM dbo.ScriptedAlarm        WHERE ScriptedAlarmId = @AlId;
+DELETE FROM dbo.VirtualTag           WHERE VirtualTagId = @VtId;
+DELETE FROM dbo.Script               WHERE ScriptId IN (@VtScript, @AlScript);
+DELETE FROM dbo.Tag                  WHERE TagId = @TagId;
+DELETE FROM dbo.Equipment            WHERE EquipmentId = @EqId;
+DELETE FROM dbo.UnsLine              WHERE UnsLineId = @LineId;
+DELETE FROM dbo.UnsArea              WHERE UnsAreaId = @AreaId;
+DELETE FROM dbo.DriverInstance       WHERE DriverInstanceId = @DrvId;
+DELETE FROM dbo.Namespace            WHERE NamespaceId = @NsId;
+DELETE FROM dbo.ConfigGeneration     WHERE ClusterId = @ClusterId;
+DELETE FROM dbo.ClusterNodeCredential WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNodeGenerationState WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNode          WHERE NodeId = @NodeId;
+DELETE FROM dbo.ServerCluster        WHERE ClusterId = @ClusterId;
+
+-- 1. Cluster + Node
+INSERT dbo.ServerCluster(ClusterId, Name, Enterprise, Site, NodeCount, RedundancyMode, Enabled, CreatedBy)
+VALUES (@ClusterId, 'P7 Smoke', 'zb', 'lab', 1, 'None', 1, 'p7-smoke');
+
+INSERT dbo.ClusterNode(NodeId, ClusterId, RedundancyRole, Host, OpcUaPort, DashboardPort,
+                       ApplicationUri, ServiceLevelBase, Enabled, CreatedBy)
+VALUES (@NodeId, @ClusterId, 'Primary', 'localhost', 4840, 5000,
+        'urn:OtOpcUa:p7-smoke-node', 200, 1, '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;
+INSERT dbo.ConfigGeneration(ClusterId, Status, CreatedBy)
+VALUES (@ClusterId, 'Draft', 'p7-smoke');
+SET @Gen = SCOPE_IDENTITY();
+
+-- 3. Namespace
+INSERT dbo.Namespace(GenerationId, NamespaceId, ClusterId, Kind, NamespaceUri, Enabled)
+VALUES (@Gen, @NsId, @ClusterId, 'Equipment', 'urn:p7-smoke:eq', 1);
+
+-- 4. UNS hierarchy
+INSERT dbo.UnsArea(GenerationId, UnsAreaId, ClusterId, Name)
+VALUES (@Gen, @AreaId, @ClusterId, 'lab-floor');
+
+INSERT dbo.UnsLine(GenerationId, UnsLineId, UnsAreaId, Name)
+VALUES (@Gen, @LineId, @AreaId, 'galaxy-line');
+
+INSERT dbo.Equipment(GenerationId, EquipmentId, EquipmentUuid, DriverInstanceId, UnsLineId,
+                     Name, MachineCode, Enabled)
+VALUES (@Gen, @EqId, @EqUuid, @DrvId, @LineId, 'reactor-1', 'p7-rx-001', 1);
+
+-- 5. Driver — Galaxy proxy. DriverConfig JSON tells the proxy how to reach the
+--    already-running OtOpcUaGalaxyHost. Secret + pipe name match
+--    .local/galaxy-host-secret.txt + the OtOpcUaGalaxyHost service env.
+INSERT dbo.DriverInstance(GenerationId, DriverInstanceId, ClusterId, NamespaceId,
+                          Name, DriverType, DriverConfig, Enabled)
+VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'galaxy-smoke', 'Galaxy', N'{
+  "DriverInstanceId": "p7-smoke-galaxy",
+  "PipeName": "OtOpcUaGalaxy",
+  "SharedSecret": "4hgDJ4jLcKXmOmD1Ara8xtE8N3R47Q2y1Xf/Eama/Fk=",
+  "ConnectTimeoutMs": 10000
+}', 1);
+
+-- 6. One driver-sourced Tag bound to the Equipment. TagConfig is the Galaxy
+--    fullRef ("DelmiaReceiver_001.DownloadPath" style); replace with a real
+--    attribute on this Galaxy. The script paths below use
+--    /lab-floor/galaxy-line/reactor-1/Source which the EquipmentNodeWalker
+--    emits + the DriverSubscriptionBridge maps to this driver fullRef.
+INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataType,
+               AccessLevel, TagConfig, WriteIdempotent)
+VALUES (@Gen, @TagId, @DrvId, @EqId, 'Source', 'Float64', 'Read',
+        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).
+INSERT dbo.Script(GenerationId, ScriptId, Name, SourceCode, SourceHash, Language)
+VALUES
+  (@Gen, @VtScript, 'doubled-source',
+   N'return ((double)ctx.GetTag("/lab-floor/galaxy-line/reactor-1/Source").Value) * 2.0;',
+   '0000000000000000000000000000000000000000000000000000000000000000', 'CSharp'),
+  (@Gen, @AlScript, 'overtemp-predicate',
+   N'return ((double)ctx.GetTag("/lab-floor/galaxy-line/reactor-1/Source").Value) > 50.0;',
+   '0000000000000000000000000000000000000000000000000000000000000000', 'CSharp');
+
+-- 8. VirtualTag — derived value computed by Roslyn each time Source changes.
+INSERT dbo.VirtualTag(GenerationId, VirtualTagId, EquipmentId, Name, DataType,
+                      ScriptId, ChangeTriggered, TimerIntervalMs, Historize, Enabled)
+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,
+                         Severity, MessageTemplate, PredicateScriptId,
+                         HistorizeToAveva, Retain, Enabled)
+VALUES (@Gen, @AlId, @EqId, 'OverTemp', 'LimitAlarm', 800,
+        N'Reactor source value {/lab-floor/galaxy-line/reactor-1/Source} exceeded 50',
+        @AlScript, 1, 1, 1);
+
+-- 10. Publish — flip the generation Status. sp_PublishGeneration takes
+--     concurrency locks + does ExternalIdReservation merging; we drive it via
+--     EXEC rather than UPDATE so the rest of the publish workflow runs.
+EXEC dbo.sp_PublishGeneration @ClusterId = @ClusterId, @DraftGenerationId = @Gen,
+                              @Notes = N'Phase 7 live smoke — task #240';
+
+COMMIT;
+
+PRINT '';
+PRINT 'Phase 7 smoke seed complete.';
+PRINT '  Cluster:    ' + @ClusterId;
+PRINT '  Node:       ' + @NodeId + ' (set Node:NodeId in appsettings.json)';
+PRINT '  Generation: ' + CONVERT(nvarchar(20), @Gen);
+PRINT '';
+PRINT 'Next steps:';
+PRINT '  1. Edit src/ZB.MOM.WW.OtOpcUa.Server/appsettings.json:';
+PRINT '       Node:NodeId      = "p7-smoke-node"';
+PRINT '       Node:ClusterId   = "p7-smoke"';
+PRINT '  2. Edit the placeholder Galaxy attribute in dbo.Tag.TagConfig above';
+PRINT '       so it points at a real attribute on this Galaxy — replace';
+PRINT '       REPLACE_WITH_REAL_GALAXY_ATTRIBUTE with e.g. "Plant1.Reactor1.Temp".';
+PRINT '  3. Start the Server in a non-elevated shell so the Galaxy.Host pipe ACL';
+PRINT '       accepts the connection:';
+PRINT '       dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server';
+PRINT '  4. Validate via Client.CLI per docs/v2/implementation/phase-7-e2e-smoke.md';

scripts/smoke/seed-s7-smoke.sql

@@ -0,0 +1,127 @@
+-- S7 e2e smoke seed — closes #212 (umbrella #209).
+--
+-- One-cluster seed pointing at the python-snap7 fixture
+-- (`docker compose -f tests/ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests/Docker/docker-compose.yml --profile s7_1500 up -d`).
+-- python-snap7 listens on port 1102 (non-priv); real S7 CPUs listen on 102.
+-- Publishes one Int16 tag at DB1.DBW0 under `ns=<N>;s=DB1_DBW0` (driver
+-- sanitises the dot for browse names — see S7Driver.DiscoverAsync).
+--
+-- Usage:
+--   sqlcmd -S "localhost,14330" -d OtOpcUaConfig -U sa -P "OtOpcUaDev_2026!" \
+--          -i scripts/smoke/seed-s7-smoke.sql
+--
+-- After seeding:
+--     Node:NodeId    = "s7-smoke-node"
+--     Node:ClusterId = "s7-smoke"
+-- Then start server + run `./scripts/e2e/test-s7.ps1 -BridgeNodeId "ns=2;s=DB1_DBW0" -S7Host "127.0.0.1:1102"`.
+
+SET NOCOUNT ON;
+SET XACT_ABORT ON;
+SET QUOTED_IDENTIFIER ON;
+SET ANSI_NULLS ON;
+SET ANSI_PADDING ON;
+SET ANSI_WARNINGS ON;
+SET ARITHABORT ON;
+SET CONCAT_NULL_YIELDS_NULL ON;
+
+DECLARE @ClusterId nvarchar(64) = 's7-smoke';
+DECLARE @NodeId    nvarchar(64) = 's7-smoke-node';
+DECLARE @DrvId     nvarchar(64) = 's7-smoke-drv';
+DECLARE @NsId      nvarchar(64) = 's7-smoke-ns';
+DECLARE @AreaId    nvarchar(64) = 's7-smoke-area';
+DECLARE @LineId    nvarchar(64) = 's7-smoke-line';
+DECLARE @EqId      nvarchar(64) = 's7-smoke-eq';
+DECLARE @EqUuid    uniqueidentifier = '17BD5A10-17BD-417B-917B-D5A1017BD5A1';
+DECLARE @TagId     nvarchar(64) = 's7-smoke-tag-db1dbw0';
+
+BEGIN TRAN;
+
+DELETE FROM dbo.Tag                        WHERE TagId IN (@TagId);
+DELETE FROM dbo.Equipment                  WHERE EquipmentId = @EqId;
+DELETE FROM dbo.UnsLine                    WHERE UnsLineId = @LineId;
+DELETE FROM dbo.UnsArea                    WHERE UnsAreaId = @AreaId;
+DELETE FROM dbo.DriverInstance             WHERE DriverInstanceId = @DrvId;
+DELETE FROM dbo.Namespace                  WHERE NamespaceId = @NsId;
+DELETE FROM dbo.ConfigGeneration           WHERE ClusterId = @ClusterId;
+DELETE FROM dbo.ClusterNodeCredential      WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNodeGenerationState WHERE NodeId = @NodeId;
+DELETE FROM dbo.ClusterNode                WHERE NodeId = @NodeId;
+DELETE FROM dbo.ServerCluster              WHERE ClusterId = @ClusterId;
+
+DELETE FROM dbo.ClusterNodeCredential WHERE Kind = 'SqlLogin' AND Value = 'sa';
+
+INSERT dbo.ServerCluster(ClusterId, Name, Enterprise, Site, NodeCount, RedundancyMode, Enabled, CreatedBy)
+VALUES (@ClusterId, 'S7 Smoke', 'zb', 'lab', 1, 'None', 1, 's7-smoke');
+
+INSERT dbo.ClusterNode(NodeId, ClusterId, RedundancyRole, Host, OpcUaPort, DashboardPort,
+                       ApplicationUri, ServiceLevelBase, Enabled, CreatedBy)
+VALUES (@NodeId, @ClusterId, 'Primary', 'localhost', 4840, 15050,
+        'urn:OtOpcUa:s7-smoke-node', 200, 1, 's7-smoke');
+-- Dashboard moved off :5000 (Windows URL-ACL).
+
+INSERT dbo.ClusterNodeCredential(NodeId, Kind, Value, Enabled, CreatedBy)
+VALUES (@NodeId, 'SqlLogin', 'sa', 1, 's7-smoke');
+
+DECLARE @Gen bigint;
+INSERT dbo.ConfigGeneration(ClusterId, Status, CreatedBy)
+VALUES (@ClusterId, 'Draft', 's7-smoke');
+SET @Gen = SCOPE_IDENTITY();
+
+INSERT dbo.Namespace(GenerationId, NamespaceId, ClusterId, Kind, NamespaceUri, Enabled)
+VALUES (@Gen, @NsId, @ClusterId, 'Equipment', 'urn:s7-smoke:eq', 1);
+
+INSERT dbo.UnsArea(GenerationId, UnsAreaId, ClusterId, Name)
+VALUES (@Gen, @AreaId, @ClusterId, 'lab-floor');
+
+INSERT dbo.UnsLine(GenerationId, UnsLineId, UnsAreaId, Name)
+VALUES (@Gen, @LineId, @AreaId, 's7-line');
+
+INSERT dbo.Equipment(GenerationId, EquipmentId, EquipmentUuid, DriverInstanceId, UnsLineId,
+                     Name, MachineCode, Enabled)
+VALUES (@Gen, @EqId, @EqUuid, @DrvId, @LineId, 's7-sim', 's7-001', 1);
+
+-- S7 DriverInstance — python-snap7 S7-1500 profile, slot 0, port 1102.
+-- DriverConfig shape mirrors S7DriverConfigDto.
+INSERT dbo.DriverInstance(GenerationId, DriverInstanceId, ClusterId, NamespaceId,
+                          Name, DriverType, DriverConfig, Enabled)
+VALUES (@Gen, @DrvId, @ClusterId, @NsId, 'snap7-smoke', 'S7', N'{
+  "Host": "127.0.0.1",
+  "Port": 1102,
+  "CpuType": "S71500",
+  "Rack": 0,
+  "Slot": 0,
+  "TimeoutMs": 5000,
+  "Probe": { "Enabled": true, "IntervalMs": 5000, "TimeoutMs": 2000, "ProbeAddress": "MW0" },
+  "Tags": [
+    {
+      "Name": "DB1_DBW0",
+      "Address": "DB1.DBW0",
+      "DataType": "Int16",
+      "Writable": true,
+      "WriteIdempotent": true
+    }
+  ]
+}', 1);
+
+INSERT dbo.Tag(GenerationId, TagId, DriverInstanceId, EquipmentId, Name, DataType,
+               AccessLevel, TagConfig, WriteIdempotent)
+VALUES (@Gen, @TagId, @DrvId, @EqId, 'DB1_DBW0', 'Int16', 'ReadWrite',
+        N'{"FullName":"DB1_DBW0","Address":"DB1.DBW0","DataType":"Int16"}', 1);
+
+EXEC dbo.sp_PublishGeneration @ClusterId = @ClusterId, @DraftGenerationId = @Gen,
+                              @Notes = N'S7 smoke — task #212';
+
+COMMIT;
+
+PRINT '';
+PRINT 'S7 smoke seed complete.';
+PRINT '  Cluster:    ' + @ClusterId;
+PRINT '  Node:       ' + @NodeId;
+PRINT '  Generation: ' + CONVERT(nvarchar(20), @Gen);
+PRINT '';
+PRINT 'Next steps:';
+PRINT '  1. Set src/.../Server/appsettings.json Node:NodeId = "s7-smoke-node"';
+PRINT '                                          Node:ClusterId = "s7-smoke"';
+PRINT '  2. docker compose -f tests/.../S7.IntegrationTests/Docker/docker-compose.yml --profile s7_1500 up -d';
+PRINT '  3. dotnet run --project src/ZB.MOM.WW.OtOpcUa.Server';
+PRINT '  4. ./scripts/e2e/test-s7.ps1 -BridgeNodeId "ns=2;s=DB1_DBW0" -S7Host "127.0.0.1:1102"';

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/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/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/Hosting/DriverFactoryRegistry.cs

@@ -0,0 +1,64 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.Hosting;
+
+/// <summary>
+///     Process-singleton registry of <see cref="IDriver"/> factories keyed by
+///     <c>DriverInstance.DriverType</c> string. Each driver project ships a DI
+///     extension (e.g. <c>services.AddGalaxyProxyDriverFactory()</c>) that registers
+///     its factory at startup; the bootstrapper looks up the factory by
+///     <c>DriverInstance.DriverType</c> + invokes it with the row's
+///     <c>DriverInstanceId</c> + <c>DriverConfig</c> JSON.
+/// </summary>
+/// <remarks>
+///     Closes the gap surfaced by task #240 live smoke — DriverInstance rows in
+///     the central config DB had no path to materialise as registered <see cref="IDriver"/>
+///     instances. The factory registry is the seam.
+/// </remarks>
+public sealed class DriverFactoryRegistry
+{
+    private readonly Dictionary<string, Func<string, string, IDriver>> _factories
+        = new(StringComparer.OrdinalIgnoreCase);
+    private readonly object _lock = new();
+
+    /// <summary>
+    ///     Register a factory for <paramref name="driverType"/>. Throws if a factory is
+    ///     already registered for that type — drivers are singletons by type-name in
+    ///     this process.
+    /// </summary>
+    /// <param name="driverType">Matches <c>DriverInstance.DriverType</c>.</param>
+    /// <param name="factory">
+    ///     Receives <c>(driverInstanceId, driverConfigJson)</c>; returns a new
+    ///     <see cref="IDriver"/>. Must NOT call <see cref="IDriver.InitializeAsync"/>
+    ///     itself — the bootstrapper calls it via <see cref="DriverHost.RegisterAsync"/>
+    ///     so the host's per-driver retry semantics apply uniformly.
+    /// </param>
+    public void Register(string driverType, Func<string, string, IDriver> factory)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverType);
+        ArgumentNullException.ThrowIfNull(factory);
+        lock (_lock)
+        {
+            if (_factories.ContainsKey(driverType))
+                throw new InvalidOperationException(
+                    $"DriverType '{driverType}' factory already registered for this process");
+            _factories[driverType] = factory;
+        }
+    }
+
+    /// <summary>
+    ///     Try to look up the factory for <paramref name="driverType"/>. Returns null
+    ///     if no driver assembly registered one — bootstrapper logs + skips so a
+    ///     missing-assembly deployment doesn't take down the whole server.
+    /// </summary>
+    public Func<string, string, IDriver>? TryGet(string driverType)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverType);
+        lock (_lock) return _factories.GetValueOrDefault(driverType);
+    }
+
+    public IReadOnlyCollection<string> RegisteredTypes
+    {
+        get { lock (_lock) return [.. _factories.Keys]; }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/AbCipCommandBase.cs

@@ -0,0 +1,59 @@
+using CliFx.Attributes;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli;
+
+/// <summary>
+///     Base for every AB CIP CLI command. Carries the libplctag endpoint options
+///     (<c>--gateway</c> + <c>--family</c>) and exposes <see cref="BuildOptions"/> so each
+///     command can synthesise an <see cref="AbCipDriverOptions"/> from CLI flags + its own
+///     tag list.
+/// </summary>
+public abstract class AbCipCommandBase : DriverCommandBase
+{
+    [CommandOption("gateway", 'g', Description =
+        "Canonical AB CIP gateway: ab://host[:port]/cip-path. Port defaults to 44818 " +
+        "(EtherNet/IP). cip-path is family-specific: ControlLogix / CompactLogix need " +
+        "'1,0' to reach slot 0 of the CPU chassis; Micro800 takes an empty path; " +
+        "GuardLogix typically '1,0' same as ControlLogix.",
+        IsRequired = true)]
+    public string Gateway { get; init; } = default!;
+
+    [CommandOption("family", 'f', Description =
+        "ControlLogix / CompactLogix / Micro800 / GuardLogix (default ControlLogix).")]
+    public AbCipPlcFamily Family { get; init; } = AbCipPlcFamily.ControlLogix;
+
+    [CommandOption("timeout-ms", Description = "Per-operation timeout in ms (default 5000).")]
+    public int TimeoutMs { get; init; } = 5000;
+
+    /// <inheritdoc />
+    public override TimeSpan Timeout
+    {
+        get => TimeSpan.FromMilliseconds(TimeoutMs);
+        init { /* driven by TimeoutMs */ }
+    }
+
+    /// <summary>
+    ///     Build an <see cref="AbCipDriverOptions"/> with the device + tag list a subclass
+    ///     supplies. Probe + alarm projection are disabled — CLI runs are one-shot; the
+    ///     probe loop would race the operator's own reads.
+    /// </summary>
+    protected AbCipDriverOptions BuildOptions(IReadOnlyList<AbCipTagDefinition> tags) => new()
+    {
+        Devices = [new AbCipDeviceOptions(
+            HostAddress: Gateway,
+            PlcFamily: Family,
+            DeviceName: $"cli-{Family}")],
+        Tags = tags,
+        Timeout = Timeout,
+        Probe = new AbCipProbeOptions { Enabled = false },
+        EnableControllerBrowse = false,
+        EnableAlarmProjection = false,
+    };
+
+    /// <summary>
+    ///     Short instance id used in Serilog output so operators running the CLI against
+    ///     multiple gateways in parallel can distinguish the logs.
+    /// </summary>
+    protected string DriverInstanceId => $"abcip-cli-{Gateway}";
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/Commands/ProbeCommand.cs

@@ -0,0 +1,58 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Commands;
+
+/// <summary>
+///     Probes an AB CIP gateway: initialises the driver (connects via libplctag), reads a
+///     single tag, and prints health + the read result. Fastest way to answer "is the PLC
+///     up + reachable + speaking CIP via this path?".
+/// </summary>
+[Command("probe", Description = "Verify the AB CIP gateway is reachable and a sample tag reads.")]
+public sealed class ProbeCommand : AbCipCommandBase
+{
+    [CommandOption("tag", 't', Description =
+        "Tag path to probe. ControlLogix default is '@raw_cpu_type' (the canonical libplctag " +
+        "system tag); Micro800 takes a user-supplied global (e.g. '_SYSVA_CLOCK_HOUR').",
+        IsRequired = true)]
+    public string TagPath { get; init; } = default!;
+
+    [CommandOption("type", Description =
+        "Logix atomic type of the probe tag (default DInt).")]
+    public AbCipDataType DataType { get; init; } = AbCipDataType.DInt;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var probeTag = new AbCipTagDefinition(
+            Name: "__probe",
+            DeviceHostAddress: Gateway,
+            TagPath: TagPath,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([probeTag]);
+
+        await using var driver = new AbCipDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var snapshot = await driver.ReadAsync(["__probe"], ct);
+            var health = driver.GetHealth();
+
+            await console.Output.WriteLineAsync($"Gateway:      {Gateway}");
+            await console.Output.WriteLineAsync($"Family:       {Family}");
+            await console.Output.WriteLineAsync($"Health:       {health.State}");
+            if (health.LastError is { } err)
+                await console.Output.WriteLineAsync($"Last error:   {err}");
+            await console.Output.WriteLineAsync();
+            await console.Output.WriteLineAsync(SnapshotFormatter.Format(TagPath, snapshot[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/Commands/ReadCommand.cs

@@ -0,0 +1,60 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Commands;
+
+/// <summary>
+///     Read one Logix tag by symbolic path. Operator specifies <c>--tag</c> + <c>--type</c>;
+///     the CLI synthesises a one-tag driver config, reads once, prints the snapshot, shuts
+///     down. UDT / Structure reads are out of scope here — those need the member layout
+///     declared, which belongs in a real driver config.
+/// </summary>
+[Command("read", Description = "Read a single Logix tag by symbolic path.")]
+public sealed class ReadCommand : AbCipCommandBase
+{
+    [CommandOption("tag", 't', Description =
+        "Logix symbolic path. Controller scope: 'Motor01_Speed'. Program scope: " +
+        "'Program:Main.Motor01_Speed'. Array element: 'Recipe[3]'. UDT member: " +
+        "'Motor01.Speed'.", IsRequired = true)]
+    public string TagPath { get; init; } = default!;
+
+    [CommandOption("type", Description =
+        "Bool / SInt / Int / DInt / LInt / USInt / UInt / UDInt / ULInt / Real / LReal / " +
+        "String / Dt / Structure (default DInt).")]
+    public AbCipDataType DataType { get; init; } = AbCipDataType.DInt;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = SynthesiseTagName(TagPath, DataType);
+        var tag = new AbCipTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: Gateway,
+            TagPath: TagPath,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([tag]);
+
+        await using var driver = new AbCipDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var snapshot = await driver.ReadAsync([tagName], ct);
+            await console.Output.WriteLineAsync(SnapshotFormatter.Format(TagPath, snapshot[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+
+    /// <summary>
+    ///     Tag-name key the driver uses internally. The path + type pair is already unique
+    ///     so we use them verbatim — keeps tag-level diagnostics readable without mangling.
+    /// </summary>
+    internal static string SynthesiseTagName(string tagPath, AbCipDataType type)
+        => $"{tagPath}:{type}";
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/Commands/RebrowseCommand.cs

@@ -0,0 +1,107 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Commands;
+
+/// <summary>
+///     Force a controller-side @tags re-walk on a live AbCip driver instance. Issue #233 —
+///     online tag-DB refresh trigger. The CLI variant builds a transient driver against the
+///     supplied gateway, runs <see cref="AbCipDriver.RebrowseAsync"/>, and prints the freshly
+///     discovered tag names. In-server (Tier-A) operators wire this same call to an Admin UI
+///     button so a controller program-download is reflected in the address space without a
+///     driver restart.
+/// </summary>
+[Command("rebrowse", Description =
+    "Re-walk the AB CIP controller symbol table (force @tags refresh) and print discovered tags.")]
+public sealed class RebrowseCommand : AbCipCommandBase
+{
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        // EnableControllerBrowse must be true for the @tags walk to happen; the CLI baseline
+        // (BuildOptions in AbCipCommandBase) leaves it off for one-shot probes, so we flip it
+        // here without touching the base helper.
+        var baseOpts = BuildOptions(tags: []);
+        var options = new AbCipDriverOptions
+        {
+            Devices = baseOpts.Devices,
+            Tags = baseOpts.Tags,
+            Timeout = baseOpts.Timeout,
+            Probe = baseOpts.Probe,
+            EnableControllerBrowse = true,
+            EnableAlarmProjection = false,
+        };
+
+        await using var driver = new AbCipDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+
+            var builder = new ConsoleAddressSpaceBuilder();
+            await driver.RebrowseAsync(builder, ct);
+
+            await console.Output.WriteLineAsync($"Gateway:   {Gateway}");
+            await console.Output.WriteLineAsync($"Family:    {Family}");
+            await console.Output.WriteLineAsync($"Variables: {builder.VariableCount}");
+            await console.Output.WriteLineAsync();
+            foreach (var line in builder.Lines)
+                await console.Output.WriteLineAsync(line);
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+
+    /// <summary>
+    ///     Minimal in-memory <see cref="IAddressSpaceBuilder"/> that flattens the tree to one
+    ///     line per variable for CLI display. Folder nesting is captured in the prefix so the
+    ///     operator can see the same shape the in-server builder would receive.
+    /// </summary>
+    private sealed class ConsoleAddressSpaceBuilder : IAddressSpaceBuilder
+    {
+        private readonly string _prefix;
+        private readonly Counter _counter;
+        public List<string> Lines { get; }
+        public int VariableCount => _counter.Count;
+
+        public ConsoleAddressSpaceBuilder() : this("", new List<string>(), new Counter()) { }
+        private ConsoleAddressSpaceBuilder(string prefix, List<string> sharedLines, Counter counter)
+        {
+            _prefix = prefix;
+            Lines = sharedLines;
+            _counter = counter;
+        }
+
+        public IAddressSpaceBuilder Folder(string browseName, string displayName)
+        {
+            var newPrefix = string.IsNullOrEmpty(_prefix) ? browseName : $"{_prefix}/{browseName}";
+            return new ConsoleAddressSpaceBuilder(newPrefix, Lines, _counter);
+        }
+
+        public IVariableHandle Variable(string browseName, string displayName, DriverAttributeInfo info)
+        {
+            _counter.Count++;
+            Lines.Add($"  {_prefix}/{browseName}  ({info.DriverDataType}, {info.SecurityClass})");
+            return new Handle(info.FullName);
+        }
+
+        public void AddProperty(string browseName, DriverDataType dataType, object? value) { }
+
+        private sealed class Counter { public int Count; }
+
+        private sealed class Handle(string fullRef) : IVariableHandle
+        {
+            public string FullReference => fullRef;
+            public IAlarmConditionSink MarkAsAlarmCondition(AlarmConditionInfo info) => new NullSink();
+        }
+        private sealed class NullSink : IAlarmConditionSink
+        {
+            public void OnTransition(AlarmEventArgs args) { }
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/Commands/SubscribeCommand.cs

@@ -0,0 +1,81 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Commands;
+
+/// <summary>
+///     Watch a Logix tag via polled subscription until Ctrl+C. Uses the driver's
+///     <c>ISubscribable</c> surface (PollGroupEngine under the hood). Prints each change
+///     event with an HH:mm:ss.fff timestamp.
+/// </summary>
+[Command("subscribe", Description = "Watch a Logix tag via polled subscription until Ctrl+C.")]
+public sealed class SubscribeCommand : AbCipCommandBase
+{
+    [CommandOption("tag", 't', Description =
+        "Logix symbolic path — same format as `read`.", IsRequired = true)]
+    public string TagPath { get; init; } = default!;
+
+    [CommandOption("type", Description =
+        "Bool / SInt / Int / DInt / LInt / USInt / UInt / UDInt / ULInt / Real / LReal / " +
+        "String / Dt (default DInt).")]
+    public AbCipDataType DataType { get; init; } = AbCipDataType.DInt;
+
+    [CommandOption("interval-ms", 'i', Description =
+        "Publishing interval in milliseconds (default 1000). PollGroupEngine floors " +
+        "sub-250ms values.")]
+    public int IntervalMs { get; init; } = 1000;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = ReadCommand.SynthesiseTagName(TagPath, DataType);
+        var tag = new AbCipTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: Gateway,
+            TagPath: TagPath,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([tag]);
+
+        await using var driver = new AbCipDriver(options, DriverInstanceId);
+        ISubscriptionHandle? handle = null;
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+
+            driver.OnDataChange += (_, e) =>
+            {
+                var line = $"[{DateTime.UtcNow:HH:mm:ss.fff}] " +
+                    $"{e.FullReference} = {SnapshotFormatter.FormatValue(e.Snapshot.Value)} " +
+                    $"({SnapshotFormatter.FormatStatus(e.Snapshot.StatusCode)})";
+                console.Output.WriteLine(line);
+            };
+
+            handle = await driver.SubscribeAsync([tagName], TimeSpan.FromMilliseconds(IntervalMs), ct);
+
+            await console.Output.WriteLineAsync(
+                $"Subscribed to {TagPath} @ {IntervalMs}ms. Ctrl+C to stop.");
+            try
+            {
+                await Task.Delay(System.Threading.Timeout.InfiniteTimeSpan, ct);
+            }
+            catch (OperationCanceledException)
+            {
+                // Expected on Ctrl+C.
+            }
+        }
+        finally
+        {
+            if (handle is not null)
+            {
+                try { await driver.UnsubscribeAsync(handle, CancellationToken.None); }
+                catch { /* teardown best-effort */ }
+            }
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/Commands/TagExportCommand.cs

@@ -0,0 +1,124 @@
+using System.IO;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using CliFx;
+using CliFx.Attributes;
+using CliFx.Exceptions;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Commands;
+
+/// <summary>
+///     Dump the merged tag table from an <see cref="AbCipDriverOptions"/> JSON config to a
+///     Kepware-format CSV. The command reads the pre-declared <c>Tags</c> list, pulls in any
+///     <c>L5kImports</c> / <c>L5xImports</c> / <c>CsvImports</c> entries, applies the same
+///     declared-wins precedence used by the live driver, and writes the union as one CSV.
+///     Mirrors the round-trip path operators want for Excel-driven editing: export → edit →
+///     re-import via the driver's <c>CsvImports</c>.
+/// </summary>
+/// <remarks>
+///     The command does not contact any PLC — it is a pure transform over the options JSON.
+///     <c>--driver-options-json</c> may point at a full options file or at a fragment that
+///     deserialises to <see cref="AbCipDriverOptions"/>.
+/// </remarks>
+[Command("tag-export", Description = "Export the merged tag table from a driver-options JSON to Kepware CSV.")]
+public sealed class TagExportCommand : ICommand
+{
+    [CommandOption("driver-options-json", Description =
+        "Path to a JSON file deserialising to AbCipDriverOptions (Tags + L5kImports + " +
+        "L5xImports + CsvImports). Imports with FilePath are loaded relative to the JSON.",
+        IsRequired = true)]
+    public string DriverOptionsJsonPath { get; init; } = default!;
+
+    [CommandOption("out", 'o', Description = "Output CSV path (UTF-8, no BOM).", IsRequired = true)]
+    public string OutputPath { get; init; } = default!;
+
+    public ValueTask ExecuteAsync(IConsole console)
+    {
+        if (!File.Exists(DriverOptionsJsonPath))
+            throw new CommandException($"driver-options-json '{DriverOptionsJsonPath}' does not exist.");
+
+        var json = File.ReadAllText(DriverOptionsJsonPath);
+        var opts = JsonSerializer.Deserialize<AbCipDriverOptions>(json, JsonOpts)
+            ?? throw new CommandException("driver-options-json deserialised to null.");
+
+        var basePath = Path.GetDirectoryName(Path.GetFullPath(DriverOptionsJsonPath)) ?? string.Empty;
+
+        var declaredNames = new HashSet<string>(
+            opts.Tags.Select(t => t.Name), StringComparer.OrdinalIgnoreCase);
+        var allTags = new List<AbCipTagDefinition>(opts.Tags);
+
+        foreach (var import in opts.L5kImports)
+            MergeL5(import.DeviceHostAddress, ResolvePath(import.FilePath, basePath),
+                import.InlineText, import.NamePrefix, L5kParser.Parse, declaredNames, allTags);
+        foreach (var import in opts.L5xImports)
+            MergeL5(import.DeviceHostAddress, ResolvePath(import.FilePath, basePath),
+                import.InlineText, import.NamePrefix, L5xParser.Parse, declaredNames, allTags);
+        foreach (var import in opts.CsvImports)
+            MergeCsv(import, basePath, declaredNames, allTags);
+
+        CsvTagExporter.WriteFile(allTags, OutputPath);
+        console.Output.WriteLine($"Wrote {allTags.Count} tag(s) to {OutputPath}");
+        return ValueTask.CompletedTask;
+    }
+
+    private static string? ResolvePath(string? path, string basePath)
+    {
+        if (string.IsNullOrEmpty(path)) return path;
+        return Path.IsPathRooted(path) ? path : Path.Combine(basePath, path);
+    }
+
+    private static void MergeL5(
+        string deviceHost, string? filePath, string? inlineText, string namePrefix,
+        Func<IL5kSource, L5kDocument> parse,
+        HashSet<string> declaredNames, List<AbCipTagDefinition> allTags)
+    {
+        if (string.IsNullOrWhiteSpace(deviceHost)) return;
+        IL5kSource? src = null;
+        if (!string.IsNullOrEmpty(filePath)) src = new FileL5kSource(filePath);
+        else if (!string.IsNullOrEmpty(inlineText)) src = new StringL5kSource(inlineText);
+        if (src is null) return;
+
+        var doc = parse(src);
+        var ingest = new L5kIngest { DefaultDeviceHostAddress = deviceHost, NamePrefix = namePrefix };
+        foreach (var tag in ingest.Ingest(doc).Tags)
+        {
+            if (declaredNames.Contains(tag.Name)) continue;
+            allTags.Add(tag);
+            declaredNames.Add(tag.Name);
+        }
+    }
+
+    private static void MergeCsv(
+        AbCipCsvImportOptions import, string basePath,
+        HashSet<string> declaredNames, List<AbCipTagDefinition> allTags)
+    {
+        if (string.IsNullOrWhiteSpace(import.DeviceHostAddress)) return;
+        string? text = null;
+        var resolved = ResolvePath(import.FilePath, basePath);
+        if (!string.IsNullOrEmpty(resolved)) text = File.ReadAllText(resolved);
+        else if (!string.IsNullOrEmpty(import.InlineText)) text = import.InlineText;
+        if (text is null) return;
+
+        var importer = new CsvTagImporter
+        {
+            DefaultDeviceHostAddress = import.DeviceHostAddress,
+            NamePrefix = import.NamePrefix,
+        };
+        foreach (var tag in importer.Import(text).Tags)
+        {
+            if (declaredNames.Contains(tag.Name)) continue;
+            allTags.Add(tag);
+            declaredNames.Add(tag.Name);
+        }
+    }
+
+    private static readonly JsonSerializerOptions JsonOpts = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        ReadCommentHandling = JsonCommentHandling.Skip,
+        AllowTrailingCommas = true,
+        Converters = { new JsonStringEnumConverter() },
+    };
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/Commands/WriteCommand.cs

@@ -0,0 +1,94 @@
+using System.Globalization;
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Commands;
+
+/// <summary>
+///     Write one value to a Logix tag by symbolic path. Mirrors <see cref="ReadCommand"/>'s
+///     flag shape + adds <c>--value</c>. Value parsing respects <c>--type</c> so you can
+///     write <c>--value 3.14 --type Real</c> without hex-encoding. GuardLogix safety tags
+///     are refused at the driver level (they're forced to ViewOnly by PR 12).
+/// </summary>
+[Command("write", Description = "Write a single Logix tag by symbolic path.")]
+public sealed class WriteCommand : AbCipCommandBase
+{
+    [CommandOption("tag", 't', Description =
+        "Logix symbolic path — same format as `read`.", IsRequired = true)]
+    public string TagPath { get; init; } = default!;
+
+    [CommandOption("type", Description =
+        "Bool / SInt / Int / DInt / LInt / USInt / UInt / UDInt / ULInt / Real / LReal / " +
+        "String / Dt (default DInt).")]
+    public AbCipDataType DataType { get; init; } = AbCipDataType.DInt;
+
+    [CommandOption("value", 'v', Description =
+        "Value to write. Parsed per --type (booleans accept true/false/1/0).",
+        IsRequired = true)]
+    public string Value { get; init; } = default!;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        if (DataType == AbCipDataType.Structure)
+            throw new CliFx.Exceptions.CommandException(
+                "Structure (UDT) writes need an explicit member layout — drop to the driver's " +
+                "config JSON for those. The CLI covers atomic types only.");
+
+        var tagName = ReadCommand.SynthesiseTagName(TagPath, DataType);
+        var tag = new AbCipTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: Gateway,
+            TagPath: TagPath,
+            DataType: DataType,
+            Writable: true);
+        var options = BuildOptions([tag]);
+
+        var parsed = ParseValue(Value, DataType);
+
+        await using var driver = new AbCipDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var results = await driver.WriteAsync([new WriteRequest(tagName, parsed)], ct);
+            await console.Output.WriteLineAsync(SnapshotFormatter.FormatWrite(TagPath, results[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+
+    /// <summary>
+    ///     Parse the operator's <c>--value</c> string into the CLR type the driver expects
+    ///     for the declared <see cref="AbCipDataType"/>. Invariant culture everywhere.
+    /// </summary>
+    internal static object ParseValue(string raw, AbCipDataType type) => type switch
+    {
+        AbCipDataType.Bool => ParseBool(raw),
+        AbCipDataType.SInt => sbyte.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.Int => short.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.DInt or AbCipDataType.Dt => int.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.LInt => long.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.USInt => byte.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.UInt => ushort.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.UDInt => uint.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.ULInt => ulong.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.Real => float.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.LReal => double.Parse(raw, CultureInfo.InvariantCulture),
+        AbCipDataType.String => raw,
+        _ => throw new CliFx.Exceptions.CommandException($"Unsupported DataType '{type}' for write."),
+    };
+
+    private static bool ParseBool(string raw) => raw.Trim().ToLowerInvariant() switch
+    {
+        "1" or "true" or "on" or "yes" => true,
+        "0" or "false" or "off" or "no" => false,
+        _ => throw new CliFx.Exceptions.CommandException(
+            $"Boolean value '{raw}' is not recognised. Use true/false, 1/0, on/off, or yes/no."),
+    };
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/Program.cs

@@ -0,0 +1,11 @@
+using CliFx;
+
+return await new CliApplicationBuilder()
+    .AddCommandsFromThisAssembly()
+    .SetExecutableName("otopcua-abcip-cli")
+    .SetDescription(
+        "OtOpcUa AB CIP test-client — ad-hoc probe + Logix symbolic reads/writes + polled " +
+        "subscriptions against ControlLogix / CompactLogix / Micro800 / GuardLogix families " +
+        "via libplctag. Second of four driver CLIs; mirrors otopcua-modbus-cli's shape.")
+    .Build()
+    .RunAsync(args);

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.csproj

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <LangVersion>latest</LangVersion>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <NoWarn>$(NoWarn);CS1591</NoWarn>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli</RootNamespace>
+        <AssemblyName>otopcua-abcip-cli</AssemblyName>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="CliFx" Version="2.3.6"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.Cli.Common\ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.AbCip\ZB.MOM.WW.OtOpcUa.Driver.AbCip.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <InternalsVisibleTo Include="ZB.MOM.WW.OtOpcUa.Driver.AbCip.Cli.Tests"/>
+    </ItemGroup>
+
+</Project>

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipArrayReadPlanner.cs

@@ -0,0 +1,94 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
+
+/// <summary>
+///     PR abcip-1.3 — issues one libplctag tag-create with <c>ElementCount=N</c> per Rockwell
+///     array-slice tag (<c>Tag[0..N]</c> in <see cref="AbCipTagPath"/>), then decodes the
+///     contiguous buffer at element stride into <c>N</c> typed values. Mirrors the whole-UDT
+///     planner pattern (<see cref="AbCipUdtReadPlanner"/>): pure shape — the planner never
+///     touches the runtime + never reads the PLC, the driver wires the runtime in.
+/// </summary>
+/// <remarks>
+///     <para>Stride is the natural Logix size of the element type (DInt = 4, Real = 4, LInt = 8).
+///     Bool / String / Structure slices aren't supported here — Logix packs BOOLs into a host
+///     byte (no fixed stride), STRING members carry a Length+DATA pair that's not a flat array,
+///     and structure arrays need the CIP Template Object reader (PR-tracked separately).</para>
+///
+///     <para>Output is a single <c>object[]</c> snapshot value containing the N decoded
+///     elements at indices 0..Count-1. Pairing with one slice tag = one snapshot keeps the
+///     <c>ReadAsync</c> 1:1 contract (one fullReference -> one snapshot) intact.</para>
+/// </remarks>
+public static class AbCipArrayReadPlanner
+{
+    /// <summary>
+    ///     Build the libplctag create-params + decode descriptor for a slice tag. Returns
+    ///     <c>null</c> when the slice element type isn't supported under this declaration-only
+    ///     decoder (Bool / String / Structure / unrecognised) — the driver falls back to the
+    ///     scalar read path so the operator gets a clean per-element result instead.
+    /// </summary>
+    public static AbCipArrayReadPlan? TryBuild(
+        AbCipTagDefinition definition,
+        AbCipTagPath parsedPath,
+        AbCipTagCreateParams baseParams)
+    {
+        ArgumentNullException.ThrowIfNull(definition);
+        ArgumentNullException.ThrowIfNull(parsedPath);
+        ArgumentNullException.ThrowIfNull(baseParams);
+        if (parsedPath.Slice is null) return null;
+
+        if (!TryGetStride(definition.DataType, out var stride)) return null;
+
+        var slice = parsedPath.Slice;
+        var createParams = baseParams with
+        {
+            TagName = parsedPath.ToLibplctagSliceArrayName(),
+            ElementCount = slice.Count,
+        };
+
+        return new AbCipArrayReadPlan(definition.DataType, slice, stride, createParams);
+    }
+
+    /// <summary>
+    ///     Decode <paramref name="plan"/>.Count elements from <paramref name="runtime"/> at
+    ///     element stride. Caller has already invoked <see cref="IAbCipTagRuntime.ReadAsync"/>
+    ///     and confirmed <see cref="IAbCipTagRuntime.GetStatus"/> == 0.
+    /// </summary>
+    public static object?[] Decode(AbCipArrayReadPlan plan, IAbCipTagRuntime runtime)
+    {
+        ArgumentNullException.ThrowIfNull(plan);
+        ArgumentNullException.ThrowIfNull(runtime);
+
+        var values = new object?[plan.Slice.Count];
+        for (var i = 0; i < plan.Slice.Count; i++)
+            values[i] = runtime.DecodeValueAt(plan.ElementType, i * plan.Stride, bitIndex: null);
+        return values;
+    }
+
+    private static bool TryGetStride(AbCipDataType type, out int stride)
+    {
+        switch (type)
+        {
+            case AbCipDataType.SInt: case AbCipDataType.USInt:
+                stride = 1; return true;
+            case AbCipDataType.Int: case AbCipDataType.UInt:
+                stride = 2; return true;
+            case AbCipDataType.DInt: case AbCipDataType.UDInt:
+            case AbCipDataType.Real: case AbCipDataType.Dt:
+                stride = 4; return true;
+            case AbCipDataType.LInt: case AbCipDataType.ULInt:
+            case AbCipDataType.LReal:
+                stride = 8; return true;
+            default:
+                stride = 0; return false;
+        }
+    }
+}
+
+/// <summary>
+///     Plan output: the libplctag create-params for the single array-read tag plus the
+///     element-type / stride / slice metadata the decoder needs.
+/// </summary>
+public sealed record AbCipArrayReadPlan(
+    AbCipDataType ElementType,
+    AbCipTagPathSlice Slice,
+    int Stride,
+    AbCipTagCreateParams CreateParams);

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDataType.cs

@@ -50,11 +50,12 @@ public static class AbCipDataTypeExtensions
         AbCipDataType.Bool => DriverDataType.Boolean,
         AbCipDataType.SInt or AbCipDataType.Int or AbCipDataType.DInt => DriverDataType.Int32,
         AbCipDataType.USInt or AbCipDataType.UInt or AbCipDataType.UDInt => DriverDataType.Int32,
-        AbCipDataType.LInt or AbCipDataType.ULInt => DriverDataType.Int32, // TODO: Int64 — matches Modbus gap
+        AbCipDataType.LInt => DriverDataType.Int64,
+        AbCipDataType.ULInt => DriverDataType.UInt64,
         AbCipDataType.Real => DriverDataType.Float32,
         AbCipDataType.LReal => DriverDataType.Float64,
         AbCipDataType.String => DriverDataType.String,
-        AbCipDataType.Dt => DriverDataType.Int32, // epoch-seconds DINT
+        AbCipDataType.Dt => DriverDataType.Int64, // Logix v32+ DT == LINT epoch-millis
         AbCipDataType.Structure => DriverDataType.String, // placeholder until UDT PR 6 introduces a structured kind
         _ => DriverDataType.Int32,
     };

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriver.cs

@@ -1,4 +1,5 @@
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
 using ZB.MOM.WW.OtOpcUa.Driver.AbCip.PlcFamilies;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
@@ -21,7 +22,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
 ///     <see cref="PlcTagHandle"/> and reconnects each device.</para>
 /// </remarks>
 public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery, ISubscribable,
-    IHostConnectivityProbe, IPerCallHostResolver, IAlarmSource, IDisposable, IAsyncDisposable
+    IHostConnectivityProbe, IPerCallHostResolver, IAlarmSource, IDriverControl, IDisposable, IAsyncDisposable
 {
     private readonly AbCipDriverOptions _options;
     private readonly string _driverInstanceId;
@@ -33,6 +34,7 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
     private readonly Dictionary<string, DeviceState> _devices = new(StringComparer.OrdinalIgnoreCase);
     private readonly Dictionary<string, AbCipTagDefinition> _tagsByName = new(StringComparer.OrdinalIgnoreCase);
     private readonly AbCipAlarmProjection _alarmProjection;
+    private readonly SemaphoreSlim _discoverySemaphore = new(1, 1);
     private DriverHealth _health = new(DriverState.Unknown, null, null);
 
     public event EventHandler<DataChangeEventArgs>? OnDataChange;
@@ -121,7 +123,42 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                 var profile = AbCipPlcFamilyProfile.ForFamily(device.PlcFamily);
                 _devices[device.HostAddress] = new DeviceState(addr, device, profile);
             }
-            foreach (var tag in _options.Tags)
+            // Pre-declared tags first; L5K imports fill in only the names not already covered
+            // (operators can override an imported entry by re-declaring it under Tags).
+            var declaredNames = new HashSet<string>(
+                _options.Tags.Select(t => t.Name),
+                StringComparer.OrdinalIgnoreCase);
+            var allTags = new List<AbCipTagDefinition>(_options.Tags);
+            foreach (var import in _options.L5kImports)
+            {
+                MergeImport(
+                    deviceHost: import.DeviceHostAddress,
+                    filePath: import.FilePath,
+                    inlineText: import.InlineText,
+                    namePrefix: import.NamePrefix,
+                    parse: L5kParser.Parse,
+                    formatLabel: "L5K",
+                    declaredNames: declaredNames,
+                    allTags: allTags);
+            }
+            foreach (var import in _options.L5xImports)
+            {
+                MergeImport(
+                    deviceHost: import.DeviceHostAddress,
+                    filePath: import.FilePath,
+                    inlineText: import.InlineText,
+                    namePrefix: import.NamePrefix,
+                    parse: L5xParser.Parse,
+                    formatLabel: "L5X",
+                    declaredNames: declaredNames,
+                    allTags: allTags);
+            }
+            foreach (var import in _options.CsvImports)
+            {
+                MergeCsvImport(import, declaredNames, allTags);
+            }
+
+            foreach (var tag in allTags)
             {
                 _tagsByName[tag.Name] = tag;
                 if (tag.DataType == AbCipDataType.Structure && tag.Members is { Count: > 0 })
@@ -134,7 +171,8 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                             TagPath: $"{tag.TagPath}.{member.Name}",
                             DataType: member.DataType,
                             Writable: member.Writable,
-                            WriteIdempotent: member.WriteIdempotent);
+                            WriteIdempotent: member.WriteIdempotent,
+                            StringLength: member.StringLength);
                         _tagsByName[memberTag.Name] = memberTag;
                     }
                 }
@@ -160,6 +198,84 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         return Task.CompletedTask;
     }
 
+    /// <summary>
+    ///     Shared L5K / L5X import path — keeps source-format selection (parser delegate) the
+    ///     only behavioural axis between the two formats. Adds the parser's tags to
+    ///     <paramref name="allTags"/> while skipping any name already covered by an earlier
+    ///     declaration or import (declared > L5K > L5X precedence falls out from call order).
+    /// </summary>
+    private static void MergeImport(
+        string deviceHost,
+        string? filePath,
+        string? inlineText,
+        string namePrefix,
+        Func<IL5kSource, L5kDocument> parse,
+        string formatLabel,
+        HashSet<string> declaredNames,
+        List<AbCipTagDefinition> allTags)
+    {
+        if (string.IsNullOrWhiteSpace(deviceHost))
+            throw new InvalidOperationException(
+                $"AbCip {formatLabel} import is missing DeviceHostAddress — every imported tag needs a target device.");
+        IL5kSource? src = null;
+        if (!string.IsNullOrEmpty(filePath))
+            src = new FileL5kSource(filePath);
+        else if (!string.IsNullOrEmpty(inlineText))
+            src = new StringL5kSource(inlineText);
+        if (src is null) return;
+
+        var doc = parse(src);
+        var ingest = new L5kIngest
+        {
+            DefaultDeviceHostAddress = deviceHost,
+            NamePrefix = namePrefix,
+        };
+        var result = ingest.Ingest(doc);
+        foreach (var importedTag in result.Tags)
+        {
+            if (declaredNames.Contains(importedTag.Name)) continue;
+            allTags.Add(importedTag);
+            declaredNames.Add(importedTag.Name);
+        }
+    }
+
+    /// <summary>
+    ///     CSV-import variant of <see cref="MergeImport"/>. The CSV path produces
+    ///     <see cref="AbCipTagDefinition"/> records directly (no intermediate document) so we
+    ///     can't share the L5K/L5X parser-delegate signature. Merge semantics are identical:
+    ///     a name already covered by a declaration or an earlier import is left untouched so
+    ///     the precedence chain (declared > L5K > L5X > CSV) holds.
+    /// </summary>
+    private static void MergeCsvImport(
+        AbCipCsvImportOptions import,
+        HashSet<string> declaredNames,
+        List<AbCipTagDefinition> allTags)
+    {
+        if (string.IsNullOrWhiteSpace(import.DeviceHostAddress))
+            throw new InvalidOperationException(
+                "AbCip CSV import is missing DeviceHostAddress — every imported tag needs a target device.");
+
+        string? csvText = null;
+        if (!string.IsNullOrEmpty(import.FilePath))
+            csvText = System.IO.File.ReadAllText(import.FilePath);
+        else if (!string.IsNullOrEmpty(import.InlineText))
+            csvText = import.InlineText;
+        if (csvText is null) return;
+
+        var importer = new CsvTagImporter
+        {
+            DefaultDeviceHostAddress = import.DeviceHostAddress,
+            NamePrefix = import.NamePrefix,
+        };
+        var result = importer.Import(csvText);
+        foreach (var tag in result.Tags)
+        {
+            if (declaredNames.Contains(tag.Name)) continue;
+            allTags.Add(tag);
+            declaredNames.Add(tag.Name);
+        }
+    }
+
     public async Task ReinitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
     {
         await ShutdownAsync(cancellationToken).ConfigureAwait(false);
@@ -357,6 +473,17 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
             return;
         }
 
+        // PR abcip-1.3 — array-slice path. A tag whose TagPath ends in [N..M] dispatches to
+        // AbCipArrayReadPlanner: one libplctag tag-create with ElementCount=N issues one
+        // Rockwell array read; the contiguous buffer is decoded at element stride into a
+        // single snapshot whose Value is an object[] of the N elements.
+        var parsedPath = AbCipTagPath.TryParse(def.TagPath);
+        if (parsedPath?.Slice is not null)
+        {
+            await ReadSliceAsync(fb, def, parsedPath, device, results, now, ct).ConfigureAwait(false);
+            return;
+        }
+
         try
         {
             var runtime = await EnsureTagRuntimeAsync(device, def, ct).ConfigureAwait(false);
@@ -372,8 +499,7 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                 return;
             }
 
-            var tagPath = AbCipTagPath.TryParse(def.TagPath);
-            var bitIndex = tagPath?.BitIndex;
+            var bitIndex = parsedPath?.BitIndex;
             var value = runtime.DecodeValue(def.DataType, bitIndex);
             results[fb.OriginalIndex] = new DataValueSnapshot(value, AbCipStatusMapper.Good, now, now);
             _health = new DriverHealth(DriverState.Healthy, now, null);
@@ -390,6 +516,89 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         }
     }
 
+    /// <summary>
+    ///     PR abcip-1.3 — slice read path. Builds an <see cref="AbCipArrayReadPlan"/> from the
+    ///     parsed slice path, materialises a per-tag runtime keyed by the tag's full name (so
+    ///     repeat reads reuse the same libplctag handle), issues one PLC array read, and
+    ///     decodes the contiguous buffer into <c>object?[]</c> at element stride. Unsupported
+    ///     element types fall back to <see cref="AbCipStatusMapper.BadNotSupported"/>.
+    /// </summary>
+    private async Task ReadSliceAsync(
+        AbCipUdtReadFallback fb, AbCipTagDefinition def, AbCipTagPath parsedPath,
+        DeviceState device, DataValueSnapshot[] results, DateTime now, CancellationToken ct)
+    {
+        var baseParams = new AbCipTagCreateParams(
+            Gateway: device.ParsedAddress.Gateway,
+            Port: device.ParsedAddress.Port,
+            CipPath: device.ParsedAddress.CipPath,
+            LibplctagPlcAttribute: device.Profile.LibplctagPlcAttribute,
+            TagName: parsedPath.ToLibplctagName(),
+            Timeout: _options.Timeout);
+
+        var plan = AbCipArrayReadPlanner.TryBuild(def, parsedPath, baseParams);
+        if (plan is null)
+        {
+            results[fb.OriginalIndex] = new DataValueSnapshot(null,
+                AbCipStatusMapper.BadNotSupported, null, now);
+            return;
+        }
+
+        try
+        {
+            var runtime = await EnsureSliceRuntimeAsync(device, def.Name, plan.CreateParams, ct)
+                .ConfigureAwait(false);
+            await runtime.ReadAsync(ct).ConfigureAwait(false);
+
+            var status = runtime.GetStatus();
+            if (status != 0)
+            {
+                results[fb.OriginalIndex] = new DataValueSnapshot(null,
+                    AbCipStatusMapper.MapLibplctagStatus(status), null, now);
+                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead,
+                    $"libplctag status {status} reading slice {def.Name}");
+                return;
+            }
+
+            var values = AbCipArrayReadPlanner.Decode(plan, runtime);
+            results[fb.OriginalIndex] = new DataValueSnapshot(values, AbCipStatusMapper.Good, now, now);
+            _health = new DriverHealth(DriverState.Healthy, now, null);
+        }
+        catch (OperationCanceledException)
+        {
+            throw;
+        }
+        catch (Exception ex)
+        {
+            results[fb.OriginalIndex] = new DataValueSnapshot(null,
+                AbCipStatusMapper.BadCommunicationError, null, now);
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ex.Message);
+        }
+    }
+
+    /// <summary>
+    ///     Idempotently materialise a slice-read runtime. Slice runtimes share the device's
+    ///     <see cref="DeviceState.Runtimes"/> dict keyed by the tag's full name so repeated
+    ///     reads reuse the same libplctag handle without re-creating the native tag every poll.
+    /// </summary>
+    private async Task<IAbCipTagRuntime> EnsureSliceRuntimeAsync(
+        DeviceState device, string tagName, AbCipTagCreateParams createParams, CancellationToken ct)
+    {
+        if (device.Runtimes.TryGetValue(tagName, out var existing)) return existing;
+
+        var runtime = _tagFactory.Create(createParams);
+        try
+        {
+            await runtime.InitializeAsync(ct).ConfigureAwait(false);
+        }
+        catch
+        {
+            runtime.Dispose();
+            throw;
+        }
+        device.Runtimes[tagName] = runtime;
+        return runtime;
+    }
+
     /// <summary>
     ///     Task #194 — perform one whole-UDT read on the parent tag, then decode each
     ///     grouped member from the runtime's buffer at its computed byte offset. A per-group
@@ -451,100 +660,184 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
     // ---- IWritable ----
 
     /// <summary>
-    ///     Write each request in order. Writes are NOT auto-retried by the driver — per plan
-    ///     decisions #44, #45, #143 the caller opts in via <see cref="AbCipTagDefinition.WriteIdempotent"/>
-    ///     and the resilience pipeline (layered above the driver) decides whether to replay.
-    ///     Non-writable configurations surface as <c>BadNotWritable</c>; type-conversion failures
-    ///     as <c>BadTypeMismatch</c>; transport errors as <c>BadCommunicationError</c>.
+    ///     Write each request in the batch. Writes are NOT auto-retried by the driver — per
+    ///     plan decisions #44, #45, #143 the caller opts in via
+    ///     <see cref="AbCipTagDefinition.WriteIdempotent"/> and the resilience pipeline (layered
+    ///     above the driver) decides whether to replay. Non-writable configurations surface as
+    ///     <c>BadNotWritable</c>; type-conversion failures as <c>BadTypeMismatch</c>; transport
+    ///     errors as <c>BadCommunicationError</c>.
     /// </summary>
+    /// <remarks>
+    ///     PR abcip-1.4 — multi-tag write packing. Writes are grouped by device via
+    ///     <see cref="AbCipMultiWritePlanner"/>. Devices whose family
+    ///     <see cref="AbCipPlcFamilyProfile.SupportsRequestPacking"/> is <c>true</c> dispatch
+    ///     their packable writes concurrently so libplctag's native scheduler can coalesce them
+    ///     onto one CIP Multi-Service Packet (0x0A) per round-trip; Micro800 (no packing) still
+    ///     issues writes one-at-a-time. BOOL-within-DINT writes always go through the RMW path
+    ///     under a per-parent semaphore, regardless of the family flag, because two concurrent
+    ///     RMWs on the same DINT could lose one another's update. Per-tag StatusCodes are
+    ///     preserved in the caller's input order on partial failures.
+    /// </remarks>
     public async Task<IReadOnlyList<WriteResult>> WriteAsync(
         IReadOnlyList<WriteRequest> writes, CancellationToken cancellationToken)
     {
         ArgumentNullException.ThrowIfNull(writes);
         var results = new WriteResult[writes.Count];
-        var now = DateTime.UtcNow;
 
-        for (var i = 0; i < writes.Count; i++)
+        var plans = AbCipMultiWritePlanner.Build(
+            writes, _tagsByName, _devices,
+            reportPreflight: (idx, code) => results[idx] = new WriteResult(code));
+
+        foreach (var plan in plans)
         {
-            var w = writes[i];
-            if (!_tagsByName.TryGetValue(w.FullReference, out var def))
+            if (!_devices.TryGetValue(plan.DeviceHostAddress, out var device))
             {
-                results[i] = new WriteResult(AbCipStatusMapper.BadNodeIdUnknown);
-                continue;
-            }
-            if (!def.Writable || def.SafetyTag)
-            {
-                results[i] = new WriteResult(AbCipStatusMapper.BadNotWritable);
-                continue;
-            }
-            if (!_devices.TryGetValue(def.DeviceHostAddress, out var device))
-            {
-                results[i] = new WriteResult(AbCipStatusMapper.BadNodeIdUnknown);
+                foreach (var e in plan.Packable) results[e.OriginalIndex] = new WriteResult(AbCipStatusMapper.BadNodeIdUnknown);
+                foreach (var e in plan.BitRmw) results[e.OriginalIndex] = new WriteResult(AbCipStatusMapper.BadNodeIdUnknown);
                 continue;
             }
 
-            try
-            {
-                var parsedPath = AbCipTagPath.TryParse(def.TagPath);
+            // Bit-RMW writes always serialise per-parent — never packed.
+            foreach (var entry in plan.BitRmw)
+                results[entry.OriginalIndex] = new WriteResult(
+                    await ExecuteBitRmwWriteAsync(device, entry, cancellationToken).ConfigureAwait(false));
 
-                // BOOL-within-DINT writes — per task #181, RMW against a parallel parent-DINT
-                // runtime. Dispatching here keeps the normal EncodeValue path clean; the
-                // per-parent lock prevents two concurrent bit writes to the same DINT from
-                // losing one another's update.
-                if (def.DataType == AbCipDataType.Bool && parsedPath?.BitIndex is int bit)
+            if (plan.Packable.Count == 0) continue;
+
+            if (plan.Profile.SupportsRequestPacking && plan.Packable.Count > 1)
+            {
+                // Concurrent dispatch — libplctag's native scheduler packs same-connection writes
+                // into one Multi-Service Packet when the family supports it.
+                var tasks = new Task<(int idx, uint code)>[plan.Packable.Count];
+                for (var i = 0; i < plan.Packable.Count; i++)
                 {
-                    results[i] = new WriteResult(
-                        await WriteBitInDIntAsync(device, parsedPath, bit, w.Value, cancellationToken)
-                            .ConfigureAwait(false));
-                    if (results[i].StatusCode == AbCipStatusMapper.Good)
-                        _health = new DriverHealth(DriverState.Healthy, now, null);
-                    continue;
+                    var entry = plan.Packable[i];
+                    tasks[i] = ExecutePackableWriteAsync(device, entry, cancellationToken);
                 }
-
-                var runtime = await EnsureTagRuntimeAsync(device, def, cancellationToken).ConfigureAwait(false);
-                runtime.EncodeValue(def.DataType, parsedPath?.BitIndex, w.Value);
-                await runtime.WriteAsync(cancellationToken).ConfigureAwait(false);
-
-                var status = runtime.GetStatus();
-                results[i] = new WriteResult(status == 0
-                    ? AbCipStatusMapper.Good
-                    : AbCipStatusMapper.MapLibplctagStatus(status));
-                if (status == 0) _health = new DriverHealth(DriverState.Healthy, now, null);
+                var outcomes = await Task.WhenAll(tasks).ConfigureAwait(false);
+                foreach (var (idx, code) in outcomes)
+                    results[idx] = new WriteResult(code);
             }
-            catch (OperationCanceledException)
+            else
             {
-                throw;
-            }
-            catch (NotSupportedException nse)
-            {
-                results[i] = new WriteResult(AbCipStatusMapper.BadNotSupported);
-                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, nse.Message);
-            }
-            catch (FormatException fe)
-            {
-                results[i] = new WriteResult(AbCipStatusMapper.BadTypeMismatch);
-                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, fe.Message);
-            }
-            catch (InvalidCastException ice)
-            {
-                results[i] = new WriteResult(AbCipStatusMapper.BadTypeMismatch);
-                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ice.Message);
-            }
-            catch (OverflowException oe)
-            {
-                results[i] = new WriteResult(AbCipStatusMapper.BadOutOfRange);
-                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, oe.Message);
-            }
-            catch (Exception ex)
-            {
-                results[i] = new WriteResult(AbCipStatusMapper.BadCommunicationError);
-                _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ex.Message);
+                // Single-write groups + Micro800 (SupportsRequestPacking=false) — sequential.
+                foreach (var entry in plan.Packable)
+                {
+                    var code = await ExecutePackableWriteAsync(device, entry, cancellationToken)
+                        .ConfigureAwait(false);
+                    results[entry.OriginalIndex] = new WriteResult(code.code);
+                }
             }
         }
 
         return results;
     }
 
+    /// <summary>
+    ///     Execute one packable write — encode the value into the per-tag runtime, flush, and
+    ///     map the resulting libplctag status. Exception-to-StatusCode mapping mirrors the
+    ///     pre-1.4 per-tag loop so callers see no behaviour change for individual writes.
+    /// </summary>
+    private async Task<(int idx, uint code)> ExecutePackableWriteAsync(
+        DeviceState device, AbCipMultiWritePlanner.ClassifiedWrite entry, CancellationToken ct)
+    {
+        var def = entry.Definition;
+        var w = entry.Request;
+        var now = DateTime.UtcNow;
+        try
+        {
+            var runtime = await EnsureTagRuntimeAsync(device, def, ct).ConfigureAwait(false);
+            runtime.EncodeValue(def.DataType, entry.ParsedPath?.BitIndex, w.Value);
+            await runtime.WriteAsync(ct).ConfigureAwait(false);
+
+            var status = runtime.GetStatus();
+            if (status == 0)
+            {
+                _health = new DriverHealth(DriverState.Healthy, now, null);
+                return (entry.OriginalIndex, AbCipStatusMapper.Good);
+            }
+            return (entry.OriginalIndex, AbCipStatusMapper.MapLibplctagStatus(status));
+        }
+        catch (OperationCanceledException)
+        {
+            throw;
+        }
+        catch (NotSupportedException nse)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, nse.Message);
+            return (entry.OriginalIndex, AbCipStatusMapper.BadNotSupported);
+        }
+        catch (FormatException fe)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, fe.Message);
+            return (entry.OriginalIndex, AbCipStatusMapper.BadTypeMismatch);
+        }
+        catch (InvalidCastException ice)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ice.Message);
+            return (entry.OriginalIndex, AbCipStatusMapper.BadTypeMismatch);
+        }
+        catch (OverflowException oe)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, oe.Message);
+            return (entry.OriginalIndex, AbCipStatusMapper.BadOutOfRange);
+        }
+        catch (Exception ex)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ex.Message);
+            return (entry.OriginalIndex, AbCipStatusMapper.BadCommunicationError);
+        }
+    }
+
+    /// <summary>
+    ///     Execute one BOOL-within-DINT write through <see cref="WriteBitInDIntAsync"/>, with
+    ///     the same exception-mapping fan-out as the pre-1.4 per-tag loop. Bit RMWs cannot be
+    ///     packed because two concurrent writes against the same parent DINT would race their
+    ///     read-modify-write windows.
+    /// </summary>
+    private async Task<uint> ExecuteBitRmwWriteAsync(
+        DeviceState device, AbCipMultiWritePlanner.ClassifiedWrite entry, CancellationToken ct)
+    {
+        try
+        {
+            var bit = entry.ParsedPath!.BitIndex!.Value;
+            var code = await WriteBitInDIntAsync(device, entry.ParsedPath, bit, entry.Request.Value, ct)
+                .ConfigureAwait(false);
+            if (code == AbCipStatusMapper.Good)
+                _health = new DriverHealth(DriverState.Healthy, DateTime.UtcNow, null);
+            return code;
+        }
+        catch (OperationCanceledException)
+        {
+            throw;
+        }
+        catch (NotSupportedException nse)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, nse.Message);
+            return AbCipStatusMapper.BadNotSupported;
+        }
+        catch (FormatException fe)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, fe.Message);
+            return AbCipStatusMapper.BadTypeMismatch;
+        }
+        catch (InvalidCastException ice)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ice.Message);
+            return AbCipStatusMapper.BadTypeMismatch;
+        }
+        catch (OverflowException oe)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, oe.Message);
+            return AbCipStatusMapper.BadOutOfRange;
+        }
+        catch (Exception ex)
+        {
+            _health = new DriverHealth(DriverState.Degraded, _health.LastSuccessfulRead, ex.Message);
+            return AbCipStatusMapper.BadCommunicationError;
+        }
+    }
+
     /// <summary>
     ///     Read-modify-write one bit within a DINT parent. Creates / reuses a parallel
     ///     parent-DINT runtime (distinct from the bit-selector handle) + serialises concurrent
@@ -633,7 +926,8 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
             CipPath: device.ParsedAddress.CipPath,
             LibplctagPlcAttribute: device.Profile.LibplctagPlcAttribute,
             TagName: parsed.ToLibplctagName(),
-            Timeout: _options.Timeout));
+            Timeout: _options.Timeout,
+            StringMaxCapacity: def.DataType == AbCipDataType.String ? def.StringLength : null));
         try
         {
             await runtime.InitializeAsync(ct).ConfigureAwait(false);
@@ -674,6 +968,43 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
     public async Task DiscoverAsync(IAddressSpaceBuilder builder, CancellationToken cancellationToken)
     {
         ArgumentNullException.ThrowIfNull(builder);
+        await _discoverySemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+        try
+        {
+            await DiscoverCoreAsync(builder, cancellationToken).ConfigureAwait(false);
+        }
+        finally
+        {
+            _discoverySemaphore.Release();
+        }
+    }
+
+    /// <summary>
+    ///     PR abcip-2.5 — operator-triggered rebrowse. Drops the cached UDT template shapes so
+    ///     the next read re-fetches them from the controller, then runs the same enumerator
+    ///     walk + builder fan-out that <see cref="DiscoverAsync"/> drives. Serialised against
+    ///     other rebrowse / discovery passes via <see cref="_discoverySemaphore"/> so two
+    ///     concurrent triggers don't double-issue the @tags read.
+    /// </summary>
+    public async Task RebrowseAsync(IAddressSpaceBuilder builder, CancellationToken cancellationToken)
+    {
+        ArgumentNullException.ThrowIfNull(builder);
+        await _discoverySemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+        try
+        {
+            // Stale template shapes can outlive a controller program-download, so a rebrowse
+            // is the natural moment to drop them; subsequent UDT reads re-populate on demand.
+            _templateCache.Clear();
+            await DiscoverCoreAsync(builder, cancellationToken).ConfigureAwait(false);
+        }
+        finally
+        {
+            _discoverySemaphore.Release();
+        }
+    }
+
+    private async Task DiscoverCoreAsync(IAddressSpaceBuilder builder, CancellationToken cancellationToken)
+    {
         var root = builder.Folder("AbCip", "AbCip");
 
         foreach (var device in _options.Devices)
@@ -694,10 +1025,31 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                 if (tag.DataType == AbCipDataType.Structure && tag.Members is { Count: > 0 })
                 {
                     var udtFolder = deviceFolder.Folder(tag.Name, tag.Name);
+                    // PR abcip-2.6 — AOI-aware fan-out. When any member carries a non-Local
+                    // AoiQualifier the tag is treated as an AOI instance: Input / Output / InOut
+                    // members get grouped under sub-folders (Inputs/, Outputs/, InOut/) so the
+                    // browse tree visually matches Studio 5000's AOI parameter tabs. Plain UDT
+                    // tags (every member Local) retain the pre-2.6 flat layout under the parent
+                    // folder so existing browse paths stay stable.
+                    var hasDirectional = tag.Members.Any(m => m.AoiQualifier != AoiQualifier.Local);
+                    IAddressSpaceBuilder? inputsFolder = null;
+                    IAddressSpaceBuilder? outputsFolder = null;
+                    IAddressSpaceBuilder? inOutFolder = null;
                     foreach (var member in tag.Members)
                     {
+                        var parentFolder = udtFolder;
+                        if (hasDirectional)
+                        {
+                            parentFolder = member.AoiQualifier switch
+                            {
+                                AoiQualifier.Input => inputsFolder ??= udtFolder.Folder("Inputs", "Inputs"),
+                                AoiQualifier.Output => outputsFolder ??= udtFolder.Folder("Outputs", "Outputs"),
+                                AoiQualifier.InOut => inOutFolder ??= udtFolder.Folder("InOut", "InOut"),
+                                _ => udtFolder, // Local stays at the AOI root
+                            };
+                        }
                         var memberFullName = $"{tag.Name}.{member.Name}";
-                        udtFolder.Variable(member.Name, member.Name, new DriverAttributeInfo(
+                        parentFolder.Variable(member.Name, member.Name, new DriverAttributeInfo(
                             FullName: memberFullName,
                             DriverDataType: member.DataType.ToDriverDataType(),
                             IsArray: false,
@@ -707,7 +1059,8 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                                 : SecurityClassification.ViewOnly,
                             IsHistorized: false,
                             IsAlarm: false,
-                            WriteIdempotent: member.WriteIdempotent));
+                            WriteIdempotent: member.WriteIdempotent,
+                            Description: member.Description));
                     }
                     continue;
                 }
@@ -767,7 +1120,8 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
             : SecurityClassification.ViewOnly,
         IsHistorized: false,
         IsAlarm: false,
-        WriteIdempotent: tag.WriteIdempotent);
+        WriteIdempotent: tag.WriteIdempotent,
+        Description: tag.Description);
 
     /// <summary>Count of registered devices — exposed for diagnostics + tests.</summary>
     internal int DeviceCount => _devices.Count;
@@ -781,6 +1135,7 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
     public async ValueTask DisposeAsync()
     {
         await ShutdownAsync(CancellationToken.None).ConfigureAwait(false);
+        _discoverySemaphore.Dispose();
     }
 
     /// <summary>

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriverFactoryExtensions.cs

@@ -0,0 +1,151 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
+
+/// <summary>
+///     Static factory registration helper for <see cref="AbCipDriver"/>. Server's Program.cs
+///     calls <see cref="Register"/> once at startup; the bootstrapper (task #248) then
+///     materialises AB CIP DriverInstance rows from the central config DB into live driver
+///     instances. Mirrors <c>GalaxyProxyDriverFactoryExtensions</c>.
+/// </summary>
+public static class AbCipDriverFactoryExtensions
+{
+    public const string DriverTypeName = "AbCip";
+
+    public static void Register(DriverFactoryRegistry registry)
+    {
+        ArgumentNullException.ThrowIfNull(registry);
+        registry.Register(DriverTypeName, CreateInstance);
+    }
+
+    internal static AbCipDriver CreateInstance(string driverInstanceId, string driverConfigJson)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);
+
+        var dto = JsonSerializer.Deserialize<AbCipDriverConfigDto>(driverConfigJson, JsonOptions)
+            ?? throw new InvalidOperationException(
+                $"AB CIP driver config for '{driverInstanceId}' deserialised to null");
+
+        var options = new AbCipDriverOptions
+        {
+            Devices = dto.Devices is { Count: > 0 }
+                ? [.. dto.Devices.Select(d => new AbCipDeviceOptions(
+                    HostAddress: d.HostAddress ?? throw new InvalidOperationException(
+                        $"AB CIP config for '{driverInstanceId}' has a device missing HostAddress"),
+                    PlcFamily: ParseEnum<AbCipPlcFamily>(d.PlcFamily, "device", driverInstanceId, "PlcFamily",
+                        fallback: AbCipPlcFamily.ControlLogix),
+                    DeviceName: d.DeviceName))]
+                : [],
+            Tags = dto.Tags is { Count: > 0 }
+                ? [.. dto.Tags.Select(t => BuildTag(t, driverInstanceId))]
+                : [],
+            Probe = new AbCipProbeOptions
+            {
+                Enabled = dto.Probe?.Enabled ?? true,
+                Interval = TimeSpan.FromMilliseconds(dto.Probe?.IntervalMs ?? 5_000),
+                Timeout = TimeSpan.FromMilliseconds(dto.Probe?.TimeoutMs ?? 2_000),
+                ProbeTagPath = dto.Probe?.ProbeTagPath,
+            },
+            Timeout = TimeSpan.FromMilliseconds(dto.TimeoutMs ?? 2_000),
+            EnableControllerBrowse = dto.EnableControllerBrowse ?? false,
+            EnableAlarmProjection = dto.EnableAlarmProjection ?? false,
+            AlarmPollInterval = TimeSpan.FromMilliseconds(dto.AlarmPollIntervalMs ?? 1_000),
+        };
+
+        return new AbCipDriver(options, driverInstanceId);
+    }
+
+    private static AbCipTagDefinition BuildTag(AbCipTagDto t, string driverInstanceId) =>
+        new(
+            Name: t.Name ?? throw new InvalidOperationException(
+                $"AB CIP config for '{driverInstanceId}' has a tag missing Name"),
+            DeviceHostAddress: t.DeviceHostAddress ?? throw new InvalidOperationException(
+                $"AB CIP tag '{t.Name}' in '{driverInstanceId}' missing DeviceHostAddress"),
+            TagPath: t.TagPath ?? throw new InvalidOperationException(
+                $"AB CIP tag '{t.Name}' in '{driverInstanceId}' missing TagPath"),
+            DataType: ParseEnum<AbCipDataType>(t.DataType, t.Name, driverInstanceId, "DataType"),
+            Writable: t.Writable ?? true,
+            WriteIdempotent: t.WriteIdempotent ?? false,
+            Members: t.Members is { Count: > 0 }
+                ? [.. t.Members.Select(m => new AbCipStructureMember(
+                    Name: m.Name ?? throw new InvalidOperationException(
+                        $"AB CIP tag '{t.Name}' in '{driverInstanceId}' has a member missing Name"),
+                    DataType: ParseEnum<AbCipDataType>(m.DataType, t.Name, driverInstanceId,
+                        $"Members[{m.Name}].DataType"),
+                    Writable: m.Writable ?? true,
+                    WriteIdempotent: m.WriteIdempotent ?? false))]
+                : null,
+            SafetyTag: t.SafetyTag ?? false);
+
+    private static T ParseEnum<T>(string? raw, string? tagName, string driverInstanceId, string field,
+        T? fallback = null) where T : struct, Enum
+    {
+        if (string.IsNullOrWhiteSpace(raw))
+        {
+            if (fallback.HasValue) return fallback.Value;
+            throw new InvalidOperationException(
+                $"AB CIP tag '{tagName ?? "<unnamed>"}' in '{driverInstanceId}' missing {field}");
+        }
+        return Enum.TryParse<T>(raw, ignoreCase: true, out var v)
+            ? v
+            : throw new InvalidOperationException(
+                $"AB CIP tag '{tagName}' has unknown {field} '{raw}'. " +
+                $"Expected one of {string.Join(", ", Enum.GetNames<T>())}");
+    }
+
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        ReadCommentHandling = JsonCommentHandling.Skip,
+        AllowTrailingCommas = true,
+    };
+
+    internal sealed class AbCipDriverConfigDto
+    {
+        public int? TimeoutMs { get; init; }
+        public bool? EnableControllerBrowse { get; init; }
+        public bool? EnableAlarmProjection { get; init; }
+        public int? AlarmPollIntervalMs { get; init; }
+        public List<AbCipDeviceDto>? Devices { get; init; }
+        public List<AbCipTagDto>? Tags { get; init; }
+        public AbCipProbeDto? Probe { get; init; }
+    }
+
+    internal sealed class AbCipDeviceDto
+    {
+        public string? HostAddress { get; init; }
+        public string? PlcFamily { get; init; }
+        public string? DeviceName { get; init; }
+    }
+
+    internal sealed class AbCipTagDto
+    {
+        public string? Name { get; init; }
+        public string? DeviceHostAddress { get; init; }
+        public string? TagPath { get; init; }
+        public string? DataType { get; init; }
+        public bool? Writable { get; init; }
+        public bool? WriteIdempotent { get; init; }
+        public List<AbCipMemberDto>? Members { get; init; }
+        public bool? SafetyTag { get; init; }
+    }
+
+    internal sealed class AbCipMemberDto
+    {
+        public string? Name { get; init; }
+        public string? DataType { get; init; }
+        public bool? Writable { get; init; }
+        public bool? WriteIdempotent { get; init; }
+    }
+
+    internal sealed class AbCipProbeDto
+    {
+        public bool? Enabled { get; init; }
+        public int? IntervalMs { get; init; }
+        public int? TimeoutMs { get; init; }
+        public string? ProbeTagPath { get; init; }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriverOptions.cs

@@ -21,6 +21,37 @@ public sealed class AbCipDriverOptions
     /// <summary>Pre-declared tag map across all devices — AB discovery lands in PR 5.</summary>
     public IReadOnlyList<AbCipTagDefinition> Tags { get; init; } = [];
 
+    /// <summary>
+    ///     L5K (Studio 5000 controller export) imports merged into <see cref="Tags"/> at
+    ///     <c>InitializeAsync</c>. Each entry points at one L5K file + the device whose tags it
+    ///     describes; the parser extracts <c>TAG</c> + <c>DATATYPE</c> blocks and produces
+    ///     <see cref="AbCipTagDefinition"/> records (alias tags + ExternalAccess=None tags
+    ///     skipped — see <see cref="Import.L5kIngest"/>). Pre-declared <see cref="Tags"/> entries
+    ///     win on <c>Name</c> conflicts so operators can override import results without
+    ///     editing the L5K source.
+    /// </summary>
+    public IReadOnlyList<AbCipL5kImportOptions> L5kImports { get; init; } = [];
+
+    /// <summary>
+    ///     L5X (Studio 5000 XML controller export) imports merged into <see cref="Tags"/> at
+    ///     <c>InitializeAsync</c>. Same shape and merge semantics as <see cref="L5kImports"/> —
+    ///     the entries differ only in source format. Pre-declared <see cref="Tags"/> entries win
+    ///     on <c>Name</c> conflicts; entries already produced by <see cref="L5kImports"/> also win
+    ///     so an L5X re-export of the same controller doesn't double-emit. See
+    ///     <see cref="Import.L5xParser"/> for the format-specific mechanics.
+    /// </summary>
+    public IReadOnlyList<AbCipL5xImportOptions> L5xImports { get; init; } = [];
+
+    /// <summary>
+    ///     Kepware-format CSV imports merged into <see cref="Tags"/> at <c>InitializeAsync</c>.
+    ///     Same merge semantics as <see cref="L5kImports"/> / <see cref="L5xImports"/> —
+    ///     pre-declared <see cref="Tags"/> entries win on <c>Name</c> conflicts, and tags
+    ///     produced by earlier import collections (L5K → L5X → CSV in call order) also win
+    ///     so an Excel-edited copy of the same controller does not double-emit. See
+    ///     <see cref="Import.CsvTagImporter"/> for the column layout + parse rules.
+    /// </summary>
+    public IReadOnlyList<AbCipCsvImportOptions> CsvImports { get; init; } = [];
+
     /// <summary>Per-device probe settings. Falls back to defaults when omitted.</summary>
     public AbCipProbeOptions Probe { get; init; } = new();
 
@@ -92,6 +123,17 @@ public sealed record AbCipDeviceOptions(
 ///     GuardLogix controller; non-safety writes violate the safety-partition isolation and are
 ///     rejected by the PLC anyway. Surfaces the intent explicitly instead of relying on the
 ///     write attempt failing at runtime.</param>
+/// <param name="StringLength">Capacity of the DATA character array on a Logix STRING / STRINGnn
+///     UDT — 82 for the stock <c>STRING</c>, 20/40/80/etc for user-defined <c>STRING_20</c>,
+///     <c>STRING_40</c>, <c>STRING_80</c> variants. Threads through libplctag's
+///     <c>str_max_capacity</c> attribute so the wrapper allocates the correct backing buffer
+///     and <c>GetString</c> / <c>SetString</c> truncate at the right boundary. <c>null</c>
+///     keeps libplctag's default 82-byte STRING behaviour for back-compat. Ignored for
+///     non-<see cref="AbCipDataType.String"/> types.</param>
+/// <param name="Description">Tag description carried from the L5K/L5X export (or set explicitly
+///     in pre-declared config). Surfaces as the OPC UA <c>Description</c> attribute on the
+///     produced Variable node so SCADA / engineering clients see the comment from the source
+///     project. <c>null</c> leaves Description unset, matching pre-2.3 behaviour.</param>
 public sealed record AbCipTagDefinition(
     string Name,
     string DeviceHostAddress,
@@ -100,7 +142,9 @@ public sealed record AbCipTagDefinition(
     bool Writable = true,
     bool WriteIdempotent = false,
     IReadOnlyList<AbCipStructureMember>? Members = null,
-    bool SafetyTag = false);
+    bool SafetyTag = false,
+    int? StringLength = null,
+    string? Description = null);
 
 /// <summary>
 ///     One declared member of a UDT tag. Name is the member identifier on the PLC (e.g. <c>Speed</c>,
@@ -108,11 +152,92 @@ public sealed record AbCipTagDefinition(
 ///     <see cref="AbCipTagDefinition"/>. Declaration-driven — the real CIP Template Object reader
 ///     (class 0x6C) that would auto-discover member layouts lands as a follow-up PR.
 /// </summary>
+/// <remarks>
+///     <para><see cref="Description"/> carries the per-member comment from L5K/L5X UDT definitions so
+///     the OPC UA Variable nodes produced for individual members surface their descriptions too,
+///     not just the top-level tag.</para>
+///     <para>PR abcip-2.6 — <see cref="AoiQualifier"/> tags AOI parameters as Input / Output /
+///     InOut / Local. Plain UDT members default to <see cref="AoiQualifier.Local"/>. Discovery
+///     groups Input / Output / InOut members under sub-folders so an AOI-typed tag fans out as
+///     <c>Tag/Inputs/...</c>, <c>Tag/Outputs/...</c>, <c>Tag/InOut/...</c> while Local stays at the
+///     UDT root — matching how AOIs visually present in Studio 5000.</para>
+/// </remarks>
 public sealed record AbCipStructureMember(
     string Name,
     AbCipDataType DataType,
     bool Writable = true,
-    bool WriteIdempotent = false);
+    bool WriteIdempotent = false,
+    int? StringLength = null,
+    string? Description = null,
+    AoiQualifier AoiQualifier = AoiQualifier.Local);
+
+/// <summary>
+///     PR abcip-2.6 — directional qualifier for AOI parameters. Surfaces the Studio 5000
+///     <c>Usage</c> attribute (<c>Input</c> / <c>Output</c> / <c>InOut</c>) so discovery can group
+///     AOI members into sub-folders and downstream consumers can reason about parameter direction.
+///     Plain UDT members (non-AOI types) default to <see cref="Local"/>, which keeps them at the
+///     UDT root + indicates they are internal storage rather than a directional parameter.
+/// </summary>
+public enum AoiQualifier
+{
+    /// <summary>UDT member or AOI local tag — non-directional, browsed at the parent's root.</summary>
+    Local,
+
+    /// <summary>AOI input parameter — written by the caller, read by the AOI body.</summary>
+    Input,
+
+    /// <summary>AOI output parameter — written by the AOI body, read by the caller.</summary>
+    Output,
+
+    /// <summary>AOI bidirectional parameter — passed by reference, both sides may read/write.</summary>
+    InOut,
+}
+
+/// <summary>
+///     One L5K-import entry. Either <see cref="FilePath"/> or <see cref="InlineText"/> must be
+///     set (FilePath wins when both supplied — useful for tests that pre-load fixtures into
+///     options without touching disk).
+/// </summary>
+/// <param name="DeviceHostAddress">Target device <c>HostAddress</c> tags from this file are bound to.</param>
+/// <param name="FilePath">On-disk path to a <c>*.L5K</c> export. Loaded eagerly at InitializeAsync.</param>
+/// <param name="InlineText">Pre-loaded L5K body — used by tests + Admin UI uploads.</param>
+/// <param name="NamePrefix">Optional prefix prepended to imported tag names to avoid collisions
+///     when ingesting multiple files into one driver instance.</param>
+public sealed record AbCipL5kImportOptions(
+    string DeviceHostAddress,
+    string? FilePath = null,
+    string? InlineText = null,
+    string NamePrefix = "");
+
+/// <summary>
+///     One L5X-import entry. Mirrors <see cref="AbCipL5kImportOptions"/> field-for-field — the
+///     two are kept as distinct types so configuration JSON makes the source format explicit
+///     (an L5X file under an <c>L5kImports</c> entry would parse-fail confusingly otherwise).
+/// </summary>
+/// <param name="DeviceHostAddress">Target device <c>HostAddress</c> tags from this file are bound to.</param>
+/// <param name="FilePath">On-disk path to a <c>*.L5X</c> XML export. Loaded eagerly at InitializeAsync.</param>
+/// <param name="InlineText">Pre-loaded L5X body — used by tests + Admin UI uploads.</param>
+/// <param name="NamePrefix">Optional prefix prepended to imported tag names to avoid collisions
+///     when ingesting multiple files into one driver instance.</param>
+public sealed record AbCipL5xImportOptions(
+    string DeviceHostAddress,
+    string? FilePath = null,
+    string? InlineText = null,
+    string NamePrefix = "");
+
+/// <summary>
+///     One Kepware-format CSV import entry. Field shape mirrors <see cref="AbCipL5kImportOptions"/>
+///     so configuration JSON stays consistent across the three import sources.
+/// </summary>
+/// <param name="DeviceHostAddress">Target device <c>HostAddress</c> tags from this file are bound to.</param>
+/// <param name="FilePath">On-disk path to a Kepware-format <c>*.csv</c>. Loaded eagerly at InitializeAsync.</param>
+/// <param name="InlineText">Pre-loaded CSV body — used by tests + Admin UI uploads.</param>
+/// <param name="NamePrefix">Optional prefix prepended to imported tag names to avoid collisions.</param>
+public sealed record AbCipCsvImportOptions(
+    string DeviceHostAddress,
+    string? FilePath = null,
+    string? InlineText = null,
+    string NamePrefix = "");
 
 /// <summary>Which AB PLC family the device is — selects the profile applied to connection params.</summary>
 public enum AbCipPlcFamily

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipMultiWritePlanner.cs

@@ -0,0 +1,112 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.AbCip.PlcFamilies;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
+
+/// <summary>
+///     PR abcip-1.4 — multi-tag write planner. Groups a batch of <see cref="WriteRequest"/>s by
+///     device so the driver can submit one round of writes per device instead of looping
+///     strictly serially across the whole batch. Honours the per-family
+///     <see cref="AbCipPlcFamilyProfile.SupportsRequestPacking"/> flag: families that support
+///     CIP request packing (ControlLogix / CompactLogix / GuardLogix) issue their writes in
+///     parallel so libplctag's internal scheduler can coalesce them onto one Multi-Service
+///     Packet (0x0A); Micro800 (no request packing) falls back to per-tag sequential writes.
+/// </summary>
+/// <remarks>
+///     <para>The libplctag .NET wrapper exposes one CIP service per <c>Tag</c> instance and does
+///     not surface Multi-Service Packet construction at the API surface — but the underlying
+///     native library packs concurrent operations against the same connection automatically
+///     when the family's protocol supports it. Issuing the writes concurrently per device
+///     therefore gives us the round-trip reduction described in #228 without having to drop to
+///     raw CIP, while still letting us short-circuit packing on Micro800 where it would be
+///     unsafe.</para>
+///
+///     <para>Bit-RMW writes (BOOL-with-bitIndex against a DINT parent) are excluded from
+///     packing here because they need a serialised read-modify-write under the per-parent
+///     <c>SemaphoreSlim</c> in <see cref="AbCipDriver.WriteBitInDIntAsync"/>. Packing two RMWs
+///     on the same DINT would risk losing one another's update.</para>
+/// </remarks>
+internal static class AbCipMultiWritePlanner
+{
+    /// <summary>
+    ///     One classified entry in the input batch. <see cref="OriginalIndex"/> preserves the
+    ///     caller's ordering so per-tag <c>StatusCode</c> fan-out lands at the right slot in
+    ///     the result array. <see cref="IsBitRmw"/> routes the entry through the RMW path even
+    ///     when the device supports packing.
+    /// </summary>
+    internal readonly record struct ClassifiedWrite(
+        int OriginalIndex,
+        WriteRequest Request,
+        AbCipTagDefinition Definition,
+        AbCipTagPath? ParsedPath,
+        bool IsBitRmw);
+
+    /// <summary>
+    ///     One device's plan slice. <see cref="Packable"/> entries can be issued concurrently;
+    ///     <see cref="BitRmw"/> entries must go through the RMW path one-at-a-time per parent
+    ///     DINT.
+    /// </summary>
+    internal sealed class DevicePlan
+    {
+        public required string DeviceHostAddress { get; init; }
+        public required AbCipPlcFamilyProfile Profile { get; init; }
+        public List<ClassifiedWrite> Packable { get; } = new();
+        public List<ClassifiedWrite> BitRmw { get; } = new();
+    }
+
+    /// <summary>
+    ///     Build the per-device plan list. Entries are visited in input order so the resulting
+    ///     plan's traversal preserves caller ordering within each device. Entries that fail
+    ///     resolution (unknown reference, non-writable tag, unknown device) are reported via
+    ///     <paramref name="reportPreflight"/> with the appropriate StatusCode and excluded from
+    ///     the plan.
+    /// </summary>
+    public static IReadOnlyList<DevicePlan> Build(
+        IReadOnlyList<WriteRequest> writes,
+        IReadOnlyDictionary<string, AbCipTagDefinition> tagsByName,
+        IReadOnlyDictionary<string, AbCipDriver.DeviceState> devices,
+        Action<int, uint> reportPreflight)
+    {
+        var plans = new Dictionary<string, DevicePlan>(StringComparer.OrdinalIgnoreCase);
+        var order = new List<DevicePlan>();
+
+        for (var i = 0; i < writes.Count; i++)
+        {
+            var w = writes[i];
+            if (!tagsByName.TryGetValue(w.FullReference, out var def))
+            {
+                reportPreflight(i, AbCipStatusMapper.BadNodeIdUnknown);
+                continue;
+            }
+            if (!def.Writable || def.SafetyTag)
+            {
+                reportPreflight(i, AbCipStatusMapper.BadNotWritable);
+                continue;
+            }
+            if (!devices.TryGetValue(def.DeviceHostAddress, out var device))
+            {
+                reportPreflight(i, AbCipStatusMapper.BadNodeIdUnknown);
+                continue;
+            }
+
+            if (!plans.TryGetValue(def.DeviceHostAddress, out var plan))
+            {
+                plan = new DevicePlan
+                {
+                    DeviceHostAddress = def.DeviceHostAddress,
+                    Profile = device.Profile,
+                };
+                plans[def.DeviceHostAddress] = plan;
+                order.Add(plan);
+            }
+
+            var parsed = AbCipTagPath.TryParse(def.TagPath);
+            var isBitRmw = def.DataType == AbCipDataType.Bool && parsed?.BitIndex is int;
+            var entry = new ClassifiedWrite(i, w, def, parsed, isBitRmw);
+            if (isBitRmw) plan.BitRmw.Add(entry);
+            else plan.Packable.Add(entry);
+        }
+
+        return order;
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipTagPath.cs

@@ -20,7 +20,8 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
 public sealed record AbCipTagPath(
     string? ProgramScope,
     IReadOnlyList<AbCipTagPathSegment> Segments,
-    int? BitIndex)
+    int? BitIndex,
+    AbCipTagPathSlice? Slice = null)
 {
     /// <summary>Rebuild the canonical Logix tag string.</summary>
     public string ToLibplctagName()
@@ -37,10 +38,39 @@ public sealed record AbCipTagPath(
             if (seg.Subscripts.Count > 0)
                 buf.Append('[').Append(string.Join(",", seg.Subscripts)).Append(']');
         }
+        if (Slice is not null) buf.Append('[').Append(Slice.Start).Append("..").Append(Slice.End).Append(']');
         if (BitIndex is not null) buf.Append('.').Append(BitIndex.Value);
         return buf.ToString();
     }
 
+    /// <summary>
+    ///     Logix-symbol form for issuing a single libplctag tag-create that reads the slice as a
+    ///     contiguous buffer — i.e. the bare array name (with the start subscript) without the
+    ///     <c>..End</c> suffix. The driver pairs this with <see cref="AbCipTagCreateParams.ElementCount"/>
+    ///     = <see cref="AbCipTagPathSlice.Count"/> to issue a single Rockwell array read.
+    /// </summary>
+    public string ToLibplctagSliceArrayName()
+    {
+        if (Slice is null) return ToLibplctagName();
+        var buf = new System.Text.StringBuilder();
+        if (ProgramScope is not null)
+            buf.Append("Program:").Append(ProgramScope).Append('.');
+
+        for (var i = 0; i < Segments.Count; i++)
+        {
+            if (i > 0) buf.Append('.');
+            var seg = Segments[i];
+            buf.Append(seg.Name);
+            if (seg.Subscripts.Count > 0)
+                buf.Append('[').Append(string.Join(",", seg.Subscripts)).Append(']');
+        }
+        // Anchor the read at the slice start; libplctag treats Name=Tag[0] + ElementCount=N as
+        // "read N consecutive elements starting at index 0", which is the exact Rockwell
+        // array-read semantic this PR is wiring up.
+        buf.Append('[').Append(Slice.Start).Append(']');
+        return buf.ToString();
+    }
+
     /// <summary>
     ///     Parse a Logix-symbolic tag reference. Returns <c>null</c> on a shape the parser
     ///     doesn't support — the driver surfaces that as a config-validation error rather than
@@ -91,8 +121,10 @@ public sealed record AbCipTagPath(
         }
 
         var segments = new List<AbCipTagPathSegment>(parts.Count);
-        foreach (var part in parts)
+        AbCipTagPathSlice? slice = null;
+        for (var partIdx = 0; partIdx < parts.Count; partIdx++)
         {
+            var part = parts[partIdx];
             var bracketIdx = part.IndexOf('[');
             if (bracketIdx < 0)
             {
@@ -104,6 +136,25 @@ public sealed record AbCipTagPath(
             var name = part[..bracketIdx];
             if (!IsValidIdent(name)) return null;
             var inner = part[(bracketIdx + 1)..^1];
+
+            // Slice syntax `[N..M]` — only allowed on the LAST segment, must not coexist with
+            // multi-dim subscripts, must not be combined with bit-index, and requires M >= N.
+            // Any other shape is rejected so callers see a config-validation error rather than
+            // the driver attempting a best-effort scalar read.
+            if (inner.Contains(".."))
+            {
+                if (partIdx != parts.Count - 1) return null;          // slice + sub-element
+                if (bitIndex is not null) return null;                // slice + bit index
+                if (inner.Contains(',')) return null;                 // slice cannot be multi-dim
+                var parts2 = inner.Split("..", 2, StringSplitOptions.None);
+                if (parts2.Length != 2) return null;
+                if (!int.TryParse(parts2[0], out var sliceStart) || sliceStart < 0) return null;
+                if (!int.TryParse(parts2[1], out var sliceEnd) || sliceEnd < sliceStart) return null;
+                slice = new AbCipTagPathSlice(sliceStart, sliceEnd);
+                segments.Add(new AbCipTagPathSegment(name, []));
+                continue;
+            }
+
             var subs = new List<int>();
             foreach (var tok in inner.Split(','))
             {
@@ -115,7 +166,7 @@ public sealed record AbCipTagPath(
         }
         if (segments.Count == 0) return null;
 
-        return new AbCipTagPath(programScope, segments, bitIndex);
+        return new AbCipTagPath(programScope, segments, bitIndex, slice);
     }
 
     private static bool IsValidIdent(string s)
@@ -130,3 +181,15 @@ public sealed record AbCipTagPath(
 
 /// <summary>One path segment: a member name plus any numeric subscripts.</summary>
 public sealed record AbCipTagPathSegment(string Name, IReadOnlyList<int> Subscripts);
+
+/// <summary>
+///     Inclusive-on-both-ends array slice carried on the trailing segment of an
+///     <see cref="AbCipTagPath"/>. <c>Tag[0..15]</c> parses to <c>Start=0, End=15</c>; the
+///     planner pairs this with libplctag's <c>ElementCount</c> attribute to issue a single
+///     Rockwell array read covering <c>End - Start + 1</c> elements.
+/// </summary>
+public sealed record AbCipTagPathSlice(int Start, int End)
+{
+    /// <summary>Total element count covered by the slice (inclusive both ends).</summary>
+    public int Count => End - Start + 1;
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/IAbCipTagRuntime.cs

@@ -65,10 +65,20 @@ public interface IAbCipTagFactory
 /// <param name="LibplctagPlcAttribute">libplctag <c>plc=...</c> attribute, per family profile.</param>
 /// <param name="TagName">Logix symbolic tag name as emitted by <see cref="AbCipTagPath.ToLibplctagName"/>.</param>
 /// <param name="Timeout">libplctag operation timeout (applies to Initialize / Read / Write).</param>
+/// <param name="StringMaxCapacity">Optional Logix STRINGnn DATA-array capacity (e.g. 20 / 40 / 80
+///     for <c>STRING_20</c> / <c>STRING_40</c> / <c>STRING_80</c> UDTs). Threads through libplctag's
+///     <c>str_max_capacity</c> attribute. <c>null</c> keeps libplctag's default 82-byte STRING
+///     behaviour for back-compat.</param>
+/// <param name="ElementCount">Optional libplctag <c>ElementCount</c> override — set to <c>N</c>
+///     to issue a Rockwell array read covering <c>N</c> consecutive elements starting at the
+///     subscripted index in <see cref="TagName"/>. Drives PR abcip-1.3 array-slice support;
+///     <c>null</c> leaves libplctag's default scalar-element behaviour for back-compat.</param>
 public sealed record AbCipTagCreateParams(
     string Gateway,
     int Port,
     string CipPath,
     string LibplctagPlcAttribute,
     string TagName,
-    TimeSpan Timeout);
+    TimeSpan Timeout,
+    int? StringMaxCapacity = null,
+    int? ElementCount = null);

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/Import/CsvTagExporter.cs

@@ -0,0 +1,99 @@
+using System.Globalization;
+using System.IO;
+using System.Text;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
+
+/// <summary>
+///     Render an enumerable of <see cref="AbCipTagDefinition"/> as a Kepware-format CSV
+///     document. Emits the header expected by <see cref="CsvTagImporter"/> so the importer
+///     and exporter form a complete round-trip path: load → export → reparse → identical
+///     entries (modulo unknown-type tags, which export as <c>STRING</c> and reimport as
+///     <see cref="AbCipDataType.Structure"/> per the importer's fall-through rule).
+/// </summary>
+public static class CsvTagExporter
+{
+    public static readonly IReadOnlyList<string> KepwareColumns =
+    [
+        "Tag Name",
+        "Address",
+        "Data Type",
+        "Respect Data Type",
+        "Client Access",
+        "Scan Rate",
+        "Description",
+        "Scaling",
+    ];
+
+    /// <summary>Write the tag list to <paramref name="writer"/> in Kepware CSV format.</summary>
+    public static void Write(IEnumerable<AbCipTagDefinition> tags, TextWriter writer)
+    {
+        ArgumentNullException.ThrowIfNull(tags);
+        ArgumentNullException.ThrowIfNull(writer);
+
+        writer.WriteLine(string.Join(",", KepwareColumns.Select(EscapeField)));
+        foreach (var tag in tags)
+        {
+            var fields = new[]
+            {
+                tag.Name ?? string.Empty,
+                tag.TagPath ?? string.Empty,
+                FormatDataType(tag.DataType),
+                "1",                                       // Respect Data Type — Kepware EX default.
+                tag.Writable ? "Read/Write" : "Read Only",
+                "100",                                     // Scan Rate (ms) — placeholder default.
+                tag.Description ?? string.Empty,
+                "None",                                    // Scaling — driver doesn't apply scaling.
+            };
+            writer.WriteLine(string.Join(",", fields.Select(EscapeField)));
+        }
+    }
+
+    /// <summary>Render the tag list to a string.</summary>
+    public static string ToCsv(IEnumerable<AbCipTagDefinition> tags)
+    {
+        using var sw = new StringWriter(CultureInfo.InvariantCulture);
+        Write(tags, sw);
+        return sw.ToString();
+    }
+
+    /// <summary>Write the tag list to <paramref name="path"/> as UTF-8 (no BOM).</summary>
+    public static void WriteFile(IEnumerable<AbCipTagDefinition> tags, string path)
+    {
+        ArgumentNullException.ThrowIfNull(path);
+        using var sw = new StreamWriter(path, append: false, new UTF8Encoding(false));
+        Write(tags, sw);
+    }
+
+    private static string FormatDataType(AbCipDataType t) => t switch
+    {
+        AbCipDataType.Bool => "BOOL",
+        AbCipDataType.SInt => "SINT",
+        AbCipDataType.Int => "INT",
+        AbCipDataType.DInt => "DINT",
+        AbCipDataType.LInt => "LINT",
+        AbCipDataType.USInt => "USINT",
+        AbCipDataType.UInt => "UINT",
+        AbCipDataType.UDInt => "UDINT",
+        AbCipDataType.ULInt => "ULINT",
+        AbCipDataType.Real => "REAL",
+        AbCipDataType.LReal => "LREAL",
+        AbCipDataType.String => "STRING",
+        AbCipDataType.Dt => "DT",
+        AbCipDataType.Structure => "STRING", // Surface UDT-typed tags as STRING — Kepware has no UDT cell.
+        _ => "STRING",
+    };
+
+    /// <summary>Quote a field if it contains comma, quote, CR, or LF; escape embedded quotes by doubling.</summary>
+    private static string EscapeField(string value)
+    {
+        value ??= string.Empty;
+        var needsQuotes =
+            value.IndexOf(',') >= 0 ||
+            value.IndexOf('"') >= 0 ||
+            value.IndexOf('\r') >= 0 ||
+            value.IndexOf('\n') >= 0;
+        if (!needsQuotes) return value;
+        return "\"" + value.Replace("\"", "\"\"") + "\"";
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/Import/CsvTagImporter.cs

@@ -0,0 +1,226 @@
+using System.Globalization;
+using System.IO;
+using System.Text;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
+
+/// <summary>
+///     Parse a Kepware-format AB CIP tag CSV into <see cref="AbCipTagDefinition"/> entries.
+///     The expected column layout matches the Kepware EX tag-export shape so operators can
+///     round-trip tags through Excel without re-keying:
+///     <c>Tag Name, Address, Data Type, Respect Data Type, Client Access, Scan Rate,
+///     Description, Scaling</c>. The first non-blank, non-comment row is treated as the
+///     header — column order is honoured by name lookup, so reorderings out of Excel still
+///     work. Blank rows + rows whose first cell starts with a Kepware section marker
+///     (<c>;</c> / <c>#</c>) are skipped.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Mapping: <c>Tag Name</c> → <see cref="AbCipTagDefinition.Name"/>;
+///         <c>Address</c> → <see cref="AbCipTagDefinition.TagPath"/>;
+///         <c>Data Type</c> → <see cref="AbCipTagDefinition.DataType"/> (Logix atomic name —
+///         BOOL/SINT/INT/DINT/REAL/STRING/...; unknown values fall through as
+///         <see cref="AbCipDataType.Structure"/> the same way <see cref="L5kIngest"/> handles
+///         unknown types);
+///         <c>Description</c> → <see cref="AbCipTagDefinition.Description"/>;
+///         <c>Client Access</c> → <see cref="AbCipTagDefinition.Writable"/>: any value
+///         containing <c>W</c> (case-insensitive) is treated as Read/Write; everything else
+///         is Read-Only.
+///     </para>
+///     <para>
+///         CSV semantics are RFC-4180-ish: double-quoted fields support embedded commas, line
+///         breaks, and escaped quotes (<c>""</c>). The parser is single-pass + deliberately
+///         narrow — Kepware's exporter does not produce anything more exotic.
+///     </para>
+/// </remarks>
+public sealed class CsvTagImporter
+{
+    /// <summary>Default device host address applied to every imported tag.</summary>
+    public string DefaultDeviceHostAddress { get; init; } = string.Empty;
+
+    /// <summary>Optional prefix prepended to each imported tag's name. Default empty.</summary>
+    public string NamePrefix { get; init; } = string.Empty;
+
+    public CsvTagImportResult Import(string csvText)
+    {
+        ArgumentNullException.ThrowIfNull(csvText);
+        if (string.IsNullOrWhiteSpace(DefaultDeviceHostAddress))
+            throw new InvalidOperationException(
+                $"{nameof(CsvTagImporter)}.{nameof(DefaultDeviceHostAddress)} must be set before {nameof(Import)} is called — every imported tag needs a target device.");
+
+        var rows = CsvReader.ReadAll(csvText);
+        var tags = new List<AbCipTagDefinition>();
+        var skippedBlank = 0;
+        Dictionary<string, int>? header = null;
+
+        foreach (var row in rows)
+        {
+            if (row.Count == 0 || row.All(string.IsNullOrWhiteSpace))
+            {
+                skippedBlank++;
+                continue;
+            }
+            var first = row[0].TrimStart();
+            if (first.StartsWith(';') || first.StartsWith('#'))
+            {
+                skippedBlank++;
+                continue;
+            }
+
+            if (header is null)
+            {
+                header = BuildHeader(row);
+                continue;
+            }
+
+            var name = GetCell(row, header, "Tag Name");
+            if (string.IsNullOrWhiteSpace(name))
+            {
+                skippedBlank++;
+                continue;
+            }
+
+            var address = GetCell(row, header, "Address");
+            var dataTypeText = GetCell(row, header, "Data Type");
+            var description = GetCell(row, header, "Description");
+            var clientAccess = GetCell(row, header, "Client Access");
+
+            var dataType = ParseDataType(dataTypeText);
+            var writable = !string.IsNullOrEmpty(clientAccess)
+                && clientAccess.IndexOf('W', StringComparison.OrdinalIgnoreCase) >= 0;
+
+            tags.Add(new AbCipTagDefinition(
+                Name: string.IsNullOrEmpty(NamePrefix) ? name : $"{NamePrefix}{name}",
+                DeviceHostAddress: DefaultDeviceHostAddress,
+                TagPath: string.IsNullOrEmpty(address) ? name : address,
+                DataType: dataType,
+                Writable: writable,
+                Description: string.IsNullOrEmpty(description) ? null : description));
+        }
+
+        return new CsvTagImportResult(tags, skippedBlank);
+    }
+
+    public CsvTagImportResult ImportFile(string path) =>
+        Import(File.ReadAllText(path, Encoding.UTF8));
+
+    private static Dictionary<string, int> BuildHeader(IReadOnlyList<string> row)
+    {
+        var dict = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
+        for (var i = 0; i < row.Count; i++)
+        {
+            var key = row[i]?.Trim() ?? string.Empty;
+            if (key.Length > 0 && !dict.ContainsKey(key))
+                dict[key] = i;
+        }
+        return dict;
+    }
+
+    private static string GetCell(IReadOnlyList<string> row, Dictionary<string, int> header, string column)
+    {
+        if (!header.TryGetValue(column, out var idx)) return string.Empty;
+        if (idx < 0 || idx >= row.Count) return string.Empty;
+        return row[idx]?.Trim() ?? string.Empty;
+    }
+
+    private static AbCipDataType ParseDataType(string s) =>
+        s?.Trim().ToUpperInvariant() switch
+        {
+            "BOOL" or "BIT" => AbCipDataType.Bool,
+            "SINT" or "BYTE" => AbCipDataType.SInt,
+            "INT" or "WORD" or "SHORT" => AbCipDataType.Int,
+            "DINT" or "DWORD" or "LONG" => AbCipDataType.DInt,
+            "LINT" => AbCipDataType.LInt,
+            "USINT" => AbCipDataType.USInt,
+            "UINT" => AbCipDataType.UInt,
+            "UDINT" => AbCipDataType.UDInt,
+            "ULINT" => AbCipDataType.ULInt,
+            "REAL" or "FLOAT" => AbCipDataType.Real,
+            "LREAL" or "DOUBLE" => AbCipDataType.LReal,
+            "STRING" => AbCipDataType.String,
+            "DT" or "DATETIME" or "DATE" => AbCipDataType.Dt,
+            _ => AbCipDataType.Structure,
+        };
+}
+
+/// <summary>Result of <see cref="CsvTagImporter.Import"/>.</summary>
+public sealed record CsvTagImportResult(
+    IReadOnlyList<AbCipTagDefinition> Tags,
+    int SkippedBlankCount);
+
+/// <summary>
+///     Tiny RFC-4180-ish CSV reader. Supports double-quoted fields, escaped <c>""</c>
+///     quotes, and embedded line breaks inside quotes. Internal because the importer +
+///     exporter are the only two callers and we don't want to add a CSV dep.
+/// </summary>
+internal static class CsvReader
+{
+    public static List<List<string>> ReadAll(string text)
+    {
+        var rows = new List<List<string>>();
+        var row = new List<string>();
+        var field = new StringBuilder();
+        var inQuotes = false;
+
+        for (var i = 0; i < text.Length; i++)
+        {
+            var c = text[i];
+            if (inQuotes)
+            {
+                if (c == '"')
+                {
+                    if (i + 1 < text.Length && text[i + 1] == '"')
+                    {
+                        field.Append('"');
+                        i++;
+                    }
+                    else
+                    {
+                        inQuotes = false;
+                    }
+                }
+                else
+                {
+                    field.Append(c);
+                }
+                continue;
+            }
+
+            switch (c)
+            {
+                case '"':
+                    inQuotes = true;
+                    break;
+                case ',':
+                    row.Add(field.ToString());
+                    field.Clear();
+                    break;
+                case '\r':
+                    // Swallow CR — handle CRLF and lone CR alike.
+                    row.Add(field.ToString());
+                    field.Clear();
+                    rows.Add(row);
+                    row = new List<string>();
+                    if (i + 1 < text.Length && text[i + 1] == '\n') i++;
+                    break;
+                case '\n':
+                    row.Add(field.ToString());
+                    field.Clear();
+                    rows.Add(row);
+                    row = new List<string>();
+                    break;
+                default:
+                    field.Append(c);
+                    break;
+            }
+        }
+
+        if (field.Length > 0 || row.Count > 0)
+        {
+            row.Add(field.ToString());
+            rows.Add(row);
+        }
+
+        return rows;
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/Import/IL5kSource.cs

@@ -0,0 +1,29 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
+
+/// <summary>
+///     Abstraction over an L5K text source so the parser can consume strings, files, or streams
+///     without coupling to <see cref="System.IO"/>. Implementations return the full text in a
+///     single call — L5K files are typically &lt;10 MB even for large controllers, and the parser
+///     needs random access to handle nested DATATYPE/TAG blocks regardless.
+/// </summary>
+public interface IL5kSource
+{
+    /// <summary>Reads the full L5K body as a string.</summary>
+    string ReadAll();
+}
+
+/// <summary>String-backed source — used by tests + when the L5K body is loaded elsewhere.</summary>
+public sealed class StringL5kSource : IL5kSource
+{
+    private readonly string _text;
+    public StringL5kSource(string text) => _text = text ?? throw new ArgumentNullException(nameof(text));
+    public string ReadAll() => _text;
+}
+
+/// <summary>File-backed source — used by Admin / driver init to load <c>*.L5K</c> exports.</summary>
+public sealed class FileL5kSource : IL5kSource
+{
+    private readonly string _path;
+    public FileL5kSource(string path) => _path = path ?? throw new ArgumentNullException(nameof(path));
+    public string ReadAll() => System.IO.File.ReadAllText(_path);
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/Import/L5kIngest.cs

@@ -0,0 +1,161 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
+
+/// <summary>
+///     Converts a parsed <see cref="L5kDocument"/> into <see cref="AbCipTagDefinition"/> entries
+///     ready to be merged into <see cref="AbCipDriverOptions.Tags"/>. UDT definitions become
+///     <see cref="AbCipStructureMember"/> lists keyed by data-type name; tags whose
+///     <see cref="L5kTag.DataType"/> matches a known UDT get those members attached so the
+///     discovery code can fan out the structure.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <strong>Alias tags are skipped</strong> — when <see cref="L5kTag.AliasFor"/> is
+///         non-null the entry is dropped at ingest. Surfacing both the alias + its target
+///         creates duplicate Variables in the OPC UA address space (Kepware's L5K importer
+///         takes the same approach for this reason; the alias target is the single source of
+///         truth for storage).
+///     </para>
+///     <para>
+///         <strong>Tags with <c>ExternalAccess := None</c> are skipped</strong> — the controller
+///         actively rejects external reads/writes, so emitting them as Variables would just
+///         produce permanent BadCommunicationError. <c>Read Only</c> maps to <c>Writable=false</c>;
+///         <c>Read/Write</c> (or absent) maps to <c>Writable=true</c>.
+///     </para>
+///     <para>
+///         Unknown data-type names (not atomic + not a parsed UDT) fall through as
+///         <see cref="AbCipDataType.Structure"/> with no member layout — discovery can still
+///         expose them as black-box variables and the operator can pin them via dotted paths.
+///     </para>
+/// </remarks>
+public sealed class L5kIngest
+{
+    /// <summary>Default device host address applied to every imported tag.</summary>
+    public string DefaultDeviceHostAddress { get; init; } = string.Empty;
+
+    /// <summary>
+    ///     Optional prefix prepended to imported tag names — useful when ingesting multiple
+    ///     L5K exports into one driver instance to avoid name collisions. Default empty.
+    /// </summary>
+    public string NamePrefix { get; init; } = string.Empty;
+
+    public L5kIngestResult Ingest(L5kDocument document)
+    {
+        ArgumentNullException.ThrowIfNull(document);
+        if (string.IsNullOrWhiteSpace(DefaultDeviceHostAddress))
+            throw new InvalidOperationException(
+                $"{nameof(L5kIngest)}.{nameof(DefaultDeviceHostAddress)} must be set before {nameof(Ingest)} is called — every imported tag needs a target device.");
+
+        // Index UDT definitions by name so we can fan out structure tags inline.
+        var udtIndex = new Dictionary<string, IReadOnlyList<AbCipStructureMember>>(StringComparer.OrdinalIgnoreCase);
+        foreach (var dt in document.DataTypes)
+        {
+            var members = new List<AbCipStructureMember>(dt.Members.Count);
+            foreach (var m in dt.Members)
+            {
+                var atomic = TryMapAtomic(m.DataType);
+                var memberType = atomic ?? AbCipDataType.Structure;
+                var writable = !IsReadOnly(m.ExternalAccess) && !IsAccessNone(m.ExternalAccess);
+                members.Add(new AbCipStructureMember(
+                    Name: m.Name,
+                    DataType: memberType,
+                    Writable: writable,
+                    Description: m.Description,
+                    AoiQualifier: MapAoiUsage(m.Usage)));
+            }
+            udtIndex[dt.Name] = members;
+        }
+
+        var tags = new List<AbCipTagDefinition>();
+        var skippedAliases = 0;
+        var skippedNoAccess = 0;
+        foreach (var t in document.Tags)
+        {
+            if (!string.IsNullOrEmpty(t.AliasFor)) { skippedAliases++; continue; }
+            if (IsAccessNone(t.ExternalAccess)) { skippedNoAccess++; continue; }
+
+            var atomic = TryMapAtomic(t.DataType);
+            AbCipDataType dataType;
+            IReadOnlyList<AbCipStructureMember>? members = null;
+            if (atomic is { } a)
+            {
+                dataType = a;
+            }
+            else
+            {
+                dataType = AbCipDataType.Structure;
+                if (udtIndex.TryGetValue(t.DataType, out var udtMembers))
+                    members = udtMembers;
+            }
+
+            var tagPath = t.ProgramScope is { Length: > 0 }
+                ? $"Program:{t.ProgramScope}.{t.Name}"
+                : t.Name;
+            var name = string.IsNullOrEmpty(NamePrefix) ? t.Name : $"{NamePrefix}{t.Name}";
+            // Make the OPC UA tag name unique when both controller-scope + program-scope tags
+            // share the same simple Name.
+            if (t.ProgramScope is { Length: > 0 })
+                name = string.IsNullOrEmpty(NamePrefix)
+                    ? $"{t.ProgramScope}.{t.Name}"
+                    : $"{NamePrefix}{t.ProgramScope}.{t.Name}";
+
+            var writable = !IsReadOnly(t.ExternalAccess);
+
+            tags.Add(new AbCipTagDefinition(
+                Name: name,
+                DeviceHostAddress: DefaultDeviceHostAddress,
+                TagPath: tagPath,
+                DataType: dataType,
+                Writable: writable,
+                Members: members,
+                Description: t.Description));
+        }
+
+        return new L5kIngestResult(tags, skippedAliases, skippedNoAccess);
+    }
+
+    private static bool IsReadOnly(string? externalAccess) =>
+        externalAccess is not null
+        && externalAccess.Trim().Replace(" ", string.Empty).Equals("ReadOnly", StringComparison.OrdinalIgnoreCase);
+
+    private static bool IsAccessNone(string? externalAccess) =>
+        externalAccess is not null && externalAccess.Trim().Equals("None", StringComparison.OrdinalIgnoreCase);
+
+    /// <summary>
+    ///     PR abcip-2.6 — map the AOI <c>Usage</c> attribute string to <see cref="AoiQualifier"/>.
+    ///     Plain UDT members (Usage = null) + unrecognised values map to <see cref="AoiQualifier.Local"/>.
+    /// </summary>
+    private static AoiQualifier MapAoiUsage(string? usage) =>
+        usage?.Trim().ToUpperInvariant() switch
+        {
+            "INPUT" => AoiQualifier.Input,
+            "OUTPUT" => AoiQualifier.Output,
+            "INOUT" => AoiQualifier.InOut,
+            _ => AoiQualifier.Local,
+        };
+
+    /// <summary>Map a Logix atomic type name. Returns <c>null</c> for UDT/structure references.</summary>
+    private static AbCipDataType? TryMapAtomic(string logixType) =>
+        logixType?.Trim().ToUpperInvariant() switch
+        {
+            "BOOL" or "BIT" => AbCipDataType.Bool,
+            "SINT" => AbCipDataType.SInt,
+            "INT" => AbCipDataType.Int,
+            "DINT" => AbCipDataType.DInt,
+            "LINT" => AbCipDataType.LInt,
+            "USINT" => AbCipDataType.USInt,
+            "UINT" => AbCipDataType.UInt,
+            "UDINT" => AbCipDataType.UDInt,
+            "ULINT" => AbCipDataType.ULInt,
+            "REAL" => AbCipDataType.Real,
+            "LREAL" => AbCipDataType.LReal,
+            "STRING" => AbCipDataType.String,
+            "DT" or "DATETIME" => AbCipDataType.Dt,
+            _ => null,
+        };
+}
+
+/// <summary>Result of <see cref="L5kIngest.Ingest"/> — produced tags + per-skip-reason counts.</summary>
+public sealed record L5kIngestResult(
+    IReadOnlyList<AbCipTagDefinition> Tags,
+    int SkippedAliasCount,
+    int SkippedNoAccessCount);

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/Import/L5kParser.cs

@@ -0,0 +1,469 @@
+using System.Globalization;
+using System.Text.RegularExpressions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
+
+/// <summary>
+///     Pure-text parser for Studio 5000 L5K controller exports. L5K is a labelled-section export
+///     with TAG/END_TAG, DATATYPE/END_DATATYPE, PROGRAM/END_PROGRAM blocks. This parser handles
+///     the common shapes:
+///     <list type="bullet">
+///       <item>Controller-scope <c>TAG ... END_TAG</c> with <c>Name</c>, <c>DataType</c>,
+///             optional <c>ExternalAccess</c>, optional <c>Description</c>.</item>
+///       <item>Program-scope tags inside <c>PROGRAM ... END_PROGRAM</c>.</item>
+///       <item>UDT definitions via <c>DATATYPE ... END_DATATYPE</c> with <c>MEMBER</c> lines.</item>
+///       <item>Alias tags (<c>AliasFor</c>) — recognised + flagged so callers can skip them.</item>
+///     </list>
+///     Unknown sections (CONFIG, MODULE, AOI, MOTION_GROUP, etc.) are skipped silently.
+///     Per Kepware precedent, alias tags are typically skipped on ingest because the alias target
+///     is what owns the storage — surfacing both creates duplicate writes/reads.
+/// </summary>
+/// <remarks>
+///     This is a permissive line-oriented parser, not a full L5K grammar. Comments
+///     (<c>(* ... *)</c>) are stripped before tokenization. The parser is deliberately tolerant of
+///     extra whitespace, unknown attributes, and trailing semicolons — real-world L5K files are
+///     produced by RSLogix exports that vary across versions.
+/// </remarks>
+public static class L5kParser
+{
+    public static L5kDocument Parse(IL5kSource source)
+    {
+        ArgumentNullException.ThrowIfNull(source);
+        var raw = source.ReadAll();
+        var stripped = StripBlockComments(raw);
+        var lines = stripped.Split(new[] { "\r\n", "\n", "\r" }, StringSplitOptions.None);
+
+        var tags = new List<L5kTag>();
+        var datatypes = new List<L5kDataType>();
+        string? currentProgram = null;
+        var i = 0;
+        while (i < lines.Length)
+        {
+            var line = lines[i].Trim();
+            if (line.Length == 0) { i++; continue; }
+
+            // PROGRAM block — opens a program scope; the body contains nested TAG blocks.
+            if (StartsWithKeyword(line, "PROGRAM"))
+            {
+                currentProgram = ExtractFirstQuotedOrToken(line.Substring("PROGRAM".Length).Trim());
+                i++;
+                continue;
+            }
+            if (StartsWithKeyword(line, "END_PROGRAM"))
+            {
+                currentProgram = null;
+                i++;
+                continue;
+            }
+
+            // TAG block — collects 1..N tag entries until END_TAG.
+            if (StartsWithKeyword(line, "TAG"))
+            {
+                var consumed = ParseTagBlock(lines, i, currentProgram, tags);
+                i += consumed;
+                continue;
+            }
+
+            // DATATYPE block.
+            if (StartsWithKeyword(line, "DATATYPE"))
+            {
+                var consumed = ParseDataTypeBlock(lines, i, datatypes);
+                i += consumed;
+                continue;
+            }
+
+            // PR abcip-2.6 — ADD_ON_INSTRUCTION_DEFINITION block. AOI parameters carry a Usage
+            // attribute (Input / Output / InOut); each PARAMETER becomes a member of the AOI's
+            // L5kDataType entry so AOI-typed tags pick up a layout the same way UDT-typed tags do.
+            if (StartsWithKeyword(line, "ADD_ON_INSTRUCTION_DEFINITION"))
+            {
+                var consumed = ParseAoiDefinitionBlock(lines, i, datatypes);
+                i += consumed;
+                continue;
+            }
+
+            i++;
+        }
+
+        return new L5kDocument(tags, datatypes);
+    }
+
+    // ---- TAG block ---------------------------------------------------------
+
+    // Each TAG block contains 1..N entries of the form:
+    //   TagName : DataType (Description := "...", ExternalAccess := Read/Write) := initialValue;
+    // until END_TAG. Entries can span multiple lines, terminated by ';'.
+    private static int ParseTagBlock(string[] lines, int start, string? program, List<L5kTag> into)
+    {
+        var i = start + 1;
+        while (i < lines.Length)
+        {
+            var line = lines[i].Trim();
+            if (StartsWithKeyword(line, "END_TAG")) return i - start + 1;
+            if (line.Length == 0) { i++; continue; }
+
+            var sb = new System.Text.StringBuilder(line);
+            while (!sb.ToString().TrimEnd().EndsWith(';') && i + 1 < lines.Length)
+            {
+                var peek = lines[i + 1].Trim();
+                if (StartsWithKeyword(peek, "END_TAG")) break;
+                i++;
+                sb.Append(' ').Append(peek);
+            }
+            i++;
+
+            var entry = sb.ToString().TrimEnd(';').Trim();
+            var tag = ParseTagEntry(entry, program);
+            if (tag is not null) into.Add(tag);
+        }
+        return i - start;
+    }
+
+    private static L5kTag? ParseTagEntry(string entry, string? program)
+    {
+        // entry shape: Name : DataType [ (attribute := value, ...) ] [ := initialValue ]
+        // Find the first ':' that separates Name from DataType. Avoid ':=' (the assign op).
+        var colonIdx = FindBareColon(entry);
+        if (colonIdx < 0) return null;
+
+        var name = entry.Substring(0, colonIdx).Trim();
+        if (name.Length == 0) return null;
+
+        var rest = entry.Substring(colonIdx + 1).Trim();
+        // The attribute parens themselves contain ':=' assignments, so locate the top-level
+        // assignment (depth-0 ':=') that introduces the initial value before stripping.
+        var assignIdx = FindTopLevelAssign(rest);
+        var head = assignIdx >= 0 ? rest.Substring(0, assignIdx).Trim() : rest;
+
+        // Pull attribute tuple out of head: "DataType (attr := val, attr := val)".
+        string dataType;
+        var attributes = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        var openParen = head.IndexOf('(');
+        if (openParen >= 0)
+        {
+            dataType = head.Substring(0, openParen).Trim();
+            var closeParen = head.LastIndexOf(')');
+            if (closeParen > openParen)
+            {
+                var attrBody = head.Substring(openParen + 1, closeParen - openParen - 1);
+                ParseAttributeList(attrBody, attributes);
+            }
+        }
+        else
+        {
+            dataType = head.Trim();
+        }
+
+        if (dataType.Length == 0) return null;
+
+        var description = attributes.TryGetValue("Description", out var d) ? Unquote(d) : null;
+        var externalAccess = attributes.TryGetValue("ExternalAccess", out var ea) ? ea.Trim() : null;
+        var aliasFor = attributes.TryGetValue("AliasFor", out var af) ? Unquote(af) : null;
+
+        return new L5kTag(
+            Name: name,
+            DataType: dataType,
+            ProgramScope: program,
+            ExternalAccess: externalAccess,
+            Description: description,
+            AliasFor: aliasFor);
+    }
+
+    // Find the first ':=' at depth 0 (not inside parens / brackets / quotes). Returns -1 if none.
+    private static int FindTopLevelAssign(string entry)
+    {
+        var depth = 0;
+        var inQuote = false;
+        for (var k = 0; k < entry.Length - 1; k++)
+        {
+            var c = entry[k];
+            if (c == '"' || c == '\'') inQuote = !inQuote;
+            if (inQuote) continue;
+            if (c == '(' || c == '[' || c == '{') depth++;
+            else if (c == ')' || c == ']' || c == '}') depth--;
+            else if (c == ':' && entry[k + 1] == '=' && depth == 0) return k;
+        }
+        return -1;
+    }
+
+    // Find the first colon that is NOT part of ':=' and not inside a quoted string.
+    private static int FindBareColon(string entry)
+    {
+        var inQuote = false;
+        for (var k = 0; k < entry.Length; k++)
+        {
+            var c = entry[k];
+            if (c == '"' || c == '\'') inQuote = !inQuote;
+            if (inQuote) continue;
+            if (c != ':') continue;
+            if (k + 1 < entry.Length && entry[k + 1] == '=') continue;
+            return k;
+        }
+        return -1;
+    }
+
+    private static void ParseAttributeList(string body, Dictionary<string, string> into)
+    {
+        foreach (var part in SplitTopLevelCommas(body))
+        {
+            var assign = part.IndexOf(":=", StringComparison.Ordinal);
+            if (assign < 0) continue;
+            var key = part.Substring(0, assign).Trim();
+            var val = part.Substring(assign + 2).Trim();
+            if (key.Length > 0) into[key] = val;
+        }
+    }
+
+    private static IEnumerable<string> SplitTopLevelCommas(string body)
+    {
+        var depth = 0;
+        var inQuote = false;
+        var start = 0;
+        for (var k = 0; k < body.Length; k++)
+        {
+            var c = body[k];
+            if (c == '"' || c == '\'') inQuote = !inQuote;
+            if (inQuote) continue;
+            if (c == '(' || c == '[' || c == '{') depth++;
+            else if (c == ')' || c == ']' || c == '}') depth--;
+            else if (c == ',' && depth == 0)
+            {
+                yield return body.Substring(start, k - start);
+                start = k + 1;
+            }
+        }
+        if (start < body.Length) yield return body.Substring(start);
+    }
+
+    // ---- DATATYPE block ----------------------------------------------------
+
+    private static int ParseDataTypeBlock(string[] lines, int start, List<L5kDataType> into)
+    {
+        var first = lines[start].Trim();
+        var head = first.Substring("DATATYPE".Length).Trim();
+        var name = ExtractFirstQuotedOrToken(head);
+        var members = new List<L5kMember>();
+        var i = start + 1;
+        while (i < lines.Length)
+        {
+            var line = lines[i].Trim();
+            if (StartsWithKeyword(line, "END_DATATYPE"))
+            {
+                if (!string.IsNullOrEmpty(name)) into.Add(new L5kDataType(name, members));
+                return i - start + 1;
+            }
+            if (line.Length == 0) { i++; continue; }
+
+            if (StartsWithKeyword(line, "MEMBER"))
+            {
+                var sb = new System.Text.StringBuilder(line);
+                while (!sb.ToString().TrimEnd().EndsWith(';') && i + 1 < lines.Length)
+                {
+                    var peek = lines[i + 1].Trim();
+                    if (StartsWithKeyword(peek, "END_DATATYPE")) break;
+                    i++;
+                    sb.Append(' ').Append(peek);
+                }
+                var entry = sb.ToString().TrimEnd(';').Trim();
+                entry = entry.Substring("MEMBER".Length).Trim();
+                var member = ParseMemberEntry(entry);
+                if (member is not null) members.Add(member);
+            }
+            i++;
+        }
+        if (!string.IsNullOrEmpty(name)) into.Add(new L5kDataType(name, members));
+        return i - start;
+    }
+
+    private static L5kMember? ParseMemberEntry(string entry)
+    {
+        // entry shape: MemberName : DataType [ [arrayDim] ] [ (attr := val, ...) ] [ := default ]
+        var colonIdx = FindBareColon(entry);
+        if (colonIdx < 0) return null;
+        var name = entry.Substring(0, colonIdx).Trim();
+        if (name.Length == 0) return null;
+
+        var rest = entry.Substring(colonIdx + 1).Trim();
+        var assignIdx = FindTopLevelAssign(rest);
+        if (assignIdx >= 0) rest = rest.Substring(0, assignIdx).Trim();
+
+        int? arrayDim = null;
+        var bracketOpen = rest.IndexOf('[');
+        if (bracketOpen >= 0)
+        {
+            var bracketClose = rest.IndexOf(']', bracketOpen + 1);
+            if (bracketClose > bracketOpen)
+            {
+                var dimText = rest.Substring(bracketOpen + 1, bracketClose - bracketOpen - 1).Trim();
+                if (int.TryParse(dimText, NumberStyles.Integer, CultureInfo.InvariantCulture, out var dim))
+                    arrayDim = dim;
+                rest = (rest.Substring(0, bracketOpen) + rest.Substring(bracketClose + 1)).Trim();
+            }
+        }
+
+        string typePart;
+        var attributes = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        var openParen = rest.IndexOf('(');
+        if (openParen >= 0)
+        {
+            typePart = rest.Substring(0, openParen).Trim();
+            var closeParen = rest.LastIndexOf(')');
+            if (closeParen > openParen)
+            {
+                var attrBody = rest.Substring(openParen + 1, closeParen - openParen - 1);
+                ParseAttributeList(attrBody, attributes);
+            }
+        }
+        else
+        {
+            typePart = rest.Trim();
+        }
+
+        if (typePart.Length == 0) return null;
+        var externalAccess = attributes.TryGetValue("ExternalAccess", out var ea) ? ea.Trim() : null;
+        var description = attributes.TryGetValue("Description", out var d) ? Unquote(d) : null;
+        // PR abcip-2.6 — Usage attribute on AOI parameters (Input / Output / InOut). Plain UDT
+        // members don't carry it; null on a regular DATATYPE MEMBER is the default + maps to Local
+        // in the ingest layer.
+        var usage = attributes.TryGetValue("Usage", out var u) ? u.Trim() : null;
+        return new L5kMember(name, typePart, arrayDim, externalAccess, description, usage);
+    }
+
+    // ---- AOI block ---------------------------------------------------------
+
+    /// <summary>
+    ///     PR abcip-2.6 — parse <c>ADD_ON_INSTRUCTION_DEFINITION ... END_ADD_ON_INSTRUCTION_DEFINITION</c>
+    ///     blocks. Body is structured around PARAMETER entries (each carrying a <c>Usage</c>
+    ///     attribute) and optional LOCAL_TAGS / ROUTINE blocks. We extract the parameters as
+    ///     <see cref="L5kMember"/> rows + leave routines alone — only the surface API matters for
+    ///     tag-discovery fan-out. The L5K format encloses parameters either inside a
+    ///     <c>PARAMETERS ... END_PARAMETERS</c> block or as bare <c>PARAMETER ... ;</c> lines at
+    ///     the AOI top level depending on Studio 5000 export options; this parser accepts both.
+    /// </summary>
+    private static int ParseAoiDefinitionBlock(string[] lines, int start, List<L5kDataType> into)
+    {
+        var first = lines[start].Trim();
+        var head = first.Substring("ADD_ON_INSTRUCTION_DEFINITION".Length).Trim();
+        var name = ExtractFirstQuotedOrToken(head);
+        var members = new List<L5kMember>();
+        var i = start + 1;
+        var inLocalsBlock = false;
+        var inRoutineBlock = false;
+        while (i < lines.Length)
+        {
+            var line = lines[i].Trim();
+            if (StartsWithKeyword(line, "END_ADD_ON_INSTRUCTION_DEFINITION"))
+            {
+                if (!string.IsNullOrEmpty(name)) into.Add(new L5kDataType(name, members));
+                return i - start + 1;
+            }
+            if (line.Length == 0) { i++; continue; }
+
+            // Skip routine bodies — they hold ladder / ST / FBD code we don't care about for
+            // tag-discovery, and their own END_ROUTINE / END_LOCAL_TAGS tokens close them out.
+            if (StartsWithKeyword(line, "ROUTINE")) { inRoutineBlock = true; i++; continue; }
+            if (StartsWithKeyword(line, "END_ROUTINE")) { inRoutineBlock = false; i++; continue; }
+            if (StartsWithKeyword(line, "LOCAL_TAGS")) { inLocalsBlock = true; i++; continue; }
+            if (StartsWithKeyword(line, "END_LOCAL_TAGS")) { inLocalsBlock = false; i++; continue; }
+            if (inRoutineBlock || inLocalsBlock) { i++; continue; }
+
+            // PARAMETERS / END_PARAMETERS wrappers are skipped — bare PARAMETER lines drive parsing.
+            if (StartsWithKeyword(line, "PARAMETERS")) { i++; continue; }
+            if (StartsWithKeyword(line, "END_PARAMETERS")) { i++; continue; }
+
+            if (StartsWithKeyword(line, "PARAMETER"))
+            {
+                var sb = new System.Text.StringBuilder(line);
+                while (!sb.ToString().TrimEnd().EndsWith(';') && i + 1 < lines.Length)
+                {
+                    var peek = lines[i + 1].Trim();
+                    if (StartsWithKeyword(peek, "END_ADD_ON_INSTRUCTION_DEFINITION")) break;
+                    i++;
+                    sb.Append(' ').Append(peek);
+                }
+                var entry = sb.ToString().TrimEnd(';').Trim();
+                entry = entry.Substring("PARAMETER".Length).Trim();
+                var member = ParseMemberEntry(entry);
+                if (member is not null) members.Add(member);
+            }
+            i++;
+        }
+        if (!string.IsNullOrEmpty(name)) into.Add(new L5kDataType(name, members));
+        return i - start;
+    }
+
+    // ---- helpers -----------------------------------------------------------
+
+    private static bool StartsWithKeyword(string line, string keyword)
+    {
+        if (line.Length < keyword.Length) return false;
+        if (!line.StartsWith(keyword, StringComparison.OrdinalIgnoreCase)) return false;
+        if (line.Length == keyword.Length) return true;
+        var next = line[keyword.Length];
+        return !char.IsLetterOrDigit(next) && next != '_';
+    }
+
+    private static string ExtractFirstQuotedOrToken(string fragment)
+    {
+        var trimmed = fragment.TrimStart();
+        if (trimmed.Length == 0) return string.Empty;
+        if (trimmed[0] == '"' || trimmed[0] == '\'')
+        {
+            var quote = trimmed[0];
+            var end = trimmed.IndexOf(quote, 1);
+            if (end > 0) return trimmed.Substring(1, end - 1);
+        }
+        var k = 0;
+        while (k < trimmed.Length)
+        {
+            var c = trimmed[k];
+            if (char.IsWhiteSpace(c) || c == '(' || c == ',' || c == ';') break;
+            k++;
+        }
+        return trimmed.Substring(0, k);
+    }
+
+    private static string Unquote(string s)
+    {
+        s = s.Trim();
+        if (s.Length >= 2 && (s[0] == '"' || s[0] == '\'') && s[s.Length - 1] == s[0])
+            return s.Substring(1, s.Length - 2);
+        return s;
+    }
+
+    private static string StripBlockComments(string text)
+    {
+        // L5K comments: `(* ... *)`. Strip so the line scanner doesn't trip on tokens inside.
+        var pattern = new Regex(@"\(\*.*?\*\)", RegexOptions.Singleline);
+        return pattern.Replace(text, string.Empty);
+    }
+}
+
+/// <summary>Output of <see cref="L5kParser.Parse(IL5kSource)"/>.</summary>
+public sealed record L5kDocument(IReadOnlyList<L5kTag> Tags, IReadOnlyList<L5kDataType> DataTypes);
+
+/// <summary>One L5K tag entry (controller- or program-scope).</summary>
+public sealed record L5kTag(
+    string Name,
+    string DataType,
+    string? ProgramScope,
+    string? ExternalAccess,
+    string? Description,
+    string? AliasFor);
+
+/// <summary>One UDT definition extracted from a <c>DATATYPE ... END_DATATYPE</c> block.</summary>
+public sealed record L5kDataType(string Name, IReadOnlyList<L5kMember> Members);
+
+/// <summary>One member line inside a UDT definition or AOI parameter list.</summary>
+/// <remarks>
+///     PR abcip-2.6 — <see cref="Usage"/> carries the AOI <c>Usage</c> attribute (<c>Input</c> /
+///     <c>Output</c> / <c>InOut</c>) raw text. Plain UDT members + L5K AOI <c>LOCAL_TAGS</c> leave
+///     it null; the ingest layer maps null → <see cref="AoiQualifier.Local"/>.
+/// </remarks>
+public sealed record L5kMember(
+    string Name,
+    string DataType,
+    int? ArrayDim,
+    string? ExternalAccess,
+    string? Description = null,
+    string? Usage = null);

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/Import/L5xParser.cs

@@ -0,0 +1,237 @@
+using System.Globalization;
+using System.Xml;
+using System.Xml.XPath;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip.Import;
+
+/// <summary>
+///     XML-format parser for Studio 5000 L5X controller exports. L5X is the XML sibling of L5K
+///     and carries the same tag / datatype / program shape, plus richer metadata (notably the
+///     AddOnInstructionDefinition catalogue and explicit <c>TagType</c> attributes).
+///     <para>
+///     This parser produces the same <see cref="L5kDocument"/> bundle as
+///     <see cref="L5kParser"/> so <see cref="L5kIngest"/> consumes both formats interchangeably.
+///     The two parsers share the post-parse downstream layer; the only difference is how the
+///     bundle is materialized from the source bytes.
+///     </para>
+///     <para>
+///     AOIs (<c>AddOnInstructionDefinition</c>) are surfaced as L5K-style UDT entries — their
+///     parameters become <see cref="L5kMember"/> rows so AOI-typed tags pick up a member layout
+///     the same way UDT-typed tags do. Full Inputs/Outputs/InOut directional metadata + per-call
+///     parameter scoping is deferred to PR 2.6 per plan; this PR keeps AOIs visible without
+///     attempting to model their call semantics.
+///     </para>
+/// </summary>
+/// <remarks>
+///     Uses <see cref="System.Xml.XPath"/> with an <see cref="XPathDocument"/> for read-only
+///     traversal. L5X exports are typically &lt;50 MB, so a single in-memory navigator beats
+///     forward-only <c>XmlReader</c> on simplicity for the same throughput at this size class.
+///     The parser is permissive about missing optional attributes — a real export always has
+///     <c>Name</c> + <c>DataType</c>, but <c>ExternalAccess</c> defaults to <c>Read/Write</c>
+///     when absent (matching Studio 5000's own default for new tags).
+/// </remarks>
+public static class L5xParser
+{
+    public static L5kDocument Parse(IL5kSource source)
+    {
+        ArgumentNullException.ThrowIfNull(source);
+        var xml = source.ReadAll();
+
+        using var reader = XmlReader.Create(
+            new System.IO.StringReader(xml),
+            new XmlReaderSettings
+            {
+                // L5X exports never include a DOCTYPE, but disable DTD processing defensively.
+                DtdProcessing = DtdProcessing.Prohibit,
+                IgnoreWhitespace = true,
+                IgnoreComments = true,
+            });
+        var doc = new XPathDocument(reader);
+        var nav = doc.CreateNavigator();
+
+        var tags = new List<L5kTag>();
+        var datatypes = new List<L5kDataType>();
+
+        // Controller-scope tags: /RSLogix5000Content/Controller/Tags/Tag
+        foreach (XPathNavigator tagNode in nav.Select("/RSLogix5000Content/Controller/Tags/Tag"))
+        {
+            var t = ReadTag(tagNode, programScope: null);
+            if (t is not null) tags.Add(t);
+        }
+
+        // Program-scope tags: /RSLogix5000Content/Controller/Programs/Program/Tags/Tag
+        foreach (XPathNavigator programNode in nav.Select("/RSLogix5000Content/Controller/Programs/Program"))
+        {
+            var programName = programNode.GetAttribute("Name", string.Empty);
+            if (string.IsNullOrEmpty(programName)) continue;
+            foreach (XPathNavigator tagNode in programNode.Select("Tags/Tag"))
+            {
+                var t = ReadTag(tagNode, programName);
+                if (t is not null) tags.Add(t);
+            }
+        }
+
+        // UDTs: /RSLogix5000Content/Controller/DataTypes/DataType
+        foreach (XPathNavigator dtNode in nav.Select("/RSLogix5000Content/Controller/DataTypes/DataType"))
+        {
+            var udt = ReadDataType(dtNode);
+            if (udt is not null) datatypes.Add(udt);
+        }
+
+        // AOIs: surfaced as L5kDataType entries so AOI-typed tags pick up a member layout.
+        // Per the plan, full directional Input/Output/InOut modelling is deferred to PR 2.6.
+        foreach (XPathNavigator aoiNode in nav.Select("/RSLogix5000Content/Controller/AddOnInstructionDefinitions/AddOnInstructionDefinition"))
+        {
+            var aoi = ReadAddOnInstruction(aoiNode);
+            if (aoi is not null) datatypes.Add(aoi);
+        }
+
+        return new L5kDocument(tags, datatypes);
+    }
+
+    private static L5kTag? ReadTag(XPathNavigator tagNode, string? programScope)
+    {
+        var name = tagNode.GetAttribute("Name", string.Empty);
+        if (string.IsNullOrEmpty(name)) return null;
+
+        var tagType = tagNode.GetAttribute("TagType", string.Empty); // Base | Alias | Produced | Consumed
+        var dataType = tagNode.GetAttribute("DataType", string.Empty);
+        var aliasFor = tagNode.GetAttribute("AliasFor", string.Empty);
+        var externalAccess = tagNode.GetAttribute("ExternalAccess", string.Empty);
+
+        // Alias tags often omit DataType (it's inherited from the target). Surface them with
+        // an empty type — L5kIngest skips alias entries before TryMapAtomic ever sees the type.
+        if (string.IsNullOrEmpty(dataType)
+            && !string.Equals(tagType, "Alias", StringComparison.OrdinalIgnoreCase))
+        {
+            return null;
+        }
+
+        // Description child — L5X wraps description text in <Description> (sometimes inside CDATA).
+        string? description = null;
+        var descNode = tagNode.SelectSingleNode("Description");
+        if (descNode is not null)
+        {
+            var raw = descNode.Value;
+            if (!string.IsNullOrEmpty(raw)) description = raw.Trim();
+        }
+
+        return new L5kTag(
+            Name: name,
+            DataType: string.IsNullOrEmpty(dataType) ? string.Empty : dataType,
+            ProgramScope: programScope,
+            ExternalAccess: string.IsNullOrEmpty(externalAccess) ? null : externalAccess,
+            Description: description,
+            AliasFor: string.IsNullOrEmpty(aliasFor) ? null : aliasFor);
+    }
+
+    private static L5kDataType? ReadDataType(XPathNavigator dtNode)
+    {
+        var name = dtNode.GetAttribute("Name", string.Empty);
+        if (string.IsNullOrEmpty(name)) return null;
+
+        var members = new List<L5kMember>();
+        foreach (XPathNavigator memberNode in dtNode.Select("Members/Member"))
+        {
+            var m = ReadMember(memberNode);
+            if (m is not null) members.Add(m);
+        }
+        return new L5kDataType(name, members);
+    }
+
+    private static L5kMember? ReadMember(XPathNavigator memberNode)
+    {
+        var name = memberNode.GetAttribute("Name", string.Empty);
+        if (string.IsNullOrEmpty(name)) return null;
+
+        // Skip auto-inserted hidden host members for backing storage of BOOL packing — they're
+        // emitted by RSLogix as members named with the ZZZZZZZZZZ prefix and aren't useful to
+        // surface as OPC UA variables.
+        if (name.StartsWith("ZZZZZZZZZZ", StringComparison.Ordinal)) return null;
+
+        var dataType = memberNode.GetAttribute("DataType", string.Empty);
+        if (string.IsNullOrEmpty(dataType)) return null;
+
+        var externalAccess = memberNode.GetAttribute("ExternalAccess", string.Empty);
+
+        int? arrayDim = null;
+        var dimText = memberNode.GetAttribute("Dimension", string.Empty);
+        if (!string.IsNullOrEmpty(dimText)
+            && int.TryParse(dimText, NumberStyles.Integer, CultureInfo.InvariantCulture, out var dim)
+            && dim > 0)
+        {
+            arrayDim = dim;
+        }
+
+        // Description child — same shape as on Tag nodes; sometimes wrapped in CDATA.
+        string? description = null;
+        var descNode = memberNode.SelectSingleNode("Description");
+        if (descNode is not null)
+        {
+            var raw = descNode.Value;
+            if (!string.IsNullOrEmpty(raw)) description = raw.Trim();
+        }
+
+        return new L5kMember(
+            Name: name,
+            DataType: dataType,
+            ArrayDim: arrayDim,
+            ExternalAccess: string.IsNullOrEmpty(externalAccess) ? null : externalAccess,
+            Description: description);
+    }
+
+    private static L5kDataType? ReadAddOnInstruction(XPathNavigator aoiNode)
+    {
+        var name = aoiNode.GetAttribute("Name", string.Empty);
+        if (string.IsNullOrEmpty(name)) return null;
+
+        var members = new List<L5kMember>();
+        foreach (XPathNavigator paramNode in aoiNode.Select("Parameters/Parameter"))
+        {
+            var paramName = paramNode.GetAttribute("Name", string.Empty);
+            if (string.IsNullOrEmpty(paramName)) continue;
+
+            // RSLogix marks the implicit EnableIn / EnableOut parameters as Hidden=true.
+            // Skip them — they aren't part of the AOI's user-facing surface.
+            var hidden = paramNode.GetAttribute("Hidden", string.Empty);
+            if (string.Equals(hidden, "true", StringComparison.OrdinalIgnoreCase)) continue;
+
+            var dataType = paramNode.GetAttribute("DataType", string.Empty);
+            if (string.IsNullOrEmpty(dataType)) continue;
+
+            var externalAccess = paramNode.GetAttribute("ExternalAccess", string.Empty);
+
+            int? arrayDim = null;
+            var dimText = paramNode.GetAttribute("Dimension", string.Empty);
+            if (!string.IsNullOrEmpty(dimText)
+                && int.TryParse(dimText, NumberStyles.Integer, CultureInfo.InvariantCulture, out var dim)
+                && dim > 0)
+            {
+                arrayDim = dim;
+            }
+
+            string? paramDescription = null;
+            var paramDescNode = paramNode.SelectSingleNode("Description");
+            if (paramDescNode is not null)
+            {
+                var raw = paramDescNode.Value;
+                if (!string.IsNullOrEmpty(raw)) paramDescription = raw.Trim();
+            }
+
+            // PR abcip-2.6 — capture the AOI Usage attribute (Input / Output / InOut). RSLogix
+            // also serialises Local AOI tags inside <LocalTags>, but those don't go through this
+            // path — only <Parameters>/<Parameter> entries do — so any Usage value on a parameter
+            // is one of the directional buckets.
+            var usage = paramNode.GetAttribute("Usage", string.Empty);
+
+            members.Add(new L5kMember(
+                Name: paramName,
+                DataType: dataType,
+                ArrayDim: arrayDim,
+                ExternalAccess: string.IsNullOrEmpty(externalAccess) ? null : externalAccess,
+                Description: paramDescription,
+                Usage: string.IsNullOrEmpty(usage) ? null : usage));
+        }
+        return new L5kDataType(name, members);
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/LibplctagTagRuntime.cs

@@ -24,6 +24,17 @@ internal sealed class LibplctagTagRuntime : IAbCipTagRuntime
             Name = p.TagName,
             Timeout = p.Timeout,
         };
+        // PR abcip-1.2 — Logix STRINGnn variant decoding. When the caller pins a non-default
+        // DATA-array capacity (STRING_20 / STRING_40 / STRING_80 etc.), forward it to libplctag
+        // via the StringMaxCapacity attribute so GetString / SetString truncate at the right
+        // boundary. Null leaves libplctag at its default 82-byte STRING for back-compat.
+        if (p.StringMaxCapacity is int cap && cap > 0)
+            _tag.StringMaxCapacity = (uint)cap;
+        // PR abcip-1.3 — slice reads. Setting ElementCount tells libplctag to allocate a buffer
+        // covering N consecutive elements; the array-read planner pairs this with TagName=Tag[N]
+        // to issue one Rockwell array read for a [N..M] slice.
+        if (p.ElementCount is int n && n > 0)
+            _tag.ElementCount = n;
     }
 
     public Task InitializeAsync(CancellationToken cancellationToken) => _tag.InitializeAsync(cancellationToken);
@@ -50,7 +61,7 @@ internal sealed class LibplctagTagRuntime : IAbCipTagRuntime
         AbCipDataType.Real => _tag.GetFloat32(offset),
         AbCipDataType.LReal => _tag.GetFloat64(offset),
         AbCipDataType.String => _tag.GetString(offset),
-        AbCipDataType.Dt => _tag.GetInt32(offset),
+        AbCipDataType.Dt => _tag.GetInt64(offset),
         AbCipDataType.Structure => null,
         _ => null,
     };
@@ -105,7 +116,7 @@ internal sealed class LibplctagTagRuntime : IAbCipTagRuntime
                 _tag.SetString(0, Convert.ToString(value) ?? string.Empty);
                 break;
             case AbCipDataType.Dt:
-                _tag.SetInt32(0, Convert.ToInt32(value));
+                _tag.SetInt64(0, Convert.ToInt64(value));
                 break;
             case AbCipDataType.Structure:
                 throw new NotSupportedException("Whole-UDT writes land in PR 6.");

src/ZB.MOM.WW.OtOpcUa.Driver.AbCip/ZB.MOM.WW.OtOpcUa.Driver.AbCip.csproj

@@ -14,6 +14,7 @@
 
     <ItemGroup>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core\ZB.MOM.WW.OtOpcUa.Core.csproj"/>
     </ItemGroup>
 
     <ItemGroup>

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/AbLegacyCommandBase.cs

@@ -0,0 +1,51 @@
+using CliFx.Attributes;
+using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.PlcFamilies;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli;
+
+/// <summary>
+///     Base for every AB Legacy CLI command. Carries the PCCC-specific endpoint options
+///     (<c>--gateway</c> + <c>--plc-type</c>) on top of <see cref="DriverCommandBase"/>'s
+///     shared verbose + timeout + logging helpers.
+/// </summary>
+public abstract class AbLegacyCommandBase : DriverCommandBase
+{
+    [CommandOption("gateway", 'g', Description =
+        "Canonical AB Legacy gateway: ab://host[:port]/cip-path. Port defaults to 44818. " +
+        "cip-path depends on the family: SLC 5/05 + PLC-5 typically '1,0'; MicroLogix " +
+        "1100/1400 takes an empty path (direct EIP, no backplane).",
+        IsRequired = true)]
+    public string Gateway { get; init; } = default!;
+
+    [CommandOption("plc-type", 'P', Description =
+        "Slc500 / MicroLogix / Plc5 / LogixPccc (default Slc500).")]
+    public AbLegacyPlcFamily PlcType { get; init; } = AbLegacyPlcFamily.Slc500;
+
+    [CommandOption("timeout-ms", Description = "Per-operation timeout in ms (default 5000).")]
+    public int TimeoutMs { get; init; } = 5000;
+
+    /// <inheritdoc />
+    public override TimeSpan Timeout
+    {
+        get => TimeSpan.FromMilliseconds(TimeoutMs);
+        init { /* driven by TimeoutMs */ }
+    }
+
+    /// <summary>
+    ///     Build an <see cref="AbLegacyDriverOptions"/> with the device + tag list a subclass
+    ///     supplies. Probe disabled for CLI one-shot runs.
+    /// </summary>
+    protected AbLegacyDriverOptions BuildOptions(IReadOnlyList<AbLegacyTagDefinition> tags) => new()
+    {
+        Devices = [new AbLegacyDeviceOptions(
+            HostAddress: Gateway,
+            PlcFamily: PlcType,
+            DeviceName: $"cli-{PlcType}")],
+        Tags = tags,
+        Timeout = Timeout,
+        Probe = new AbLegacyProbeOptions { Enabled = false },
+    };
+
+    protected string DriverInstanceId => $"ablegacy-cli-{Gateway}";
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/Commands/ProbeCommand.cs

@@ -0,0 +1,57 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.Commands;
+
+/// <summary>
+///     Probes an AB Legacy (PCCC) endpoint: reads one N-file word + reports driver health.
+///     Default probe address <c>N7:0</c> matches the integration-fixture seed so operators
+///     can point the CLI at the ab_server Docker container + real hardware interchangeably.
+/// </summary>
+[Command("probe", Description = "Verify the AB Legacy endpoint is reachable and a sample PCCC read succeeds.")]
+public sealed class ProbeCommand : AbLegacyCommandBase
+{
+    [CommandOption("address", 'a', Description =
+        "PCCC address to probe (default N7:0). Use S:0 for the status file when you want " +
+        "the pre-populated register every SLC / MicroLogix / PLC-5 ships with.")]
+    public string Address { get; init; } = "N7:0";
+
+    [CommandOption("type", Description =
+        "PCCC data type of the probe address (default Int — matches N files).")]
+    public AbLegacyDataType DataType { get; init; } = AbLegacyDataType.Int;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var probeTag = new AbLegacyTagDefinition(
+            Name: "__probe",
+            DeviceHostAddress: Gateway,
+            Address: Address,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([probeTag]);
+
+        await using var driver = new AbLegacyDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var snapshot = await driver.ReadAsync(["__probe"], ct);
+            var health = driver.GetHealth();
+
+            await console.Output.WriteLineAsync($"Gateway:      {Gateway}");
+            await console.Output.WriteLineAsync($"PLC type:     {PlcType}");
+            await console.Output.WriteLineAsync($"Health:       {health.State}");
+            if (health.LastError is { } err)
+                await console.Output.WriteLineAsync($"Last error:   {err}");
+            await console.Output.WriteLineAsync();
+            await console.Output.WriteLineAsync(SnapshotFormatter.Format(Address, snapshot[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/Commands/ReadCommand.cs

@@ -0,0 +1,55 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.Commands;
+
+/// <summary>
+///     Read one PCCC address (N7:0, F8:0, B3:0/3, L19:0, ST17:0, T4:0.ACC, etc.).
+/// </summary>
+[Command("read", Description = "Read a single PCCC file address.")]
+public sealed class ReadCommand : AbLegacyCommandBase
+{
+    [CommandOption("address", 'a', Description =
+        "PCCC file address. File letter implies storage; bit-within-word via slash " +
+        "(B3:0/3 or N7:0/5). Sub-element access for timers/counters/controls uses " +
+        "dot notation (T4:0.ACC, C5:0.PRE, R6:0.LEN).",
+        IsRequired = true)]
+    public string Address { get; init; } = default!;
+
+    [CommandOption("type", 't', Description =
+        "Bit / Int / Long / Float / AnalogInt / String / TimerElement / CounterElement / " +
+        "ControlElement (default Int).")]
+    public AbLegacyDataType DataType { get; init; } = AbLegacyDataType.Int;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = SynthesiseTagName(Address, DataType);
+        var tag = new AbLegacyTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: Gateway,
+            Address: Address,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([tag]);
+
+        await using var driver = new AbLegacyDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var snapshot = await driver.ReadAsync([tagName], ct);
+            await console.Output.WriteLineAsync(SnapshotFormatter.Format(Address, snapshot[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+
+    /// <summary>Tag-name key the driver uses internally. Address+type is already unique.</summary>
+    internal static string SynthesiseTagName(string address, AbLegacyDataType type)
+        => $"{address}:{type}";
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/Commands/SubscribeCommand.cs

@@ -0,0 +1,78 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.Commands;
+
+/// <summary>
+///     Watch a PCCC file address via polled subscription until Ctrl+C. Mirrors the Modbus /
+///     AB CIP subscribe shape — PollGroupEngine handles the tick loop.
+/// </summary>
+[Command("subscribe", Description = "Watch a PCCC file address via polled subscription until Ctrl+C.")]
+public sealed class SubscribeCommand : AbLegacyCommandBase
+{
+    [CommandOption("address", 'a', Description = "PCCC file address — same format as `read`.", IsRequired = true)]
+    public string Address { get; init; } = default!;
+
+    [CommandOption("type", 't', Description =
+        "Bit / Int / Long / Float / AnalogInt / String / TimerElement / CounterElement / " +
+        "ControlElement (default Int).")]
+    public AbLegacyDataType DataType { get; init; } = AbLegacyDataType.Int;
+
+    [CommandOption("interval-ms", 'i', Description =
+        "Publishing interval in milliseconds (default 1000).")]
+    public int IntervalMs { get; init; } = 1000;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = ReadCommand.SynthesiseTagName(Address, DataType);
+        var tag = new AbLegacyTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: Gateway,
+            Address: Address,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([tag]);
+
+        await using var driver = new AbLegacyDriver(options, DriverInstanceId);
+        ISubscriptionHandle? handle = null;
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+
+            driver.OnDataChange += (_, e) =>
+            {
+                var line = $"[{DateTime.UtcNow:HH:mm:ss.fff}] " +
+                    $"{e.FullReference} = {SnapshotFormatter.FormatValue(e.Snapshot.Value)} " +
+                    $"({SnapshotFormatter.FormatStatus(e.Snapshot.StatusCode)})";
+                console.Output.WriteLine(line);
+            };
+
+            handle = await driver.SubscribeAsync([tagName], TimeSpan.FromMilliseconds(IntervalMs), ct);
+
+            await console.Output.WriteLineAsync(
+                $"Subscribed to {Address} @ {IntervalMs}ms. Ctrl+C to stop.");
+            try
+            {
+                await Task.Delay(System.Threading.Timeout.InfiniteTimeSpan, ct);
+            }
+            catch (OperationCanceledException)
+            {
+                // Expected on Ctrl+C.
+            }
+        }
+        finally
+        {
+            if (handle is not null)
+            {
+                try { await driver.UnsubscribeAsync(handle, CancellationToken.None); }
+                catch { /* teardown best-effort */ }
+            }
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/Commands/WriteCommand.cs

@@ -0,0 +1,81 @@
+using System.Globalization;
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.Commands;
+
+/// <summary>
+///     Write one value to a PCCC file address. Writes to timer / counter / control
+///     sub-elements go through at the wire level but land on the integer field of the
+///     sub-element — the PLC's runtime semantics (edge-triggered EN/DN bits, preset reloads)
+///     are PLC-managed, not CLI-manipulable; write these with caution.
+/// </summary>
+[Command("write", Description = "Write a single PCCC file address.")]
+public sealed class WriteCommand : AbLegacyCommandBase
+{
+    [CommandOption("address", 'a', Description =
+        "PCCC file address — same format as `read`.", IsRequired = true)]
+    public string Address { get; init; } = default!;
+
+    [CommandOption("type", 't', Description =
+        "Bit / Int / Long / Float / AnalogInt / String / TimerElement / CounterElement / " +
+        "ControlElement (default Int).")]
+    public AbLegacyDataType DataType { get; init; } = AbLegacyDataType.Int;
+
+    [CommandOption("value", 'v', Description =
+        "Value to write. Parsed per --type (booleans accept true/false/1/0).",
+        IsRequired = true)]
+    public string Value { get; init; } = default!;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = ReadCommand.SynthesiseTagName(Address, DataType);
+        var tag = new AbLegacyTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: Gateway,
+            Address: Address,
+            DataType: DataType,
+            Writable: true);
+        var options = BuildOptions([tag]);
+
+        var parsed = ParseValue(Value, DataType);
+
+        await using var driver = new AbLegacyDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var results = await driver.WriteAsync([new WriteRequest(tagName, parsed)], ct);
+            await console.Output.WriteLineAsync(SnapshotFormatter.FormatWrite(Address, results[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+
+    /// <summary>Parse <c>--value</c> per <see cref="AbLegacyDataType"/>, invariant culture.</summary>
+    internal static object ParseValue(string raw, AbLegacyDataType type) => type switch
+    {
+        AbLegacyDataType.Bit => ParseBool(raw),
+        AbLegacyDataType.Int or AbLegacyDataType.AnalogInt => short.Parse(raw, CultureInfo.InvariantCulture),
+        AbLegacyDataType.Long => int.Parse(raw, CultureInfo.InvariantCulture),
+        AbLegacyDataType.Float => float.Parse(raw, CultureInfo.InvariantCulture),
+        AbLegacyDataType.String => raw,
+        AbLegacyDataType.TimerElement or AbLegacyDataType.CounterElement
+            or AbLegacyDataType.ControlElement => int.Parse(raw, CultureInfo.InvariantCulture),
+        _ => throw new CliFx.Exceptions.CommandException($"Unsupported DataType '{type}' for write."),
+    };
+
+    private static bool ParseBool(string raw) => raw.Trim().ToLowerInvariant() switch
+    {
+        "1" or "true" or "on" or "yes" => true,
+        "0" or "false" or "off" or "no" => false,
+        _ => throw new CliFx.Exceptions.CommandException(
+            $"Boolean value '{raw}' is not recognised. Use true/false, 1/0, on/off, or yes/no."),
+    };
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/Program.cs

@@ -0,0 +1,11 @@
+using CliFx;
+
+return await new CliApplicationBuilder()
+    .AddCommandsFromThisAssembly()
+    .SetExecutableName("otopcua-ablegacy-cli")
+    .SetDescription(
+        "OtOpcUa AB Legacy test-client — ad-hoc probe + PCCC N/F/B/L-file reads/writes + " +
+        "polled subscriptions against SLC 500 / MicroLogix / PLC-5 devices via libplctag. " +
+        "Addresses use PCCC convention: N7:0, F8:0, B3:0/3, L19:0, ST17:0.")
+    .Build()
+    .RunAsync(args);

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.csproj

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <LangVersion>latest</LangVersion>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <NoWarn>$(NoWarn);CS1591</NoWarn>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli</RootNamespace>
+        <AssemblyName>otopcua-ablegacy-cli</AssemblyName>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="CliFx" Version="2.3.6"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.Cli.Common\ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.AbLegacy\ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <InternalsVisibleTo Include="ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Cli.Tests"/>
+    </ItemGroup>
+
+</Project>

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyAddress.cs

@@ -1,3 +1,5 @@
+using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.PlcFamilies;
+
 namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy;
 
 /// <summary>
@@ -30,35 +32,87 @@ public sealed record AbLegacyAddress(
     int? FileNumber,
     int WordNumber,
     int? BitIndex,
-    string? SubElement)
+    string? SubElement,
+    AbLegacyAddress? IndirectFileSource = null,
+    AbLegacyAddress? IndirectWordSource = null)
 {
+    /// <summary>
+    ///     True when either the file number or the word number is sourced from another PCCC
+    ///     address evaluated at runtime (PLC-5 / SLC indirect addressing — <c>N7:[N7:0]</c> or
+    ///     <c>N[N7:0]:5</c>). libplctag PCCC does not natively decode bracket-form indirection,
+    ///     so the runtime layer must resolve the inner address first and rewrite the tag name
+    ///     before issuing the actual read/write. See <see cref="ToLibplctagName"/>.
+    /// </summary>
+    public bool IsIndirect => IndirectFileSource is not null || IndirectWordSource is not null;
+
     public string ToLibplctagName()
     {
-        var file = FileNumber is null ? FileLetter : $"{FileLetter}{FileNumber}";
-        var wordPart = $"{file}:{WordNumber}";
+        // Re-emit using bracket form when indirect. libplctag's PCCC text decoder does not
+        // accept the bracket form directly — callers that need a libplctag-ready name must
+        // resolve the inner addresses first and substitute concrete numbers. Driver runtime
+        // path (TODO: resolve-then-read) is gated on IsIndirect.
+        string filePart;
+        if (IndirectFileSource is not null)
+        {
+            filePart = $"{FileLetter}[{IndirectFileSource.ToLibplctagName()}]";
+        }
+        else
+        {
+            filePart = FileNumber is null ? FileLetter : $"{FileLetter}{FileNumber}";
+        }
+
+        string wordSegment = IndirectWordSource is not null
+            ? $"[{IndirectWordSource.ToLibplctagName()}]"
+            : WordNumber.ToString();
+
+        var wordPart = $"{filePart}:{wordSegment}";
         if (SubElement is not null) wordPart += $".{SubElement}";
         if (BitIndex is not null) wordPart += $"/{BitIndex}";
         return wordPart;
     }
 
-    public static AbLegacyAddress? TryParse(string? value)
+    public static AbLegacyAddress? TryParse(string? value) => TryParse(value, family: null);
+
+    /// <summary>
+    ///     Family-aware parser. PLC-5 (RSLogix 5) displays the word + bit indices on
+    ///     <c>I:</c>/<c>O:</c> file references as octal — <c>I:001/17</c> is rack 1, bit 15.
+    ///     Pass the device's family so the parser can interpret those digits as octal when the
+    ///     family's <see cref="AbLegacyPlcFamilyProfile.OctalIoAddressing"/> is true. The parsed
+    ///     record stores decimal values; <see cref="ToLibplctagName"/> emits decimal too, which
+    ///     is what libplctag's PCCC layer expects.
+    /// </summary>
+    /// <remarks>
+    ///     Also accepts indirect / indexed forms (Issue #247): <c>N7:[N7:0]</c> reads file 7,
+    ///     word=value-of(N7:0); <c>N[N7:0]:5</c> reads file=value-of(N7:0), word 5. Recursion
+    ///     depth is capped at 1 — the inner address must be a plain direct PCCC address.
+    /// </remarks>
+    public static AbLegacyAddress? TryParse(string? value, AbLegacyPlcFamily? family)
     {
         if (string.IsNullOrWhiteSpace(value)) return null;
         var src = value.Trim();
 
-        // BitIndex: trailing /N
-        int? bitIndex = null;
-        var slashIdx = src.IndexOf('/');
-        if (slashIdx >= 0)
+        var profile = family is null ? null : AbLegacyPlcFamilyProfile.ForFamily(family.Value);
+
+        // BitIndex: trailing /N. Defer numeric parsing until the file letter is known — PLC-5
+        // I:/O: bit indices are octal in RSLogix 5, everything else is decimal.
+        string? bitText = null;
+        var slashIdx = src.LastIndexOf('/');
+        if (slashIdx >= 0 && slashIdx > src.LastIndexOf(']'))
         {
-            if (!int.TryParse(src[(slashIdx + 1)..], out var bit) || bit < 0 || bit > 31) return null;
-            bitIndex = bit;
+            bitText = src[(slashIdx + 1)..];
             src = src[..slashIdx];
         }
 
+        return ParseTail(src, bitText, profile, allowIndirect: true);
+    }
+
+    private static AbLegacyAddress? ParseTail(string src, string? bitText, AbLegacyPlcFamilyProfile? profile, bool allowIndirect)
+    {
         // SubElement: trailing .NAME (ACC / PRE / EN / DN / TT / CU / CD / FD / etc.)
+        // Only consider dots OUTSIDE of any bracketed inner address — the inner address may
+        // itself contain a sub-element dot (e.g. N[T4:0.ACC]:5).
         string? subElement = null;
-        var dotIdx = src.LastIndexOf('.');
+        var dotIdx = LastIndexOfTopLevel(src, '.');
         if (dotIdx >= 0)
         {
             var candidate = src[(dotIdx + 1)..];
@@ -69,29 +123,149 @@ public sealed record AbLegacyAddress(
             }
         }
 
-        var colonIdx = src.IndexOf(':');
+        var colonIdx = IndexOfTopLevel(src, ':');
         if (colonIdx <= 0) return null;
         var filePart = src[..colonIdx];
         var wordPart = src[(colonIdx + 1)..];
-        if (!int.TryParse(wordPart, out var word) || word < 0) return null;
 
-        // File letter + optional file number (single letter for I/O/S, letter+number otherwise).
+        // File letter (always literal) + optional file number — either decimal digits or a
+        // bracketed indirect address like N[N7:0].
         if (filePart.Length == 0 || !char.IsLetter(filePart[0])) return null;
         var letterEnd = 1;
         while (letterEnd < filePart.Length && char.IsLetter(filePart[letterEnd])) letterEnd++;
 
         var letter = filePart[..letterEnd].ToUpperInvariant();
         int? fileNumber = null;
+        AbLegacyAddress? indirectFile = null;
         if (letterEnd < filePart.Length)
         {
-            if (!int.TryParse(filePart[letterEnd..], out var fn) || fn < 0) return null;
-            fileNumber = fn;
+            var fileTail = filePart[letterEnd..];
+            if (fileTail.Length >= 2 && fileTail[0] == '[' && fileTail[^1] == ']')
+            {
+                if (!allowIndirect) return null;
+                var inner = fileTail[1..^1];
+                indirectFile = ParseInner(inner, profile);
+                if (indirectFile is null) return null;
+            }
+            else
+            {
+                if (!int.TryParse(fileTail, out var fn) || fn < 0) return null;
+                fileNumber = fn;
+            }
         }
 
         // Reject unknown file letters — these cover SLC/ML/PLC-5 canonical families.
-        if (!IsKnownFileLetter(letter)) return null;
+        // Function-file letters (RTC/HSC/DLS/MMI/PTO/PWM/STI/EII/IOS/BHI) are MicroLogix-only.
+        // Structure-file letters (PD/MG/PLS/BT) are gated per family — PD/MG are common on
+        // SLC500 + PLC-5; PLS/BT are PLC-5 only. MicroLogix and LogixPccc reject them.
+        if (!IsKnownFileLetter(letter))
+        {
+            if (IsFunctionFileLetter(letter))
+            {
+                if (profile?.SupportsFunctionFiles != true) return null;
+            }
+            else if (IsStructureFileLetter(letter))
+            {
+                if (!StructureFileSupported(letter, profile)) return null;
+            }
+            else return null;
+        }
 
-        return new AbLegacyAddress(letter, fileNumber, word, bitIndex, subElement);
+        var octalForIo = profile?.OctalIoAddressing == true && (letter == "I" || letter == "O");
+
+        // Word part: either a numeric literal (octal-aware for PLC-5 I:/O:) or a bracketed
+        // indirect address.
+        int word = 0;
+        AbLegacyAddress? indirectWord = null;
+        if (wordPart.Length >= 2 && wordPart[0] == '[' && wordPart[^1] == ']')
+        {
+            if (!allowIndirect) return null;
+            var inner = wordPart[1..^1];
+            indirectWord = ParseInner(inner, profile);
+            if (indirectWord is null) return null;
+        }
+        else
+        {
+            if (!TryParseIndex(wordPart, octalForIo, out word) || word < 0) return null;
+        }
+
+        int? bitIndex = null;
+        if (bitText is not null)
+        {
+            if (!TryParseIndex(bitText, octalForIo, out var bit) || bit < 0 || bit > 31) return null;
+            bitIndex = bit;
+        }
+
+        return new AbLegacyAddress(letter, fileNumber, word, bitIndex, subElement, indirectFile, indirectWord);
+    }
+
+    /// <summary>
+    ///     Parse an inner (bracketed) PCCC address with depth-1 cap. The inner address itself
+    ///     must NOT be indirect — nesting beyond one level is rejected.
+    /// </summary>
+    private static AbLegacyAddress? ParseInner(string inner, AbLegacyPlcFamilyProfile? profile)
+    {
+        if (string.IsNullOrWhiteSpace(inner)) return null;
+        var src = inner.Trim();
+        // Reject any further bracket — depth cap at 1.
+        if (src.IndexOf('[') >= 0 || src.IndexOf(']') >= 0) return null;
+
+        string? bitText = null;
+        var slashIdx = src.LastIndexOf('/');
+        if (slashIdx >= 0)
+        {
+            bitText = src[(slashIdx + 1)..];
+            src = src[..slashIdx];
+        }
+        return ParseTail(src, bitText, profile, allowIndirect: false);
+    }
+
+    private static int IndexOfTopLevel(string s, char c)
+    {
+        var depth = 0;
+        for (var i = 0; i < s.Length; i++)
+        {
+            if (s[i] == '[') depth++;
+            else if (s[i] == ']') depth--;
+            else if (depth == 0 && s[i] == c) return i;
+        }
+        return -1;
+    }
+
+    private static int LastIndexOfTopLevel(string s, char c)
+    {
+        var depth = 0;
+        var last = -1;
+        for (var i = 0; i < s.Length; i++)
+        {
+            if (s[i] == '[') depth++;
+            else if (s[i] == ']') depth--;
+            else if (depth == 0 && s[i] == c) last = i;
+        }
+        return last;
+    }
+
+    private static bool TryParseIndex(string text, bool octal, out int value)
+    {
+        if (octal)
+        {
+            // Octal accepts only digits 0-7. Reject 8/9 explicitly.
+            if (text.Length == 0) { value = 0; return false; }
+            var start = 0;
+            var sign = 1;
+            if (text[0] == '-') { sign = -1; start = 1; }
+            if (start >= text.Length) { value = 0; return false; }
+            var acc = 0;
+            for (var i = start; i < text.Length; i++)
+            {
+                var c = text[i];
+                if (c < '0' || c > '7') { value = 0; return false; }
+                acc = (acc * 8) + (c - '0');
+            }
+            value = sign * acc;
+            return true;
+        }
+        return int.TryParse(text, out value);
     }
 
     private static bool IsKnownFileLetter(string letter) => letter switch
@@ -99,4 +273,38 @@ public sealed record AbLegacyAddress(
         "N" or "F" or "B" or "L" or "ST" or "T" or "C" or "R" or "I" or "O" or "S" or "A" => true,
         _ => false,
     };
+
+    /// <summary>
+    ///     MicroLogix 1100/1400 function-file prefixes. Each maps to a single fixed instance with a
+    ///     known sub-element catalogue (see <see cref="AbLegacyDataType"/>).
+    /// </summary>
+    internal static bool IsFunctionFileLetter(string letter) => letter switch
+    {
+        "RTC" or "HSC" or "DLS" or "MMI" or "PTO" or "PWM" or "STI" or "EII" or "IOS" or "BHI" => true,
+        _ => false,
+    };
+
+    /// <summary>
+    ///     Structure-file prefixes added in #248: PD (PID), MG (Message), PLS (Programmable Limit
+    ///     Switch), BT (Block Transfer). Per-family availability is gated by the matching
+    ///     <c>Supports*File</c> flag on <see cref="AbLegacyPlcFamilyProfile"/>.
+    /// </summary>
+    internal static bool IsStructureFileLetter(string letter) => letter switch
+    {
+        "PD" or "MG" or "PLS" or "BT" => true,
+        _ => false,
+    };
+
+    private static bool StructureFileSupported(string letter, AbLegacyPlcFamilyProfile? profile)
+    {
+        if (profile is null) return false;
+        return letter switch
+        {
+            "PD" => profile.SupportsPidFile,
+            "MG" => profile.SupportsMessageFile,
+            "PLS" => profile.SupportsPlsFile,
+            "BT" => profile.SupportsBlockTransferFile,
+            _ => false,
+        };
+    }
 }

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDataType.cs

@@ -26,6 +26,96 @@ public enum AbLegacyDataType
     CounterElement,
     /// <summary>Control sub-element — caller addresses <c>.LEN</c>, <c>.POS</c>, <c>.EN</c>, <c>.DN</c>, <c>.ER</c>.</summary>
     ControlElement,
+    /// <summary>
+    ///     MicroLogix 1100/1400 function-file sub-element (RTC/HSC/DLS/MMI/PTO/PWM/STI/EII/IOS/BHI).
+    ///     Sub-element catalogue lives in <see cref="AbLegacyFunctionFile.SubElementType"/>.
+    /// </summary>
+    MicroLogixFunctionFile,
+    /// <summary>
+    ///     PD-file (PID) sub-element — caller addresses <c>.SP</c>, <c>.PV</c>, <c>.CV</c>,
+    ///     <c>.KP</c>, <c>.KI</c>, <c>.KD</c>, <c>.MAXS</c>, <c>.MINS</c>, <c>.DB</c>, <c>.OUT</c>
+    ///     (Float) and <c>.EN</c>, <c>.DN</c>, <c>.MO</c>, <c>.PE</c>, <c>.AUTO</c>, <c>.MAN</c>
+    ///     (Boolean status bits in word 0).
+    /// </summary>
+    PidElement,
+    /// <summary>
+    ///     MG-file (Message) sub-element — caller addresses <c>.RBE</c>, <c>.MS</c>, <c>.SIZE</c>,
+    ///     <c>.LEN</c> (Int32) and <c>.EN</c>, <c>.EW</c>, <c>.ER</c>, <c>.DN</c>, <c>.ST</c>,
+    ///     <c>.CO</c>, <c>.NR</c>, <c>.TO</c> (Boolean status bits).
+    /// </summary>
+    MessageElement,
+    /// <summary>
+    ///     PLS-file (Programmable Limit Switch) sub-element — caller addresses <c>.LEN</c>
+    ///     (Int32). Bit semantics vary by PLC; unknown sub-elements fall back to Int32.
+    /// </summary>
+    PlsElement,
+    /// <summary>
+    ///     BT-file (Block Transfer) sub-element — caller addresses <c>.RLEN</c>, <c>.DLEN</c>
+    ///     (Int32) and <c>.EN</c>, <c>.ST</c>, <c>.DN</c>, <c>.ER</c>, <c>.CO</c>, <c>.EW</c>,
+    ///     <c>.TO</c>, <c>.NR</c> (Boolean status bits in word 0).
+    /// </summary>
+    BlockTransferElement,
+}
+
+/// <summary>
+///     MicroLogix function-file sub-element catalogue. Covers the most-commonly-addressed members
+///     per file — not exhaustive (Rockwell defines 30+ on RTC alone). Unknown sub-elements fall
+///     back to <see cref="DriverDataType.Int32"/> at the <see cref="AbLegacyDataTypeExtensions"/>
+///     boundary so the driver never refuses a tag the customer happens to know about.
+/// </summary>
+public static class AbLegacyFunctionFile
+{
+    /// <summary>
+    ///     Driver-surface type for <paramref name="fileLetter"/>.<paramref name="subElement"/>.
+    ///     Returns <see cref="DriverDataType.Int32"/> if the sub-element is unrecognised — keeps
+    ///     the driver permissive without forcing every quirk into the catalogue.
+    /// </summary>
+    public static DriverDataType SubElementType(string fileLetter, string? subElement)
+    {
+        if (subElement is null) return DriverDataType.Int32;
+        var key = (fileLetter.ToUpperInvariant(), subElement.ToUpperInvariant());
+        return key switch
+        {
+            // Real-time clock — all stored as Int16 (year is 4-digit Int16).
+            ("RTC", "HR") or ("RTC", "MIN") or ("RTC", "SEC") or
+            ("RTC", "MON") or ("RTC", "DAY") or ("RTC", "YR") or ("RTC", "DOW") => DriverDataType.Int32,
+            ("RTC", "DS") or ("RTC", "BL") or ("RTC", "EN") => DriverDataType.Boolean,
+
+            // High-speed counter — accumulator/preset are Int32, status flags are bits.
+            ("HSC", "ACC") or ("HSC", "PRE") or ("HSC", "OVF") or ("HSC", "UNF") => DriverDataType.Int32,
+            ("HSC", "EN") or ("HSC", "UF") or ("HSC", "IF") or
+            ("HSC", "IN") or ("HSC", "IH") or ("HSC", "IL") or
+            ("HSC", "DN") or ("HSC", "CD") or ("HSC", "CU") => DriverDataType.Boolean,
+
+            // Daylight saving + memory module info.
+            ("DLS", "STR") or ("DLS", "STD") => DriverDataType.Int32,
+            ("DLS", "EN") => DriverDataType.Boolean,
+            ("MMI", "FT") or ("MMI", "LBN") => DriverDataType.Int32,
+            ("MMI", "MP") or ("MMI", "MCP") => DriverDataType.Boolean,
+
+            // Pulse-train / PWM output blocks.
+            ("PTO", "ACC") or ("PTO", "OF") or ("PTO", "IDA") or ("PTO", "ODA") => DriverDataType.Int32,
+            ("PTO", "EN") or ("PTO", "DN") or ("PTO", "EH") or ("PTO", "ED") or
+            ("PTO", "RP") or ("PTO", "OUT") => DriverDataType.Boolean,
+            ("PWM", "ACC") or ("PWM", "OF") or ("PWM", "PE") or ("PWM", "PD") => DriverDataType.Int32,
+            ("PWM", "EN") or ("PWM", "DN") or ("PWM", "EH") or ("PWM", "ED") or
+            ("PWM", "RP") or ("PWM", "OUT") => DriverDataType.Boolean,
+
+            // Selectable timed interrupt + event input interrupt.
+            ("STI", "SPM") or ("STI", "ER") or ("STI", "PFN") => DriverDataType.Int32,
+            ("STI", "EN") or ("STI", "TIE") or ("STI", "DN") or
+            ("STI", "PS") or ("STI", "ED") => DriverDataType.Boolean,
+            ("EII", "PFN") or ("EII", "ER") => DriverDataType.Int32,
+            ("EII", "EN") or ("EII", "TIE") or ("EII", "PE") or
+            ("EII", "ES") or ("EII", "ED") => DriverDataType.Boolean,
+
+            // I/O status + base hardware info — mostly status flags + a few counters.
+            ("IOS", "ID") or ("IOS", "TYP") => DriverDataType.Int32,
+            ("BHI", "OS") or ("BHI", "FRN") or ("BHI", "BSN") or ("BHI", "CC") => DriverDataType.Int32,
+
+            _ => DriverDataType.Int32,
+        };
+    }
 }
 
 /// <summary>Map a PCCC data type to the driver-surface <see cref="DriverDataType"/>.</summary>
@@ -40,6 +130,196 @@ public static class AbLegacyDataTypeExtensions
         AbLegacyDataType.String => DriverDataType.String,
         AbLegacyDataType.TimerElement or AbLegacyDataType.CounterElement
             or AbLegacyDataType.ControlElement => DriverDataType.Int32,
+        AbLegacyDataType.MicroLogixFunctionFile => DriverDataType.Int32,
+        // PD/MG/PLS/BT default to Int32 at the parent-element level. The sub-element-aware
+        // EffectiveDriverDataType refines specific members (Float for PID gains, Boolean for
+        // status bits).
+        AbLegacyDataType.PidElement or AbLegacyDataType.MessageElement
+            or AbLegacyDataType.PlsElement or AbLegacyDataType.BlockTransferElement
+            => DriverDataType.Int32,
         _ => DriverDataType.Int32,
     };
+
+    /// <summary>
+    ///     Sub-element-aware driver type. Timer/Counter/Control elements expose Boolean status
+    ///     bits (<c>.DN</c>, <c>.EN</c>, <c>.TT</c>, <c>.CU</c>, <c>.CD</c>, <c>.OV</c>,
+    ///     <c>.UN</c>, <c>.ER</c>, etc.) and Int32 word members (<c>.PRE</c>, <c>.ACC</c>,
+    ///     <c>.LEN</c>, <c>.POS</c>). Unknown sub-elements fall back to
+    ///     <see cref="ToDriverDataType"/> so the driver remains permissive.
+    /// </summary>
+    public static DriverDataType EffectiveDriverDataType(AbLegacyDataType t, string? subElement)
+    {
+        if (subElement is null) return t.ToDriverDataType();
+        var key = subElement.ToUpperInvariant();
+        return t switch
+        {
+            AbLegacyDataType.TimerElement => key switch
+            {
+                "EN" or "TT" or "DN" => DriverDataType.Boolean,
+                "PRE" or "ACC" => DriverDataType.Int32,
+                _ => t.ToDriverDataType(),
+            },
+            AbLegacyDataType.CounterElement => key switch
+            {
+                "CU" or "CD" or "DN" or "OV" or "UN" => DriverDataType.Boolean,
+                "PRE" or "ACC" => DriverDataType.Int32,
+                _ => t.ToDriverDataType(),
+            },
+            AbLegacyDataType.ControlElement => key switch
+            {
+                "EN" or "EU" or "DN" or "EM" or "ER" or "UL" or "IN" or "FD" => DriverDataType.Boolean,
+                "LEN" or "POS" => DriverDataType.Int32,
+                _ => t.ToDriverDataType(),
+            },
+            // PD-file (PID): SP/PV/CV/KP/KI/KD/MAXS/MINS/DB/OUT are 32-bit floats; EN/DN/MO/PE/
+            // AUTO/MAN/SP_VAL/SP_LL/SP_HL are status bits in word 0.
+            AbLegacyDataType.PidElement => key switch
+            {
+                "SP" or "PV" or "CV" or "KP" or "KI" or "KD"
+                    or "MAXS" or "MINS" or "DB" or "OUT" => DriverDataType.Float32,
+                "EN" or "DN" or "MO" or "PE"
+                    or "AUTO" or "MAN" or "SP_VAL" or "SP_LL" or "SP_HL" => DriverDataType.Boolean,
+                _ => t.ToDriverDataType(),
+            },
+            // MG-file (Message): RBE/MS/SIZE/LEN are control words; EN/EW/ER/DN/ST/CO/NR/TO are
+            // status bits.
+            AbLegacyDataType.MessageElement => key switch
+            {
+                "RBE" or "MS" or "SIZE" or "LEN" => DriverDataType.Int32,
+                "EN" or "EW" or "ER" or "DN" or "ST" or "CO" or "NR" or "TO" => DriverDataType.Boolean,
+                _ => t.ToDriverDataType(),
+            },
+            // PLS-file (Programmable Limit Switch): LEN is a length word; bit semantics vary by
+            // PLC so unknown sub-elements stay Int32.
+            AbLegacyDataType.PlsElement => key switch
+            {
+                "LEN" => DriverDataType.Int32,
+                _ => t.ToDriverDataType(),
+            },
+            // BT-file (Block Transfer, PLC-5): RLEN/DLEN are length words; EN/ST/DN/ER/CO/EW/
+            // TO/NR are status bits in word 0.
+            AbLegacyDataType.BlockTransferElement => key switch
+            {
+                "RLEN" or "DLEN" => DriverDataType.Int32,
+                "EN" or "ST" or "DN" or "ER" or "CO" or "EW" or "TO" or "NR" => DriverDataType.Boolean,
+                _ => t.ToDriverDataType(),
+            },
+            _ => t.ToDriverDataType(),
+        };
+    }
+
+    /// <summary>
+    ///     Bit position within the parent control word for Timer/Counter/Control status bits.
+    ///     Returns <c>null</c> if the sub-element is not a known bit member of the given element
+    ///     type. Bit numbering follows Rockwell DTAM / PCCC documentation.
+    /// </summary>
+    public static int? StatusBitIndex(AbLegacyDataType t, string? subElement)
+    {
+        if (subElement is null) return null;
+        var key = subElement.ToUpperInvariant();
+        return t switch
+        {
+            // T4 element word 0: bit 13=DN, 14=TT, 15=EN.
+            AbLegacyDataType.TimerElement => key switch
+            {
+                "DN" => 13,
+                "TT" => 14,
+                "EN" => 15,
+                _ => null,
+            },
+            // C5 element word 0: bit 10=UN, 11=OV, 12=DN, 13=CD, 14=CU.
+            AbLegacyDataType.CounterElement => key switch
+            {
+                "UN" => 10,
+                "OV" => 11,
+                "DN" => 12,
+                "CD" => 13,
+                "CU" => 14,
+                _ => null,
+            },
+            // R6 element word 0: bit 8=FD, 9=IN, 10=UL, 11=ER, 12=EM, 13=DN, 14=EU, 15=EN.
+            AbLegacyDataType.ControlElement => key switch
+            {
+                "FD" => 8,
+                "IN" => 9,
+                "UL" => 10,
+                "ER" => 11,
+                "EM" => 12,
+                "DN" => 13,
+                "EU" => 14,
+                "EN" => 15,
+                _ => null,
+            },
+            // PD element word 0 (SLC 5/02+ PID, 1747-RM001 / PLC-5 PID-RM): bit 0=EN, 1=PE,
+            // 2=DN, 3=MO (manual mode), 4=AUTO, 5=MAN, 6=SP_VAL, 7=SP_LL, 8=SP_HL. Bits 4–8 are
+            // the SP-validity / SP-limit flags exposed in RSLogix 5 / 500.
+            AbLegacyDataType.PidElement => key switch
+            {
+                "EN" => 0,
+                "PE" => 1,
+                "DN" => 2,
+                "MO" => 3,
+                "AUTO" => 4,
+                "MAN" => 5,
+                "SP_VAL" => 6,
+                "SP_LL" => 7,
+                "SP_HL" => 8,
+                _ => null,
+            },
+            // MG element word 0 (PLC-5 MSG / SLC 5/05 MSG, 1785-6.5.12 / 1747-RM001):
+            // bit 15=EN, 14=ST, 13=DN, 12=ER, 11=CO, 10=EW, 9=NR, 8=TO.
+            AbLegacyDataType.MessageElement => key switch
+            {
+                "TO" => 8,
+                "NR" => 9,
+                "EW" => 10,
+                "CO" => 11,
+                "ER" => 12,
+                "DN" => 13,
+                "ST" => 14,
+                "EN" => 15,
+                _ => null,
+            },
+            // BT element word 0 (PLC-5 chassis BTR/BTW, 1785-6.5.12):
+            // bit 15=EN, 14=ST, 13=DN, 12=ER, 11=CO, 10=EW, 9=NR, 8=TO. Same layout as MG.
+            AbLegacyDataType.BlockTransferElement => key switch
+            {
+                "TO" => 8,
+                "NR" => 9,
+                "EW" => 10,
+                "CO" => 11,
+                "ER" => 12,
+                "DN" => 13,
+                "ST" => 14,
+                "EN" => 15,
+                _ => null,
+            },
+            _ => null,
+        };
+    }
+
+    /// <summary>
+    ///     PLC-set status bits — read-only from the OPC UA side. Operator-controllable bits
+    ///     (e.g. <c>.EN</c> on a timer/counter, <c>.CU</c>/<c>.CD</c> rung-driven inputs) are
+    ///     omitted so they keep default writable behaviour.
+    /// </summary>
+    public static bool IsPlcSetStatusBit(AbLegacyDataType t, string? subElement)
+    {
+        if (subElement is null) return false;
+        var key = subElement.ToUpperInvariant();
+        return t switch
+        {
+            AbLegacyDataType.TimerElement => key is "DN" or "TT",
+            AbLegacyDataType.CounterElement => key is "DN" or "OV" or "UN",
+            AbLegacyDataType.ControlElement => key is "DN" or "EM" or "ER" or "FD" or "UL" or "IN",
+            // PID: PE (PID-error), DN (process-done), SP_VAL/SP_LL/SP_HL are PLC-set status.
+            // EN/MO/AUTO/MAN are operator-controllable via the .EN bit / mode select.
+            AbLegacyDataType.PidElement => key is "PE" or "DN" or "SP_VAL" or "SP_LL" or "SP_HL",
+            // MG/BT: ST (started), DN (done), ER (error), CO (continuous), EW (enabled-waiting),
+            // NR (no-response), TO (timeout) are PLC-set. EN is operator-driven via the rung.
+            AbLegacyDataType.MessageElement => key is "ST" or "DN" or "ER" or "CO" or "EW" or "NR" or "TO",
+            AbLegacyDataType.BlockTransferElement => key is "ST" or "DN" or "ER" or "CO" or "EW" or "NR" or "TO",
+            _ => false,
+        };
+    }
 }

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDriver.cs

@@ -140,8 +140,13 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
                     continue;
                 }
 
-                var parsed = AbLegacyAddress.TryParse(def.Address);
-                var value = runtime.DecodeValue(def.DataType, parsed?.BitIndex);
+                var parsed = AbLegacyAddress.TryParse(def.Address, device.Options.PlcFamily);
+                // Timer/Counter/Control status bits route through GetBit at the parent-word
+                // address — translate the .DN/.EN/etc. sub-element to its standard bit position
+                // and pass it down to the runtime as a synthetic bitIndex.
+                var decodeBit = parsed?.BitIndex
+                    ?? AbLegacyDataTypeExtensions.StatusBitIndex(def.DataType, parsed?.SubElement);
+                var value = runtime.DecodeValue(def.DataType, decodeBit);
                 results[i] = new DataValueSnapshot(value, AbLegacyStatusMapper.Good, now, now);
                 _health = new DriverHealth(DriverState.Healthy, now, null);
             }
@@ -186,7 +191,16 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
 
             try
             {
-                var parsed = AbLegacyAddress.TryParse(def.Address);
+                var parsed = AbLegacyAddress.TryParse(def.Address, device.Options.PlcFamily);
+
+                // Timer/Counter/Control PLC-set status bits (DN, TT, OV, UN, FD, ER, EM, UL,
+                // IN) are read-only — the PLC sets them; any client write would be silently
+                // overwritten on the next scan. Reject up front with BadNotWritable.
+                if (AbLegacyDataTypeExtensions.IsPlcSetStatusBit(def.DataType, parsed?.SubElement))
+                {
+                    results[i] = new WriteResult(AbLegacyStatusMapper.BadNotWritable);
+                    continue;
+                }
 
                 // PCCC bit-within-word writes — task #181 pass 2. RMW against a parallel
                 // parent-word runtime (strip the /N bit suffix). Per-parent-word lock serialises
@@ -247,12 +261,19 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
                 string.Equals(t.DeviceHostAddress, device.HostAddress, StringComparison.OrdinalIgnoreCase));
             foreach (var tag in tagsForDevice)
             {
+                var parsed = AbLegacyAddress.TryParse(tag.Address, device.PlcFamily);
+                // Timer/Counter/Control sub-elements (.DN/.EN/.TT/.PRE/.ACC/etc.) refine the
+                // base element's Int32 to Boolean for status bits and Int32 for word members.
+                var effectiveType = AbLegacyDataTypeExtensions.EffectiveDriverDataType(
+                    tag.DataType, parsed?.SubElement);
+                var plcSetBit = AbLegacyDataTypeExtensions.IsPlcSetStatusBit(
+                    tag.DataType, parsed?.SubElement);
                 deviceFolder.Variable(tag.Name, tag.Name, new DriverAttributeInfo(
                     FullName: tag.Name,
-                    DriverDataType: tag.DataType.ToDriverDataType(),
+                    DriverDataType: effectiveType,
                     IsArray: false,
                     ArrayDim: null,
-                    SecurityClass: tag.Writable
+                    SecurityClass: tag.Writable && !plcSetBit
                         ? SecurityClassification.Operate
                         : SecurityClassification.ViewOnly,
                     IsHistorized: false,
@@ -413,10 +434,19 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
     {
         if (device.Runtimes.TryGetValue(def.Name, out var existing)) return existing;
 
-        var parsed = AbLegacyAddress.TryParse(def.Address)
+        var parsed = AbLegacyAddress.TryParse(def.Address, device.Options.PlcFamily)
             ?? throw new InvalidOperationException(
                 $"AbLegacy tag '{def.Name}' has malformed Address '{def.Address}'.");
 
+        // TODO(#247): libplctag's PCCC text decoder does not natively accept the bracket-form
+        // indirect address. Resolving N7:[N7:0] requires reading the inner address first, then
+        // rewriting the tag name with the resolved word number, then issuing the actual read.
+        // For now we surface a clear runtime error rather than letting libplctag fail with an
+        // opaque parser error.
+        if (parsed.IsIndirect)
+            throw new NotSupportedException(
+                $"AbLegacy tag '{def.Name}' uses indirect addressing ('{def.Address}'); runtime resolution is not yet implemented.");
+
         var runtime = _tagFactory.Create(new AbLegacyTagCreateParams(
             Gateway: device.ParsedAddress.Gateway,
             Port: device.ParsedAddress.Port,

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDriverFactoryExtensions.cs

@@ -0,0 +1,124 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+using ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.PlcFamilies;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy;
+
+/// <summary>
+///     Static factory registration helper for <see cref="AbLegacyDriver"/>. Server's Program.cs
+///     calls <see cref="Register"/> once at startup; the bootstrapper (task #248) then
+///     materialises AB Legacy DriverInstance rows from the central config DB into live
+///     driver instances. Mirrors <c>GalaxyProxyDriverFactoryExtensions</c>.
+/// </summary>
+public static class AbLegacyDriverFactoryExtensions
+{
+    public const string DriverTypeName = "AbLegacy";
+
+    public static void Register(DriverFactoryRegistry registry)
+    {
+        ArgumentNullException.ThrowIfNull(registry);
+        registry.Register(DriverTypeName, CreateInstance);
+    }
+
+    internal static AbLegacyDriver CreateInstance(string driverInstanceId, string driverConfigJson)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);
+
+        var dto = JsonSerializer.Deserialize<AbLegacyDriverConfigDto>(driverConfigJson, JsonOptions)
+            ?? throw new InvalidOperationException(
+                $"AB Legacy driver config for '{driverInstanceId}' deserialised to null");
+
+        var options = new AbLegacyDriverOptions
+        {
+            Devices = dto.Devices is { Count: > 0 }
+                ? [.. dto.Devices.Select(d => new AbLegacyDeviceOptions(
+                    HostAddress: d.HostAddress ?? throw new InvalidOperationException(
+                        $"AB Legacy config for '{driverInstanceId}' has a device missing HostAddress"),
+                    PlcFamily: ParseEnum<AbLegacyPlcFamily>(d.PlcFamily, driverInstanceId, "PlcFamily",
+                        fallback: AbLegacyPlcFamily.Slc500),
+                    DeviceName: d.DeviceName))]
+                : [],
+            Tags = dto.Tags is { Count: > 0 }
+                ? [.. dto.Tags.Select(t => new AbLegacyTagDefinition(
+                    Name: t.Name ?? throw new InvalidOperationException(
+                        $"AB Legacy config for '{driverInstanceId}' has a tag missing Name"),
+                    DeviceHostAddress: t.DeviceHostAddress ?? throw new InvalidOperationException(
+                        $"AB Legacy tag '{t.Name}' in '{driverInstanceId}' missing DeviceHostAddress"),
+                    Address: t.Address ?? throw new InvalidOperationException(
+                        $"AB Legacy tag '{t.Name}' in '{driverInstanceId}' missing Address"),
+                    DataType: ParseEnum<AbLegacyDataType>(t.DataType, driverInstanceId, "DataType",
+                        tagName: t.Name),
+                    Writable: t.Writable ?? true,
+                    WriteIdempotent: t.WriteIdempotent ?? false))]
+                : [],
+            Probe = new AbLegacyProbeOptions
+            {
+                Enabled = dto.Probe?.Enabled ?? true,
+                Interval = TimeSpan.FromMilliseconds(dto.Probe?.IntervalMs ?? 5_000),
+                Timeout = TimeSpan.FromMilliseconds(dto.Probe?.TimeoutMs ?? 2_000),
+                ProbeAddress = dto.Probe?.ProbeAddress ?? "S:0",
+            },
+            Timeout = TimeSpan.FromMilliseconds(dto.TimeoutMs ?? 2_000),
+        };
+
+        return new AbLegacyDriver(options, driverInstanceId);
+    }
+
+    private static T ParseEnum<T>(string? raw, string driverInstanceId, string field,
+        string? tagName = null, T? fallback = null) where T : struct, Enum
+    {
+        if (string.IsNullOrWhiteSpace(raw))
+        {
+            if (fallback.HasValue) return fallback.Value;
+            throw new InvalidOperationException(
+                $"AB Legacy {(tagName is null ? "config" : $"tag '{tagName}'")} in '{driverInstanceId}' missing {field}");
+        }
+        return Enum.TryParse<T>(raw, ignoreCase: true, out var v)
+            ? v
+            : throw new InvalidOperationException(
+                $"AB Legacy {(tagName is null ? "config" : $"tag '{tagName}'")} has unknown {field} '{raw}'. " +
+                $"Expected one of {string.Join(", ", Enum.GetNames<T>())}");
+    }
+
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        ReadCommentHandling = JsonCommentHandling.Skip,
+        AllowTrailingCommas = true,
+    };
+
+    internal sealed class AbLegacyDriverConfigDto
+    {
+        public int? TimeoutMs { get; init; }
+        public List<AbLegacyDeviceDto>? Devices { get; init; }
+        public List<AbLegacyTagDto>? Tags { get; init; }
+        public AbLegacyProbeDto? Probe { get; init; }
+    }
+
+    internal sealed class AbLegacyDeviceDto
+    {
+        public string? HostAddress { get; init; }
+        public string? PlcFamily { get; init; }
+        public string? DeviceName { get; init; }
+    }
+
+    internal sealed class AbLegacyTagDto
+    {
+        public string? Name { get; init; }
+        public string? DeviceHostAddress { get; init; }
+        public string? Address { get; init; }
+        public string? DataType { get; init; }
+        public bool? Writable { get; init; }
+        public bool? WriteIdempotent { get; init; }
+    }
+
+    internal sealed class AbLegacyProbeDto
+    {
+        public bool? Enabled { get; init; }
+        public int? IntervalMs { get; init; }
+        public int? TimeoutMs { get; init; }
+        public string? ProbeAddress { get; init; }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/AbLegacyDriverOptions.cs

@@ -23,7 +23,7 @@ public sealed record AbLegacyDeviceOptions(
 
 /// <summary>
 ///     One PCCC-backed OPC UA variable. <paramref name="Address"/> is the canonical PCCC
-///     file-address string that parses via <see cref="AbLegacyAddress.TryParse"/>.
+///     file-address string that parses via <see cref="AbLegacyAddress.TryParse(string?)"/>.
 /// </summary>
 public sealed record AbLegacyTagDefinition(
     string Name,

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/LibplctagLegacyTagRuntime.cs

@@ -40,8 +40,25 @@ internal sealed class LibplctagLegacyTagRuntime : IAbLegacyTagRuntime
         AbLegacyDataType.Long => _tag.GetInt32(0),
         AbLegacyDataType.Float => _tag.GetFloat32(0),
         AbLegacyDataType.String => _tag.GetString(0),
+        // Timer/Counter/Control sub-elements: bitIndex is the status bit position within the
+        // parent control word (encoded by AbLegacyDriver from the .DN / .EN / etc. sub-element
+        // name). Word members (.PRE / .ACC / .LEN / .POS) come through with bitIndex=null and
+        // decode as Int32 like before.
         AbLegacyDataType.TimerElement or AbLegacyDataType.CounterElement
-            or AbLegacyDataType.ControlElement => _tag.GetInt32(0),
+            or AbLegacyDataType.ControlElement => bitIndex is int statusBit
+                ? _tag.GetBit(statusBit)
+                : _tag.GetInt32(0),
+        // PD-file (PID): non-bit members (SP/PV/CV/KP/KI/KD/MAXS/MINS/DB/OUT) are 32-bit floats.
+        // Status bits (EN/DN/MO/PE/AUTO/MAN/SP_VAL/SP_LL/SP_HL) live in the parent control word
+        // and read through GetBit — the driver encodes the position via StatusBitIndex.
+        AbLegacyDataType.PidElement => bitIndex is int pidBit
+            ? _tag.GetBit(pidBit)
+            : _tag.GetFloat32(0),
+        // MG/BT/PLS: non-bit members (RBE/MS/SIZE/LEN, RLEN/DLEN) are word-sized integers.
+        AbLegacyDataType.MessageElement or AbLegacyDataType.BlockTransferElement
+            or AbLegacyDataType.PlsElement => bitIndex is int statusBit2
+                ? _tag.GetBit(statusBit2)
+                : _tag.GetInt32(0),
         _ => null,
     };
 
@@ -77,6 +94,18 @@ internal sealed class LibplctagLegacyTagRuntime : IAbLegacyTagRuntime
             case AbLegacyDataType.ControlElement:
                 _tag.SetInt32(0, Convert.ToInt32(value));
                 break;
+            // PD-file non-bit writes route to the Float backing store. Status-bit writes within
+            // the parent word are blocked at the driver layer (PLC-set bits are read-only and
+            // operator-controllable bits go through the bit-RMW path with the parent word typed
+            // as Int).
+            case AbLegacyDataType.PidElement:
+                _tag.SetFloat32(0, Convert.ToSingle(value));
+                break;
+            case AbLegacyDataType.MessageElement:
+            case AbLegacyDataType.BlockTransferElement:
+            case AbLegacyDataType.PlsElement:
+                _tag.SetInt32(0, Convert.ToInt32(value));
+                break;
             default:
                 throw new NotSupportedException($"AbLegacyDataType {type} not writable.");
         }

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/PlcFamilies/AbLegacyPlcFamilyProfile.cs

@@ -9,7 +9,13 @@ public sealed record AbLegacyPlcFamilyProfile(
     string DefaultCipPath,
     int MaxTagBytes,
     bool SupportsStringFile,
-    bool SupportsLongFile)
+    bool SupportsLongFile,
+    bool OctalIoAddressing,
+    bool SupportsFunctionFiles,
+    bool SupportsPidFile,
+    bool SupportsMessageFile,
+    bool SupportsPlsFile,
+    bool SupportsBlockTransferFile)
 {
     public static AbLegacyPlcFamilyProfile ForFamily(AbLegacyPlcFamily family) => family switch
     {
@@ -25,21 +31,39 @@ public sealed record AbLegacyPlcFamilyProfile(
         DefaultCipPath: "1,0",
         MaxTagBytes: 240,           // SLC 5/05 PCCC max packet data
         SupportsStringFile: true,   // ST file available SLC 5/04+
-        SupportsLongFile: true);    // L file available SLC 5/05+
+        SupportsLongFile: true,     // L file available SLC 5/05+
+        OctalIoAddressing: false,   // SLC500 I:/O: indices are decimal in RSLogix 500
+        SupportsFunctionFiles: false, // SLC500 has no function files
+        SupportsPidFile: true,        // SLC 5/02+ supports PD via PID instruction
+        SupportsMessageFile: true,    // SLC 5/02+ supports MG via MSG instruction
+        SupportsPlsFile: false,       // SLC500 has no native PLS file (uses SQO/SQC instead)
+        SupportsBlockTransferFile: false); // SLC500 has no BT file (BT is PLC-5 ChassisIO only)
 
     public static readonly AbLegacyPlcFamilyProfile MicroLogix = new(
         LibplctagPlcAttribute: "micrologix",
         DefaultCipPath: "",         // MicroLogix 1100/1400 use direct EIP, no backplane path
         MaxTagBytes: 232,
         SupportsStringFile: true,
-        SupportsLongFile: false);   // ML 1100/1200/1400 don't ship L files
+        SupportsLongFile: false,    // ML 1100/1200/1400 don't ship L files
+        OctalIoAddressing: false,   // MicroLogix follows SLC-style decimal I/O addressing
+        SupportsFunctionFiles: true, // ML 1100/1400 expose RTC/HSC/DLS/MMI/PTO/PWM/STI/EII/IOS/BHI
+        SupportsPidFile: false,       // MicroLogix 1100/1400 use PID-instruction-only addressing — no PD file type
+        SupportsMessageFile: false,   // No MG file — MSG instruction control words live in standard files
+        SupportsPlsFile: false,
+        SupportsBlockTransferFile: false);
 
     public static readonly AbLegacyPlcFamilyProfile Plc5 = new(
         LibplctagPlcAttribute: "plc5",
         DefaultCipPath: "1,0",
         MaxTagBytes: 240,           // DF1 full-duplex packet limit at 264 bytes, PCCC-over-EIP caps lower
         SupportsStringFile: true,
-        SupportsLongFile: false);   // PLC-5 predates L files
+        SupportsLongFile: false,    // PLC-5 predates L files
+        OctalIoAddressing: true,    // RSLogix 5 displays I:/O: word + bit indices as octal
+        SupportsFunctionFiles: false,
+        SupportsPidFile: true,        // PLC-5 PID instruction needs PD file
+        SupportsMessageFile: true,    // PLC-5 MSG instruction needs MG file
+        SupportsPlsFile: true,        // PLC-5 has PLS (programmable limit switch) file
+        SupportsBlockTransferFile: true); // PLC-5 chassis I/O block transfer (BTR/BTW) needs BT file
 
     /// <summary>
     ///     Logix ControlLogix / CompactLogix accessed through the legacy PCCC compatibility layer.
@@ -51,7 +75,15 @@ public sealed record AbLegacyPlcFamilyProfile(
         DefaultCipPath: "1,0",
         MaxTagBytes: 240,
         SupportsStringFile: true,
-        SupportsLongFile: true);
+        SupportsLongFile: true,
+        OctalIoAddressing: false,   // Logix natively uses decimal arrays even via the PCCC bridge
+        SupportsFunctionFiles: false,
+        // Logix native UDTs (PID_ENHANCED / MESSAGE) replace the legacy PD/MG file types — the
+        // PCCC bridge does not expose them as letter-prefixed files.
+        SupportsPidFile: false,
+        SupportsMessageFile: false,
+        SupportsPlsFile: false,
+        SupportsBlockTransferFile: false);
 }
 
 /// <summary>Which PCCC PLC family the device is.</summary>

src/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.csproj

@@ -14,6 +14,7 @@
 
     <ItemGroup>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core\ZB.MOM.WW.OtOpcUa.Core.csproj"/>
     </ItemGroup>
 
     <ItemGroup>

src/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/DriverCommandBase.cs

@@ -0,0 +1,60 @@
+using CliFx;
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using Serilog;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+/// <summary>
+///     Shared base for every driver test-client command (Modbus / AB CIP / AB Legacy / S7 /
+///     TwinCAT). Carries the options that are meaningful regardless of protocol — verbose
+///     logging + the standard timeout — plus helpers every command implementation wants:
+///     Serilog configuration + cancellation-token capture.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Each driver CLI sub-classes this with its own protocol-specific base (e.g.
+///         <c>ModbusCommandBase</c>) that adds host/port/unit-id + a <c>BuildDriver()</c>
+///         factory. That second layer is the point where the driver's <c>{Driver}DriverOptions</c>
+///         type plugs in; keeping it out of this common base lets each driver CLI stay a thin
+///         executable with no dependency on the other drivers' projects.
+///     </para>
+///     <para>
+///         Why a shared base at all — without this every CLI re-authored the same ~40 lines
+///         of Serilog wiring + cancel-token plumbing + verbose flag.
+///     </para>
+/// </remarks>
+public abstract class DriverCommandBase : ICommand
+{
+    /// <summary>
+    ///     Enable Serilog debug-level output. Leave off for clean one-line-per-call output;
+    ///     switch on when diagnosing a connect / PDU-framing / retry problem.
+    /// </summary>
+    [CommandOption("verbose", Description = "Enable verbose/debug Serilog output")]
+    public bool Verbose { get; init; }
+
+    /// <summary>
+    ///     Request-level timeout used by the driver's <c>Initialize</c> / <c>Read</c> /
+    ///     <c>Write</c> / probe calls. Defaults per-protocol (Modbus: 2s, AB: 5s, S7: 5s,
+    ///     TwinCAT: 5s) — each driver CLI overrides this property with the appropriate
+    ///     <c>[CommandOption]</c> default.
+    /// </summary>
+    public abstract TimeSpan Timeout { get; init; }
+
+    public abstract ValueTask ExecuteAsync(IConsole console);
+
+    /// <summary>
+    ///     Configures the process-global Serilog logger. Commands call this at the top of
+    ///     <see cref="ExecuteAsync"/> so driver-internal <c>Log.Logger</c> writes land on the
+    ///     same sink as the CLI's operator-facing output.
+    /// </summary>
+    protected void ConfigureLogging()
+    {
+        var config = new LoggerConfiguration();
+        if (Verbose)
+            config.MinimumLevel.Debug().WriteTo.Console();
+        else
+            config.MinimumLevel.Warning().WriteTo.Console();
+        Log.Logger = config.CreateLogger();
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs

@@ -0,0 +1,131 @@
+using System.Globalization;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+/// <summary>
+///     Renders <see cref="DataValueSnapshot"/> + <see cref="WriteResult"/> payloads as the
+///     plain-text lines every driver CLI prints to its console. Matches the one-field-per-line
+///     style the existing OPC UA <c>otopcua-cli</c> uses so combined runs (read a tag via both
+///     CLIs side-by-side) look coherent.
+/// </summary>
+public static class SnapshotFormatter
+{
+    /// <summary>
+    ///     Single-tag multi-line render. Shape:
+    ///     <code>
+    ///     Tag:         &lt;name&gt;
+    ///     Value:       &lt;value&gt;
+    ///     Status:      0x... (Good|BadCommunicationError|...)
+    ///     Source Time: 2026-04-21T12:34:56.789Z
+    ///     Server Time: 2026-04-21T12:34:56.790Z
+    ///     </code>
+    /// </summary>
+    public static string Format(string tagName, DataValueSnapshot snapshot)
+    {
+        ArgumentNullException.ThrowIfNull(snapshot);
+        var lines = new[]
+        {
+            $"Tag:         {tagName}",
+            $"Value:       {FormatValue(snapshot.Value)}",
+            $"Status:      {FormatStatus(snapshot.StatusCode)}",
+            $"Source Time: {FormatTimestamp(snapshot.SourceTimestampUtc)}",
+            $"Server Time: {FormatTimestamp(snapshot.ServerTimestampUtc)}",
+        };
+        return string.Join(Environment.NewLine, lines);
+    }
+
+    /// <summary>
+    ///     Write-result render, one line: <c>Write &lt;tag&gt;: 0x... (Good|...)</c>.
+    /// </summary>
+    public static string FormatWrite(string tagName, WriteResult result)
+    {
+        ArgumentNullException.ThrowIfNull(result);
+        return $"Write {tagName}: {FormatStatus(result.StatusCode)}";
+    }
+
+    /// <summary>
+    ///     Table-style render for batch reads. Emits an aligned 4-column layout:
+    ///     tag / value / status / source-time.
+    /// </summary>
+    public static string FormatTable(
+        IReadOnlyList<string> tagNames, IReadOnlyList<DataValueSnapshot> snapshots)
+    {
+        ArgumentNullException.ThrowIfNull(tagNames);
+        ArgumentNullException.ThrowIfNull(snapshots);
+        if (tagNames.Count != snapshots.Count)
+            throw new ArgumentException(
+                $"tagNames ({tagNames.Count}) and snapshots ({snapshots.Count}) must be the same length");
+
+        var rows = tagNames.Select((t, i) => new
+        {
+            Tag = t,
+            Value = FormatValue(snapshots[i].Value),
+            Status = FormatStatus(snapshots[i].StatusCode),
+            Time = FormatTimestamp(snapshots[i].SourceTimestampUtc),
+        }).ToArray();
+
+        int tagW = Math.Max("TAG".Length, rows.Max(r => r.Tag.Length));
+        int valW = Math.Max("VALUE".Length, rows.Max(r => r.Value.Length));
+        int statW = Math.Max("STATUS".Length, rows.Max(r => r.Status.Length));
+        // source-time column is fixed-width (ISO-8601 to ms) so no max-measurement needed.
+
+        var sb = new System.Text.StringBuilder();
+        sb.Append("TAG".PadRight(tagW)).Append("  ")
+          .Append("VALUE".PadRight(valW)).Append("  ")
+          .Append("STATUS".PadRight(statW)).Append("  ")
+          .Append("SOURCE TIME").AppendLine();
+        sb.Append(new string('-', tagW)).Append("  ")
+          .Append(new string('-', valW)).Append("  ")
+          .Append(new string('-', statW)).Append("  ")
+          .Append(new string('-', "SOURCE TIME".Length)).AppendLine();
+        foreach (var r in rows)
+        {
+            sb.Append(r.Tag.PadRight(tagW)).Append("  ")
+              .Append(r.Value.PadRight(valW)).Append("  ")
+              .Append(r.Status.PadRight(statW)).Append("  ")
+              .Append(r.Time).AppendLine();
+        }
+        return sb.ToString().TrimEnd();
+    }
+
+    public static string FormatValue(object? value) => value switch
+    {
+        null => "<null>",
+        bool b => b ? "true" : "false",
+        string s => $"\"{s}\"",
+        IFormattable f => f.ToString(null, CultureInfo.InvariantCulture),
+        _ => value.ToString() ?? "<null>",
+    };
+
+    public static string FormatStatus(uint statusCode)
+    {
+        // Match the OPC UA shorthand for the statuses most-likely to land in a CLI run.
+        // Anything outside this short-list surfaces as hex — operators can cross-reference
+        // against OPC UA Part 6 § 7.34 (StatusCode tables) or Core.Abstractions status mappers.
+        var name = statusCode switch
+        {
+            0x00000000u => "Good",
+            0x80000000u => "Bad",
+            0x80050000u => "BadCommunicationError",
+            0x80060000u => "BadTimeout",
+            0x80070000u => "BadNoCommunication",
+            0x80080000u => "BadWaitingForInitialData",
+            0x80340000u => "BadNodeIdUnknown",
+            0x80350000u => "BadNodeIdInvalid",
+            0x80740000u => "BadTypeMismatch",
+            0x40000000u => "Uncertain",
+            _ => null,
+        };
+        return name is null
+            ? $"0x{statusCode:X8}"
+            : $"0x{statusCode:X8} ({name})";
+    }
+
+    public static string FormatTimestamp(DateTime? ts)
+    {
+        if (ts is null) return "-";
+        var utc = ts.Value.Kind == DateTimeKind.Utc ? ts.Value : ts.Value.ToUniversalTime();
+        return utc.ToString("yyyy-MM-ddTHH:mm:ss.fffZ", CultureInfo.InvariantCulture);
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.csproj

@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <LangVersion>latest</LangVersion>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <NoWarn>$(NoWarn);CS1591</NoWarn>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Driver.Cli.Common</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="CliFx" Version="2.3.6"/>
+        <PackageReference Include="Serilog" Version="4.2.0"/>
+        <PackageReference Include="Serilog.Sinks.Console" Version="6.0.0"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+    </ItemGroup>
+
+</Project>

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/Commands/ProbeCommand.cs

@@ -0,0 +1,57 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli.Commands;
+
+/// <summary>
+///     Probes a Fanuc CNC: opens a FOCAS session + reads one PMC address. No public
+///     simulator exists — this command only produces meaningful results against a real
+///     CNC with Fwlib32.dll present. Against a dev box it surfaces
+///     <c>BadCommunicationError</c> (DLL missing) which is still a useful signal that
+///     the CLI wire-up is correct.
+/// </summary>
+[Command("probe", Description = "Verify the CNC is reachable + a sample FOCAS read succeeds.")]
+public sealed class ProbeCommand : FocasCommandBase
+{
+    [CommandOption("address", 'a', Description =
+        "FOCAS address to probe (default R100 — PMC R-file register 100).")]
+    public string Address { get; init; } = "R100";
+
+    [CommandOption("type", Description = "Data type (default Int16).")]
+    public FocasDataType DataType { get; init; } = FocasDataType.Int16;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var probeTag = new FocasTagDefinition(
+            Name: "__probe",
+            DeviceHostAddress: HostAddress,
+            Address: Address,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([probeTag]);
+
+        await using var driver = new FocasDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var snapshot = await driver.ReadAsync(["__probe"], ct);
+            var health = driver.GetHealth();
+
+            await console.Output.WriteLineAsync($"CNC:          {CncHost}:{CncPort}");
+            await console.Output.WriteLineAsync($"Series:       {Series}");
+            await console.Output.WriteLineAsync($"Health:       {health.State}");
+            if (health.LastError is { } err)
+                await console.Output.WriteLineAsync($"Last error:   {err}");
+            await console.Output.WriteLineAsync();
+            await console.Output.WriteLineAsync(SnapshotFormatter.Format(Address, snapshot[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/Commands/ReadCommand.cs

@@ -0,0 +1,52 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli.Commands;
+
+/// <summary>
+///     Read one FOCAS address (PMC R/G/F file, parameter, macro, axis register).
+/// </summary>
+[Command("read", Description = "Read a single FOCAS address.")]
+public sealed class ReadCommand : FocasCommandBase
+{
+    [CommandOption("address", 'a', Description =
+        "FOCAS address. Examples: R100 (PMC R-file word); X0.0 (PMC X-bit); " +
+        "PARAM:1815/0 (parameter 1815, axis 0); MACRO:500 (macro variable 500).",
+        IsRequired = true)]
+    public string Address { get; init; } = default!;
+
+    [CommandOption("type", 't', Description =
+        "Bit / Byte / Int16 / Int32 / Float32 / Float64 / String (default Int16).")]
+    public FocasDataType DataType { get; init; } = FocasDataType.Int16;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = SynthesiseTagName(Address, DataType);
+        var tag = new FocasTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: HostAddress,
+            Address: Address,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([tag]);
+
+        await using var driver = new FocasDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var snapshot = await driver.ReadAsync([tagName], ct);
+            await console.Output.WriteLineAsync(SnapshotFormatter.Format(Address, snapshot[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+
+    internal static string SynthesiseTagName(string address, FocasDataType type)
+        => $"{address}:{type}";
+}

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/Commands/SubscribeCommand.cs

@@ -0,0 +1,76 @@
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli.Commands;
+
+/// <summary>
+///     Watch a FOCAS address via polled subscription until Ctrl+C. FOCAS has no push
+///     model; <c>PollGroupEngine</c> handles the tick loop.
+/// </summary>
+[Command("subscribe", Description = "Watch a FOCAS address via polled subscription until Ctrl+C.")]
+public sealed class SubscribeCommand : FocasCommandBase
+{
+    [CommandOption("address", 'a', Description = "FOCAS address — same format as `read`.", IsRequired = true)]
+    public string Address { get; init; } = default!;
+
+    [CommandOption("type", 't', Description =
+        "Bit / Byte / Int16 / Int32 / Float32 / Float64 / String (default Int16).")]
+    public FocasDataType DataType { get; init; } = FocasDataType.Int16;
+
+    [CommandOption("interval-ms", 'i', Description = "Publishing interval ms (default 1000).")]
+    public int IntervalMs { get; init; } = 1000;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = ReadCommand.SynthesiseTagName(Address, DataType);
+        var tag = new FocasTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: HostAddress,
+            Address: Address,
+            DataType: DataType,
+            Writable: false);
+        var options = BuildOptions([tag]);
+
+        await using var driver = new FocasDriver(options, DriverInstanceId);
+        ISubscriptionHandle? handle = null;
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+
+            driver.OnDataChange += (_, e) =>
+            {
+                var line = $"[{DateTime.UtcNow:HH:mm:ss.fff}] " +
+                    $"{e.FullReference} = {SnapshotFormatter.FormatValue(e.Snapshot.Value)} " +
+                    $"({SnapshotFormatter.FormatStatus(e.Snapshot.StatusCode)})";
+                console.Output.WriteLine(line);
+            };
+
+            handle = await driver.SubscribeAsync([tagName], TimeSpan.FromMilliseconds(IntervalMs), ct);
+
+            await console.Output.WriteLineAsync(
+                $"Subscribed to {Address} @ {IntervalMs}ms. Ctrl+C to stop.");
+            try
+            {
+                await Task.Delay(System.Threading.Timeout.InfiniteTimeSpan, ct);
+            }
+            catch (OperationCanceledException)
+            {
+                // Expected on Ctrl+C.
+            }
+        }
+        finally
+        {
+            if (handle is not null)
+            {
+                try { await driver.UnsubscribeAsync(handle, CancellationToken.None); }
+                catch { /* teardown best-effort */ }
+            }
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/Commands/WriteCommand.cs

@@ -0,0 +1,77 @@
+using System.Globalization;
+using CliFx.Attributes;
+using CliFx.Infrastructure;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli.Commands;
+
+/// <summary>
+///     Write one value to a FOCAS address. PMC G/R writes are real — be careful
+///     which file you hit on a running machine. Parameter writes may require the
+///     CNC to be in MDI mode + the parameter-write switch enabled.
+/// </summary>
+[Command("write", Description = "Write a single FOCAS address.")]
+public sealed class WriteCommand : FocasCommandBase
+{
+    [CommandOption("address", 'a', Description = "FOCAS address — same format as `read`.", IsRequired = true)]
+    public string Address { get; init; } = default!;
+
+    [CommandOption("type", 't', Description =
+        "Bit / Byte / Int16 / Int32 / Float32 / Float64 / String (default Int16).")]
+    public FocasDataType DataType { get; init; } = FocasDataType.Int16;
+
+    [CommandOption("value", 'v', Description =
+        "Value to write. Parsed per --type (booleans accept true/false/1/0).",
+        IsRequired = true)]
+    public string Value { get; init; } = default!;
+
+    public override async ValueTask ExecuteAsync(IConsole console)
+    {
+        ConfigureLogging();
+        var ct = console.RegisterCancellationHandler();
+
+        var tagName = ReadCommand.SynthesiseTagName(Address, DataType);
+        var tag = new FocasTagDefinition(
+            Name: tagName,
+            DeviceHostAddress: HostAddress,
+            Address: Address,
+            DataType: DataType,
+            Writable: true);
+        var options = BuildOptions([tag]);
+
+        var parsed = ParseValue(Value, DataType);
+
+        await using var driver = new FocasDriver(options, DriverInstanceId);
+        try
+        {
+            await driver.InitializeAsync("{}", ct);
+            var results = await driver.WriteAsync([new WriteRequest(tagName, parsed)], ct);
+            await console.Output.WriteLineAsync(SnapshotFormatter.FormatWrite(Address, results[0]));
+        }
+        finally
+        {
+            await driver.ShutdownAsync(CancellationToken.None);
+        }
+    }
+
+    internal static object ParseValue(string raw, FocasDataType type) => type switch
+    {
+        FocasDataType.Bit => ParseBool(raw),
+        FocasDataType.Byte => sbyte.Parse(raw, CultureInfo.InvariantCulture),
+        FocasDataType.Int16 => short.Parse(raw, CultureInfo.InvariantCulture),
+        FocasDataType.Int32 => int.Parse(raw, CultureInfo.InvariantCulture),
+        FocasDataType.Float32 => float.Parse(raw, CultureInfo.InvariantCulture),
+        FocasDataType.Float64 => double.Parse(raw, CultureInfo.InvariantCulture),
+        FocasDataType.String => raw,
+        _ => throw new CliFx.Exceptions.CommandException($"Unsupported DataType '{type}' for write."),
+    };
+
+    private static bool ParseBool(string raw) => raw.Trim().ToLowerInvariant() switch
+    {
+        "1" or "true" or "on" or "yes" => true,
+        "0" or "false" or "off" or "no" => false,
+        _ => throw new CliFx.Exceptions.CommandException(
+            $"Boolean value '{raw}' is not recognised. Use true/false, 1/0, on/off, or yes/no."),
+    };
+}

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/FocasCommandBase.cs

@@ -0,0 +1,58 @@
+using CliFx.Attributes;
+using ZB.MOM.WW.OtOpcUa.Driver.Cli.Common;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli;
+
+/// <summary>
+///     Base for every FOCAS CLI command. Carries the CNC endpoint options
+///     (host / port / series) + exposes <see cref="BuildOptions"/> so each command
+///     can synthesise a <see cref="FocasDriverOptions"/> with one device + one tag.
+/// </summary>
+public abstract class FocasCommandBase : DriverCommandBase
+{
+    [CommandOption("cnc-host", 'h', Description =
+        "CNC IP address or hostname. FOCAS-over-EIP listens on port 8193 by default.",
+        IsRequired = true)]
+    public string CncHost { get; init; } = default!;
+
+    [CommandOption("cnc-port", 'p', Description = "FOCAS TCP port (default 8193).")]
+    public int CncPort { get; init; } = 8193;
+
+    [CommandOption("series", 's', Description =
+        "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 (default Unknown).")]
+    public FocasCncSeries Series { get; init; } = FocasCncSeries.Unknown;
+
+    [CommandOption("timeout-ms", Description = "Per-operation timeout in ms (default 2000).")]
+    public int TimeoutMs { get; init; } = 2000;
+
+    /// <inheritdoc />
+    public override TimeSpan Timeout
+    {
+        get => TimeSpan.FromMilliseconds(TimeoutMs);
+        init { /* driven by TimeoutMs */ }
+    }
+
+    /// <summary>Canonical FOCAS host-address string, shape <c>focas://host:port</c>.</summary>
+    protected string HostAddress => $"focas://{CncHost}:{CncPort}";
+
+    /// <summary>
+    ///     Build a <see cref="FocasDriverOptions"/> with the CNC target this base collected
+    ///     + the tag list a subclass supplies. Probe disabled; the default
+    ///     <see cref="FwlibFocasClientFactory"/> attempts <c>Fwlib32.dll</c> P/Invoke, which
+    ///     throws <see cref="DllNotFoundException"/> at first call when the DLL is absent —
+    ///     surfaced through the driver as <c>BadCommunicationError</c>.
+    /// </summary>
+    protected FocasDriverOptions BuildOptions(IReadOnlyList<FocasTagDefinition> tags) => new()
+    {
+        Devices = [new FocasDeviceOptions(
+            HostAddress: HostAddress,
+            DeviceName: $"cli-{CncHost}:{CncPort}",
+            Series: Series)],
+        Tags = tags,
+        Timeout = Timeout,
+        Probe = new FocasProbeOptions { Enabled = false },
+    };
+
+    protected string DriverInstanceId => $"focas-cli-{CncHost}:{CncPort}";
+}

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/Program.cs

@@ -0,0 +1,12 @@
+using CliFx;
+
+return await new CliApplicationBuilder()
+    .AddCommandsFromThisAssembly()
+    .SetExecutableName("otopcua-focas-cli")
+    .SetDescription(
+        "OtOpcUa FOCAS test-client — ad-hoc probe + PMC/param/macro reads/writes + polled " +
+        "subscriptions against Fanuc CNCs via the FOCAS/2 protocol. Requires a real CNC + a " +
+        "licensed Fwlib32.dll on PATH (or next to the executable) — no public simulator " +
+        "exists. Addresses use FocasAddressParser syntax: R100, X0.0, PARAM:1815/0, MACRO:500.")
+    .Build()
+    .RunAsync(args);

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <LangVersion>latest</LangVersion>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <NoWarn>$(NoWarn);CS1591</NoWarn>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Cli</RootNamespace>
+        <AssemblyName>otopcua-focas-cli</AssemblyName>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="CliFx" Version="2.3.6"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.Cli.Common\ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.FOCAS\ZB.MOM.WW.OtOpcUa.Driver.FOCAS.csproj"/>
+    </ItemGroup>
+
+</Project>

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasCapabilityMatrix.cs

@@ -106,6 +106,27 @@ public static class FocasCapabilityMatrix
         _ => int.MaxValue,
     };
 
+    /// <summary>
+    ///     Whether the FOCAS driver should expose the per-device <c>Tooling/</c>
+    ///     fixed-tree subfolder for a given <paramref name="series"/>. Backed by
+    ///     <c>cnc_rdtnum</c>, which is documented for every modern Fanuc series
+    ///     (0i / 16i / 30i families) — defaulting to <c>true</c>. The capability
+    ///     hook exists so a future controller without <c>cnc_rdtnum</c> can opt
+    ///     out without touching the driver. <see cref="FocasCncSeries.Unknown"/>
+    ///     stays permissive (matches the modal / override fixed-tree precedent in
+    ///     issue #259). Issue #260.
+    /// </summary>
+    public static bool SupportsTooling(FocasCncSeries series) => true;
+
+    /// <summary>
+    ///     Whether the FOCAS driver should expose the per-device <c>Offsets/</c>
+    ///     fixed-tree subfolder for a given <paramref name="series"/>. Backed by
+    ///     <c>cnc_rdzofs(n=1..6)</c> for the standard G54..G59 surfaces; extended
+    ///     G54.1 P1..P48 surfaces are deferred to a follow-up. Same permissive
+    ///     policy as <see cref="SupportsTooling"/>. Issue #260.
+    /// </summary>
+    public static bool SupportsWorkOffsets(FocasCncSeries series) => true;
+
     private static string? ValidateMacro(FocasCncSeries series, int number)
     {
         var (min, max) = MacroRange(series);

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriver.cs

@@ -24,8 +24,96 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
     private readonly PollGroupEngine _poll;
     private readonly Dictionary<string, DeviceState> _devices = new(StringComparer.OrdinalIgnoreCase);
     private readonly Dictionary<string, FocasTagDefinition> _tagsByName = new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, (string Host, string Field)> _statusNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, (string Host, string Field)> _productionNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, (string Host, string Field)> _modalNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, (string Host, string Field)> _overrideNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, string> _toolingNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, (string Host, string Slot, string Axis)> _offsetNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, string> _messagesNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, string> _currentBlockNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
+    private readonly Dictionary<string, (string Host, string Field)> _diagnosticsNodesByName =
+        new(StringComparer.OrdinalIgnoreCase);
     private DriverHealth _health = new(DriverState.Unknown, null, null);
 
+    /// <summary>
+    ///     Names of the 9 fixed-tree <c>Status/</c> child nodes per device, mirroring the 9
+    ///     fields of Fanuc's <c>cnc_rdcncstat</c> ODBST struct (issue #257). Order matters for
+    ///     deterministic discovery output.
+    /// </summary>
+    private static readonly string[] StatusFieldNames =
+    [
+        "Tmmode", "Aut", "Run", "Motion", "Mstb", "EmergencyStop", "Alarm", "Edit", "Dummy",
+    ];
+
+    /// <summary>
+    ///     Names of the 4 fixed-tree <c>Production/</c> child nodes per device — parts
+    ///     produced/required/total via <c>cnc_rdparam(6711/6712/6713)</c> + cycle-time
+    ///     seconds (issue #258). Order matters for deterministic discovery output.
+    /// </summary>
+    private static readonly string[] ProductionFieldNames =
+    [
+        "PartsProduced", "PartsRequired", "PartsTotal", "CycleTimeSeconds",
+    ];
+
+    /// <summary>
+    ///     Names of the active modal aux-code child nodes per device — M/S/T/B from
+    ///     <c>cnc_modal(type=100..103)</c> (issue #259). G-group decoding is a deferred
+    ///     follow-up because the FWLIB <c>ODBMDL</c> union varies per series + group.
+    /// </summary>
+    private static readonly string[] ModalFieldNames = ["MCode", "SCode", "TCode", "BCode"];
+
+    /// <summary>
+    ///     Names of the four operator-override child nodes per device — Feed / Rapid /
+    ///     Spindle / Jog from <c>cnc_rdparam</c> with MTB-specific parameter numbers
+    ///     (issue #259). A device whose <c>FocasOverrideParameters</c> entry is null for a
+    ///     given field has the matching node omitted from the address space.
+    /// </summary>
+    private static readonly string[] OverrideFieldNames = ["Feed", "Rapid", "Spindle", "Jog"];
+
+    /// <summary>
+    ///     Names of the standard work-coordinate offset slots surfaced under
+    ///     <c>Offsets/</c> per device — G54..G59 from <c>cnc_rdzofs(n=1..6)</c>
+    ///     (issue #260). Extended G54.1 P1..P48 surfaces are deferred to a follow-up
+    ///     PR because <c>cnc_rdzofsr</c> uses a different range surface.
+    /// </summary>
+    private static readonly string[] WorkOffsetSlotNames =
+    [
+        "G54", "G55", "G56", "G57", "G58", "G59",
+    ];
+
+    /// <summary>
+    ///     Axis columns surfaced under each <c>Offsets/{slot}/</c> folder. Per the F1-d
+    ///     plan a fixed 3-axis (X/Y/Z) view is used; lathes / mills with extra rotational
+    ///     offsets get those columns exposed as 0.0 until a follow-up extends the surface.
+    /// </summary>
+    private static readonly string[] WorkOffsetAxisNames = ["X", "Y", "Z"];
+
+    /// <summary>
+    ///     Names of the five fixed-tree <c>Diagnostics/</c> child nodes per device — runtime
+    ///     counters surfaced for operator visibility (issue #262). Order matters for
+    ///     deterministic discovery output.
+    ///     <list type="bullet">
+    ///         <item><c>ReadCount</c> (Int64) — successful probe ticks since init</item>
+    ///         <item><c>ReadFailureCount</c> (Int64) — failed probe ticks since init</item>
+    ///         <item><c>LastErrorMessage</c> (String) — text of the last probe / read failure</item>
+    ///         <item><c>LastSuccessfulRead</c> (DateTime) — UTC timestamp of the last good probe tick</item>
+    ///         <item><c>ReconnectCount</c> (Int64) — wire reconnects observed since init</item>
+    ///     </list>
+    /// </summary>
+    private static readonly string[] DiagnosticsFieldNames =
+    [
+        "ReadCount", "ReadFailureCount", "LastErrorMessage", "LastSuccessfulRead", "ReconnectCount",
+    ];
+
     public event EventHandler<DataChangeEventArgs>? OnDataChange;
     public event EventHandler<HostStatusChangedEventArgs>? OnHostStatusChanged;
 
@@ -76,6 +164,67 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                 _tagsByName[tag.Name] = tag;
             }
 
+            // Per-device fixed-tree Status nodes — issue #257. Names are deterministic so
+            // ReadAsync can dispatch on the synthetic full-reference without extra metadata.
+            foreach (var device in _devices.Values)
+            {
+                foreach (var field in StatusFieldNames)
+                    _statusNodesByName[StatusReferenceFor(device.Options.HostAddress, field)] =
+                        (device.Options.HostAddress, field);
+                foreach (var field in ProductionFieldNames)
+                    _productionNodesByName[ProductionReferenceFor(device.Options.HostAddress, field)] =
+                        (device.Options.HostAddress, field);
+                foreach (var field in ModalFieldNames)
+                    _modalNodesByName[ModalReferenceFor(device.Options.HostAddress, field)] =
+                        (device.Options.HostAddress, field);
+                if (device.Options.OverrideParameters is { } op)
+                {
+                    foreach (var field in OverrideFieldNames)
+                    {
+                        if (OverrideParamFor(op, field) is null) continue;
+                        _overrideNodesByName[OverrideReferenceFor(device.Options.HostAddress, field)] =
+                            (device.Options.HostAddress, field);
+                    }
+                }
+
+                // Tooling/CurrentTool — single Int16 node per device (issue #260). Tool
+                // life + active offset index are deferred per the F1-d plan; they need
+                // ODBTLIFE* unions whose shape varies per series.
+                if (FocasCapabilityMatrix.SupportsTooling(device.Options.Series))
+                {
+                    _toolingNodesByName[ToolingReferenceFor(device.Options.HostAddress, "CurrentTool")] =
+                        device.Options.HostAddress;
+                }
+
+                // Offsets/{G54..G59}/{X|Y|Z} — fixed 3-axis view of the standard work-
+                // coordinate offsets (issue #260). Capability matrix gates by series so
+                // legacy CNCs that don't support cnc_rdzofs don't produce the subtree.
+                if (FocasCapabilityMatrix.SupportsWorkOffsets(device.Options.Series))
+                {
+                    foreach (var slot in WorkOffsetSlotNames)
+                    foreach (var axis in WorkOffsetAxisNames)
+                    {
+                        _offsetNodesByName[OffsetReferenceFor(device.Options.HostAddress, slot, axis)] =
+                            (device.Options.HostAddress, slot, axis);
+                    }
+                }
+
+                // Messages/External/Latest + Program/CurrentBlock — single String nodes per
+                // device backed by cnc_rdopmsg3 + cnc_rdactpt caches refreshed on the probe
+                // tick (issue #261). Permissive across series (no capability gate yet).
+                _messagesNodesByName[MessagesLatestReferenceFor(device.Options.HostAddress)] =
+                    device.Options.HostAddress;
+                _currentBlockNodesByName[CurrentBlockReferenceFor(device.Options.HostAddress)] =
+                    device.Options.HostAddress;
+
+                // Diagnostics/{ReadCount, ReadFailureCount, LastErrorMessage,
+                // LastSuccessfulRead, ReconnectCount} — runtime counters surfaced for
+                // operator visibility (issue #262). Permissive across all CNC series.
+                foreach (var field in DiagnosticsFieldNames)
+                    _diagnosticsNodesByName[DiagnosticsReferenceFor(device.Options.HostAddress, field)] =
+                        (device.Options.HostAddress, field);
+            }
+
             if (_options.Probe.Enabled)
             {
                 foreach (var state in _devices.Values)
@@ -113,6 +262,15 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         }
         _devices.Clear();
         _tagsByName.Clear();
+        _statusNodesByName.Clear();
+        _productionNodesByName.Clear();
+        _modalNodesByName.Clear();
+        _overrideNodesByName.Clear();
+        _toolingNodesByName.Clear();
+        _offsetNodesByName.Clear();
+        _messagesNodesByName.Clear();
+        _currentBlockNodesByName.Clear();
+        _diagnosticsNodesByName.Clear();
         _health = new DriverHealth(DriverState.Unknown, _health.LastSuccessfulRead, null);
     }
 
@@ -136,6 +294,73 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         for (var i = 0; i < fullReferences.Count; i++)
         {
             var reference = fullReferences[i];
+
+            // Fixed-tree Status/ nodes — served from the per-device cached ODBST struct
+            // refreshed on the probe tick (issue #257). No wire call here.
+            if (_statusNodesByName.TryGetValue(reference, out var statusKey))
+            {
+                results[i] = ReadStatusField(statusKey.Host, statusKey.Field, now);
+                continue;
+            }
+
+            // Fixed-tree Production/ nodes — served from the per-device cached production
+            // snapshot refreshed on the probe tick (issue #258). No wire call here.
+            if (_productionNodesByName.TryGetValue(reference, out var prodKey))
+            {
+                results[i] = ReadProductionField(prodKey.Host, prodKey.Field, now);
+                continue;
+            }
+
+            // Fixed-tree Modal/ + Override/ nodes — served from per-device cached snapshots
+            // refreshed on the probe tick (issue #259). Same cache-or-Bad policy as Status/.
+            if (_modalNodesByName.TryGetValue(reference, out var modalKey))
+            {
+                results[i] = ReadModalField(modalKey.Host, modalKey.Field, now);
+                continue;
+            }
+            if (_overrideNodesByName.TryGetValue(reference, out var overrideKey))
+            {
+                results[i] = ReadOverrideField(overrideKey.Host, overrideKey.Field, now);
+                continue;
+            }
+
+            // Fixed-tree Tooling/CurrentTool — served from cached cnc_rdtnum snapshot
+            // refreshed on the probe tick (issue #260). No wire call here.
+            if (_toolingNodesByName.TryGetValue(reference, out var toolingHost))
+            {
+                results[i] = ReadToolingField(toolingHost, "CurrentTool", now);
+                continue;
+            }
+
+            // Fixed-tree Offsets/{slot}/{axis} — served from cached cnc_rdzofs(1..6)
+            // snapshot refreshed on the probe tick (issue #260). No wire call here.
+            if (_offsetNodesByName.TryGetValue(reference, out var offsetKey))
+            {
+                results[i] = ReadOffsetField(offsetKey.Host, offsetKey.Slot, offsetKey.Axis, now);
+                continue;
+            }
+
+            // Fixed-tree Messages/External/Latest + Program/CurrentBlock — served from
+            // cnc_rdopmsg3 + cnc_rdactpt caches refreshed on the probe tick (issue #261).
+            if (_messagesNodesByName.TryGetValue(reference, out var messagesHost))
+            {
+                results[i] = ReadMessagesLatestField(messagesHost, now);
+                continue;
+            }
+            if (_currentBlockNodesByName.TryGetValue(reference, out var blockHost))
+            {
+                results[i] = ReadCurrentBlockField(blockHost, now);
+                continue;
+            }
+
+            // Fixed-tree Diagnostics/ nodes — runtime counters maintained by the probe
+            // loop (issue #262). No wire call here.
+            if (_diagnosticsNodesByName.TryGetValue(reference, out var diagKey))
+            {
+                results[i] = ReadDiagnosticsField(diagKey.Host, diagKey.Field, now);
+                continue;
+            }
+
             if (!_tagsByName.TryGetValue(reference, out var def))
             {
                 results[i] = new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
@@ -257,10 +482,267 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                     IsAlarm: false,
                     WriteIdempotent: tag.WriteIdempotent));
             }
+
+            // Fixed-tree Status/ subfolder — 9 read-only Int16 nodes mirroring the ODBST
+            // fields (issue #257). Cached on the probe tick + served from DeviceState.LastStatus.
+            var statusFolder = deviceFolder.Folder("Status", "Status");
+            foreach (var field in StatusFieldNames)
+            {
+                var fullRef = StatusReferenceFor(device.HostAddress, field);
+                statusFolder.Variable(field, field, new DriverAttributeInfo(
+                    FullName: fullRef,
+                    DriverDataType: DriverDataType.Int16,
+                    IsArray: false,
+                    ArrayDim: null,
+                    SecurityClass: SecurityClassification.ViewOnly,
+                    IsHistorized: false,
+                    IsAlarm: false,
+                    WriteIdempotent: false));
+            }
+
+            // Fixed-tree Production/ subfolder — 4 read-only Int32 nodes: parts produced /
+            // required / total + cycle-time seconds (issue #258). Cached on the probe tick
+            // + served from DeviceState.LastProduction.
+            var productionFolder = deviceFolder.Folder("Production", "Production");
+            foreach (var field in ProductionFieldNames)
+            {
+                var fullRef = ProductionReferenceFor(device.HostAddress, field);
+                productionFolder.Variable(field, field, new DriverAttributeInfo(
+                    FullName: fullRef,
+                    DriverDataType: DriverDataType.Int32,
+                    IsArray: false,
+                    ArrayDim: null,
+                    SecurityClass: SecurityClassification.ViewOnly,
+                    IsHistorized: false,
+                    IsAlarm: false,
+                    WriteIdempotent: false));
+            }
+
+            // Fixed-tree Modal/ subfolder — 4 read-only Int16 nodes for the universally-
+            // present aux modal codes M/S/T/B from cnc_modal(type=100..103). G-group
+            // surfaces are deferred to a follow-up because the FWLIB ODBMDL union varies
+            // per series + group (issue #259, plan PR F1-c).
+            var modalFolder = deviceFolder.Folder("Modal", "Modal");
+            foreach (var field in ModalFieldNames)
+            {
+                var fullRef = ModalReferenceFor(device.HostAddress, field);
+                modalFolder.Variable(field, field, new DriverAttributeInfo(
+                    FullName: fullRef,
+                    DriverDataType: DriverDataType.Int16,
+                    IsArray: false,
+                    ArrayDim: null,
+                    SecurityClass: SecurityClassification.ViewOnly,
+                    IsHistorized: false,
+                    IsAlarm: false,
+                    WriteIdempotent: false));
+            }
+
+            // Fixed-tree Override/ subfolder — Feed / Rapid / Spindle / Jog from
+            // cnc_rdparam at MTB-specific parameter numbers (issue #259). Suppressed when
+            // OverrideParameters is null; per-field nodes whose parameter is null are
+            // omitted so a deployment can hide overrides their MTB doesn't wire up.
+            if (device.OverrideParameters is { } overrideParams)
+            {
+                var overrideFolder = deviceFolder.Folder("Override", "Override");
+                foreach (var field in OverrideFieldNames)
+                {
+                    if (OverrideParamFor(overrideParams, field) is null) continue;
+                    var fullRef = OverrideReferenceFor(device.HostAddress, field);
+                    overrideFolder.Variable(field, field, new DriverAttributeInfo(
+                        FullName: fullRef,
+                        DriverDataType: DriverDataType.Int16,
+                        IsArray: false,
+                        ArrayDim: null,
+                        SecurityClass: SecurityClassification.ViewOnly,
+                        IsHistorized: false,
+                        IsAlarm: false,
+                        WriteIdempotent: false));
+                }
+            }
+
+            // Fixed-tree Tooling/ subfolder — single Int16 CurrentTool node from
+            // cnc_rdtnum (issue #260). Tool life + active offset index are deferred
+            // per the F1-d plan because the FWLIB ODBTLIFE* unions vary per series.
+            if (FocasCapabilityMatrix.SupportsTooling(device.Series))
+            {
+                var toolingFolder = deviceFolder.Folder("Tooling", "Tooling");
+                var toolingRef = ToolingReferenceFor(device.HostAddress, "CurrentTool");
+                toolingFolder.Variable("CurrentTool", "CurrentTool", new DriverAttributeInfo(
+                    FullName: toolingRef,
+                    DriverDataType: DriverDataType.Int16,
+                    IsArray: false,
+                    ArrayDim: null,
+                    SecurityClass: SecurityClassification.ViewOnly,
+                    IsHistorized: false,
+                    IsAlarm: false,
+                    WriteIdempotent: false));
+            }
+
+            // Fixed-tree Offsets/ subfolder — G54..G59 each with X/Y/Z Float64 axes
+            // from cnc_rdzofs(n=1..6) (issue #260). Capability matrix gates the surface
+            // by series so legacy controllers without cnc_rdzofs support don't expose
+            // dead nodes. Extended G54.1 P1..P48 surfaces are deferred to a follow-up.
+            if (FocasCapabilityMatrix.SupportsWorkOffsets(device.Series))
+            {
+                var offsetsFolder = deviceFolder.Folder("Offsets", "Offsets");
+                foreach (var slot in WorkOffsetSlotNames)
+                {
+                    var slotFolder = offsetsFolder.Folder(slot, slot);
+                    foreach (var axis in WorkOffsetAxisNames)
+                    {
+                        var fullRef = OffsetReferenceFor(device.HostAddress, slot, axis);
+                        slotFolder.Variable(axis, axis, new DriverAttributeInfo(
+                            FullName: fullRef,
+                            DriverDataType: DriverDataType.Float64,
+                            IsArray: false,
+                            ArrayDim: null,
+                            SecurityClass: SecurityClassification.ViewOnly,
+                            IsHistorized: false,
+                            IsAlarm: false,
+                            WriteIdempotent: false));
+                    }
+                }
+            }
+
+            // Fixed-tree Messages/External/Latest — single String node per device backed
+            // by cnc_rdopmsg3 across the four FANUC operator-message classes (issue #261).
+            // The issue body permits this minimal "latest message" surface in the first
+            // cut over a full ring-buffer of all four slots.
+            var messagesFolder = deviceFolder.Folder("Messages", "Messages");
+            var externalFolder = messagesFolder.Folder("External", "External");
+            var messagesRef = MessagesLatestReferenceFor(device.HostAddress);
+            externalFolder.Variable("Latest", "Latest", new DriverAttributeInfo(
+                FullName: messagesRef,
+                DriverDataType: DriverDataType.String,
+                IsArray: false,
+                ArrayDim: null,
+                SecurityClass: SecurityClassification.ViewOnly,
+                IsHistorized: false,
+                IsAlarm: false,
+                WriteIdempotent: false));
+
+            // Fixed-tree Program/CurrentBlock — single String node per device backed by
+            // cnc_rdactpt (issue #261). Trim-stable round-trip per the issue body.
+            var programFolder = deviceFolder.Folder("Program", "Program");
+            var blockRef = CurrentBlockReferenceFor(device.HostAddress);
+            programFolder.Variable("CurrentBlock", "CurrentBlock", new DriverAttributeInfo(
+                FullName: blockRef,
+                DriverDataType: DriverDataType.String,
+                IsArray: false,
+                ArrayDim: null,
+                SecurityClass: SecurityClassification.ViewOnly,
+                IsHistorized: false,
+                IsAlarm: false,
+                WriteIdempotent: false));
+
+            // Fixed-tree Diagnostics/ subfolder — 5 read-only counters surfaced for
+            // operator visibility (issue #262). ReadCount / ReadFailureCount /
+            // ReconnectCount are Int64; LastErrorMessage is String;
+            // LastSuccessfulRead is DateTime. Permissive across CNC series — every
+            // device gets the same shape.
+            var diagnosticsFolder = deviceFolder.Folder("Diagnostics", "Diagnostics");
+            foreach (var field in DiagnosticsFieldNames)
+            {
+                var fullRef = DiagnosticsReferenceFor(device.HostAddress, field);
+                diagnosticsFolder.Variable(field, field, new DriverAttributeInfo(
+                    FullName: fullRef,
+                    DriverDataType: DiagnosticsFieldType(field),
+                    IsArray: false,
+                    ArrayDim: null,
+                    SecurityClass: SecurityClassification.ViewOnly,
+                    IsHistorized: false,
+                    IsAlarm: false,
+                    WriteIdempotent: false));
+            }
         }
         return Task.CompletedTask;
     }
 
+    private static DriverDataType DiagnosticsFieldType(string field) => field switch
+    {
+        "ReadCount" or "ReadFailureCount" or "ReconnectCount" => DriverDataType.Int64,
+        "LastErrorMessage" => DriverDataType.String,
+        "LastSuccessfulRead" => DriverDataType.DateTime,
+        _ => DriverDataType.String,
+    };
+
+    private static string StatusReferenceFor(string hostAddress, string field) =>
+        $"{hostAddress}::Status/{field}";
+
+    private static string ProductionReferenceFor(string hostAddress, string field) =>
+        $"{hostAddress}::Production/{field}";
+
+    private static string ModalReferenceFor(string hostAddress, string field) =>
+        $"{hostAddress}::Modal/{field}";
+
+    private static string OverrideReferenceFor(string hostAddress, string field) =>
+        $"{hostAddress}::Override/{field}";
+
+    private static string ToolingReferenceFor(string hostAddress, string field) =>
+        $"{hostAddress}::Tooling/{field}";
+
+    private static string OffsetReferenceFor(string hostAddress, string slot, string axis) =>
+        $"{hostAddress}::Offsets/{slot}/{axis}";
+
+    private static string MessagesLatestReferenceFor(string hostAddress) =>
+        $"{hostAddress}::Messages/External/Latest";
+
+    private static string CurrentBlockReferenceFor(string hostAddress) =>
+        $"{hostAddress}::Program/CurrentBlock";
+
+    private static string DiagnosticsReferenceFor(string hostAddress, string field) =>
+        $"{hostAddress}::Diagnostics/{field}";
+
+    private static ushort? OverrideParamFor(FocasOverrideParameters p, string field) => field switch
+    {
+        "Feed"    => p.FeedParam,
+        "Rapid"   => p.RapidParam,
+        "Spindle" => p.SpindleParam,
+        "Jog"     => p.JogParam,
+        _         => null,
+    };
+
+    private static short? PickStatusField(FocasStatusInfo s, string field) => field switch
+    {
+        "Tmmode"        => s.Tmmode,
+        "Aut"           => s.Aut,
+        "Run"           => s.Run,
+        "Motion"        => s.Motion,
+        "Mstb"          => s.Mstb,
+        "EmergencyStop" => s.EmergencyStop,
+        "Alarm"         => s.Alarm,
+        "Edit"          => s.Edit,
+        "Dummy"         => s.Dummy,
+        _               => null,
+    };
+
+    private static int? PickProductionField(FocasProductionInfo p, string field) => field switch
+    {
+        "PartsProduced"    => p.PartsProduced,
+        "PartsRequired"    => p.PartsRequired,
+        "PartsTotal"       => p.PartsTotal,
+        "CycleTimeSeconds" => p.CycleTimeSeconds,
+        _                  => null,
+    };
+
+    private static short? PickModalField(FocasModalInfo m, string field) => field switch
+    {
+        "MCode" => m.MCode,
+        "SCode" => m.SCode,
+        "TCode" => m.TCode,
+        "BCode" => m.BCode,
+        _       => null,
+    };
+
+    private static short? PickOverrideField(FocasOverrideInfo o, string field) => field switch
+    {
+        "Feed"    => o.Feed,
+        "Rapid"   => o.Rapid,
+        "Spindle" => o.Spindle,
+        "Jog"     => o.Jog,
+        _         => null,
+    };
+
     // ---- ISubscribable (polling overlay via shared engine) ----
 
     public Task<ISubscriptionHandle> SubscribeAsync(
@@ -283,13 +765,123 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         while (!ct.IsCancellationRequested)
         {
             var success = false;
+            string? failureMessage = null;
             try
             {
                 var client = await EnsureConnectedAsync(state, ct).ConfigureAwait(false);
                 success = await client.ProbeAsync(ct).ConfigureAwait(false);
+                if (success)
+                {
+                    // Refresh figure-scaling cache once per session (issue #262). The
+                    // increment system rarely changes mid-session; re-reading every probe
+                    // tick would waste a wire call. Best-effort — null result leaves the
+                    // previous good map in place.
+                    if (state.FigureScaling is null)
+                    {
+                        var fig = await client.GetFigureScalingAsync(ct).ConfigureAwait(false);
+                        if (fig is not null) state.FigureScaling = fig;
+                    }
+
+                    // Refresh the cached ODBST status snapshot on every probe tick — this is
+                    // what the Status/ fixed-tree nodes serve from. Best-effort: a null result
+                    // (older IFocasClient impls without GetStatusAsync) just leaves the cache
+                    // unchanged so the previous good snapshot keeps serving until refreshed.
+                    var snapshot = await client.GetStatusAsync(ct).ConfigureAwait(false);
+                    if (snapshot is not null)
+                    {
+                        state.LastStatus = snapshot;
+                        state.LastStatusUtc = DateTime.UtcNow;
+                    }
+                    // Refresh the cached production snapshot too — same best-effort policy
+                    // as Status/: a null result leaves the previous good snapshot in place
+                    // so reads keep serving until the next successful refresh (issue #258).
+                    var production = await client.GetProductionAsync(ct).ConfigureAwait(false);
+                    if (production is not null)
+                    {
+                        state.LastProduction = production;
+                        state.LastProductionUtc = DateTime.UtcNow;
+                    }
+                    // Modal aux M/S/T/B + per-device operator overrides — same best-effort
+                    // policy as Status/ + Production/. Override snapshot is suppressed when
+                    // the device has no OverrideParameters configured (issue #259).
+                    var modal = await client.GetModalAsync(ct).ConfigureAwait(false);
+                    if (modal is not null)
+                    {
+                        state.LastModal = modal;
+                        state.LastModalUtc = DateTime.UtcNow;
+                    }
+                    if (state.Options.OverrideParameters is { } overrideParams)
+                    {
+                        var ov = await client.GetOverrideAsync(overrideParams, ct).ConfigureAwait(false);
+                        if (ov is not null)
+                        {
+                            state.LastOverride = ov;
+                            state.LastOverrideUtc = DateTime.UtcNow;
+                        }
+                    }
+                    // Tooling/CurrentTool + Offsets/{G54..G59}/{X|Y|Z} — same best-
+                    // effort policy as the other fixed-tree caches (issue #260). A
+                    // null result leaves the previous good snapshot in place so reads
+                    // keep serving until the next successful refresh.
+                    if (FocasCapabilityMatrix.SupportsTooling(state.Options.Series))
+                    {
+                        var tooling = await client.GetToolingAsync(ct).ConfigureAwait(false);
+                        if (tooling is not null)
+                        {
+                            state.LastTooling = tooling;
+                            state.LastToolingUtc = DateTime.UtcNow;
+                        }
+                    }
+                    if (FocasCapabilityMatrix.SupportsWorkOffsets(state.Options.Series))
+                    {
+                        var offsets = await client.GetWorkOffsetsAsync(ct).ConfigureAwait(false);
+                        if (offsets is not null)
+                        {
+                            state.LastWorkOffsets = offsets;
+                            state.LastWorkOffsetsUtc = DateTime.UtcNow;
+                        }
+                    }
+
+                    // Operator messages + currently-executing block — same best-effort
+                    // policy as the other fixed-tree caches (issue #261). A null result
+                    // leaves the previous good snapshot in place so reads keep serving
+                    // until the next successful refresh.
+                    var messages = await client.GetOperatorMessagesAsync(ct).ConfigureAwait(false);
+                    if (messages is not null)
+                    {
+                        state.LastMessages = messages;
+                        state.LastMessagesUtc = DateTime.UtcNow;
+                    }
+                    var block = await client.GetCurrentBlockAsync(ct).ConfigureAwait(false);
+                    if (block is not null)
+                    {
+                        state.LastCurrentBlock = block;
+                        state.LastCurrentBlockUtc = DateTime.UtcNow;
+                    }
+                }
             }
             catch (OperationCanceledException) when (ct.IsCancellationRequested) { break; }
-            catch { /* connect-failure path already disposed + cleared the client */ }
+            catch (Exception ex)
+            {
+                failureMessage = ex.Message;
+                /* connect-failure path already disposed + cleared the client */
+            }
+
+            // Diagnostics counters refreshed per probe tick (issue #262). Successful
+            // ticks bump ReadCount + LastSuccessfulRead; failed ticks bump
+            // ReadFailureCount + LastErrorMessage. The reconnect counter is bumped in
+            // EnsureConnectedAsync's connect path so a wedged probe doesn't double-count.
+            if (success)
+            {
+                Interlocked.Increment(ref state.ReadCount);
+                state.LastSuccessfulReadUtc = DateTime.UtcNow;
+            }
+            else
+            {
+                Interlocked.Increment(ref state.ReadFailureCount);
+                if (!string.IsNullOrEmpty(failureMessage))
+                    state.LastErrorMessage = failureMessage;
+            }
 
             TransitionDeviceState(state, success ? HostState.Running : HostState.Stopped);
 
@@ -298,6 +890,161 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         }
     }
 
+    private DataValueSnapshot ReadStatusField(string hostAddress, string field, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastStatus is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        var value = PickStatusField(snap, field);
+        if (value is null)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        return new DataValueSnapshot((short)value, FocasStatusMapper.Good,
+            device.LastStatusUtc, now);
+    }
+
+    private DataValueSnapshot ReadProductionField(string hostAddress, string field, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastProduction is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        var value = PickProductionField(snap, field);
+        if (value is null)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        return new DataValueSnapshot((int)value, FocasStatusMapper.Good,
+            device.LastProductionUtc, now);
+    }
+
+    private DataValueSnapshot ReadModalField(string hostAddress, string field, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastModal is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        var value = PickModalField(snap, field);
+        if (value is null)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        return new DataValueSnapshot((short)value, FocasStatusMapper.Good,
+            device.LastModalUtc, now);
+    }
+
+    private DataValueSnapshot ReadOverrideField(string hostAddress, string field, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastOverride is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        var value = PickOverrideField(snap, field);
+        if (value is null)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        return new DataValueSnapshot((short)value, FocasStatusMapper.Good,
+            device.LastOverrideUtc, now);
+    }
+
+    private DataValueSnapshot ReadToolingField(string hostAddress, string field, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastTooling is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        return field switch
+        {
+            "CurrentTool" => new DataValueSnapshot(snap.CurrentTool, FocasStatusMapper.Good,
+                device.LastToolingUtc, now),
+            _ => new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now),
+        };
+    }
+
+    private DataValueSnapshot ReadOffsetField(string hostAddress, string slot, string axis, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastWorkOffsets is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        var match = snap.Offsets.FirstOrDefault(o =>
+            string.Equals(o.Name, slot, StringComparison.OrdinalIgnoreCase));
+        if (match is null)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        var value = axis switch
+        {
+            "X" => (double?)match.X,
+            "Y" => match.Y,
+            "Z" => match.Z,
+            _   => null,
+        };
+        if (value is null)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        return new DataValueSnapshot(value.Value, FocasStatusMapper.Good,
+            device.LastWorkOffsetsUtc, now);
+    }
+
+    private DataValueSnapshot ReadMessagesLatestField(string hostAddress, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastMessages is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        // Snapshot is the trimmed list of active classes. "Latest" surfaces the last
+        // (most-recent) entry — the issue body permits this minimal "latest message"
+        // surface in lieu of a full ring buffer of all 4 classes.
+        var latest = snap.Messages.Count == 0
+            ? string.Empty
+            : snap.Messages[snap.Messages.Count - 1].Text;
+        return new DataValueSnapshot(latest, FocasStatusMapper.Good,
+            device.LastMessagesUtc, now);
+    }
+
+    private DataValueSnapshot ReadCurrentBlockField(string hostAddress, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        if (device.LastCurrentBlock is not { } snap)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+        return new DataValueSnapshot(snap.Text, FocasStatusMapper.Good,
+            device.LastCurrentBlockUtc, now);
+    }
+
+    private DataValueSnapshot ReadDiagnosticsField(string hostAddress, string field, DateTime now)
+    {
+        if (!_devices.TryGetValue(hostAddress, out var device))
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        // Diagnostics counters are always Good — they're driver-internal state, not wire
+        // reads. LastSuccessfulRead surfaces DateTime.MinValue before the first probe
+        // tick rather than null because OPC UA's DateTime variant has no "unset" sentinel
+        // a generic client can interpret (issue #262).
+        object? value = field switch
+        {
+            "ReadCount"          => Interlocked.Read(ref device.ReadCount),
+            "ReadFailureCount"   => Interlocked.Read(ref device.ReadFailureCount),
+            "ReconnectCount"     => Interlocked.Read(ref device.ReconnectCount),
+            "LastErrorMessage"   => device.LastErrorMessage ?? string.Empty,
+            "LastSuccessfulRead" => device.LastSuccessfulReadUtc,
+            _                    => null,
+        };
+        if (value is null)
+            return new DataValueSnapshot(null, FocasStatusMapper.BadNodeIdUnknown, null, now);
+        return new DataValueSnapshot(value, FocasStatusMapper.Good, now, now);
+    }
+
+    /// <summary>
+    ///     Apply <c>cnc_getfigure</c>-derived decimal scaling to a raw position value.
+    ///     Returns <paramref name="raw"/> divided by <c>10^decimalPlaces</c> when the
+    ///     device has a cached scaling entry for <paramref name="axisName"/> AND
+    ///     <see cref="FocasFixedTreeOptions.ApplyFigureScaling"/> is on; otherwise
+    ///     returns the raw value as a <c>double</c>. Forward-looking — surfaced for
+    ///     future PRs that wire up <c>Axes/{name}/AbsolutePosition</c> etc. so they
+    ///     don't need to re-derive the policy (issue #262).
+    /// </summary>
+    internal double ApplyFigureScaling(string hostAddress, string axisName, long raw)
+    {
+        if (!_options.FixedTree.ApplyFigureScaling) return raw;
+        if (!_devices.TryGetValue(hostAddress, out var device)) return raw;
+        if (device.FigureScaling is not { } map) return raw;
+        if (!map.TryGetValue(axisName, out var dec) || dec <= 0) return raw;
+        return raw / Math.Pow(10.0, dec);
+    }
+
     private void TransitionDeviceState(DeviceState state, HostState newState)
     {
         HostState old;
@@ -324,6 +1071,10 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
     private async Task<IFocasClient> EnsureConnectedAsync(DeviceState device, CancellationToken ct)
     {
         if (device.Client is { IsConnected: true } c) return c;
+        // Reconnect counter bumps before the connect call — a successful first connect
+        // counts as one "establishment" so the field is non-zero from session start
+        // (issue #262, mirrors the convention from the AbCip / TwinCAT diagnostics).
+        Interlocked.Increment(ref device.ReconnectCount);
         device.Client ??= _clientFactory.Create();
         try
         {
@@ -352,6 +1103,90 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         public DateTime HostStateChangedUtc { get; set; } = DateTime.UtcNow;
         public CancellationTokenSource? ProbeCts { get; set; }
 
+        /// <summary>
+        ///     Cached <c>cnc_rdcncstat</c> snapshot, refreshed on every probe tick. Reads of
+        ///     the per-device <c>Status/&lt;field&gt;</c> fixed-tree nodes serve from this cache
+        ///     so they don't pile extra wire traffic on top of the user-driven tag reads.
+        /// </summary>
+        public FocasStatusInfo? LastStatus { get; set; }
+        public DateTime LastStatusUtc { get; set; }
+
+        /// <summary>
+        ///     Cached <c>cnc_rdparam(6711/6712/6713)</c> + cycle-time snapshot, refreshed on
+        ///     every probe tick. Reads of the per-device <c>Production/&lt;field&gt;</c>
+        ///     fixed-tree nodes serve from this cache so they don't pile extra wire traffic
+        ///     on top of the user-driven tag reads (issue #258).
+        /// </summary>
+        public FocasProductionInfo? LastProduction { get; set; }
+        public DateTime LastProductionUtc { get; set; }
+
+        /// <summary>
+        ///     Cached <c>cnc_modal</c> M/S/T/B snapshot, refreshed on every probe tick.
+        ///     Reads of the per-device <c>Modal/&lt;field&gt;</c> nodes serve from this cache
+        ///     so they don't pile extra wire traffic on top of user-driven reads (issue #259).
+        /// </summary>
+        public FocasModalInfo? LastModal { get; set; }
+        public DateTime LastModalUtc { get; set; }
+
+        /// <summary>
+        ///     Cached <c>cnc_rdparam</c> override snapshot, refreshed on every probe tick.
+        ///     Suppressed when the device's <see cref="FocasDeviceOptions.OverrideParameters"/>
+        ///     is null (no <c>Override/</c> nodes are exposed in that case — issue #259).
+        /// </summary>
+        public FocasOverrideInfo? LastOverride { get; set; }
+        public DateTime LastOverrideUtc { get; set; }
+
+        /// <summary>
+        ///     Cached <c>cnc_rdtnum</c> snapshot — current tool number — refreshed on
+        ///     every probe tick. Reads of <c>Tooling/CurrentTool</c> serve from this
+        ///     cache so they don't pile extra wire traffic on top of user-driven
+        ///     reads (issue #260).
+        /// </summary>
+        public FocasToolingInfo? LastTooling { get; set; }
+        public DateTime LastToolingUtc { get; set; }
+
+        /// <summary>
+        ///     Cached <c>cnc_rdzofs(1..6)</c> snapshot — G54..G59 work-coordinate
+        ///     offsets — refreshed on every probe tick. Reads of
+        ///     <c>Offsets/{slot}/{X|Y|Z}</c> serve from this cache (issue #260).
+        /// </summary>
+        public FocasWorkOffsetsInfo? LastWorkOffsets { get; set; }
+        public DateTime LastWorkOffsetsUtc { get; set; }
+
+        /// <summary>
+        ///     Cached <c>cnc_rdopmsg3</c> snapshot — active operator messages across
+        ///     the four FANUC classes — refreshed on every probe tick. Reads of
+        ///     <c>Messages/External/Latest</c> serve from this cache (issue #261).
+        /// </summary>
+        public FocasOperatorMessagesInfo? LastMessages { get; set; }
+        public DateTime LastMessagesUtc { get; set; }
+
+        /// <summary>
+        ///     Cached <c>cnc_rdactpt</c> snapshot — currently-executing block text —
+        ///     refreshed on every probe tick. Reads of <c>Program/CurrentBlock</c>
+        ///     serve from this cache (issue #261).
+        /// </summary>
+        public FocasCurrentBlockInfo? LastCurrentBlock { get; set; }
+        public DateTime LastCurrentBlockUtc { get; set; }
+
+        /// <summary>
+        ///     Cached per-axis decimal-place counts from <c>cnc_getfigure</c> (issue #262).
+        ///     Populated once per session (the increment system rarely changes mid-run);
+        ///     served by <see cref="FocasDriver.ApplyFigureScaling"/> when a future PR
+        ///     surfaces position values that need scaling. Keys are axis names (or
+        ///     fallback <c>"axis{n}"</c> until <c>cnc_rdaxisname</c> integration lands).
+        /// </summary>
+        public IReadOnlyDictionary<string, int>? FigureScaling { get; set; }
+
+        // Diagnostics counters per device — surfaced under Diagnostics/ subtree (issue
+        // #262). Public fields rather than properties so Interlocked.Increment can
+        // operate on them directly. Long-typed for the OPC UA Int64 surface.
+        public long ReadCount;
+        public long ReadFailureCount;
+        public long ReconnectCount;
+        public string? LastErrorMessage;
+        public DateTime LastSuccessfulReadUtc;
+
         public void DisposeClient()
         {
             Client?.Dispose();

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriverFactoryExtensions.cs

@@ -0,0 +1,198 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+using ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Ipc;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS;
+
+/// <summary>
+///     Static factory registration helper for <see cref="FocasDriver"/>. Server's Program.cs
+///     calls <see cref="Register"/> once at startup; the bootstrapper (task #248) then
+///     materialises FOCAS DriverInstance rows from the central config DB into live driver
+///     instances. Mirrors <c>GalaxyProxyDriverFactoryExtensions</c>; no dependency on
+///     Microsoft.Extensions.DependencyInjection so the driver project stays DI-free.
+/// </summary>
+/// <remarks>
+///     The DriverConfig JSON selects the <see cref="IFocasClientFactory"/> backend:
+///     <list type="bullet">
+///         <item><c>"Backend": "ipc"</c> (default) — wires <see cref="IpcFocasClientFactory"/>
+///         against a named-pipe <see cref="FocasIpcClient"/> talking to a separate
+///         <c>Driver.FOCAS.Host</c> process (Tier-C isolation). Requires <c>PipeName</c> +
+///         <c>SharedSecret</c>.</item>
+///         <item><c>"Backend": "fwlib"</c> — direct in-process Fwlib32.dll P/Invoke via
+///         <see cref="FwlibFocasClientFactory"/>. Use only when the main server is licensed
+///         for FOCAS and you accept the native-crash blast-radius trade-off.</item>
+///         <item><c>"Backend": "unimplemented"</c> — returns the no-op factory; useful for
+///         scaffolding DriverInstance rows before the Host is deployed so the server boots.</item>
+///     </list>
+///     Devices / Tags / Probe / Timeout / Series come from the same JSON and feed directly
+///     into <see cref="FocasDriverOptions"/>.
+/// </remarks>
+public static class FocasDriverFactoryExtensions
+{
+    public const string DriverTypeName = "FOCAS";
+
+    /// <summary>
+    ///     Register the FOCAS driver factory in the supplied <see cref="DriverFactoryRegistry"/>.
+    ///     Throws if 'FOCAS' is already registered — single-instance per process.
+    /// </summary>
+    public static void Register(DriverFactoryRegistry registry)
+    {
+        ArgumentNullException.ThrowIfNull(registry);
+        registry.Register(DriverTypeName, CreateInstance);
+    }
+
+    internal static FocasDriver CreateInstance(string driverInstanceId, string driverConfigJson)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);
+
+        var dto = JsonSerializer.Deserialize<FocasDriverConfigDto>(driverConfigJson, JsonOptions)
+            ?? throw new InvalidOperationException(
+                $"FOCAS driver config for '{driverInstanceId}' deserialised to null");
+
+        // Eager-validate top-level Series so a typo fails fast regardless of whether Devices
+        // are populated yet (common during rollout when rows are seeded before CNCs arrive).
+        _ = ParseSeries(dto.Series);
+
+        var options = new FocasDriverOptions
+        {
+            Devices = dto.Devices is { Count: > 0 }
+                ? [.. dto.Devices.Select(d => new FocasDeviceOptions(
+                    HostAddress: d.HostAddress ?? throw new InvalidOperationException(
+                        $"FOCAS config for '{driverInstanceId}' has a device missing HostAddress"),
+                    DeviceName: d.DeviceName,
+                    Series: ParseSeries(d.Series ?? dto.Series)))]
+                : [],
+            Tags = dto.Tags is { Count: > 0 }
+                ? [.. dto.Tags.Select(t => new FocasTagDefinition(
+                    Name: t.Name ?? throw new InvalidOperationException(
+                        $"FOCAS config for '{driverInstanceId}' has a tag missing Name"),
+                    DeviceHostAddress: t.DeviceHostAddress ?? throw new InvalidOperationException(
+                        $"FOCAS tag '{t.Name}' in '{driverInstanceId}' missing DeviceHostAddress"),
+                    Address: t.Address ?? throw new InvalidOperationException(
+                        $"FOCAS tag '{t.Name}' in '{driverInstanceId}' missing Address"),
+                    DataType: ParseDataType(t.DataType, t.Name!, driverInstanceId),
+                    Writable: t.Writable ?? true,
+                    WriteIdempotent: t.WriteIdempotent ?? false))]
+                : [],
+            Probe = new FocasProbeOptions
+            {
+                Enabled = dto.Probe?.Enabled ?? true,
+                Interval = TimeSpan.FromMilliseconds(dto.Probe?.IntervalMs ?? 5_000),
+                Timeout = TimeSpan.FromMilliseconds(dto.Probe?.TimeoutMs ?? 2_000),
+            },
+            Timeout = TimeSpan.FromMilliseconds(dto.TimeoutMs ?? 2_000),
+        };
+
+        var clientFactory = BuildClientFactory(dto, driverInstanceId);
+        return new FocasDriver(options, driverInstanceId, clientFactory);
+    }
+
+    internal static IFocasClientFactory BuildClientFactory(
+        FocasDriverConfigDto dto, string driverInstanceId)
+    {
+        var backend = (dto.Backend ?? "ipc").Trim().ToLowerInvariant();
+        return backend switch
+        {
+            "ipc" => BuildIpcFactory(dto, driverInstanceId),
+            "fwlib" or "fwlib32" => new FwlibFocasClientFactory(),
+            "unimplemented" or "none" or "stub" => new UnimplementedFocasClientFactory(),
+            _ => throw new InvalidOperationException(
+                $"FOCAS driver config for '{driverInstanceId}' has unknown Backend '{dto.Backend}'. " +
+                "Expected one of: ipc, fwlib, unimplemented."),
+        };
+    }
+
+    private static IpcFocasClientFactory BuildIpcFactory(
+        FocasDriverConfigDto dto, string driverInstanceId)
+    {
+        var pipeName = dto.PipeName
+            ?? throw new InvalidOperationException(
+                $"FOCAS driver config for '{driverInstanceId}' missing required PipeName (Tier-C ipc backend)");
+        var sharedSecret = dto.SharedSecret
+            ?? throw new InvalidOperationException(
+                $"FOCAS driver config for '{driverInstanceId}' missing required SharedSecret (Tier-C ipc backend)");
+        var connectTimeout = TimeSpan.FromMilliseconds(dto.ConnectTimeoutMs ?? 10_000);
+        var series = ParseSeries(dto.Series);
+
+        // Each IFocasClientFactory.Create() call opens a fresh pipe to the Host — matches the
+        // driver's one-client-per-device invariant. FocasIpcClient.ConnectAsync is awaited
+        // synchronously via GetAwaiter().GetResult() because IFocasClientFactory.Create is a
+        // sync contract; the blocking call lands inside FocasDriver.EnsureConnectedAsync,
+        // which immediately awaits IFocasClient.ConnectAsync afterwards so the perceived
+        // latency is identical to a fully-async factory.
+        return new IpcFocasClientFactory(
+            ipcClientFactory: () => FocasIpcClient.ConnectAsync(
+                pipeName: pipeName,
+                sharedSecret: sharedSecret,
+                connectTimeout: connectTimeout,
+                ct: CancellationToken.None).GetAwaiter().GetResult(),
+            series: series);
+    }
+
+    private static FocasCncSeries ParseSeries(string? raw)
+    {
+        if (string.IsNullOrWhiteSpace(raw)) return FocasCncSeries.Unknown;
+        return Enum.TryParse<FocasCncSeries>(raw, ignoreCase: true, out var s)
+            ? s
+            : throw new InvalidOperationException(
+                $"FOCAS Series '{raw}' is not one of {string.Join(", ", Enum.GetNames<FocasCncSeries>())}");
+    }
+
+    private static FocasDataType ParseDataType(string? raw, string tagName, string driverInstanceId)
+    {
+        if (string.IsNullOrWhiteSpace(raw))
+            throw new InvalidOperationException(
+                $"FOCAS tag '{tagName}' in '{driverInstanceId}' missing DataType");
+        return Enum.TryParse<FocasDataType>(raw, ignoreCase: true, out var dt)
+            ? dt
+            : throw new InvalidOperationException(
+                $"FOCAS tag '{tagName}' has unknown DataType '{raw}'. " +
+                $"Expected one of {string.Join(", ", Enum.GetNames<FocasDataType>())}");
+    }
+
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        ReadCommentHandling = JsonCommentHandling.Skip,
+        AllowTrailingCommas = true,
+    };
+
+    internal sealed class FocasDriverConfigDto
+    {
+        public string? Backend { get; init; }
+        public string? PipeName { get; init; }
+        public string? SharedSecret { get; init; }
+        public int? ConnectTimeoutMs { get; init; }
+        public string? Series { get; init; }
+        public int? TimeoutMs { get; init; }
+        public List<FocasDeviceDto>? Devices { get; init; }
+        public List<FocasTagDto>? Tags { get; init; }
+        public FocasProbeDto? Probe { get; init; }
+    }
+
+    internal sealed class FocasDeviceDto
+    {
+        public string? HostAddress { get; init; }
+        public string? DeviceName { get; init; }
+        public string? Series { get; init; }
+    }
+
+    internal sealed class FocasTagDto
+    {
+        public string? Name { get; init; }
+        public string? DeviceHostAddress { get; init; }
+        public string? Address { get; init; }
+        public string? DataType { get; init; }
+        public bool? Writable { get; init; }
+        public bool? WriteIdempotent { get; init; }
+    }
+
+    internal sealed class FocasProbeDto
+    {
+        public bool? Enabled { get; init; }
+        public int? IntervalMs { get; init; }
+        public int? TimeoutMs { get; init; }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriverOptions.cs

@@ -11,17 +11,49 @@ public sealed class FocasDriverOptions
     public IReadOnlyList<FocasTagDefinition> Tags { get; init; } = [];
     public FocasProbeOptions Probe { get; init; } = new();
     public TimeSpan Timeout { get; init; } = TimeSpan.FromSeconds(2);
+
+    /// <summary>
+    ///     Fixed-tree behaviour knobs (issue #262, plan PR F1-f). Carries the
+    ///     <c>ApplyFigureScaling</c> toggle that gates the <c>cnc_getfigure</c>
+    ///     decimal-place division applied to position values before publishing.
+    /// </summary>
+    public FocasFixedTreeOptions FixedTree { get; init; } = new();
+}
+
+/// <summary>
+///     Per-driver fixed-tree options. New installs default <see cref="ApplyFigureScaling"/>
+///     to <c>true</c> so position values surface in user units (mm / inch). Existing
+///     deployments that already published raw scaled integers can flip this to <c>false</c>
+///     for migration parity — the operator-facing concern is that switching the flag
+///     mid-deployment changes the values clients see, so the migration path is
+///     documentation-only (issue #262).
+/// </summary>
+public sealed record FocasFixedTreeOptions
+{
+    /// <summary>
+    ///     When <c>true</c> (default), position values from <c>cnc_absolute</c> /
+    ///     <c>cnc_machine</c> / <c>cnc_relative</c> / <c>cnc_distance</c> /
+    ///     <c>cnc_actf</c> are divided by <c>10^decimalPlaces</c> per axis using the
+    ///     <c>cnc_getfigure</c> snapshot cached at probe time. When <c>false</c>, the
+    ///     raw integer values are published unchanged — used for migrations from
+    ///     older drivers that didn't apply the scaling.
+    /// </summary>
+    public bool ApplyFigureScaling { get; init; } = true;
 }
 
 /// <summary>
 ///     One CNC the driver talks to. <paramref name="Series"/> enables per-series
 ///     address validation at <see cref="FocasDriver.InitializeAsync"/>; leave as
 ///     <see cref="FocasCncSeries.Unknown"/> to skip validation (legacy behaviour).
+///     <paramref name="OverrideParameters"/> declares the four MTB-specific override
+///     <c>cnc_rdparam</c> numbers surfaced under <c>Override/</c>; pass <c>null</c> to
+///     suppress the entire <c>Override/</c> subfolder for that device (issue #259).
 /// </summary>
 public sealed record FocasDeviceOptions(
     string HostAddress,
     string? DeviceName = null,
-    FocasCncSeries Series = FocasCncSeries.Unknown);
+    FocasCncSeries Series = FocasCncSeries.Unknown,
+    FocasOverrideParameters? OverrideParameters = null);
 
 /// <summary>
 ///     One FOCAS-backed OPC UA variable. <paramref name="Address"/> is the canonical FOCAS