docs: close the plan-bookkeeping drift and state the tier truth (§8.5, §8.6, #522 )

Bookkeeping: 13 .tasks.json files closed — the 8 the audit named, plus mesh-phase4 (Task 9 landed 3a590a0c), the 4th stillpending phase file, and historian-tcp-transport closed as OBSOLETE (it targets the retired Wonderware sidecar; there is no Wonderware backend in the tree). Each carries a closureNote naming the evidence rather than just a status flip. 11 archreview live gates written back from STATUS.md, which had recorded them passed since 2026-07-13/15 without ever updating the task files: R2-01 #11, R2-02 #15/#18, R2-05 T15, R2-06 T12, R2-07 T5/T6/T12/T14, R2-11 T22/T24. R2-03 and R2-10 were deliberately NOT closed. STATUS.md's headline says "every Round-2 live gate is now GREEN", but its own per-item detail says R2-03 is "live-blocked on this data-less rig" and R2-10 verified the pipeline with "breaker-OPEN state not forced". Both now carry an openNote recording the actual blocker. The point of the sweep: ~140 phantom pending tasks are gone, so the genuinely unexecuted 19-task AdminUI follow-ups plan is now the largest open item in docs/plans/ instead of being buried under work that shipped months ago. Tier truth: docs/v2/driver-stability.md now states that its tier table is aspirational — every driver runs Tier A because no factory passes a tier, so MemoryRecycle and ScheduledRecycleScheduler have never engaged, and the config parser validates a RecycleIntervalSeconds that does nothing. It also corrects a staleness the audit missed: the separate-Windows-service hosting it describes for Tier C no longer exists (Galaxy moved to the mxaccessgw sidecar in PR 7.2, FOCAS went in-process with its managed wire client). docs/drivers/README.md already said Tier A for both, so the two no longer contradict. No runtime change — enabling recycle on two live drivers wants its own live gate, not a docs-pass side effect. Keep-or-delete tracked as Gitea #522.
fix(adminui): guard the driver dispatch maps and close G-1..G-6 (§8.4)
2026-07-27 19:54:41 -04:00 · 2026-07-27 19:52:02 -04:00 · 2026-07-27 19:32:46 -04:00 · 2026-07-27 18:57:09 -04:00 · 2026-07-27 18:47:34 -04:00 · 2026-07-27 18:36:48 -04:00
392 changed files with 69104 additions and 5285 deletions
@@ -58,3 +58,6 @@ lib/
 # Session working notes — never stage (pending.md's own hard rule; R2-12/U-4)
 /pending.md
 /current.md
+
+# Subagent-driven-development git worktrees
+.worktrees/
@@ -55,6 +55,28 @@ about OtOpcUa changes here — remote/push status, the driver set, the Galaxy da
 shared-lib consumption, or per-project commands — update the **OtOpcUa entry in
 `../scadaproj/CLAUDE.md`** in the same change so the index never drifts from this repo.

+**The index edit belongs on `scadaproj`'s `main`, and must be pushed.** `scadaproj` is a
+separate repo with its own checkout, so committing there inherits whatever branch it
+happens to be on — which is usually *not* `main` and is often an unrelated feature branch
+with no upstream. That silently drifts the index for as long as that branch stays
+unmerged, which is the exact failure the rule above exists to prevent. Do this explicitly:
+
+```bash
+cd ~/Desktop/scadaproj
+git rev-parse --abbrev-ref HEAD            # note it, to restore afterwards
+git stash list                             # never commit onto a dirty unrelated branch
+git checkout main && git pull
+#   …edit the OtOpcUa entry in CLAUDE.md…
+git commit -am "docs(index): <what changed about OtOpcUa>"
+git push origin main
+git checkout -                             # restore the original branch
+```
+
+Observed 2026-07-27: the `Sql` poll driver's index entry had sat unpushed on an unrelated
+feature branch since 2026-07-24 because it was committed onto the current checkout, so the
+index disagreed with reality for three days despite this rule. If you find index commits
+stranded on a feature branch, cherry-pick them onto `main` rather than merging that branch.
+
 ## Architecture Overview

 ### Data Flow
@@ -131,7 +153,50 @@ Galaxy `mx_data_type` values map to OPC UA types (Boolean, Int32, Float, Double,

 ### Change Detection

-`DeployWatcher` (`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Browse/DeployWatcher.cs`) polls the gateway's deploy-event signal and raises `IRediscoverable.OnRediscoveryNeeded` when the Galaxy redeploys. The server's `DriverHost` consumes the signal and rebuilds the address space.
+`DeployWatcher` (`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Browse/DeployWatcher.cs`) polls the gateway's deploy-event signal and raises `IRediscoverable.OnRediscoveryNeeded` when the Galaxy redeploys.
+
+**The signal is consumed as an operator prompt, not as an address-space rebuild** (§8.2, 2026-07-27).
+`DriverInstanceActor` subscribes in `PreStart` and unsubscribes in `PostStop` — the detach is
+load-bearing, because the `IDriver` instance outlives the actor when the host respawns a child around
+the same driver object. A raise is recorded and rides the driver-health snapshot
+(`DriverHealthChanged.RediscoveryNeededUtc` / `.RediscoveryReason`) to the AdminUI `/hosts` page as a
+**"re-browse" chip**.
+
+⚠️ **It is advisory: a Galaxy redeploy still does NOT change the served address space.** v3 authors raw
+tags explicitly through the `/raw` browse-commit flow, so an operator must re-browse the device and
+commit. Injecting nodes at runtime would materialise nodes nobody approved and no deployment artifact
+records.
+
+Two gotchas if you touch this:
+
+- `PublishHealthSnapshot` dedups on a health fingerprint. The rediscovery timestamp **must** stay in
+  that tuple, or a raise on an otherwise-unchanged Healthy driver is swallowed and never reaches the
+  operator. Pinned by `DriverInstanceActorRediscoverySignalTests`.
+- The shared test `StubDriver.GetHealth()` returns `DateTime.UtcNow`, so its fingerprint differs on
+  every call and the dedup never engages — a test built on it passes vacuously. The rediscovery tests
+  use a stub with stable health for exactly this reason.
+
+**#507 is closed as superseded, and the injection path is deleted.** Its retained code read
+`EquipmentNode.DriverInstanceId` and `EquipmentTags`, both *structurally empty* in v3
+(`AddressSpaceComposer.cs`, `DeploymentArtifact.cs`), so removing the guard would have changed a log
+line and injected nothing. Gone with it: `HandleDiscoveredNodes`, `PartitionDiscoveredByDeviceHost`,
+`ApplyDiscoveredPlansForDriver`, the redeploy re-inject tail, `DiscoveredNodeMapper`,
+`AddressSpaceApplier.MaterialiseDiscoveredNodes`, the connect-time discovery loop
+(`StartDiscovery`/`RediscoverTick`/`DiscoveredNodesReady`/`TriggerRediscovery`), and the 18
+`DiscoveryInjectionDormantV3` tests — v2 characterization tests asserting an equipment-rooted graft
+(`EquipmentRootNodeId == "EQ-1"`) that v3 cannot produce. `ITagDiscovery` itself stays: the `/raw`
+browse picker drives it through `Commons/Browsing/DiscoveryDriverBrowser`, which never went through
+the actor.
+
+**Deliberately NOT built: a discovered-vs-authored drift detector.** Modbus, S7, MQTT, AbLegacy and Sql
+all *echo authored config* from `DiscoverAsync` rather than browsing the device, so such a diff is
+permanently empty for them — another plausible-looking inert seam. `IRediscoverable` is the
+trustworthy signal because the driver asserts it deliberately.
+
+⚠️ **`IHostConnectivityProbe` is still unconsumed.** `GetHostStatuses()` has no production call site and
+nothing ever writes a `DriverHostStatus` row (the table was re-created in the v3 initial migration, so
+confirm intent before deleting). The separable `OnHostStatusChanged` event is the useful half. Tracked
+as Gitea **#521**.

 ## mxaccessgw

@@ -168,13 +233,29 @@ central SQL Server.
 > recipes (S7 blackhole, GLAuth outage, HistorianGateway LiveIntegration), the integration-test
 > harness, the docker-dev rig, and the deploy setup. Start there; the sections below + `docs/v2/dev-environment.md` carry the detail.

-> **Migrated 2026-04-28**: Docker config + host moved off this dev VM (DESKTOP-6JL3KKO) onto the shared Linux Docker host (`DOCKER`, 10.100.0.35) so the dev VM could shed WSL2/Hyper-V and have its GPU re-attached via ESXi passthrough. Docker Desktop is no longer installed here. All checked-in `appsettings.json` defaults, fixture-class default endpoints, and `e2e-config.sample.json` were rewritten to target `10.100.0.35`. The driver fixture compose files under `tests/.../Docker/docker-compose.yml` now carry a `project: lmxopcua` label on every service. See `docs/v2/dev-environment.md` for the full rewrite (header dated 2026-04-28).
+> **Migrated 2026-04-28**: Docker config + host moved off this dev VM (DESKTOP-6JL3KKO) onto the shared Linux Docker host (`DOCKER`, 10.100.0.35) so the dev VM could shed WSL2/Hyper-V and have its GPU re-attached via ESXi passthrough. Docker Desktop is no longer installed here. All checked-in `appsettings.json` defaults, fixture-class default endpoints, and `e2e-config.sample.json` were rewritten to target `10.100.0.35`. See `docs/v2/dev-environment.md` for the full rewrite (header dated 2026-04-28).
+
+> ⚠️ **The `project: lmxopcua` label is aspirational, not universal.** This note used to claim every fixture compose file carries it. As of 2026-07-24 only the **MQTT** fixture actually does — `grep -rn "labels:" tests --include=*.yml` matches `Driver.Mqtt.IntegrationTests/Docker/docker-compose.yml` and nothing else. So `docker ps --filter label=project=lmxopcua` returns the MQTT fixture alone, not the fleet. Add the label when you touch an older fixture; until then enumerate by container name.

 Docker workloads run on a shared Linux host at **`10.100.0.35`** — not on this VM. Stacks live at `/opt/otopcua-<driver>/` on the host and carry the `project=lmxopcua` label so they're discoverable via `docker ps --filter label=project=lmxopcua`.

-**`docker -H ssh://...` does NOT work from this VM.** Windows OpenSSH ↔ docker.exe stdio bridging hangs (`docker system dial-stdio` runs server-side but no API data flows). Use the helper below — it SSHes into the docker host and runs `docker compose` server-side.
+**`docker -H ssh://...` does NOT work from the Windows VM.** Windows OpenSSH ↔ docker.exe stdio bridging hangs (`docker system dial-stdio` runs server-side but no API data flows). Use the helper below — it SSHes into the docker host and runs `docker compose` server-side.

-**Use `lmxopcua-fix.ps1` (in `~/bin`) to control fixtures from this VM:**
+> **On macOS there is no `lmxopcua-fix` — drive the host over SSH directly.** The helper is a Windows-VM
+> script; `~/bin` is empty on the Mac and the commands below will not resolve. Use passwordless SSH
+> (and `rsync` in place of `sync`), which is what `infra/README.md` §1 documents as the Mac path:
+>
+> ```bash
+> ssh dohertj2@10.100.0.35 'docker ps --format "{{.Names}}\t{{.Status}}"'
+> ssh dohertj2@10.100.0.35 'cd /opt/otopcua-mqtt && docker compose up -d'
+> rsync -av tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.IntegrationTests/Docker/ \
+>     dohertj2@10.100.0.35:/opt/otopcua-mqtt/          # the `sync` step, by hand
+> ```
+>
+> A local container runtime *does* exist on the Mac (OrbStack), so the `docker-dev/` rig itself runs
+> locally there — it is only the shared **fixtures** that live on `10.100.0.35`.
+
+**Use `lmxopcua-fix.ps1` (in `~/bin`) to control fixtures from the Windows VM:**

 ```powershell
 lmxopcua-fix ls                            # list all lmxopcua-tagged containers on the host
@@ -195,6 +276,16 @@ lmxopcua-fix sync modbus                   # rsync this repo's tests/.../Docker/
 - AB CIP: `10.100.0.35:44818` (`AB_SERVER_ENDPOINT`)
 - S7: `10.100.0.35:1102` (`S7_SIM_ENDPOINT`)
 - OPC UA reference (opc-plc): `opc.tcp://10.100.0.35:50000` (`OPCUA_SIM_ENDPOINT`)
+- MQTT (Mosquitto, **auth on both listeners — no anonymous fallback**): `10.100.0.35:8883` TLS+auth
+  (`MQTT_FIXTURE_ENDPOINT`) · `10.100.0.35:1883` plaintext-but-authenticated (`MQTT_FIXTURE_PLAIN_ENDPOINT`).
+  Also needs `MQTT_FIXTURE_USERNAME` / `MQTT_FIXTURE_PASSWORD`, and `MQTT_FIXTURE_CA_CERT` to pin the
+  fixture CA (`scp dohertj2@10.100.0.35:/opt/otopcua-mqtt/secrets/ca.crt`). A co-running publisher loops
+  JSON under `otopcua/fixture/…`.
+- MQTT **Sparkplug B**: the same broker, plus the `sparkplug` compose profile's `otopcua-sparkplug-sim`
+  (project-owned C# edge-node simulator) — group **`OtOpcUaSim`**, edge nodes **`EdgeA`**/**`EdgeB`**,
+  `EdgeA` device **`Filler1`**, ~2 s cadence. It subscribes to `spBv1.0/OtOpcUaSim/NCMD/{node}` and
+  re-births on request. **Births are never retained**, so `docker restart otopcua-sparkplug-sim` is how
+  you force a fresh one while a browse window is open.

 Override any endpoint via the env var to point at a real PLC. The local OtOpcUa server runs on this VM at `opc.tcp://localhost:4840` — **that's not on the docker host**.

@@ -221,7 +312,7 @@ The server supports non-transparent warm/hot redundancy via the `Redundancy` sec

 **Two corrections landed 2026-07-21 — both were total-outage or wrong-node defects, and both are worth knowing before touching this area.**

- **Downing is `auto-down`, not `keep-oldest`.** `Cluster:SplitBrainResolverStrategy` (default `auto-down`) selects the provider via `ServiceCollectionExtensions.BuildDowningHocon`; an unknown value fails host start. A two-node pair running the previous `keep-oldest` + `down-if-alone` **could not survive a crash of the oldest node**: Akka's `KeepOldest.OldestDecision` only lets `down-if-alone` rescue a side holding ≥ 2 members, so the 1-vs-1 survivor downs *itself* and exits. `down-if-alone` is a 3+-node feature. The accepted trade for `auto-down` is dual-active during a genuine network partition. **Its live gate is still open** — the pathology only appears 1-vs-1 and docker-dev is a single six-node mesh, so the crash-the-oldest drill is deferred to the per-cluster mesh work.
+- **Downing is `auto-down`, not `keep-oldest`.** `Cluster:SplitBrainResolverStrategy` (default `auto-down`) selects the provider via `ServiceCollectionExtensions.BuildDowningHocon`; an unknown value fails host start. A two-node pair running the previous `keep-oldest` + `down-if-alone` **could not survive a crash of the oldest node**: Akka's `KeepOldest.OldestDecision` only lets `down-if-alone` rescue a side holding ≥ 2 members, so the 1-vs-1 survivor downs *itself* and exits. `down-if-alone` is a 3+-node feature. The accepted trade for `auto-down` is dual-active during a genuine network partition. **Its live gate is CLOSED** — Phase 7 drill D4 (2026-07-24) ran the 1-vs-1 crash-the-oldest survival drill on the three-mesh docker-dev rig and every survivor stayed Up, never self-downing (`c50ebcf7`; `docs/plans/2026-07-24-mesh-phase7-failover-drills.md`).
 - **The Primary is the oldest Up `driver` member, not the role leader.** `RedundancyStateActor` previously used `ClusterState.RoleLeader("driver")` (lowest *address*), while `ClusterSingletonManager` places singletons on the *oldest*. They agree only on a freshly-formed cluster and diverge after any restart, so the Primary-gated data plane (writes, alarm acks, alerts emit, alarm-history drain) could enable on a node not hosting the singletons. `NodeRedundancyState.IsRoleLeaderForDriver` was renamed **`IsDriverPrimary`**.

 **A third bootstrap gap closed 2026-07-22 — downing was never the whole story, and the fix changed twice.** Even under `auto-down`, a node cold-starting while its peer was dead **never came Up**: Akka runs `FirstSeedNodeProcess` — the only bootstrap path that can form a *new* cluster when no peer answers `InitJoin` — exclusively when `seed-nodes[0]` is the node’s own address; every other node runs `JoinSeedNodeProcess` and retries `InitJoin` forever. **`Cluster:SeedNodes` is therefore ORDERED: every node that is one of its own seeds lists ITSELF first, partner second** (docker-dev `central-2` was swapped; site nodes list only `central-1` and are legitimately not seeds). `AkkaClusterOptionsValidator` (`AddValidatedOptions`/`ValidateOnStart` in `AddOtOpcUaCluster`) enforces it at boot — **conditionally** (self must be entry 0 only *if* self is in the list, or every site node would refuse to start), matching on `PublicHostname`+`Port`, never the `0.0.0.0` bind address. The earlier fix — a `Cluster:SelfFormAfter` timer calling `Cluster.Join(SelfAddress)` — is **deleted**: it sat outside Akka’s join handshake, so it could not tell "no seed answered" from "a seed answered and the join is in flight", and it islanded a manually-failed-over node live before a TCP reachability guard patched that one shape. Pinned by `SelfFirstSeedBootstrapTests` (real in-process clusters, incl. a falsifiability control proving peer-first ordering never forms) + `AkkaClusterOptionsValidatorTests`. See `docs/Redundancy.md` §"Bootstrap: self-first seed ordering".
@@ -332,7 +423,7 @@ Flip only the site nodes with `OTOPCUA_CONFIG_MODE=FetchAndCache` at `docker com

 ## Live telemetry transport (`Telemetry` / `TelemetryDial`)

-Per-cluster mesh **Phase 5** (code-complete on `feat/mesh-phase5`, live gate pending) added a second
+Per-cluster mesh **Phase 5** (merged `35552a96`; live gate PASSED `f134935f`) added a second
 transport for the four live-observability channels the AdminUI's `/alerts`, `/script-log`, and
 `/hosts` panels feed on, selected by `Telemetry:Mode` (node/serve side) and `TelemetryDial:Mode`
 (central/dial side): `Dps` — the four existing DPS SignalR bridges, **the default**, today's
@@ -442,7 +533,8 @@ unaffected (it keeps ConfigDb via its admin role). Consequences:
 - **Scripted-alarm Part 9 condition state moved to LocalDb.** `LocalDbAlarmConditionStateStore`
  (replicated `alarm_condition_state` table, pair-local like the Phase-2 alarm S&F buffer) replaces
  `EfAlarmConditionStateStore` on every driver-role node, fused central included. The DB-backed
-  `ScriptedAlarmState` table is now unused (dropping it is a deferred follow-up, tracked as Task 9).
+  `ScriptedAlarmState` table **was dropped** (Task 9, `3a590a0c`, migration
+  `20260723183050_DropScriptedAlarmStateTable`); `EfAlarmConditionStateStore` is deleted.
 - **Central persists deploy acks.** `DriverHostActor` no longer writes `NodeDeploymentState` to SQL on
  a driver-only node — `ConfigPublishCoordinator.PersistNodeAck` (already fed by every ApplyAck) is
  the system of record.
@@ -451,8 +543,8 @@ unaffected (it keeps ConfigDb via its admin role). Consequences:
  `OtOpcUaGroupRoleMapper` falls back to the `Security:Ldap:GroupToRole` appsettings baseline only —
  the same rows a driver node never received via config either, so this is not a regression.

-Code-complete on `feat/mesh-phase4`; the table-drop (Task 9) and the live gate (Task 10) are still
-open. See `docs/plans/2026-07-23-mesh-phase4-cut-driver-configdb.md` and
+Merged to master (`26fad75c`); **live gate PASSED** (`1281aebf` — driver nodes run ConfigDb-free) and
+Task 9 landed (`3a590a0c`). See `docs/plans/2026-07-23-mesh-phase4-cut-driver-configdb.md` and
 `docs/plans/2026-07-22-per-cluster-mesh-program.md` §Phase 4.

 ## LDAP Authentication
@@ -75,8 +75,26 @@
    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
    <PackageVersion Include="Microsoft.Playwright" Version="1.51.0" />
    <PackageVersion Include="Moq" Version="4.20.72" />
+    <!--
+      MQTT client for the Mqtt / Sparkplug B driver. MQTTnet v5 is the first line shipping a
+      net10.0 TFM (lib/net10.0, and an EMPTY net10.0 dependency group — zero transitive
+      packages, so it cannot participate in a diamond under this repo's deliberately-OFF
+      CentralPackageTransitivePinningEnabled). Sparkplug B payloads are hand-rolled rather than
+      taken from SparkplugNet, whose newest release (1.3.10) still pins MQTTnet 4.3.6.1152 and
+      ships net6.0/net8.0 only.
+    -->
+    <PackageVersion Include="MQTTnet" Version="5.2.0.1603" />
+    <!-- Driver.MTConnect carries NO backend NuGet. The TrakHound MTConnect.NET-Common/-HTTP pins
+         Task 0 added were removed in Task 7 (2026-07-24): neither package can parse an MTConnect
+         document (the XML formatter ships in a third, unreferenced package) nor frame the /sample
+         multipart stream socket-free. The driver uses HttpClient + System.Xml.Linq only. See the
+         Task 0 CORRECTION block in docs/plans/2026-07-24-mtconnect-driver.md. -->
    <PackageVersion Include="Novell.Directory.Ldap.NETStandard" Version="3.6.0" />
    <PackageVersion Include="OPCFoundation.NetStandard.Opc.Ua.Client" Version="1.5.378.106" />
+    <!-- Core carries Opc.Ua.StatusCodes, the oracle StatusCodeParityTests checks the drivers'
+         hard-coded uint constants against. Referenced by that TEST project only — the drivers
+         themselves stay SDK-free by design and keep spelling status codes as bare uints. -->
+    <PackageVersion Include="OPCFoundation.NetStandard.Opc.Ua.Core" Version="1.5.378.106" />
    <PackageVersion Include="OPCFoundation.NetStandard.Opc.Ua.Configuration" Version="1.5.378.106" />
    <PackageVersion Include="OPCFoundation.NetStandard.Opc.Ua.Server" Version="1.5.378.106" />
    <!-- OpenTelemetry.Api < 1.15.3 has GHSA-g94r-2vxg-569j (header-parsing memory DoS). The trio
@@ -1,6 +1,6 @@
 # OtOpcUa

-OPC UA server (.NET 10 AnyCPU) that exposes a fleet of industrial drivers as a single OPC UA address space. Drivers ship in-process for AVEVA System Platform Galaxy (via the sibling `mxaccessgw` repo), Modbus TCP, Siemens S7, Allen-Bradley CIP (ControlLogix / CompactLogix), Allen-Bradley Legacy (SLC 500 / MicroLogix), Beckhoff TwinCAT (ADS), FANUC FOCAS, and OPC UA Client (gateway).
+OPC UA server (.NET 10 AnyCPU) that exposes a fleet of industrial drivers as a single OPC UA address space. Drivers ship in-process for AVEVA System Platform Galaxy (via the sibling `mxaccessgw` repo), Modbus TCP, Siemens S7, Allen-Bradley CIP (ControlLogix / CompactLogix), Allen-Bradley Legacy (SLC 500 / MicroLogix), Beckhoff TwinCAT (ADS), FANUC FOCAS, OPC UA Client (gateway), and MQTT (broker subscribe; Sparkplug B in progress).

 A cross-platform client stack (.NET 10) — shared library, CLI, and Avalonia desktop app — connects to any OPC UA server.

@@ -15,7 +15,7 @@ A cross-platform client stack (.NET 10) — shared library, CLI, and Avalonia de
                    |   address space + capability fan-out|
                    +-------------------------------------+
                    |    |    |    |    |    |    |    |
-              Galaxy  Modbus  S7  AbCip AbLeg TwinCAT FOCAS OpcUaClient
+          Galaxy Modbus S7 AbCip AbLeg TwinCAT FOCAS OpcUaClient MQTT
                |
                v
       mxaccessgw (sibling repo, gRPC)
@@ -91,7 +91,7 @@ See [docs/Client.CLI.md](docs/Client.CLI.md) and [docs/Client.UI.md](docs/Client
 |---|---|
 | Driver specs (per-driver capability surface, config, addressing) | [docs/v2/driver-specs.md](docs/v2/driver-specs.md) |
 | Galaxy driver | [docs/drivers/Galaxy.md](docs/drivers/Galaxy.md) |
-| Modbus / S7 / AbCip / AbLegacy / TwinCAT / FOCAS / OpcUaClient | [docs/drivers/](docs/drivers/) |
+| Modbus / S7 / AbCip / AbLegacy / TwinCAT / FOCAS / OpcUaClient / MQTT | [docs/drivers/](docs/drivers/) |
 | Galaxy parity rig (mxaccessgw setup) | [docs/v2/Galaxy.ParityRig.md](docs/v2/Galaxy.ParityRig.md) |
 | Galaxy performance + tracing | [docs/v2/Galaxy.Performance.md](docs/v2/Galaxy.Performance.md) |

@@ -29,6 +29,11 @@
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus/ZB.MOM.WW.OtOpcUa.Driver.Modbus.csproj" />
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing.csproj" />
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Contracts/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Contracts.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql/ZB.MOM.WW.OtOpcUa.Driver.Sql.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql.Browser/ZB.MOM.WW.OtOpcUa.Driver.Sql.Browser.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql.Contracts/ZB.MOM.WW.OtOpcUa.Driver.Sql.Contracts.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Contracts/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Contracts.csproj" />
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/ZB.MOM.WW.OtOpcUa.Driver.S7.csproj" />
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7.Contracts/ZB.MOM.WW.OtOpcUa.Driver.S7.Contracts.csproj" />
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/ZB.MOM.WW.OtOpcUa.Driver.AbCip.csproj" />
@@ -42,6 +47,9 @@
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.csproj" />
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts.csproj" />
    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.Contracts/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.Contracts.csproj" />
+    <Project Path="src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.Browser/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.Browser.csproj" />
  </Folder>
  <Folder Name="/src/Drivers/Driver CLIs/">
    <Project Path="src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.csproj" />
@@ -90,6 +98,11 @@
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Tests.csproj" />
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing.Tests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.Addressing.Tests.csproj" />
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql.Tests/ZB.MOM.WW.OtOpcUa.Driver.Sql.Tests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql.Browser.Tests/ZB.MOM.WW.OtOpcUa.Driver.Sql.Browser.Tests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.Sql.IntegrationTests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests.csproj" />
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7.Tests/ZB.MOM.WW.OtOpcUa.Driver.S7.Tests.csproj" />
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests.csproj" />
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Tests/ZB.MOM.WW.OtOpcUa.Driver.AbCip.Tests.csproj" />
@@ -104,6 +117,9 @@
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests.csproj" />
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.Tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.Tests.csproj" />
    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.Tests/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.Tests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.IntegrationTests/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.IntegrationTests.csproj" />
+    <Project Path="tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.IntegrationTests/SparkplugSimulator/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.SparkplugSimulator.csproj" />
  </Folder>
  <Folder Name="/tests/Drivers/Driver CLIs/">
    <Project Path="tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common.Tests.csproj" />
@@ -9,78 +9,110 @@
    },
    {
      "id": 1,
-      "subject": "RED: connect-timeout regression tests T1+T3 (read/write degrade instead of throwing OCE) — must FAIL at f6eaa267",
+      "subject": "RED: connect-timeout regression tests T1+T3 (read/write degrade instead of throwing OCE) \u2014 must FAIL at f6eaa267",
      "status": "completed",
-      "blockedBy": [0]
+      "blockedBy": [
+        0
+      ]
    },
    {
      "id": 2,
      "subject": "RED: poll-loop-survival test T2 (subscription survives connect-timeout outage) + caller-cancel pinning test T4",
      "status": "completed",
-      "blockedBy": [0, 1]
+      "blockedBy": [
+        0,
+        1
+      ]
    },
    {
      "id": 3,
      "subject": "GREEN: EnsureConnectedAsync + InitializeAsync connect-timeout OCE -> TimeoutException conversion (STAB-14 root fix)",
      "status": "completed",
-      "blockedBy": [1, 2]
+      "blockedBy": [
+        1,
+        2
+      ]
    },
    {
      "id": 4,
      "subject": "Defensive when-filters on ensure-wrapper OCE rethrows (:488/:1000) + poll-loop OCE catches (:1383/:1396/:1404)",
      "status": "completed",
-      "blockedBy": [3]
+      "blockedBy": [
+        3
+      ]
    },
    {
      "id": 5,
      "subject": "Finding-1 close gate: full S7 unit + CLI test-project sweep green",
      "status": "completed",
-      "blockedBy": [4]
+      "blockedBy": [
+        4
+      ]
    },
    {
      "id": 6,
-      "subject": "RED: framing-fault classification Theory T5 (TPKT/TPDU/WrongNumberOfBytes/PlcException-WrongNumberReceivedBytes reopen) — must FAIL",
+      "subject": "RED: framing-fault classification Theory T5 (TPKT/TPDU/WrongNumberOfBytes/PlcException-WrongNumberReceivedBytes reopen) \u2014 must FAIL",
      "status": "completed",
-      "blockedBy": [0]
+      "blockedBy": [
+        0
+      ]
    },
    {
      "id": 7,
      "subject": "GREEN: broaden IsS7ConnectionFatal to the ISO-on-TCP framing surface (NOT InvalidDataException) + xmldoc (STAB-15a)",
      "status": "completed",
-      "blockedBy": [6]
+      "blockedBy": [
+        6
+      ]
    },
    {
      "id": 8,
      "subject": "RED->GREEN: cancellation-during-I/O marks handle dead (T6 read + T7 write; per-item OCE catches set _plcDead before propagating)",
      "status": "completed",
-      "blockedBy": [7]
+      "blockedBy": [
+        7
+      ]
    },
    {
      "id": 9,
      "subject": "RED->GREEN: probe marks handle dead under the gate (T8 persistent probe fault + T9 probe timeout; ProbeLoopAsync inner catch restructure, STAB-15b)",
      "status": "completed",
-      "blockedBy": [8]
+      "blockedBy": [
+        8
+      ]
    },
    {
      "id": 10,
      "subject": "Doc: R2-09 connect-throttle seam note on EnsureConnectedAsync <remarks> (STAB-8 S7 part, note-only)",
      "status": "completed",
-      "blockedBy": [3]
+      "blockedBy": [
+        3
+      ]
    },
    {
      "id": 11,
      "subject": "Env-gated live connect-timeout outage test (S7_TIMEOUT_OUTAGE_START_CMD/STOP_CMD blackhole design; skips cleanly offline)",
-      "status": "deferred-live",
+      "status": "completed",
      "note": "env-gated; runs in serial live pass (integration suite; serialized heavy pass). Test authored + committed; verified it SKIPs cleanly offline.",
-      "blockedBy": [5]
+      "blockedBy": [
+        5
+      ],
+      "closureNote": "LIVE GATE CLOSED 2026-07-15 \u2014 S7 blackhole run via `docker pause` on the 10.100.0.35 s7_1500 fixture. Found + fixed a real read-leg wall-clock gap (PR #453). STATUS.md 'docker-dev live-/run pass'."
    },
    {
      "id": 12,
      "subject": "Close-out: whole-suite sweep + update archreview STATUS.md and 05 prior-finding table (STAB-14/15 FIXED, STAB-8 seam noted)",
      "status": "completed",
      "note": "S7 unit 246/246 green; S7 CLI 48/49 (1 pre-existing unrelated comment-scan failure, see deviations); solution BUILD clean (0 errors). Whole-solution dotnet test NOT run per controller memory-constraint (integration suites deferred to serial heavy pass).",
-      "blockedBy": [5, 7, 8, 9, 10, 11]
+      "blockedBy": [
+        5,
+        7,
+        8,
+        9,
+        10,
+        11
+      ]
    }
  ],
-  "lastUpdated": "2026-07-13"
+  "lastUpdated": "2026-07-27"
 }
@@ -1,25 +1,170 @@
 {
  "planPath": "archreview/plans/R2-02-resilience-config-hardening-plan.md",
  "tasks": [
-    { "id": 0, "subject": "S-6 brick-repro test (RED): parsed timeoutSeconds:0 / breakerFailureThreshold:1 must not brick capability calls — ResilienceConfigBrickTests, expect 2 failures on f6eaa267", "status": "completed", "blockedBy": [] },
-    { "id": 1, "subject": "Add ResiliencePolicyRanges constants to Core.Abstractions (single source of truth for parser/builder/AdminUI, derived from Polly.Core 8.6.6 validation)", "status": "completed", "blockedBy": [] },
-    { "id": 2, "subject": "S-6 parser: clamp timeout/retry/breaker overrides with appending diagnostics (timeout<=0 -> tier default; breaker==1 -> 2; caps) + 8 parser tests", "status": "completed", "blockedBy": [0, 1] },
-    { "id": 3, "subject": "S-6 builder: belt-and-braces clamp in Build so pipeline construction can never throw ValidationException + Build_NeverThrows_ForHostileDirectOptions (turns task 0 green)", "status": "completed", "blockedBy": [0, 1] },
-    { "id": 4, "subject": "S-6 production-wiring guard: DriverCapabilityInvokerFactory.Create with hostile JSON yields a working invoker + logged clamp diagnostic; re-run ResilienceInvokerFactoryRegistrationTests", "status": "completed", "blockedBy": [2, 3] },
-    { "id": 5, "subject": "S-6 AdminUI: ResilienceFormModel.Validate() range messages (via ResiliencePolicyRanges through the transitive Core.Abstractions ref) + warning block in DriverResilienceSection", "status": "completed", "blockedBy": [1] },
-    { "id": 6, "subject": "S-8 parser layer: force Write/AlarmAcknowledge retryCount overrides to 0 with diagnostic (spec invariant, honest dead-knob surfacing) + tests + GetTierDefaults doc", "status": "completed", "blockedBy": [2] },
-    { "id": 7, "subject": "S-8 dispatch layer: flip HandleWriteAsync to isIdempotent:false — RED the DriverInstanceActorResilienceWiringTests expectation first, then flip; full Runtime suite green", "status": "completed", "blockedBy": [6] },
-    { "id": 8, "subject": "S-8/P-4 invoker: cache the no-retry options snapshot once per invoker + add RecordCallStart/Complete tracker accounting to the non-idempotent arm + 2 CapabilityInvokerTests", "status": "completed", "blockedBy": [7] },
-    { "id": 9, "subject": "S-8 docs + form: fix WriteIdempotentAttribute's false 'reads via reflection' claim; note the non-idempotent production default; disable Write/Ack retry cells in the razor", "status": "completed", "blockedBy": [7, 5] },
-    { "id": 10, "subject": "U-6 delete (Core): remove BulkheadMaxConcurrent/MaxQueue from DriverResilienceOptions + parser shape/merge/doc-example; add BulkheadKeys_InStoredJson_AreIgnored (migration-free contract)", "status": "completed", "blockedBy": [2, 6] },
-    { "id": 11, "subject": "U-6 delete (AdminUI): strip bulkhead fields from ResilienceFormModel + the two razor inputs; update ResilienceFormModelTests", "status": "completed", "blockedBy": [5, 10] },
-    { "id": 12, "subject": "U-6 doc sweep (seam xmldocs, OTOPCUA0001 message + analyzer tests, operator docs; leave migrations/WedgeDetector/historical plans) + Options_properties_are_exactly_the_pipeline_wired_set knob-inertness guard", "status": "completed", "blockedBy": [10, 11] },
-    { "id": 13, "subject": "C-7 RED tests: unknown top-level key / unknown capability / unknown per-policy field survive round-trip; malformed JSON sets ParseFailed and ToJson returns the original text", "status": "completed", "blockedBy": [11] },
-    { "id": 14, "subject": "C-7 implement: JsonObject-bag FromJson/ToJson (TagConfigJson idiom), ParseFailed + RawStoredJson, blank->null contract preserved, parser-interop test green", "status": "completed", "blockedBy": [13] },
-    { "id": 15, "subject": "C-7 razor: ParseFailed warning banner + input lockout + explicit discard button; raw pane shows the stored ResilienceConfig; live-/run on docker-dev :9200 (rebuild BOTH centrals; SQL-mangle + unknown-key survival checks; also drive task 5 warnings and task 9 disabled cells)", "status": "deferred-live", "note": "docker-dev :9200 live-/run; serial live pass", "blockedBy": [14] },
-    { "id": 16, "subject": "S-7 builder: add options-generation to PipelineKey + GetOrCreate(optionsGeneration=0) + thread through CapabilityInvoker; StaleGeneration_ReCache_IsNotServed_ToNewGeneration", "status": "completed", "blockedBy": [3] },
-    { "id": 17, "subject": "S-7 factory: Interlocked per-Create generation stamp + Respawn_interleaved_with_old_invoker_call_still_applies_new_options wiring proof; update Invalidate comment (cleanup, not correctness)", "status": "completed", "blockedBy": [16] },
-    { "id": 18, "subject": "Wrap-up: whole-solution build (0 warnings, analyzer silent) + full dotnet test gate; record the pass + the two report anchor drifts in archreview/plans/STATUS.md", "status": "deferred-live", "note": "integration/full sweep; serialized heavy pass", "blockedBy": [4, 8, 9, 12, 15, 17] }
+    {
+      "id": 0,
+      "subject": "S-6 brick-repro test (RED): parsed timeoutSeconds:0 / breakerFailureThreshold:1 must not brick capability calls \u2014 ResilienceConfigBrickTests, expect 2 failures on f6eaa267",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": 1,
+      "subject": "Add ResiliencePolicyRanges constants to Core.Abstractions (single source of truth for parser/builder/AdminUI, derived from Polly.Core 8.6.6 validation)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": 2,
+      "subject": "S-6 parser: clamp timeout/retry/breaker overrides with appending diagnostics (timeout<=0 -> tier default; breaker==1 -> 2; caps) + 8 parser tests",
+      "status": "completed",
+      "blockedBy": [
+        0,
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "S-6 builder: belt-and-braces clamp in Build so pipeline construction can never throw ValidationException + Build_NeverThrows_ForHostileDirectOptions (turns task 0 green)",
+      "status": "completed",
+      "blockedBy": [
+        0,
+        1
+      ]
+    },
+    {
+      "id": 4,
+      "subject": "S-6 production-wiring guard: DriverCapabilityInvokerFactory.Create with hostile JSON yields a working invoker + logged clamp diagnostic; re-run ResilienceInvokerFactoryRegistrationTests",
+      "status": "completed",
+      "blockedBy": [
+        2,
+        3
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "S-6 AdminUI: ResilienceFormModel.Validate() range messages (via ResiliencePolicyRanges through the transitive Core.Abstractions ref) + warning block in DriverResilienceSection",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "S-8 parser layer: force Write/AlarmAcknowledge retryCount overrides to 0 with diagnostic (spec invariant, honest dead-knob surfacing) + tests + GetTierDefaults doc",
+      "status": "completed",
+      "blockedBy": [
+        2
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "S-8 dispatch layer: flip HandleWriteAsync to isIdempotent:false \u2014 RED the DriverInstanceActorResilienceWiringTests expectation first, then flip; full Runtime suite green",
+      "status": "completed",
+      "blockedBy": [
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "subject": "S-8/P-4 invoker: cache the no-retry options snapshot once per invoker + add RecordCallStart/Complete tracker accounting to the non-idempotent arm + 2 CapabilityInvokerTests",
+      "status": "completed",
+      "blockedBy": [
+        7
+      ]
+    },
+    {
+      "id": 9,
+      "subject": "S-8 docs + form: fix WriteIdempotentAttribute's false 'reads via reflection' claim; note the non-idempotent production default; disable Write/Ack retry cells in the razor",
+      "status": "completed",
+      "blockedBy": [
+        7,
+        5
+      ]
+    },
+    {
+      "id": 10,
+      "subject": "U-6 delete (Core): remove BulkheadMaxConcurrent/MaxQueue from DriverResilienceOptions + parser shape/merge/doc-example; add BulkheadKeys_InStoredJson_AreIgnored (migration-free contract)",
+      "status": "completed",
+      "blockedBy": [
+        2,
+        6
+      ]
+    },
+    {
+      "id": 11,
+      "subject": "U-6 delete (AdminUI): strip bulkhead fields from ResilienceFormModel + the two razor inputs; update ResilienceFormModelTests",
+      "status": "completed",
+      "blockedBy": [
+        5,
+        10
+      ]
+    },
+    {
+      "id": 12,
+      "subject": "U-6 doc sweep (seam xmldocs, OTOPCUA0001 message + analyzer tests, operator docs; leave migrations/WedgeDetector/historical plans) + Options_properties_are_exactly_the_pipeline_wired_set knob-inertness guard",
+      "status": "completed",
+      "blockedBy": [
+        10,
+        11
+      ]
+    },
+    {
+      "id": 13,
+      "subject": "C-7 RED tests: unknown top-level key / unknown capability / unknown per-policy field survive round-trip; malformed JSON sets ParseFailed and ToJson returns the original text",
+      "status": "completed",
+      "blockedBy": [
+        11
+      ]
+    },
+    {
+      "id": 14,
+      "subject": "C-7 implement: JsonObject-bag FromJson/ToJson (TagConfigJson idiom), ParseFailed + RawStoredJson, blank->null contract preserved, parser-interop test green",
+      "status": "completed",
+      "blockedBy": [
+        13
+      ]
+    },
+    {
+      "id": 15,
+      "subject": "C-7 razor: ParseFailed warning banner + input lockout + explicit discard button; raw pane shows the stored ResilienceConfig; live-/run on docker-dev :9200 (rebuild BOTH centrals; SQL-mangle + unknown-key survival checks; also drive task 5 warnings and task 9 disabled cells)",
+      "status": "completed",
+      "note": "docker-dev :9200 live-/run; serial live pass",
+      "blockedBy": [
+        14
+      ],
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 range-validation banner verified on the docker-dev Modbus driver's Resilience overrides (`timeoutSeconds:0`). STATUS.md 'docker-dev live-/run pass'."
+    },
+    {
+      "id": 16,
+      "subject": "S-7 builder: add options-generation to PipelineKey + GetOrCreate(optionsGeneration=0) + thread through CapabilityInvoker; StaleGeneration_ReCache_IsNotServed_ToNewGeneration",
+      "status": "completed",
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 17,
+      "subject": "S-7 factory: Interlocked per-Create generation stamp + Respawn_interleaved_with_old_invoker_call_still_applies_new_options wiring proof; update Invalidate comment (cleanup, not correctness)",
+      "status": "completed",
+      "blockedBy": [
+        16
+      ]
+    },
+    {
+      "id": 18,
+      "subject": "Wrap-up: whole-solution build (0 warnings, analyzer silent) + full dotnet test gate; record the pass + the two report anchor drifts in archreview/plans/STATUS.md",
+      "status": "completed",
+      "note": "integration/full sweep; serialized heavy pass",
+      "blockedBy": [
+        4,
+        8,
+        9,
+        12,
+        15,
+        17
+      ],
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 S-8 verified: Write and AlarmAcknowledge RETRIES cells disabled ('never'). STATUS.md 'docker-dev live-/run pass'."
+    }
  ],
-  "lastUpdated": "2026-07-12"
+  "lastUpdated": "2026-07-27"
 }
@@ -3,7 +3,7 @@
  "tasks": [
    {
      "id": "R2-03-T1",
-      "subject": "S13 stale-Good repro test at host level (RED — must fail on f6eaa267): fail-after-success evaluator, publish probe sees Good then expects Bad AttributeValueUpdate",
+      "subject": "S13 stale-Good repro test at host level (RED \u2014 must fail on f6eaa267): fail-after-success evaluator, publish probe sees Good then expects Bad AttributeValueUpdate",
      "status": "completed",
      "blockedBy": []
    },
@@ -62,7 +62,7 @@
    },
    {
      "id": "R2-03-T9",
-      "subject": "P7 wiring-guard rewrite (RED): ApplyVirtualTags clears the compile cache only when the expression set changes — identical redeploy must NOT clear; expression edit must; shared-expression removal must not",
+      "subject": "P7 wiring-guard rewrite (RED): ApplyVirtualTags clears the compile cache only when the expression set changes \u2014 identical redeploy must NOT clear; expression edit must; shared-expression removal must not",
      "status": "completed",
      "blockedBy": [
        "R2-03-T3"
@@ -86,7 +86,8 @@
        "R2-03-T8",
        "R2-03-T10"
      ],
-      "note": "integration/full sweep; serialized heavy pass (build clean, Runtime.Tests 372/372, RoslynVirtualTagEvaluatorTests 20/20 verified locally; whole-solution/cross-suite sweep deferred per controller memory constraint)"
+      "note": "integration/full sweep; serialized heavy pass (build clean, Runtime.Tests 372/372, RoslynVirtualTagEvaluatorTests 20/20 verified locally; whole-solution/cross-suite sweep deferred per controller memory constraint)",
+      "openNote": "STILL OPEN \u2014 live-blocked on a data-less rig: every materialised node reads Bad_WaitingForInitialData because no driver data flows, so a VT cannot be staged Good->Bad. Needs a reachable driver fixture feeding the VT. Unit-verified meanwhile."
    },
    {
      "id": "R2-03-T12",
@@ -95,8 +96,9 @@
      "blockedBy": [
        "R2-03-T11"
      ],
-      "note": "docker-dev live-/run; serial live pass"
+      "note": "docker-dev live-/run; serial live pass",
+      "openNote": "STILL OPEN \u2014 same blocker as T11. Confirmed still open 2026-07-27 (deferment.md \u00a78.5)."
    }
  ],
-  "lastUpdated": "2026-07-13"
+  "lastUpdated": "2026-07-27"
 }
@@ -1,22 +1,146 @@
 {
  "planPath": "archreview/plans/R2-05-adminui-authz-plan.md",
-  "lastUpdated": "2026-07-12",
+  "lastUpdated": "2026-07-27",
  "tasks": [
-    { "id": "T1", "subject": "Add AdminUiPolicies constants class (Security/Auth/AdminUiPolicies.cs)", "status": "completed", "blockedBy": [] },
-    { "id": "T2", "subject": "Policy-semantics unit test AdminUiPoliciesTests (RED: ConfigEditor/AuthenticatedRead unregistered)", "status": "completed", "blockedBy": ["T1"] },
-    { "id": "T3", "subject": "Reflection PageAuthorizationGuardTests (RED: must list ~35 ungated/mis-idiom pages)", "status": "completed", "blockedBy": ["T1"] },
-    { "id": "T4", "subject": "Register ConfigEditor + AuthenticatedRead policies; switch existing AddPolicy literals to constants (GREEN for T2)", "status": "completed", "blockedBy": ["T2"] },
-    { "id": "T5", "subject": "_Imports.razor usings (Authorization + Security.Auth) + de-dupe Deployments/Alerts in-file @using", "status": "completed", "blockedBy": ["T1"] },
-    { "id": "T6", "subject": "Gate UNS pages with ConfigEditor (GlobalUns, EquipmentPage)", "status": "completed", "blockedBy": ["T4", "T5"] },
-    { "id": "T7", "subject": "Gate cluster editors with ConfigEditor (NewCluster, ClusterEdit, NodeEdit, NamespaceEdit, AclEdit)", "status": "completed", "blockedBy": ["T4", "T5"] },
-    { "id": "T8", "subject": "Gate driver pages + routers with ConfigEditor (8 driver pages, DriverTypePicker, DriverEditRouter)", "status": "completed", "blockedBy": ["T4", "T5"] },
-    { "id": "T9", "subject": "Converge Deployments/Scripts/ScriptEdit from Roles-string to ConfigEditor policy", "status": "completed", "blockedBy": ["T4", "T5"] },
-    { "id": "T10", "subject": "Read pages to AuthenticatedRead (16 incl. Home insert) + RoleGrants to FleetAdmin constant", "status": "completed", "blockedBy": ["T4", "T5"] },
-    { "id": "T11", "subject": "Guard GREEN checkpoint + full AdminUI.Tests; commit the gate", "status": "completed", "blockedBy": ["T3", "T6", "T7", "T8", "T9", "T10"] },
-    { "id": "T12", "subject": "Converge non-page literals to constants (ScriptAnalysisEndpoints, imperative DriverOperator x4, Certificates FleetAdmin x2)", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T13", "subject": "Docs: CLAUDE.md ScriptAnalysis gate sentence, docs/security.md, STATUS.md R2-05 row", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T14", "subject": "Full-solution test sweep (dotnet test ZB.MOM.WW.OtOpcUa.slnx)", "status": "completed", "blockedBy": ["T12", "T13"], "note": "Impacted unit suites authoritative + green: AdminUI.Tests 517/517, Security.Tests 80/80. One whole-solution sweep ran BEFORE the controller's no-whole-solution/no-IntegrationTests constraint arrived; all failures are pre-existing/env and outside the R2-05 diff (Core.Abstractions.Tests InterfaceIndependence flags pre-existing Historian.* namespace types; Runtime historian retry timing; OpcUaClient.Browser needs a live OPC endpoint; AbCip/OpcUaServer/Host IntegrationTests need Docker fixtures). Will NOT be re-run per constraint." },
-    { "id": "T15", "subject": "Live /run positive pass on docker-dev :9200 (rebuild BOTH centrals; auto-admin drives all page tiers; negative proof stays in T2/T3)", "status": "deferred-live", "blockedBy": ["T14"], "note": "docker-dev live authz /run; serial live pass. Heavy integration/Playwright-dependent gate — controller runs serialized. docker-dev DisableLogin=true auto-authenticates as full-access admin, so role-deny differentiation is NOT observable there; the negative proof is CI-side (T2 AdminUiPoliciesTests + T3 PageAuthorizationGuardTests, both green). This pass only regression-checks over-gating (a typo'd policy name would render the deny slot even for the auto-admin)." },
-    { "id": "T16", "subject": "Merge + bookkeeping (flip 04/C-1 row, record Reservations/ClusterRedundancy corrections)", "status": "completed", "blockedBy": ["T15"] }
+    {
+      "id": "T1",
+      "subject": "Add AdminUiPolicies constants class (Security/Auth/AdminUiPolicies.cs)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T2",
+      "subject": "Policy-semantics unit test AdminUiPoliciesTests (RED: ConfigEditor/AuthenticatedRead unregistered)",
+      "status": "completed",
+      "blockedBy": [
+        "T1"
+      ]
+    },
+    {
+      "id": "T3",
+      "subject": "Reflection PageAuthorizationGuardTests (RED: must list ~35 ungated/mis-idiom pages)",
+      "status": "completed",
+      "blockedBy": [
+        "T1"
+      ]
+    },
+    {
+      "id": "T4",
+      "subject": "Register ConfigEditor + AuthenticatedRead policies; switch existing AddPolicy literals to constants (GREEN for T2)",
+      "status": "completed",
+      "blockedBy": [
+        "T2"
+      ]
+    },
+    {
+      "id": "T5",
+      "subject": "_Imports.razor usings (Authorization + Security.Auth) + de-dupe Deployments/Alerts in-file @using",
+      "status": "completed",
+      "blockedBy": [
+        "T1"
+      ]
+    },
+    {
+      "id": "T6",
+      "subject": "Gate UNS pages with ConfigEditor (GlobalUns, EquipmentPage)",
+      "status": "completed",
+      "blockedBy": [
+        "T4",
+        "T5"
+      ]
+    },
+    {
+      "id": "T7",
+      "subject": "Gate cluster editors with ConfigEditor (NewCluster, ClusterEdit, NodeEdit, NamespaceEdit, AclEdit)",
+      "status": "completed",
+      "blockedBy": [
+        "T4",
+        "T5"
+      ]
+    },
+    {
+      "id": "T8",
+      "subject": "Gate driver pages + routers with ConfigEditor (8 driver pages, DriverTypePicker, DriverEditRouter)",
+      "status": "completed",
+      "blockedBy": [
+        "T4",
+        "T5"
+      ]
+    },
+    {
+      "id": "T9",
+      "subject": "Converge Deployments/Scripts/ScriptEdit from Roles-string to ConfigEditor policy",
+      "status": "completed",
+      "blockedBy": [
+        "T4",
+        "T5"
+      ]
+    },
+    {
+      "id": "T10",
+      "subject": "Read pages to AuthenticatedRead (16 incl. Home insert) + RoleGrants to FleetAdmin constant",
+      "status": "completed",
+      "blockedBy": [
+        "T4",
+        "T5"
+      ]
+    },
+    {
+      "id": "T11",
+      "subject": "Guard GREEN checkpoint + full AdminUI.Tests; commit the gate",
+      "status": "completed",
+      "blockedBy": [
+        "T3",
+        "T6",
+        "T7",
+        "T8",
+        "T9",
+        "T10"
+      ]
+    },
+    {
+      "id": "T12",
+      "subject": "Converge non-page literals to constants (ScriptAnalysisEndpoints, imperative DriverOperator x4, Certificates FleetAdmin x2)",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T13",
+      "subject": "Docs: CLAUDE.md ScriptAnalysis gate sentence, docs/security.md, STATUS.md R2-05 row",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T14",
+      "subject": "Full-solution test sweep (dotnet test ZB.MOM.WW.OtOpcUa.slnx)",
+      "status": "completed",
+      "blockedBy": [
+        "T12",
+        "T13"
+      ],
+      "note": "Impacted unit suites authoritative + green: AdminUI.Tests 517/517, Security.Tests 80/80. One whole-solution sweep ran BEFORE the controller's no-whole-solution/no-IntegrationTests constraint arrived; all failures are pre-existing/env and outside the R2-05 diff (Core.Abstractions.Tests InterfaceIndependence flags pre-existing Historian.* namespace types; Runtime historian retry timing; OpcUaClient.Browser needs a live OPC endpoint; AbCip/OpcUaServer/Host IntegrationTests need Docker fixtures). Will NOT be re-run per constraint."
+    },
+    {
+      "id": "T15",
+      "subject": "Live /run positive pass on docker-dev :9200 (rebuild BOTH centrals; auto-admin drives all page tiers; negative proof stays in T2/T3)",
+      "status": "completed",
+      "blockedBy": [
+        "T14"
+      ],
+      "note": "docker-dev live authz /run; serial live pass. Heavy integration/Playwright-dependent gate \u2014 controller runs serialized. docker-dev DisableLogin=true auto-authenticates as full-access admin, so role-deny differentiation is NOT observable there; the negative proof is CI-side (T2 AdminUiPoliciesTests + T3 PageAuthorizationGuardTests, both green). This pass only regression-checks over-gating (a typo'd policy name would render the deny slot even for the auto-admin).",
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 (partial by design) \u2014 every config/read page renders under the all-roles multi-role-test session, so named-policy gating does not over-gate a legitimate admin. The DENY direction is unobservable on docker-dev (DisableLogin=true), as documented."
+    },
+    {
+      "id": "T16",
+      "subject": "Merge + bookkeeping (flip 04/C-1 row, record Reservations/ClusterRedundancy corrections)",
+      "status": "completed",
+      "blockedBy": [
+        "T15"
+      ]
+    }
  ]
 }
@@ -1,16 +1,16 @@
 {
  "planPath": "archreview/plans/R2-06-serverhistorian-failfast-plan.md",
-  "lastUpdated": "2026-07-12",
+  "lastUpdated": "2026-07-27",
  "tasks": [
    {
      "id": "T1",
-      "subject": "RED: misconfig repro test — HistorianGatewayClientAdapter.Create with empty/malformed Endpoint must throw a named InvalidOperationException (currently UriFormatException; test MUST fail on current code)",
+      "subject": "RED: misconfig repro test \u2014 HistorianGatewayClientAdapter.Create with empty/malformed Endpoint must throw a named InvalidOperationException (currently UriFormatException; test MUST fail on current code)",
      "status": "completed",
      "blockedBy": []
    },
    {
      "id": "T2",
-      "subject": "GREEN: adapter guard — Uri.TryCreate + InvalidOperationException naming ServerHistorian:Endpoint in HistorianGatewayClientAdapter.Create (defense in depth)",
+      "subject": "GREEN: adapter guard \u2014 Uri.TryCreate + InvalidOperationException naming ServerHistorian:Endpoint in HistorianGatewayClientAdapter.Create (defense in depth)",
      "status": "completed",
      "blockedBy": [
        "T1"
@@ -50,7 +50,7 @@
    },
    {
      "id": "T7",
-      "subject": "U-7 pin: GatewayTagProvisionerTests Boolean_definition_carries_explicit_Int1_presence (asserts HistorianDataType.Int1 AND HasDataType — 0.2.0 proto3-optional presence witness; pin, no RED phase)",
+      "subject": "U-7 pin: GatewayTagProvisionerTests Boolean_definition_carries_explicit_Int1_presence (asserts HistorianDataType.Int1 AND HasDataType \u2014 0.2.0 proto3-optional presence witness; pin, no RED phase)",
      "status": "completed",
      "blockedBy": []
    },
@@ -89,12 +89,13 @@
    {
      "id": "T12",
      "subject": "OPERATOR GATE: run Category=LiveIntegration on the VPN against a 0.2.0 gateway (all 6 tests, incl. Boolean EnsureTags + retype probe); record the observed retype policy back into docs/Historian.md + STATUS.md; also discharges 06/U-2's full documented run",
-      "status": "deferred-live",
+      "status": "completed",
      "blockedBy": [
        "T9",
        "T11"
      ],
-      "note": "DONE 2026-07-13 on VPN vs a real 0.2.0 gateway (deployed locally in Docker → real AVEVA historian on wonder-sql-vd03 + Runtime SQL). 5/6 green. Found+FIXED a real OtOpcUa bug (PR #439, master 666908d7): GatewayTagProvisioner sent StorageRateMs=0 → gateway EnsureTags threw ArgumentOutOfRangeException → ALL historized-tag provisioning silently failed; stamp 1000ms + regression test. U-7 retype policy ANSWERED: EnsureTags is a real upsert; in-place retype between SUPPORTED types is ACCEPTED (Float→Double=success); but Int1 (0.2.0 Boolean target) is NOT creatable on this histsdk (ProtocolEvidenceMissingException — Int1-only; Int2/UInt2/Int4/UInt4/Float/Double all provision), so a pre-bump Float Boolean asked to become Int1 FAILS the provision (not silently retyped/data-lost). The 1 red test (Boolean→Int1) is a gateway histsdk type-support gap, not OtOpcUa. Deployment fixes: FQDN host + libgssapi-krb5-2/gss-ntlmssp in the gateway image + wonderapp SQL login for Runtime. Full record in STATUS.md."
+      "note": "DONE 2026-07-13 on VPN vs a real 0.2.0 gateway (deployed locally in Docker \u2192 real AVEVA historian on wonder-sql-vd03 + Runtime SQL). 5/6 green. Found+FIXED a real OtOpcUa bug (PR #439, master 666908d7): GatewayTagProvisioner sent StorageRateMs=0 \u2192 gateway EnsureTags threw ArgumentOutOfRangeException \u2192 ALL historized-tag provisioning silently failed; stamp 1000ms + regression test. U-7 retype policy ANSWERED: EnsureTags is a real upsert; in-place retype between SUPPORTED types is ACCEPTED (Float\u2192Double=success); but Int1 (0.2.0 Boolean target) is NOT creatable on this histsdk (ProtocolEvidenceMissingException \u2014 Int1-only; Int2/UInt2/Int4/UInt4/Float/Double all provision), so a pre-bump Float Boolean asked to become Int1 FAILS the provision (not silently retyped/data-lost). The 1 red test (Boolean\u2192Int1) is a gateway histsdk type-support gap, not OtOpcUa. Deployment fixes: FQDN host + libgssapi-krb5-2/gss-ntlmssp in the gateway image + wonderapp SQL login for Runtime. Full record in STATUS.md.",
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 (6/6) \u2014 vs. the local 0.2.0 gateway + real historian over VPN. STATUS.md 'docker-dev live-/run pass'."
    }
  ]
 }
@@ -1,6 +1,6 @@
 {
  "planPath": "archreview/plans/R2-07-surgical-pure-adds-plan.md",
-  "lastUpdated": "2026-07-12",
+  "lastUpdated": "2026-07-27",
  "tasks": [
    {
      "id": "T1",
@@ -45,20 +45,22 @@
    {
      "id": "T5",
      "subject": "Phase 1: over-the-wire SubscriptionSurvivalTests \u2014 subscribe, pure-add, item survives + new node browsable",
-      "status": "deferred-live",
+      "status": "completed",
      "blockedBy": [
        "T4b"
      ],
-      "note": "authored + compiles (dotnet build green); NOT run \u2014 *.IntegrationTests suite leaks ~16GB/run per the memory constraint. MUST run in the serial heavy integration pass (single-test, boots one in-process server + client)."
+      "note": "authored + compiles (dotnet build green); NOT run \u2014 *.IntegrationTests suite leaks ~16GB/run per the memory constraint. MUST run in the serial heavy integration pass (single-test, boots one in-process server + client).",
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 central-1 boot logged PureAdd (added=91, rebuild=False)."
    },
    {
      "id": "T6",
      "subject": "Phase 1: MANDATORY live-/run gate on docker-dev (rebuild BOTH centrals; Client.CLI subscribe survives +1-tag deploy; kind=PureAdd rebuild=False) \u2014 Phase 1 shippable boundary",
-      "status": "deferred-live",
+      "status": "completed",
      "blockedBy": [
        "T5"
      ],
-      "note": "docker-dev live /run surgical-path; serial heavy pass \u2014 F10b inertness risk, MUST run (subscribe survives +1-tag deploy; central log kind=PureAdd, rebuild=False; new node browsable/Good)."
+      "note": "docker-dev live /run surgical-path; serial heavy pass \u2014 F10b inertness risk, MUST run (subscribe survives +1-tag deploy; central log kind=PureAdd, rebuild=False; new node browsable/Good).",
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 deleting a UNS virtual tag logged PureRemove (removed=1, rebuild=False) and the node vanished from the address space."
    },
    {
      "id": "T7",
@@ -104,11 +106,12 @@
    {
      "id": "T12",
      "subject": "Phase 2: remove-side subscription-survival integration test + live-/run remove gate (kind=PureRemove rebuild=False) \u2014 Phase 2 shippable boundary",
-      "status": "deferred-live",
+      "status": "completed",
      "blockedBy": [
        "T11"
      ],
-      "note": "remove-side SubscriptionSurvivalTests authored + compiles (dotnet build green); NOT run \u2014 *.IntegrationTests memory constraint. Live docker-dev pure-remove gate (survivor subscription uninterrupted; central log kind=PureRemove, rebuild=False; removed node reads BadNodeIdUnknown) MUST run in the serial heavy pass \u2014 F10b inertness risk."
+      "note": "remove-side SubscriptionSurvivalTests authored + compiles (dotnet build green); NOT run \u2014 *.IntegrationTests memory constraint. Live docker-dev pure-remove gate (survivor subscription uninterrupted; central log kind=PureRemove, rebuild=False; removed node reads BadNodeIdUnknown) MUST run in the serial heavy pass \u2014 F10b inertness risk.",
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 surgical add AND remove both execute in prod with no full rebuild; the remove path's 3 new sink members are wired, not inert."
    },
    {
      "id": "T13",
@@ -121,11 +124,12 @@
    {
      "id": "T14",
      "subject": "Phase 3: mixed-deploy integration test + live-/run mixed gate + STATUS.md/P1 close-out \u2014 plan complete",
-      "status": "deferred-live",
+      "status": "completed",
      "blockedBy": [
        "T13"
      ],
-      "note": "mixed-deploy SubscriptionSurvivalTests authored + compiles (dotnet build green); docs close-out DONE (STATUS.md + 03/P1 marked REMEDIATED + plan deviations). Live docker-dev mixed gate (one deploy +1/-1; kind=AddRemoveMix, rebuild=False; survivor uninterrupted) MUST run in the serial heavy pass \u2014 F10b inertness risk."
+      "note": "mixed-deploy SubscriptionSurvivalTests authored + compiles (dotnet build green); docs close-out DONE (STATUS.md + 03/P1 marked REMEDIATED + plan deviations). Live docker-dev mixed gate (one deploy +1/-1; kind=AddRemoveMix, rebuild=False; survivor uninterrupted) MUST run in the serial heavy pass \u2014 F10b inertness risk.",
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 see T5/T6/T12. STATUS.md 'docker-dev live-/run pass'."
    }
  ]
 }
@@ -1,17 +1,94 @@
 {
  "planPath": "archreview/plans/R2-10-resilience-observability-plan.md",
-  "lastUpdated": "2026-07-12",
+  "lastUpdated": "2026-07-27",
  "tasks": [
-    { "id": "T1", "subject": "Tracker: LastBreakerClosedUtc + IsBreakerOpen + RecordBreakerClose (Core, TDD in DriverResilienceStatusTrackerTests)", "status": "completed", "blockedBy": [] },
-    { "id": "T2", "subject": "Builder: OnClosed records breaker-close on the tracker (TDD in DriverResiliencePipelineBuilderTests)", "status": "completed", "blockedBy": ["T1"] },
-    { "id": "T3", "subject": "Invoker: successful Execute* resets ConsecutiveFailures (TDD in CapabilityInvokerTests)", "status": "completed", "blockedBy": ["T1"] },
-    { "id": "T4", "subject": "Commons: DriverResilienceStatusChanged record + driver-resilience-status TopicName", "status": "completed", "blockedBy": [] },
-    { "id": "T5", "subject": "Host: DriverResilienceStatusPublisherService (BuildMessages mapping + 5s DPS timer shell; TDD mapping in Host.IntegrationTests)", "status": "completed", "blockedBy": ["T1", "T4"] },
-    { "id": "T6", "subject": "Host DI: register the publisher in AddOtOpcUaDriverFactories + ResilienceStatusReaderRegistrationTests wiring guard (tracker HAS a production reader)", "status": "completed", "blockedBy": ["T5"] },
-    { "id": "T7", "subject": "AdminUI: IDriverResilienceStatusStore + InMemory impl + AddOtOpcUaDriverStatusServices registration (TDD mirroring DriverStatusSnapshotStoreTests)", "status": "completed", "blockedBy": ["T4"] },
-    { "id": "T8", "subject": "AdminUI: DriverResilienceStatusBridge DPS actor + spawn in WithOtOpcUaSignalRBridges", "status": "completed", "blockedBy": ["T7"] },
-    { "id": "T9", "subject": "AdminUI: resilience chip section in DriverStatusPanel.razor (in-process store read; no bUnit — verified by T10)", "status": "completed", "blockedBy": ["T7"] },
-    { "id": "T10", "subject": "Live-/run gate on docker-dev: rebuild BOTH centrals, S7 dead-endpoint breaker-open, both-replica chips, recovery clear, staleness dim", "status": "deferred-live", "blockedBy": ["T6", "T8", "T9"] },
-    { "id": "T11", "subject": "Docs + review ledger: mark 03/U10 + 04/U-5 remediated; update STATUS.md + FOLLOWUP-10", "status": "completed", "blockedBy": ["T10"] }
+    {
+      "id": "T1",
+      "subject": "Tracker: LastBreakerClosedUtc + IsBreakerOpen + RecordBreakerClose (Core, TDD in DriverResilienceStatusTrackerTests)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T2",
+      "subject": "Builder: OnClosed records breaker-close on the tracker (TDD in DriverResiliencePipelineBuilderTests)",
+      "status": "completed",
+      "blockedBy": [
+        "T1"
+      ]
+    },
+    {
+      "id": "T3",
+      "subject": "Invoker: successful Execute* resets ConsecutiveFailures (TDD in CapabilityInvokerTests)",
+      "status": "completed",
+      "blockedBy": [
+        "T1"
+      ]
+    },
+    {
+      "id": "T4",
+      "subject": "Commons: DriverResilienceStatusChanged record + driver-resilience-status TopicName",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T5",
+      "subject": "Host: DriverResilienceStatusPublisherService (BuildMessages mapping + 5s DPS timer shell; TDD mapping in Host.IntegrationTests)",
+      "status": "completed",
+      "blockedBy": [
+        "T1",
+        "T4"
+      ]
+    },
+    {
+      "id": "T6",
+      "subject": "Host DI: register the publisher in AddOtOpcUaDriverFactories + ResilienceStatusReaderRegistrationTests wiring guard (tracker HAS a production reader)",
+      "status": "completed",
+      "blockedBy": [
+        "T5"
+      ]
+    },
+    {
+      "id": "T7",
+      "subject": "AdminUI: IDriverResilienceStatusStore + InMemory impl + AddOtOpcUaDriverStatusServices registration (TDD mirroring DriverStatusSnapshotStoreTests)",
+      "status": "completed",
+      "blockedBy": [
+        "T4"
+      ]
+    },
+    {
+      "id": "T8",
+      "subject": "AdminUI: DriverResilienceStatusBridge DPS actor + spawn in WithOtOpcUaSignalRBridges",
+      "status": "completed",
+      "blockedBy": [
+        "T7"
+      ]
+    },
+    {
+      "id": "T9",
+      "subject": "AdminUI: resilience chip section in DriverStatusPanel.razor (in-process store read; no bUnit \u2014 verified by T10)",
+      "status": "completed",
+      "blockedBy": [
+        "T7"
+      ]
+    },
+    {
+      "id": "T10",
+      "subject": "Live-/run gate on docker-dev: rebuild BOTH centrals, S7 dead-endpoint breaker-open, both-replica chips, recovery clear, staleness dim",
+      "status": "deferred-live",
+      "blockedBy": [
+        "T6",
+        "T8",
+        "T9"
+      ],
+      "openNote": "PARTIAL \u2014 the resilience PIPELINE is live-verified (Polly CircuitBreaker -> Retry -> Timeout -> CapabilityInvoker in central-1 stack traces), but breaker-OPEN state was never forced: R2-09's ConnectionBackoff throttles retries so failures don't accumulate fast enough to open the Polly breaker. The reliable trigger is a rapid idempotent write to a dead endpoint. Confirmed still open 2026-07-27 (deferment.md \u00a78.5)."
+    },
+    {
+      "id": "T11",
+      "subject": "Docs + review ledger: mark 03/U10 + 04/U-5 remediated; update STATUS.md + FOLLOWUP-10",
+      "status": "completed",
+      "blockedBy": [
+        "T10"
+      ]
+    }
  ]
 }
@@ -1,30 +1,213 @@
 {
  "planPath": "archreview/plans/R2-11-tagconfig-consolidation-plan.md",
-  "lastUpdated": "2026-07-12",
+  "lastUpdated": "2026-07-27",
  "tasks": [
-    { "id": "T1",  "subject": "Golden TagConfig corpus + compose→encode→decode parity characterization test (Runtime.Tests, green on unmodified tree)", "status": "completed", "blockedBy": [] },
-    { "id": "T2",  "subject": "FullName-semantics characterization for EquipmentNodeWalker (Core.Tests) + DraftValidator Galaxy rule (Configuration.Tests)", "status": "completed", "blockedBy": [] },
-    { "id": "T3",  "subject": "TagConfigIntent + TagAlarmIntent in Commons/Types (TDD; port composer semantics verbatim + OpcUaServer ExtractTag* test tables)", "status": "completed", "blockedBy": [] },
-    { "id": "T4",  "subject": "DeviceConfigIntent (TryExtractHost/NormalizeHost) in Commons/Types (TDD)", "status": "completed", "blockedBy": [] },
-    { "id": "T5",  "subject": "AddressSpaceComposer swap: single TagConfigIntent.Parse per tag, delete 4 Extract* statics (P-1 parse-once)", "status": "completed", "blockedBy": ["T1", "T3"] },
-    { "id": "T6",  "subject": "Device-host re-home: composer TryExtractDeviceHost/NormalizeDeviceHost → DeviceConfigIntent; update DriverHostActor + DeploymentArtifact callers", "status": "completed", "blockedBy": ["T4", "T5"] },
-    { "id": "T7",  "subject": "DeploymentArtifact swap: delete 4 private mirrors, parse once per tag element via TagConfigIntent", "status": "completed", "blockedBy": ["T5"] },
-    { "id": "T8",  "subject": "DraftValidator swap: Configuration→Commons ProjectReference; ExtractTagConfigFullName → TagConfigIntent.ExplicitFullName (null-on-absent preserved)", "status": "completed", "blockedBy": ["T2", "T3"] },
-    { "id": "T9",  "subject": "EquipmentNodeWalker.ExtractFullName delegates to TagConfigIntent; repoint tree-wide canonical-parser doc cites", "status": "completed", "blockedBy": ["T2", "T3"] },
-    { "id": "T10", "subject": "Retire OpcUaServer.Tests ExtractTag*Tests (authority moved to Commons.Tests); verify zero 'MUST parse identically' hits", "status": "completed", "blockedBy": ["T3", "T5"] },
-    { "id": "T11", "subject": "TagConfigJson strict-capable readers in Core.Abstractions (TryReadEnum Absent/Valid/Invalid, ReadEnumOrDefault, ReadWritable, DescribeInvalidEnum) (TDD)", "status": "completed", "blockedBy": [] },
-    { "id": "T12", "subject": "Modbus equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T13", "subject": "S7 equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings (+ amend Contracts banner)", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T14", "subject": "AbCip equipment-tag parser: freeze test, shared readers (writable already honoured), Inspect warnings", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T15", "subject": "AbLegacy equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T16", "subject": "TwinCAT equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T17", "subject": "FOCAS equipment-tag parser: force Writable:false (05/UNDER-1 correction), shared readers, Inspect warnings (+ amend Contracts banner)", "status": "completed", "blockedBy": ["T11"] },
-    { "id": "T18", "subject": "FOCAS capability-matrix pre-flight on the equipment-tag _parseRef resolve path (BadNodeIdUnknown on rejection)", "status": "completed", "blockedBy": ["T17"] },
-    { "id": "T19", "subject": "Modbus probe parses the factory DTO shape (timeoutMs round-trip; OpcUaClient parity rule)", "status": "completed", "blockedBy": [] },
-    { "id": "T20", "subject": "EquipmentTagConfigInspector DriverType-dispatch map in ControlPlane (+6 Contracts references)", "status": "completed", "blockedBy": ["T12", "T13", "T14", "T15", "T16", "T17"] },
-    { "id": "T21", "subject": "AdminOperationsActor deploy-gate wiring + Deployment:TagConfigValidationMode (Warn default | Error opt-in); actor-level consuming test", "status": "completed", "blockedBy": ["T20"] },
-    { "id": "T22", "subject": "AdminUI writable checkbox in the six driver-typed tag editors (models + razor; live /run verify at execution)", "status": "deferred-live", "blockedBy": [] },
-    { "id": "T23", "subject": "Docs + decision record: two-mode rollout, unknown-keys non-goal, FOCAS writable migration note, STATUS.md/00-INDEX.md entries + Phase-C follow-up", "status": "completed", "blockedBy": ["T17", "T21"] },
-    { "id": "T24", "subject": "Final sweep: zero parity-comment/ReadEnum-copy grep hits; whole-solution build + test gate", "status": "deferred-live", "blockedBy": ["T5", "T6", "T7", "T8", "T9", "T10", "T12", "T13", "T14", "T15", "T16", "T17", "T18", "T19", "T21", "T22", "T23"] }
+    {
+      "id": "T1",
+      "subject": "Golden TagConfig corpus + compose\u2192encode\u2192decode parity characterization test (Runtime.Tests, green on unmodified tree)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T2",
+      "subject": "FullName-semantics characterization for EquipmentNodeWalker (Core.Tests) + DraftValidator Galaxy rule (Configuration.Tests)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T3",
+      "subject": "TagConfigIntent + TagAlarmIntent in Commons/Types (TDD; port composer semantics verbatim + OpcUaServer ExtractTag* test tables)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T4",
+      "subject": "DeviceConfigIntent (TryExtractHost/NormalizeHost) in Commons/Types (TDD)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T5",
+      "subject": "AddressSpaceComposer swap: single TagConfigIntent.Parse per tag, delete 4 Extract* statics (P-1 parse-once)",
+      "status": "completed",
+      "blockedBy": [
+        "T1",
+        "T3"
+      ]
+    },
+    {
+      "id": "T6",
+      "subject": "Device-host re-home: composer TryExtractDeviceHost/NormalizeDeviceHost \u2192 DeviceConfigIntent; update DriverHostActor + DeploymentArtifact callers",
+      "status": "completed",
+      "blockedBy": [
+        "T4",
+        "T5"
+      ]
+    },
+    {
+      "id": "T7",
+      "subject": "DeploymentArtifact swap: delete 4 private mirrors, parse once per tag element via TagConfigIntent",
+      "status": "completed",
+      "blockedBy": [
+        "T5"
+      ]
+    },
+    {
+      "id": "T8",
+      "subject": "DraftValidator swap: Configuration\u2192Commons ProjectReference; ExtractTagConfigFullName \u2192 TagConfigIntent.ExplicitFullName (null-on-absent preserved)",
+      "status": "completed",
+      "blockedBy": [
+        "T2",
+        "T3"
+      ]
+    },
+    {
+      "id": "T9",
+      "subject": "EquipmentNodeWalker.ExtractFullName delegates to TagConfigIntent; repoint tree-wide canonical-parser doc cites",
+      "status": "completed",
+      "blockedBy": [
+        "T2",
+        "T3"
+      ]
+    },
+    {
+      "id": "T10",
+      "subject": "Retire OpcUaServer.Tests ExtractTag*Tests (authority moved to Commons.Tests); verify zero 'MUST parse identically' hits",
+      "status": "completed",
+      "blockedBy": [
+        "T3",
+        "T5"
+      ]
+    },
+    {
+      "id": "T11",
+      "subject": "TagConfigJson strict-capable readers in Core.Abstractions (TryReadEnum Absent/Valid/Invalid, ReadEnumOrDefault, ReadWritable, DescribeInvalidEnum) (TDD)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T12",
+      "subject": "Modbus equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T13",
+      "subject": "S7 equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings (+ amend Contracts banner)",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T14",
+      "subject": "AbCip equipment-tag parser: freeze test, shared readers (writable already honoured), Inspect warnings",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T15",
+      "subject": "AbLegacy equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T16",
+      "subject": "TwinCAT equipment-tag parser: freeze test, shared readers, honour writable key, Inspect warnings",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T17",
+      "subject": "FOCAS equipment-tag parser: force Writable:false (05/UNDER-1 correction), shared readers, Inspect warnings (+ amend Contracts banner)",
+      "status": "completed",
+      "blockedBy": [
+        "T11"
+      ]
+    },
+    {
+      "id": "T18",
+      "subject": "FOCAS capability-matrix pre-flight on the equipment-tag _parseRef resolve path (BadNodeIdUnknown on rejection)",
+      "status": "completed",
+      "blockedBy": [
+        "T17"
+      ]
+    },
+    {
+      "id": "T19",
+      "subject": "Modbus probe parses the factory DTO shape (timeoutMs round-trip; OpcUaClient parity rule)",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": "T20",
+      "subject": "EquipmentTagConfigInspector DriverType-dispatch map in ControlPlane (+6 Contracts references)",
+      "status": "completed",
+      "blockedBy": [
+        "T12",
+        "T13",
+        "T14",
+        "T15",
+        "T16",
+        "T17"
+      ]
+    },
+    {
+      "id": "T21",
+      "subject": "AdminOperationsActor deploy-gate wiring + Deployment:TagConfigValidationMode (Warn default | Error opt-in); actor-level consuming test",
+      "status": "completed",
+      "blockedBy": [
+        "T20"
+      ]
+    },
+    {
+      "id": "T22",
+      "subject": "AdminUI writable checkbox in the six driver-typed tag editors (models + razor; live /run verify at execution)",
+      "status": "completed",
+      "blockedBy": [],
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 the typed Modbus tag editor shows the Writable toggle and saving persists `writable: yes`."
+    },
+    {
+      "id": "T23",
+      "subject": "Docs + decision record: two-mode rollout, unknown-keys non-goal, FOCAS writable migration note, STATUS.md/00-INDEX.md entries + Phase-C follow-up",
+      "status": "completed",
+      "blockedBy": [
+        "T17",
+        "T21"
+      ]
+    },
+    {
+      "id": "T24",
+      "subject": "Final sweep: zero parity-comment/ReadEnum-copy grep hits; whole-solution build + test gate",
+      "status": "completed",
+      "blockedBy": [
+        "T5",
+        "T6",
+        "T7",
+        "T8",
+        "T9",
+        "T10",
+        "T12",
+        "T13",
+        "T14",
+        "T15",
+        "T16",
+        "T17",
+        "T18",
+        "T19",
+        "T21",
+        "T22",
+        "T23"
+      ],
+      "closureNote": "LIVE GATE CLOSED 2026-07-13 \u2014 see T22. STATUS.md 'docker-dev live-/run pass'."
+    }
  ]
 }
@@ -0,0 +1,593 @@
+# Deferment register — new drivers, open issues, deferred work
+
+> **Scope.** A source-verified inventory of what is unfinished in this repo: the status of the
+> recently-added drivers, every open tracker issue, in-code deferrals, open live gates, and the
+> documentation that misstates any of it.
+>
+> **Method.** Five parallel agents swept the tree independently; every claim below was checked
+> against **source** (`src/`, `tests/`, `git log`), not against documentation. Where a doc and the
+> code disagreed, the code won and the doc is listed in §7. Findings that could not be verified
+> without hardware or a live rig are marked **CANNOT VERIFY** rather than asserted.
+>
+> **Baseline.** `master` @ `90bdaa44`, 2026-07-27. All local branches are merged into master; the
+> only unmerged remotes are three abandoned branches (`origin/auto/driver-gaps` 184 commits behind
+> since 2026-04-26, `origin/auto/driver-gaps-stash`, `origin/refactor/galaxy-mxgateway-client-rename`).
+
+---
+
+## 0. The short version
+
+The driver runtime is in good shape — **no new driver contains a stub, a `NotImplementedException`,
+or an unregistered factory.** What is unfinished clusters into four groups, in descending order of
+how much they should worry you:
+
+| # | Theme | Why it matters |
+|---|---|---|
+| **1** | **Three subsystems are fully authored, persisted, and shipped — and never executed.** Node ACLs, `IRediscoverable`/`IHostConnectivityProbe`, and `DriverTypeRegistry`. | An operator can author a rule, save it, deploy it green, and have it do **nothing**. §3 |
+| **2** | **AdminUI authoring-dispatch gaps.** Calculation is offered in the driver picker but has no config form; three drivers have no device form; CSV + browse-commit dispatch maps miss the new drivers. | The "registered but unauthorable" class that has now bitten twice. §1.2 |
+| **3** | **17 open issues, all confirmed still open**, several broader than filed. | §2 |
+| **4** | **Bookkeeping drift.** 8 `.tasks.json` files show ~140 "pending" tasks for work that shipped; 5 CLAUDE.md status claims are stale. | Someone follows the tracker and rebuilds a shipped driver. §6, §7 |
+
+Nothing here is a data-loss or outage defect. The sharpest edge is §3 — silent non-enforcement.
+
+---
+
+## 1. New drivers — source-verified status
+
+Cross-cutting facts, verified once: all 12 driver types register in one place
+(`src/Server/ZB.MOM.WW.OtOpcUa.Host/Drivers/DriverFactoryBootstrap.cs:147-164`); all 12 register a
+probe (`:119-130`) via `AddOtOpcUaDriverProbes()`, called from **both** the driver path (`:93`) and
+the admin path — **no probe is admin-node-missing**. `DriverTypeNames`
+(`src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverTypeNames.cs`) is guarded bidirectionally by
+reflection in `tests/Core/…Core.Abstractions.Tests/DriverTypeNamesGuardTests.cs`.
+
+### 1.1 Status table
+
+| Driver | Verdict | Merged | Capabilities | Notes |
+|---|---|---|---|---|
+| **MTConnect** | Complete-with-gaps | `90bdaa44` (#506) | `IDriver, IReadable, ISubscribable, ITagDiscovery, IHostConnectivityProbe, IRediscoverable` (`MTConnectDriver.cs:63`) | No `IWritable` **by design** (`:50`). No device form. |
+| **MQTT / Sparkplug B** | **Complete** | `c3a2b0f7` | `+ IRediscoverable, IAsyncDisposable` (`MqttDriver.cs:65-66`) | Cleanest of the five: picker + driver form + device form + tag editor all present. 8 open follow-up issues. |
+| **Sql** | Complete-with-gaps | `4ad54037`, follow-ups `28c28667` | `IDriver, ITagDiscovery, IReadable, ISubscribable, IHostConnectivityProbe` (`SqlDriver.cs:28-29`) | No device form; no browse-commit branch; stale comments. |
+| **Modbus RTU-over-TCP** | **Complete** | `0f38f486` (#495) | transport mode inside Modbus (`ModbusTransportMode.cs`, `ModbusRtuOverTcpTransport.cs`) | Parses transport **by name** (`ModbusDriverFactoryExtensions.cs:77-78`) — dodges the systemic numeric-enum authoring bug. |
+| **Calculation** | **Partial (authoring gap)** | pre-existing | `IDriver, IDependencyConsumer, ISubscribable, IReadable` (`CalculationDriver.cs:38`) | **Registered + offered in the picker, but has no config form.** See §1.2. |
+
+`IWritable` is absent from MTConnect, MQTT, Sql and Calculation. In all four this is **structural and
+documented**, not a stub (`MTConnectDriver.cs:50`, `MqttDriver.cs:483`, `SqlDriver.cs:15`).
+
+**Zero `NotImplementedException`** across all five drivers. Every `NotSupportedException` is either a
+`catch` filter or a deliberate domain error.
+
+### 1.2 Gaps found — AdminUI authoring & dispatch layer
+
+Every gap below is in the **authoring/dispatch layer, not driver runtime code**.
+
+| # | Gap | Evidence | Impact |
+|---|---|---|---|
+| G-1 | **`DriverConfigModal.razor` has no `Calculation` case** — falls to the `default` "No typed config form" warning; no `CalculationDriverForm.razor` exists | `DriverConfigModal.razor:34-72`, default arm `:69-71` | `CalculationDriverOptions.RunTimeout` (`CalculationDriverOptions.cs:19`) is **unauthorable via the UI**. Create/rename still work, so degraded — not a hard block. **This is the same class as the Sql picker defect, one modal further downstream.** |
+| G-2 | **`DeviceModal.razor` is missing Sql, MTConnect, Calculation** | `DeviceModal.razor:42-74`, default arm `:71-73` | Mitigated: Sql/MTConnect hold connection at the **driver** level, and Test Connect still works via `BuildMergedProbeConfig` (`:180-184`). |
+| G-3 | **`DriverConfigModal.razor:77` tells Sql/MTConnect operators the wrong thing** — the single-connection branch is hardcoded to `Galaxy or Mqtt`, so Sql/MTConnect users are told the endpoint lives on the *device* when they just authored it on the driver | `DriverConfigModal.razor:77`, `:86-88` | Actively misleading, compounds G-2. |
+| G-4 | **No parity test guards `DriverConfigModal` or `DeviceModal`** — `RawDriverTypeDialogCoverageTests`/`…ParityTests` assert `DriverTypeNames` ↔ **picker** parity only | — | **This is exactly why G-1 and G-2 survived review.** The guard pattern exists and simply was not extended to the two downstream dispatch maps. |
+| G-5 | **`CsvColumnMap` has no typed columns for Sql, MQTT, MTConnect** | `CsvColumnMap.cs:340-452` | CSV import/export degrades to the raw `TagConfigJson` fallback while the 7 older drivers get typed columns. |
+| G-6 | **`RawBrowseCommitMapper` has no Sql branch** — falls to the generic `WriteSingleKey("address", …)` whose comment claims "Browsable drivers are all handled above" | `RawBrowseCommitMapper.cs:121-141`, fallback `:145` | Untrue since `SqlDriverBrowser` was registered (`EndpointRouteBuilderExtensions.cs:83`). Same failure mode the MTConnect branch (`:135-139`) was added to avoid: typed editor opens empty, blanks the field on save. |
+| G-7 | **`EquipmentTagConfigInspector` covers only 6 driver types** | `:24-29` | Pre-existing (OpcUaClient + Galaxy absent too); no new driver was added. |
+
+### 1.3 Stale in-code comments (harmless at runtime, misleading to the next reader)
+
+- `DriverTypeNames.cs:22-25` — Calculation described as "not-yet-registered"; it registers at `DriverFactoryBootstrap.cs:149`.
+- `TagConfigEditorMap.cs:25-28` + `TagConfigValidator.cs:27-28` — "`DriverTypeNames.Sql` deliberately absent until Task 11"; the constant exists (`DriverTypeNames.cs:57`) and the values are identical, so behaviour is correct.
+- `RawDriverTypeDialog.razor:2-4, 59-60` — "its factory lands in Wave C".
+- `CsvColumnMap.cs:322-324` — hardcodes `CalculationDriverType = "Calculation"` "Not yet a `DriverTypeNames` constant"; it has been one since `DriverTypeNames.cs:54`.
+- ~~`SqlDriver.cs:218-220` — justifies not re-parsing config on the premise "the factory builds a fresh
+  instance", **disproved** by `DriverInstanceActor.cs:316` + `DriverHostActor.cs:2565`.~~ ✅ **Fixed** —
+  the comment now says the premise was false when written and is true *now* because a config change
+  respawns. See §9.
+
+---
+
+## 2. Open tracker issues — all 17 verified against source
+
+**No issue was found stale.** 11 CONFIRMED, 4 PARTIALLY (core claim holds, a sub-claim is wrong or
+incomplete), 2 CANNOT VERIFY (correctly filed as hardware/fixture-gated).
+
+| # | Title (abbrev.) | Verdict | Key evidence | Kind |
+|---|---|---|---|---|
+| **518** | `IRediscoverable` + `IHostConnectivityProbe` have no consumer; CLAUDE.md wrong | **CONFIRMED — worse than filed** | Only `+=` in `src/` are Galaxy self-wiring (`GalaxyDriver.cs:586`, `:221`). `GetHostStatuses()` has **zero call sites** outside the interface + implementations; `DriverHostStatuses` DbSet is referenced only by its declaration and a test. | Defect + doc error |
+| **507** | Discovered-node injection inert in v3 | **CONFIRMED** | `DriverHostActor.cs:986-1002` hard-`return;` + `#pragma warning disable CS0162` (restored `:1077`) | Deferred (deliberate guard) |
+| **519** | No Bad/Uncertain **sub-code** reaches a client | **CONFIRMED** | Collapse at `DriverInstanceActor.cs:1033-1041` (`statusCode >> 30`), re-expand at `OtOpcUaNodeManager.cs:3318-3322`. Enum is 3-state at `IOpcUaAddressSpaceSink.cs:165`. **Wider than filed** — `StatusFromQuality` also used at `:429/:506/:576/:761`, so alarm-condition Quality collapses too. | Design consequence |
+| **517** | Health published AFTER teardown | **CONFIRMED, fleet-wide** | `ModbusDriver.cs:244-250`, `MTConnectDriver.cs:579-590`, `S7Driver.cs:292-326` — all `Teardown…` then `WriteHealth(Unknown)`; `GetHealth()` is a plain field read | Defect (race) |
+| **516** | Driver config edits silently discarded | **CONFIRMED — survey now complete** | `DriverInstanceActor.cs:316` (only `_driver` assignment) + `DriverHostActor.cs:2565` (`Tell` existing child, no respawn) + `:653/:660` (green seal). **Affected: Modbus, FOCAS, OpcUaClient, + AbLegacy (issue missed it), + Sql (deliberate/documented).** AbCip/TwinCAT re-parse ✅; Galaxy fails **loud** (throws, `GalaxyDriver.cs:600-641`) | Defect |
+| **515** | Sparkplug `DataSet`/`Template`/`PropertySet` | **CONFIRMED** | `SparkplugCodec.cs:207-210` decode to `Unsupported` — visible refusal, not silent drop. *(`PropertySet` isn't a `ValueOneofCase`; it rides `metric.Properties`)* | Deferred feature |
+| **514** | Rebirth unarmable on a plant that hasn't birthed | **CONFIRMED** | `RawBrowseModal.razor:119-120` disabled; `_rebirthTarget` set only by tree-click handlers (`:432`, `:437`, `:439-451`). Empty tree ⇒ permanently disabled | Defect (chicken-and-egg) |
+| **513** | Meaningless `payloadFormat` in Sparkplug blob | **CONFIRMED** | `MqttTagConfigModel.cs:210` unconditional `Set`, vs. mode-aware `:216` | Defect (cosmetic) |
+| **512** | `.Browser` → `.Driver` layering | **CONFIRMED** | `…Mqtt.Browser.csproj:43` (**not :44**), boxed "KNOWN, DELIBERATE EXCEPTION" at `:16-42` | Deferred refactor |
+| **511** | `ActAsPrimaryHost` does nothing | **CONFIRMED** | Option at `MqttDriverOptions.cs:193`, round-tripped in the UI, handled only by a warning at `MqttDriver.cs:933-948`. No STATE publish, no Last Will | Deferred feature |
+| **510** | `_canRebirth` captured at browse-open | **CONFIRMED** | `RawBrowseModal.razor:377` sole `true` assignment; failure path `:516-539` never re-evaluates | Defect (stale affordance) |
+| **509** | Metric name with `/` unbrowse-committable | **CONFIRMED** | `RawBrowseCommitMapper.cs:63` uses browse name verbatim → `RawPaths.cs:39` rejects `/` → `RawTreeService.cs:976` **all-or-nothing** kills the whole batch | Defect |
+| **508** | MQTT write-through | **CONFIRMED** | `MqttDriver.cs:66` — no `IWritable`; consequence at `DriverInstanceActor.cs:673-677` | Deferred feature |
+| **507**→ see above | | | | |
+| **491** | Continuous-historization live gate | **CANNOT VERIFY** (needs VPN'd gateway) | Code **is** complete: `AddressSpaceApplier.cs:238`→`:540`→`ActorHistorizedTagSubscriptionSink.cs:27-38`→`ContinuousHistorizationRecorder.cs:84`, wired `ServiceCollectionExtensions.cs:435` | Deferred test |
+| **489** | Hot-rebind renamed raw tag | **CONFIRMED** | No implementation exists | Deferred feature |
+| **481** | Comms-loss → scripted-alarm quality (Layer 4) | **CONFIRMED** | `DriverHostActor.cs:1356-1379` iterates `_alarmNodeIdByDriverRef` only. **Issue is wrong that the per-driver ref set is missing** — `_nodeIdByDriverRef` exists at `:193`; only the fan-out into the mux is absent, so the work is *smaller* than filed | Deferred feature |
+| **468** | Wave-0 browser tree render | **CANNOT VERIFY** (fixture) | Code path present (`AbCipDriver.cs:1092-1095`, `LibplctagTagEnumerator.cs:29-37`); `ab_server` returns `ErrorUnsupported` for CIP Symbol Object enumeration | Deferred verification |
+
+### 2.1 Cross-cutting observations
+
+1. **#518 → #507 are the same failure, stacked.** The event has no subscriber *and* its downstream
+   handler hard-returns. **Fixing either alone changes nothing observable** — schedule them together.
+2. **#516 is a superset of part of #489.** For the five drivers that discard reinit config, the
+   renamed-tag-never-rebinds symptom follows mechanically (their `_tagsByRawPath` still keys on the
+   old RawPath). Re-scope #489 after #516.
+3. **#519 and #481 share the same `statusCode >> 30` collapse idiom** at three independent sites
+   (`DriverInstanceActor.cs:1033`, `ScriptedAlarmEngine.cs:745`, `:777`). Widening the status path
+   must cover all three.
+
+---
+
+## 3. Dead seams — authored, shipped, never executed
+
+**The most consequential category in this register**, and the one nothing in the code flags. Three
+subsystems are fully built and reachable by operators, but no production code path executes them.
+
+### 3.1 Node-level ACLs are authorable, deployed — and unenforced
+
+- `IPermissionEvaluator`, `TriePermissionEvaluator`, `PermissionTrieCache`, `PermissionTrieBuilder`
+  have **zero references outside `src/Core/ZB.MOM.WW.OtOpcUa.Core/Authorization/` and their own
+  tests** (independently re-verified for this report: every other grep hit is a `bin/`/`obj/` XML doc artifact).
+- `OtOpcUaNodeManager` contains **no reference to `Permission` or `Evaluator` at all.**
+- Meanwhile `ClusterAcls.razor` + `AclEdit.razor` let operators author `NodeAcl` rows, and
+  **`ConfigComposer.cs:51` snapshots them into every deployment artifact.**
+
+**Impact:** an operator authors a deny rule, deploys it green, and it has no effect. Actual
+enforcement is coarse LDAP roles plus the realm-qualified `WriteOperate` gate in the node manager —
+and that is a **write** gate; reads carry no per-node ACL check.
+**`docs/ReadWriteOperations.md:13,21` states the opposite** (see §7.1) — it is the single
+highest-risk doc error found.
+
+### 3.2 `IRediscoverable` + `IHostConnectivityProbe` raise into the void
+
+Gitea #518/#507. Nine drivers raise; nothing consumes. `DriverHostStatus` table exists
+(`OtOpcUaConfigDbContext.cs:48`, migration `20260715230637_V3Initial.cs:108`) with a doc-comment
+claiming a writer — **nothing ever writes a row.**
+
+**Impact:** an Agent/PLC/Galaxy restart leaves a stale address space behind a Healthy driver, and the
+per-host connectivity table is permanently empty.
+
+### 3.3 `DriverTypeRegistry` is vestigial
+
+Independently verified for this report: `src/Core/…Core.Abstractions/DriverTypeRegistry.cs:20` is
+referenced **only** by `tests/Core/…/DriverTypeRegistryTests.cs`. Nothing registers metadata at
+startup; nothing validates `DriverInstance.DriverType` against it. Its `AllowedNamespaceKinds` field
+was retired with the v3 `Namespace` entity (`DriverTypeRegistry.cs:97`).
+
+**Knock-on:** the driver **stability tier** does not come from here either. The live source is
+`DriverFactoryRegistry.cs:46` (`DriverTier tier = DriverTier.A`) and **no factory in `src/Drivers/`
+passes a tier** — so all 12 drivers run Tier A, and the Tier-C-only protections are dormant for
+every driver: `MemoryRecycle.cs:54` (`when _tier == DriverTier.C`) and
+`ScheduledRecycleScheduler.cs:43` (refuses unless Tier C). `docs/v2/driver-stability.md` still
+assigns Galaxy and FOCAS to Tier C.
+
+### 3.4 Related dead/dormant code
+
+| Item | Evidence |
+|---|---|
+| `IDriverConfigEditor` — interface, zero implementors, zero production consumers | `Core.Abstractions/IDriverConfigEditor.cs:9`; superseded by `TagConfigEditorMap` / `DriverConfigModal` |
+| `GenericDriverNodeManager` — explicitly **not** a production dispatch path | `Core/OpcUa/GenericDriverNodeManager.cs:71` ("verified 07/#10: zero production references") |
+| `IDriverSupervisor` — Tier-C recycle machinery has **zero implementations**, yet the parser still validates `RecycleIntervalSeconds` | archreview 01/U-2 |
+| Resilience **bulkhead** — documented, defaulted, parsed, AdminUI-authorable; `Build` never adds a concurrency limiter | archreview 01/U-6 |
+| `WriteIdempotentAttribute` — zero readers; write dispatch hardcodes `isIdempotent: true` | archreview 01/S-8 = 03/S12 |
+| ~60 lines of unreachable code retained behind #507's guard | `DriverHostActor.cs:1002`, `#pragma warning disable CS0162` |
+| Three empty `Driver.Historian.Wonderware*` directories (0 `.cs`, no `.csproj`, absent from `.slnx`) | verified for this report — only stale `bin/`+`obj/` remain |
+
+---
+
+## 4. In-code deferrals by subsystem
+
+The tree is unusually clean on classic markers: **9 `TODO`s across 1,812 files; zero
+`FIXME`/`HACK`/`XXX`/`WORKAROUND`; zero `#if false`; zero `[Obsolete]` on project code; zero
+commented-out DI registrations.** Real deferred work lives in prose doc-comments and skipped tests.
+
+### 4.1 Highest-consequence
+
+| Item | Evidence |
+|---|---|
+| **Telemetry snapshot cache never evicted** — a decommissioned driver replays last-known Health/Resilience to new subscribers forever | `TelemetryLocalHub.cs:40` `TODO(mesh-phase5+)` — self-declared, bounded, "pre-production, accepted" |
+| **Device host recovered by string-matching instead of `DeviceConfig`** — 7 of the repo's 9 TODOs are this one item, across 4 drivers | `FocasDriver.cs:137,287`; `TwinCATDriver.cs:775`; `AbLegacyDriver.cs:557`; `AbCipDriver.cs:89,1272` + `AbCipDriverOptions.cs:130` — all `TODO(v3 WaveC)` |
+| **Galaxy writes can never confirm a COM commit** — empty status array ⇒ provisional Good, metered `galaxy.writes.unconfirmed` | `GatewayGalaxyDataWriter.cs:44,328,354` — **cross-repo**, blocked on mxaccessgw |
+| **Subscription liveness undetectable** — `ISubscriptionHandle` is opaque | `DriverInstanceActor.cs:527` (#488) — well-reasoned, deferred "until a real occurrence" |
+| **`/raw` "Browse device" is still a placeholder** despite the universal discovery browser landing | `RawTree.razor:15,426` — **verify**; may be reachable now via `DiscoveryDriverBrowser` |
+
+### 4.2 Per-driver
+
+- **S7** — array **writes** unsupported entirely (`S7Driver.cs:1139`); several array *read* types unsupported (`:386,404,413,419,428,442,465,807,959`) — all fail fast at config-validation; legacy C-area counter reinterpretation live-hardware-gated (`:759`); Counter BCD on S7-300/400 undecoded.
+- **AbCip** — ALMD-only alarm projection, ALMA deferred (`AbCipAlarmProjection.cs:16,324`); no CIP Template Object reader, UDT layouts declaration-driven (`AbCipDriverOptions.cs:172`); whole-UDT writer deferred (`LibplctagTagRuntime.cs:190`); `AckCmd` pulse must be wired client-side (`:30`).
+- **Sql** — `SqlTagModel.Query` deferred to P3, **enforced end-to-end** across parser, validator, planner and editor (`SqlProvider.cs:22,37`; `SqlEquipmentTagParser.cs:24,103`; `SqlGroupPlanner.cs:44,249`; `SqlTagConfigModel.cs:114`) — exemplary deferral discipline. Postgres/ODBC dialects deferred behind `ISqlDialect`.
+- **MTConnect** — `TIME_SERIES` vectors deferred to P1.5; `DATA_SET`/`TABLE` coded `BadNotSupported` with a null value rather than approximated (`MTConnectObservationIndex.cs:53,272`) — deliberately chosen over a Good-coded lie. `RawTagEntry.DeviceName` ignored for routing (two `/raw` Devices under one driver share an Agent connection) — "a design change, not a bug fix". No DataType-vs-blob validation at authoring.
+- **MQTT** — `MaxPayloadBytes` is a constructor knob, not operator-facing (`MqttSubscriptionManager.cs:170`).
+- **TwinCAT** — Flat-mode struct expansion carries a **LIVE RISK** note, unverified against a real TC3 target (`AdsTwinCATClient.cs:270`); VirtualTree-mode browse unverified; TC2 coverage, multi-hop AMS route and lab rig all hardware-blocked (`docs/v3/twincat-backlog.md`).
+- **FOCAS** — forces read-only regardless of authored `writable:true`; servo-load semantics inferred from the wire, unconfirmed against a real CNC (`FocasWireClient.cs:944`); `"Backend": "unimplemented"` is a **deliberate fail-fast stub**, not unfinished work.
+- **Historian.Gateway** — String/DateTime/Reference writes deferred, gated on the analog SQL write path; `UInt16 → Uint4` widening because the `UInt2` write path is deferred upstream (`HistorianTypeMapper.cs:27-51`).
+
+### 4.3 Fleet-wide OPC UA gaps
+
+- **Array writes deferred across all drivers**; **multi-dimensional arrays (`ValueRank>1`) unsupported**; **array historization** is an opaque blob with no per-element history (`docs/Uns.md:288-292`, `AddressSpaceApplier.cs:873`, `OtOpcUaNodeManager.cs:1764`).
+- **`HistoryUpdate`** — permission bit `1<<12` shipped but excluded from every composite bundle; no service surface (`NodePermissions.cs:34`).
+- **`Utils.Log*` is `[Obsolete]`** in SDK 1.5.378, suppressed at 8 sites in `OtOpcUaNodeManager` pending an `ITelemetryContext` rewire.
+
+### 4.4 Skipped tests — 36, from 4 reason constants
+
+| Count | Reason | Assessment |
+|---|---|---|
+| 18 | `DiscoveryInjectionDormantV3` | **Real** — blocked on #507 |
+| 13 | `EquipmentTagsDarkBatch4` | **STALE** — the reason says these unblock "at Batch 4"; Batch 4 shipped as v3.0 and the path was *retired* (`AddressSpaceApplier.cs:415` calls it "the vestigial equipment-tag path"). These will never unskip as written — delete or rewrite the reason. |
+| 4 + 1 | `EquipmentDeviceBindingRetired`, `DarkBatch4` | Intentional tombstones preserving retirement rationale — fine as-is |
+
+Plus **4 whole OpcUaClient test suites that are scaffold-only**, awaiting an in-process OPC UA server
+fixture that was never built (`OpcUaClientSubscribeAndProbeTests`, `…DiscoveryTests`,
+`…ReadWriteTests`, `…HistoryTests`, all `:10`).
+
+All env-gated integration suites **skip cleanly** when their vars are absent. The MTConnect gate is
+notably a **real `/probe` reachability + payload-shape check** (`MTConnectAgentFixture.cs:42`), not
+mere env-var presence, so it cannot pass vacuously.
+
+---
+
+## 5. Open live gates
+
+| Gate | Status | Evidence |
+|---|---|---|
+| **Continuous-historization value capture** (#491) | **OPEN** — code complete, unproven in production | `CLAUDE.md:710`; no gate-passed commit exists |
+| **Wave-0 universal discovery browser** full tree render (#468) | **OPEN** — fixture-blocked | tracking doc §Wave 0; named as blocking BACnet browse |
+| **archreview R2-03** — VT Good→Bad on a data-fed rig | **OPEN** — explicitly "live-blocked on this data-less rig" | `archreview/plans/STATUS.md` |
+| **archreview R2-10** — force breaker-OPEN live | **OPEN** — breaker-OPEN state never forced live | `archreview/plans/R2-10-*.tasks.json` |
+| **Driver-reconfigure-while-faulted** Task 3 | **OPEN** — task subject literally "DEFERRED" | `2026-07-14-driver-reconfigure-while-faulted-plan.md.tasks.json` |
+| Galaxy `ScanStateProbeParityTests` | **OPEN** — licence-gated (one `$WinPlatform` on this box) | `docs/v2/Galaxy.ParityRig.md:180` |
+| **v2 GA exit criteria** — FOCAS live-CNC wire smoke (#54), OPC UA CTT/compliance pass, Ignition 8.3 redundancy cutover | **OPEN** — manual/hardware/external-tool | `docs/v2/v2-release-readiness.md:105-120` |
+| mesh Phase 4 | ✅ **PASSED** `1281aebf` | CLAUDE.md said open — **corrected**, §7.2 |
+| mesh Phase 5 | ✅ **PASSED** `f134935f` | CLAUDE.md said pending — **corrected**, §7.2 |
+| auto-down 1-vs-1 crash-the-oldest | ✅ **PASSED** — Phase 7 drill D4, `c50ebcf7` | CLAUDE.md said open — **corrected**, §7.2 |
+
+**Note on the 14 archreview `deferred-live` tasks across 8 plans:** `archreview/plans/STATUS.md:242-305`
+records a 2026-07-13 live pass closing several (R2-02, R2-07, R2-11, R2-04, R2-05-partial) and
+2026-07-15 closures for R2-01/R2-08/R2-06 — **but the `.tasks.json` files were never updated.** Only
+R2-03 and R2-10 have no closure record anywhere.
+
+---
+
+## 6. Plan bookkeeping — stale vs. live
+
+**59 of 78 `docs/plans/*.tasks.json` are 100 % complete.** Of the remaining 19, most are stale
+bookkeeping, not backlog.
+
+### 6.1 STALE — work shipped, file never updated (~140 phantom "pending" tasks)
+
+| File | Recorded | Reality |
+|---|---|---|
+| `2026-07-24-mtconnect-driver.md.tasks.json` | 23 pending | Merged at master tip `90bdaa44`, 5-leg live gate PASSED |
+| `2026-07-24-mqtt-sparkplug-driver.md.tasks.json` | 27 pending | All 27 done, both phases live-gated |
+| `2026-07-24-sql-poll-driver.md.tasks.json` | 22 pending | Merged `4ad54037` + follow-ups `28c28667` |
+| `2026-07-24-modbus-rtu-driver.md.tasks.json` | 11 pending | Merged `0f38f486` (#495), live gate PASSED |
+| `2026-06-26-otopcua-historian-gateway-integration.md.tasks.json` | 21 pending | Shipped as PR #423, live-validated |
+| `2026-06-15/16-stillpending-phase-{0-1,2,3,4}.md.tasks.json` | 12+9+10+8 pending | Shipped — audit §D cites `1e95856b`, `ada01e1a`, `fc8121cb`, `3e609a2b`, `70e6d3d2`, `c236263e`, `bd8fee61`, `5e27b5f7`, `fcb38014` |
+| `2026-07-22-per-cluster-mesh-program.md.tasks.json` | Phase 2 in_progress, 3–7 pending | Plan body `:331-342` says **program COMPLETE** |
+| `2026-06-12-historian-tcp-transport.md.tasks.json` | 12 pending | **OBSOLETE** — targets the retired Wonderware sidecar |
+
+### 6.2 GENUINELY LIVE
+
+| File | Open | Note |
+|---|---|---|
+| **`2026-05-29-adminui-followups.md.tasks.json`** | **19 pending / 0 completed** | **The largest unexecuted plan in the tree.** Generic `CollectionEditor<TRow>`; per-driver device/tag editors ×7; typed resilience form; `RoleMapper.Merge` + DB-backed LDAP→role mapping + `RoleGrants.razor` + FleetAdmin authz. **Several items look superseded by v3's `TagConfigEditorMap` — verify overlap before executing.** |
+| `2026-06-19-followups-batch.md.tasks.json` | 4 pending + 1 partial | B4 F10b surgical DataType/IsArray writes and B5 alarm-severity `SetSeverity` are **OPEN-by-choice, not built** |
+| `2026-06-26-otopcua-fixedtree-followups.md.tasks.json` | 1 pending | Task 11 build + regression |
+| `2026-05-26-akka-hosting-alignment-plan.md.tasks.json` | 5 partial | F8/F9/F10/F13/F14 — oldest open items; **likely superseded by v3, verify** |
+| `2026-05-28-adminui-driver-pages-plan.md.tasks.json` | 1 partial | 10.4 manual smoke checklist |
+
+`docs/plans/2026-07-23-mesh-phase4-…tasks.json` Task 9 was the only `deferred`-flagged mesh task —
+**it has since landed** (`3a590a0c`), so that file is now stale too.
+
+### 6.3 Review-directory state
+
+- **`code-reviews/`** — 51 modules, **zero Open findings**. One textual "Left Open pending a decision"
+  survives in a finding body (`Configuration/findings.md:254`, LDAP collation) whose status field
+  reads Deferred — the only index inconsistency.
+- **`code-reviews/` coverage gap** — **10 shipped source projects have never been reviewed**:
+  `Driver.Calculation`, `Driver.Historian.Gateway`, `Driver.Mqtt` (+`.Browser`, `.Contracts`),
+  `Driver.MTConnect` (+`.Contracts`), `Driver.Sql` (+`.Browser`, `.Contracts`). Meanwhile three
+  modules review the **retired** Wonderware backend.
+- **`archreview/`** — `00-OVERALL.md:60-79` carries an explicit "Carried open … no remediation branch
+  targeted them" block. The largest coherent batch is the **failure-visibility trio**: 01/S-1
+  (`AddressSpaceApplier` swallows every sink failure, deploy reports Applied even when broken), 03/S4
+  (primary gate default-allow on unknown role), 06/S-1 (Galaxy optimistic write success).
+- **`stillpending.md` does not exist** — the backlog is `docs/plans/2026-06-18-stillpending-backlog-audit.md`.
+
+---
+
+## 7. Documentation corrections
+
+### 7.1 Applied in this pass
+
+| File | Was | Now |
+|---|---|---|
+| `CLAUDE.md` §Change Detection (`:156`) | "The server's `DriverHost` consumes the signal and rebuilds the address space" | ⚠️ nothing consumes it; names `DriverHostActor.cs:986`, #518/#507, and the four affected drivers |
+| `CLAUDE.md` §Redundancy (`:272`) | auto-down "live gate is still open … docker-dev is a single six-node mesh" | gate **CLOSED** by Phase 7 drill D4 (`c50ebcf7`); the six-node-mesh claim also contradicted CLAUDE.md's own Phase 6 paragraph |
+| `CLAUDE.md` §Telemetry (`:383`) | Phase 5 "code-complete on `feat/mesh-phase5`, live gate pending" | merged `35552a96`; live gate PASSED `f134935f` |
+| `CLAUDE.md` §Phase 4 (`:493`, `:502-503`) | `ScriptedAlarmState` "dropping it is a deferred follow-up, tracked as Task 9"; "Task 9 and the live gate (Task 10) are still open" | table **dropped** (`3a590a0c`, migration `20260723183050_DropScriptedAlarmStateTable`); live gate PASSED `1281aebf` |
+| `docs/plans/2026-07-24-driver-expansion-tracking.md` | Modbus RTU "pending merge"; SQL poll "📝 Plan ready (22 tasks)"; **an "Executing a plan" table instructing you to rebuild both** | both marked ✅ Done with merge SHAs; the two shipped rows struck from the command table; Wave 1/2 headings and §Next actions corrected |
+| `docs/drivers/README.md` | `DriverTypeRegistry` "registered at startup"; "namespace kinds (Equipment + SystemPlatform)"; no Sql/Calculation rows; "Modbus TCP" only | registry marked vestigial + tier truth; namespace line corrected to Raw+UNS; Sql + Calculation rows added; Modbus row covers RTU-over-TCP |
+| `docs/drivers/TwinCAT.md` (`:95`, `:99-103`, `:151`) | "so the address space is rebuilt" / "so Core rebuilds the address space" | raises-but-unconsumed caveat, mirroring the wording `Mqtt.md`/`MTConnect.md` already use correctly |
+| `docs/drivers/Galaxy.md` (`:73`) | `IRediscoverable` row with no caveat | same caveat added |
+| `docs/v2/Runtime.md` (`:106`) | "named-pipe IPC to the Wonderware historian sidecar + `SqliteStoreAndForwardSink`" | gRPC to HistorianGateway + `LocalDbStoreAndForwardSink` |
+| **`docs/ReadWriteOperations.md`** (`:13`, `:21` + banner) | "ACL enforcement (`WriteAuthzPolicy` + `AuthorizationGate`) runs before the source branch"; "**A denied read never hits the driver**" | Both struck through and corrected; banner states plainly that **no per-node ACL gate exists on any operation** and that `GenericDriverNodeManager` is test scaffolding. **This was the highest-risk doc error found.** |
+| **`docs/IncrementalSync.md`** (banner) | whole "Rebuild flow" + generation-publish path presented as current | Banner: `GenericDriverNodeManager` is non-production, rediscovery has no consumer, `sp_PublishGeneration`/`sp_ComputeGenerationDiff` `RAISERROR`, `DraftRevisionToken` gone; names the one live path (deploy artifact) |
+| **`docs/AddressSpace.md`** (banner) | "single custom namespace"; `Phase7Applier`/`Phase7Composer`/`GalaxyTagPlan`; `SystemPlatform` | Banner: two namespaces w/ `V3NodeIds`, the `AddressSpace*` rename (`40e8a23e`), `AddressSpaceComposition` as the result type, `SystemPlatform` retired |
+| `docs/v2/phase-7-status.md`, `v2-release-readiness.md`, `redundancy-interop-playbook.md`, `AdminUI-rebuild-plan.md` (banners) | present-tense claims about types that no longer exist | Dated "⚠️ Historical" banners naming the specific dead types. `v2-release-readiness.md`'s banner also flags that its `:41` "ACL enforcement Closed" row is false, while noting its unchecked GA exit criteria **are** still live. (`docs/StatusDashboard.md` already self-declares Superseded — left alone.) |
+| `docs/OpcUaServer.md` (`:14`, `:51`), `docs/README.md` (`:65`), `docs/drivers/OpcUaClient-Test-Fixture.md` (`:127`) | `WriteAlarmState`; `LdapUserAuthenticator` ×2; `RedundancyCoordinator` | `WriteAlarmCondition`; `LdapOpcUaUserAuthenticator`; `RedundancyStateActor` + `IRedundancyRoleView` |
+| `docs/Historian.md` | no mention of #491 or the provisioning gap | ⚠️ block added: continuous value capture is **code-complete but unproven in production**, with the wiring chain; plus the `EnsureTags`-skips-existing-tags gap |
+
+### 7.2 Recorded, NOT applied — needs a decision or a rewrite, not a line edit
+
+The three highest-priority items in this list were **bannered rather than rewritten** in this pass
+(cheap, stops the misleading, preserves the record) — the underlying rewrite is still owed. They now
+appear in §7.1 as well.
+
+| Priority | File | Problem |
+|---|---|---|
+| **1 (security-relevant)** | `docs/ReadWriteOperations.md:13,21` | **Bannered + struck through.** Claimed ACL enforcement via `WriteAuthzPolicy` + `AuthorizationGate` + `NodeScopeResolver` and that "a denied read never hits the driver". All four names have zero hits in `src/`; §3.1 shows there is no read-path ACL gate at all. **Still owed:** a proper §-rewrite against the real node-manager write gate. Same false claim at `docs/v2/v2-release-readiness.md:41` (bannered). |
+| **2** | `docs/IncrementalSync.md` | **Bannered.** Entire "Rebuild flow" (`:37-47`) built on non-production `GenericDriverNodeManager`; `:26-34` cites `sp_PublishGeneration`/`sp_ComputeGenerationDiff`, both retired stubs that `RAISERROR` (`20260715230637_V3Initial.StoredProcedures.cs:194`); `:31` cites `DraftRevisionToken` (0 hits); `:49-51` describes a `ScopeHint` no consumer reads. **Still owed:** rewrite around the deploy-artifact path, or archive to `docs/v1/`. |
+| **2** | `docs/AddressSpace.md` | **Bannered.** v2-era throughout: `:7,42` claim a single namespace (v3 has two); `:7,48,70` cite `Phase7Applier` + `GalaxyTagPlan` + a nonexistent file path; `:62-64` repeats the rediscovery claim. **Still owed:** rewrite §"Root folder" + §"NodeId scheme" against `V3NodeIds` / `AddressSpaceRealm`. |
+| 3 | 6 docs, ~20 citations | **`Phase7*` → `AddressSpace*`** rename (`40e8a23e`). Mostly mechanical, **except three that are not renames** and need the real member identified first: `Phase7CompositionResult` → **`AddressSpaceComposition`** (`AddressSpaceComposer.cs:13`, verified for this report); `Phase7Composer.ExtractTagFullName` → nearest live seam is `ScriptTagCatalog.ExtractFullNameFromTagConfig`; **`Phase7EngineComposer.RouteToHistorianAsync` is simply gone** — the real seam is `HistorianAdapterActor` → `IAlarmHistorianSink`. |
+| 3 | `docs/v2/driver-specs.md` | Covers 8 of 12 drivers (missing MQTT, MTConnect, Sql, Calculation, and the Modbus `Transport` selector) while `docs/drivers/README.md` calls it authoritative "for **every** driver". Either add four sections or downgrade the claim. |
+| 3 | `docs/v2/driver-stability.md:47-54` | Puts Galaxy and FOCAS in Tier C; `docs/drivers/README.md` says Tier A for both. **Moot at runtime** — see §3.3 — but the two docs contradict each other. |
+| 3 | `docs/drivers/Sql.md`, `docs/drivers/Calculation.md` | **Do not exist.** Sql is documented only in design/plan/research files; Calculation only at `docs/Raw.md:66-69`. |
+| — | `docs/operations/2026-07-16-secrets-clustered-master-key.md:38` | `NoOpSecretReplicator` exists **only** in a test. **Investigate before editing** — the sentence makes a security-relevant claim ("no built-in cross-node replication today"), so it needs the real behaviour identified, not a rename. Left untouched deliberately. |
+| — | `docs/v2/driver-specs.md` §2 | `docs/drivers/Modbus.md:10-11` points readers here for the Modbus config shape, and this file omits the `Transport` selector. Folded into the driver-specs item above. |
+
+---
+
+## 8. Recommended sequencing
+
+1. ~~**§3.1 ACL enforcement** — decide: wire `IPermissionEvaluator` into `OtOpcUaNodeManager`, or
+   remove the authoring UI and say plainly that ACLs are not enforced. Either way fix
+   `docs/ReadWriteOperations.md` first; it is the one that could mislead a security review.~~
+   ✅ **Done** — decided *make non-enforcement explicit*; wire-up tracked as Gitea **#520**. See §9.
+   (`docs/ReadWriteOperations.md` was **not** the sharpest one — `docs/security.md` was.)
+2. ~~**#518 + #507 together** — neither fix is observable alone.~~ ✅ **Done.** The framing was right
+   that they had to be handled together, but wrong about the resolution: **#507 was not revivable**,
+   so it was deleted rather than fixed. See §9.
+3. ~~**#516** — silent config discard on 5 drivers; then re-scope #489, which it partly subsumes.~~
+   ✅ **Done.** See §9. #489 is still open and should now be re-scoped.
+4. ~~**G-4** — extend the existing picker-parity test to `DriverConfigModal` + `DeviceModal`; it would
+   have caught G-1 and G-2 for free, and this class has now recurred twice.~~ ✅ **Done**, together with
+   G-1, G-2, G-3, G-5 and G-6. See §9.
+5. ~~**Bookkeeping sweep** — mark the 8 stale `.tasks.json` files complete so the 19-task AdminUI plan
+   (§6.2) is visible as the real backlog it is.~~ ✅ **Done.** See §9.
+6. ~~**§3.3 tier truth** — either pass real tiers at factory registration or delete the Tier-C
+   machinery; today it is documented, authorable and dormant.~~ ✅ **Documented**; the keep-or-delete
+   code decision is Gitea **#522**. See §9.
+
+---
+
+## 9. Execution log
+
+Remediation of §8, on branch `feat/deferment-remediation`. Status is updated in the **same commit** as
+the work, so this register never disagrees with the tree.
+
+| §8 item | Status | Commit |
+|---|---|---|
+| 1. ACL enforcement decision | ✅ **Done** — decided *make non-enforcement explicit*; Gitea **#520** tracks the wire-up | `d1e88dc4` |
+| 2. #518 + #507 | ✅ **Done** — `IRediscoverable` consumed as a re-browse prompt; #507's injection path **deleted**; `IHostConnectivityProbe` half split to Gitea **#521** | `09a401b8`, `97c9f4b4` |
+| 3. #516 config discard | ✅ **Done** — seam respawn + re-parse on 3 drivers; Sql/FOCAS deliberately respawn-only | `2dc19f30` |
+| 4. G-4 dispatch-map parity | ✅ **Done** — G-1…G-6 all closed, live-verified on docker-dev | `abacf4cf` |
+| 5. Bookkeeping sweep | ✅ **Done** — 13 plan files closed, 11 archreview gates written back | `03658c2e` |
+| 6. Tier truth | ✅ **Done** — docs reconciled; keep-or-delete is Gitea **#522** | `03658c2e` |
+
+### 2026-07-27 — §8.1 ACL non-enforcement made explicit
+
+Decision: **do not wire the evaluator, do not delete it** — state plainly that it does not run, and
+track the wire-up as **Gitea #520**.
+
+Applied:
+
+- `docs/security.md` — the `NodeScope`/`PermissionTrie`/"Dispatch gate" block now leads with a
+  **What is enforced today** table (the three real checks) before the design material, which is
+  labelled *Designed but not wired*.
+- `docs/ReadWriteOperations.md` — **rewritten**, not bannered.
+- `docs/v2/acl-design.md` — ⚠️ NEVER WIRED banner.
+- `docs/v2/v2-release-readiness.md` §"Security — Phase 6.2 dispatch wiring" — the CLOSED claim marked
+  as not holding.
+- `ClusterAcls.razor` + `AclEdit.razor` — warning alerts stating rules are stored and deployed but
+  never evaluated.
+
+**Four things this pass found that §7 and the original audit missed** — all worse than what was
+already recorded:
+
+1. **`docs/security.md` was the highest-risk doc, not `ReadWriteOperations.md`.** `:115` claimed an
+   anonymous session is "default-denie[d] any node a session has no ACL grant for". The opposite is
+   true: an anonymous session can Browse, Read, Subscribe and HistoryRead the **entire** address
+   space. It is refused only writes and alarm acks — and only because it carries no roles.
+2. **Three of the five documented data-plane role strings do nothing.** `OpcUaDataPlaneRoles` declares
+   exactly `WriteOperate` and `AlarmAck`. `ReadOnly`, `WriteTune` and `WriteConfigure` are compared
+   against nowhere in `src/`, so mapping a group to `WriteTune` grants nothing and mapping one to
+   `ReadOnly` restricts nothing. The doc called all five "exact, case-insensitive, and **code-true**".
+3. **`ReadWriteOperations.md` was fiction well beyond the ACL claims.** `OnReadValue` has **zero**
+   occurrences in `src/` — the whole documented read path did not exist. Reads never reach a driver at
+   all: the node manager is push-model and the SDK serves a client Read from the cached pushed value.
+   `WriteAuthzPolicy`, `_sourceByFullRef`, `_writeIdempotentByFullRef` and `IRoleBearer` are likewise
+   zero-hit, and `CapabilityInvoker` is not referenced by the `OpcUaServer` project at all.
+4. **`v2-release-readiness.md` claimed a whole enforcement layer shipped.** Beyond the `:41` row §7.1
+   already flagged, `:46-50` describe `FilterBrowseReferences`, `GateCallMethodRequests`,
+   `MapCallOperation`, `AuthorizationBootstrap` and `Node:Authorization:*` config keys as Closed or
+   Partial. None of them exist. Whatever landed on the v2 branch did not survive into the shipped tree.
+
+Also recorded in #520 and not previously known: every existing evaluator unit test runs in
+`PermissionTrieBuilder`'s no-`scopePaths` *deterministic test mode*, so the production hierarchy path
+is effectively untested; and `NodeAcl.ScopeId` has no FK or existence check, so scope ids dangle
+silently.
+
+### 2026-07-27 — §8.2 rediscovery as a signal; injection deleted
+
+Decision: **signal, not mutation.**
+
+`DriverInstanceActor` now consumes `IRediscoverable.OnRediscoveryNeeded` (attach in `PreStart`, detach
+in `PostStop`) and carries it on the driver-health snapshot to `/hosts` as a **re-browse chip**. It is
+advisory — the served address space is unchanged, because v3 authors raw tags through `/raw`
+browse-commit and a runtime graft would materialise nodes nobody approved.
+
+**#507's injection path was deleted, not fixed.** §2 recorded it as a "deferred (deliberate guard)".
+That was too generous: its two inputs — `EquipmentNode.DriverInstanceId` and `EquipmentTags` — are
+*structurally empty* in v3, so removing the guard would have changed a log line and injected nothing.
+Deleted with it: `HandleDiscoveredNodes`, `PartitionDiscoveredByDeviceHost`,
+`ApplyDiscoveredPlansForDriver`, the redeploy re-inject tail, `DiscoveredNodeMapper`,
+`AddressSpaceApplier.MaterialiseDiscoveredNodes`, `OpcUaPublishActor.MaterialiseDiscoveredNodes`, the
+connect-time discovery loop, and 4 files' worth of tests. `ITagDiscovery` stays — the `/raw` browse
+picker drives it through `Commons/Browsing/DiscoveryDriverBrowser`, which never went through the actor.
+
+**§4.4's "18 `DiscoveryInjectionDormantV3` — Real, blocked on #507" was wrong.** They were v2
+characterization tests asserting an equipment-rooted graft (`EquipmentRootNodeId == "EQ-1"`) that v3
+cannot produce. They could never have unskipped as written; they are deleted. Skipped tests in
+`Runtime.Tests` went 31 → 13.
+
+**The planned drift detector was deliberately NOT built.** The plan proposed diffing each connect-time
+discovery pass against the authored raw tags. Reading the drivers killed it: **Modbus, S7, MQTT,
+AbLegacy and Sql all echo authored config from `DiscoverAsync`** rather than browsing the device, so
+the diff is permanently empty for them. It would have been another plausible-looking inert seam —
+precisely the class this register exists to remove. That also removed the last consumer of the
+connect-time loop, which is why the loop went too: it was browsing real devices up to ~15× per connect
+and dropping the result.
+
+Two traps worth keeping:
+
+- `PublishHealthSnapshot` dedups on a health fingerprint, and a rediscovery raise changes none of the
+  four fields it hashed. The timestamp had to join the tuple or the dedup swallows the signal.
+  **Verified by reverting the one line — 3 of the 5 new tests go red.**
+- The shared `StubDriver.GetHealth()` returns `DateTime.UtcNow`, so its fingerprint differs every call
+  and the dedup never engages. A dedup test built on it would pass whether or not the fix is present;
+  the new tests use a stub with stable health.
+
+`IHostConnectivityProbe` was **not** resolved — it is a keep-or-delete decision, and the
+`DriverHostStatus` table was re-created deliberately in the v3 initial migration, so deleting on
+inference would be wrong. Split to Gitea **#521** with both options costed.
+
+### 2026-07-27 — §8.5 bookkeeping + §8.6 tier truth
+
+**13 plan files closed.** The 8 the register named, plus `mesh-phase4` (Task 9 landed `3a590a0c`), the
+4th `stillpending` phase file, and `historian-tcp-transport` closed as **OBSOLETE** (it targets the
+retired Wonderware sidecar; there is no Wonderware backend in the tree). Each carries a `closureNote`
+naming the evidence, so the next reader can check rather than trust.
+
+**11 archreview live gates written back** from `STATUS.md`, which had recorded them passed since
+2026-07-13/15 without ever updating the `.tasks.json` files: R2-01 #11, R2-02 #15/#18, R2-05 T15,
+R2-06 T12, R2-07 T5/T6/T12/T14, R2-11 T22/T24.
+
+**R2-03 and R2-10 were NOT closed** — and reading `STATUS.md` rather than trusting its own headline
+("Every Round-2 live gate is now GREEN") is what kept that honest. Its per-item detail says R2-03 is
+"live-blocked on this data-less rig" and R2-10 verified the pipeline but "breaker-OPEN state not
+forced". Both now carry an `openNote` recording the blocker: R2-03 needs a reachable driver fixture
+feeding a VT; R2-10 needs a rapid idempotent write to a dead endpoint, because R2-09's
+`ConnectionBackoff` throttles retries so failures never accumulate fast enough to open the Polly breaker.
+
+**Net effect (the point of the sweep):** ~140 phantom pending tasks are gone, so the genuinely
+unexecuted **19-task AdminUI follow-ups plan** is now the largest open item in `docs/plans/` rather than
+being buried. The remaining open plans are 8, and one of those (`mesh-phase6` Task 6) is a documented
+`resolved-no-flip` decision rather than work.
+
+**Tier truth:** `docs/v2/driver-stability.md` now states plainly that its tier table is aspirational —
+every driver runs Tier A, and `MemoryRecycle` / `ScheduledRecycleScheduler` have never engaged. It also
+corrects a second stale claim the register did not flag: the **separate-Windows-service hosting** it
+describes for Tier C no longer exists (Galaxy went to the mxaccessgw sidecar in PR 7.2; FOCAS went
+in-process when its managed wire client landed). No runtime change — turning recycle on for two live
+drivers deserves its own live gate, not a docs-pass side effect. Tracked as Gitea **#522**.
+
+### 2026-07-27 — §8.4 dispatch-map parity (G-1 … G-6)
+
+**The maps had to become data before they could be guarded.** A Razor `@switch` compiles into
+`BuildRenderTree`'s IL, so nothing can enumerate its cases — that is the whole reason G-1 and G-2
+survived review while the sibling picker guard stayed green (the picker test works only because
+`RawDriverTypeDialog` keeps its data in a *field* the markup enumerates). Both modals now render from
+`DriverConfigFormMap` / `DeviceFormMap` via `<DynamicComponent>`, and being `public` those maps need
+none of the picker test's `BindingFlags.NonPublic` fragility.
+
+| Gap | Resolution |
+|---|---|
+| G-1 | `CalculationDriverForm.razor` added — `RunTimeout` was unauthorable through the UI. |
+| G-2 | Sql / MTConnect / Calculation are declared **single-connection** rather than given hollow device forms — each holds one connection at the driver level, so a per-device endpoint editor would be meaningless. |
+| G-3 | `DriverConfigModal`'s hardcoded `Galaxy or Mqtt` replaced by `DeviceFormMap.IsSingleConnection`. |
+| G-4 | `DriverFormMapParityTests` (5 cases, both directions) + `DriverDispatchMapParityTests` (3). |
+| G-5 | `CsvColumnMap` entries for Sql, Mqtt, MTConnect. |
+| G-6 | `RawBrowseCommitMapper` Sql branch — **and the browser end too**, which the register missed. |
+
+**G-6 was bigger than filed.** The register said the mapper lacked a Sql branch. It also turned out that
+`SqlBrowseSession` emitted **no `AddressFields` at all**, so a browsed leaf carried only a column name —
+and a column name alone cannot address a Sql tag, which needs its table. The browser now travels
+schema/table/column and the mapper builds a `WideRow` `SqlTagConfigModel` from them. A branch alone
+would have produced a half-built blob.
+
+**Two extra findings while writing the guards:**
+
+- The G-6 test found **Modbus and Calculation** also fall through to the generic `{"address": …}` key.
+  Both are correct — neither is browsable — so the test asserts the fall-through set **equals** a
+  documented non-browsable list, in both directions. A one-way check would let a newly-browsable driver
+  be quietly added to the exclusion list instead of getting a branch.
+- `TagConfigDriverTypeNameGuardTests` was **hollow**: it enumerated a hand-written `TheoryData` that had
+  already drifted (omitting Galaxy, Sql and Mqtt), so it guarded against renames but not gaps — a new
+  `DriverTypeNames` constant would simply never appear. Now enumerated from the map, paired with a
+  coverage test in the other direction.
+
+**Live-verified on docker-dev** (`localhost:9200`, central pair rebuilt), because this repo has no bUnit
+and no unit test can cover Blazor parameter binding: opened Calculation's config — the form renders where
+it previously showed "No typed config form" — typed `3500`, saved, reopened, and the value **persisted**,
+proving the `DynamicComponent` two-way binding round-trips. Sql's form renders fully (regression check on
+the conversion) and now reads "This driver holds a single connection, authored above" (G-3). The rebuilt
+image also showed `RediscoveryNeededUtc`/`RediscoveryReason` on the wire, confirming §8.2 end-to-end.
+
+### 2026-07-27 — §8.3 #516 driver config edits silently discarded
+
+Decision: **both** — per-driver re-parse *and* the seam respawn. Reading the drivers split the
+"per-driver" half in two, which the register did not anticipate:
+
+- **Re-parse in place** (`Modbus`, `AbLegacy`, `OpcUaClient`) — `ParseOptions` extracted from each
+  factory, called from `InitializeAsync` behind a `HasConfigBody` guard so `"{}"` still keeps the
+  constructor options.
+- **Respawn-only, deliberately NOT re-parsed** (`Sql`, `FOCAS`) — each builds **more than options**
+  from config: Sql's `ISqlDialect` + resolved connection string, FOCAS's client-factory backend, both
+  injected at construction. Adopting new options alone would run a **new tag set against an old
+  connection**. Half a re-parse is worse than none. Their doc-comments now say so.
+
+**The seam respawn is the load-bearing half.** `DriverSpawnPlanner` now routes a changed
+`DriverConfig` to `ToStop` + `ToSpawn`, making the factory the single parse authority.
+`ToApplyDelta` is consequently always empty from the reconcile path. This **reverses the deliberate
+decision documented at `DriverSpawnPlan.cs:49-50`** ("a pure DriverConfig change stays an in-place
+delta — no reconnect"). That reasoning was right about resilience and wrong about the driver; the
+accepted price is a reconnect on every config edit.
+
+Two seals removed from `ApplyChildDelta`: it overwrote the cached `Spec` **synchronously, before the
+child had dequeued the message**, so the host immediately believed the new config was live and the
+next reconcile computed no delta — sealing the drift permanently; and it `Tell`d with no
+`Receive<ApplyResult>` registered, so a failed reinit (including Galaxy's deliberate
+`NotSupportedException`) dead-lettered.
+
+**A new visibility gap this change exposed, not created:** a factory throw is a *config* error
+(`TryCreate` is pure parsing; device I/O happens later), and `SpawnChild` catches it and silently
+substitutes a stub. Previously only a brand-new driver could hit it; now an ordinary config edit can.
+Raised from `Warning` to `Error` with an actionable message. It still does **not** fail the
+deployment — making it do so would let one malformed driver block a fleet deploy, so that is a
+deliberate follow-up rather than a drive-by change.
+
+**Tests.** Every pre-existing reinit test in the five suites passes `"{}"` — precisely the input a
+guarded re-parser treats as "keep the constructor options", so they were blind to this defect *by
+construction*. The new tests pass **changed** JSON. The Modbus one was verified falsifiable by
+deleting the re-parse line (goes red). Two existing tests asserted the old behaviour and were
+rewritten: `DriverSpawnPlannerTests` (two cases), and
+`DriverHostActorUnreadableArtifactTests.Dropping_a_drivers_last_tag_does_clear_its_subscription` —
+a **positive control** for a sibling absence assertion, whose observable moved from `UnsubscribeAsync`
+to `ShutdownAsync` because the teardown now happens by stopping the child rather than emptying its
+desired set. Same event, different route; the control still calibrates the settle window.
+
+Full-solution run: only pre-existing environment failures remain — `Host.IntegrationTests` (3,
+verified identical on the pre-change tree) and `Driver.AbLegacy.IntegrationTests` (4, docker
+fixture-gated, and notably these **fail rather than skip**, unlike every other fixture-gated suite).
+
+---
+
+*Generated 2026-07-27 against `master` @ `90bdaa44` by five parallel source-verification agents.
+Every `path:line` reference was read from source. Items marked CANNOT VERIFY require hardware, a
+VPN'd gateway, or a live rig and are listed as unproven rather than assumed.*
@@ -0,0 +1,34 @@
+# Isolated MQTT/Sparkplug live-gate overlay (Task 26).
+#
+# Runs the MAIN central pair ONLY, from this worktree's image, under its own
+# compose project + offset host ports, so the shared `otopcua-dev` rig and the
+# sibling driver worktrees that share `otopcua-host:dev` are untouched.
+#
+#   docker build -f docker-dev/Dockerfile --target runtime -t otopcua-host:mqtt .
+#   docker compose -p otopcua-mqtt -f docker-dev/docker-compose.yml \
+#                  -f docker-dev/docker-compose.mqtt.yml \
+#                  up -d sql migrator cluster-seed central-1 central-2
+#
+#   AdminUI  -> http://localhost:9210   (login disabled; auto-admin)
+#   OPC UA   -> opc.tcp://localhost:4850 (central-1) / :4851 (central-2)
+#   SQL      -> localhost,14350
+#
+# `!override` on every `ports` list: compose MERGES list-valued keys by
+# appending, so a plain re-declaration keeps the base file's "14330:1433" /
+# "4840:4840" and collides with the running `otopcua-dev` rig.
+services:
+
+  sql:
+    ports: !override
+      - "14350:1433"
+
+  central-1:
+    image: otopcua-host:mqtt
+    ports: !override
+      - "4850:4840"
+      - "9210:9000"
+
+  central-2:
+    image: otopcua-host:mqtt
+    ports: !override
+      - "4851:4840"
@@ -0,0 +1,45 @@
+# Isolated MTConnect live-gate overlay (Task 21).
+#
+# Runs the MAIN central pair ONLY, from this worktree's image, under its own
+# compose project + offset host ports, so the shared `otopcua-dev` rig and the
+# three sibling driver worktrees that share `otopcua-host:dev` are untouched.
+# Mirrors how the mqtt-sparkplug worktree isolated itself (`otopcua-host:mqtt`,
+# project `otopcua-mqtt`, ports 9210/4850).
+#
+#   docker build -f docker-dev/Dockerfile --target runtime -t otopcua-host:mtconnect .
+#   docker compose -p otopcua-mtc -f docker-dev/docker-compose.yml \
+#                  -f docker-dev/docker-compose.mtconnect.yml \
+#                  up -d sql migrator cluster-seed central-1 central-2
+#
+#   AdminUI  -> http://localhost:9220   (login disabled; auto-admin)
+#   OPC UA   -> opc.tcp://localhost:4860 (central-1) / :4861 (central-2)
+#   SQL      -> localhost,14340
+#
+# Both MAIN nodes run because `cluster-seed` declares MAIN as a 2-node cluster:
+# ConfigPublishCoordinator sources its expected-ack set from enabled ClusterNode
+# rows, so deploying with one node down fails at the apply deadline.
+#
+# Traefik is deliberately not started — central-1 publishes its AdminUI port
+# directly, which removes the :9200 round-robin that otherwise makes it
+# ambiguous which node served a request.
+
+# NOTE: `!override` is required on every `ports` list. Compose MERGES list-valued
+# keys by appending, so a plain re-declaration would keep the base file's
+# "14330:1433" / "4840:4840" alongside the offsets and collide with the running
+# `otopcua-dev` rig ("Bind for 0.0.0.0:14330 failed: port is already allocated").
+services:
+
+  sql:
+    ports: !override
+      - "14340:1433"
+
+  central-1:
+    image: otopcua-host:mtconnect
+    ports: !override
+      - "4860:4840"
+      - "9220:9000"
+
+  central-2:
+    image: otopcua-host:mtconnect
+    ports: !override
+      - "4861:4840"
@@ -272,6 +272,12 @@ services:
      OTOPCUA_ROLES: "admin,driver,cluster-MAIN"
      ASPNETCORE_URLS: "http://+:9000"
      ConnectionStrings__ConfigDb: "Server=sql,1433;Database=OtOpcUa;User Id=sa;Password=OtOpcUa!Dev123;TrustServerCertificate=True;"
+      # Sql poll driver — the named connection string a Sql driver instance references by
+      # `connectionStringRef: "DevSql"`. Resolved in-process by SqlConnectionStringResolver (driver
+      # node) and SqlDriverBrowser (AdminUI browse), env-only, never persisted to ConfigDb. Points at
+      # the rig's own `sql` container, a SEPARATE `DevSql` database seeded with dbo.TagValues (KeyValue)
+      # + dbo.LatestStatus (WideRow). Committed-dev-secret exception, same as ConfigDb above.
+      Sql__ConnectionStrings__DevSql: "Server=sql,1433;Database=DevSql;User Id=sa;Password=OtOpcUa!Dev123;TrustServerCertificate=True;"
      Cluster__Hostname: "0.0.0.0"
      Cluster__Port: "4053"
      Cluster__PublicHostname: "central-1"
@@ -391,6 +397,12 @@ services:
      OTOPCUA_ROLES: "admin,driver,cluster-MAIN"
      ASPNETCORE_URLS: "http://+:9000"
      ConnectionStrings__ConfigDb: "Server=sql,1433;Database=OtOpcUa;User Id=sa;Password=OtOpcUa!Dev123;TrustServerCertificate=True;"
+      # Sql poll driver — the named connection string a Sql driver instance references by
+      # `connectionStringRef: "DevSql"`. Resolved in-process by SqlConnectionStringResolver (driver
+      # node) and SqlDriverBrowser (AdminUI browse), env-only, never persisted to ConfigDb. Points at
+      # the rig's own `sql` container, a SEPARATE `DevSql` database seeded with dbo.TagValues (KeyValue)
+      # + dbo.LatestStatus (WideRow). Committed-dev-secret exception, same as ConfigDb above.
+      Sql__ConnectionStrings__DevSql: "Server=sql,1433;Database=DevSql;User Id=sa;Password=OtOpcUa!Dev123;TrustServerCertificate=True;"
      Cluster__Hostname: "0.0.0.0"
      Cluster__Port: "4053"
      Cluster__PublicHostname: "central-2"
@@ -106,6 +106,28 @@ IF NOT EXISTS (SELECT 1 FROM dbo.ClusterNode WHERE NodeId = 'site-b-2:4053')
        (NodeId, ClusterId, Host, OpcUaPort, DashboardPort, AkkaPort, GrpcPort, ApplicationUri, ServiceLevelBase, Enabled, CreatedBy)
    VALUES ('site-b-2:4053', 'SITE-B', 'site-b-2', 4840, 8081, 4053, 4056, 'urn:OtOpcUa:site-b-2', 150, 1, 'docker-dev-seed');

+------------------------------------------------------------------------------
+-- Backfill: GrpcPort on rows that predate the column (#493)
+--
+-- Every insert above is INSERT-if-not-exists, which is the right shape for a re-runnable seed
+-- but means a *new nullable* column never reaches rows created by an earlier version of this
+-- file. On a persisted volume that is exactly what happened when Phase 5 added GrpcPort: the
+-- six ClusterNode rows already existed, so they kept NULL, TelemetryNodeSource found no dial
+-- targets, and TelemetryDial:Mode=Grpc silently connected to nothing (throttled Warning per
+-- node — the code degrades gracefully, so nothing failed loudly).
+--
+-- Backfills NULL only. It must not overwrite a port an operator set deliberately on a
+-- long-lived dev volume; a NULL is the unambiguous "this row predates the column" marker.
+--
+-- AkkaPort deliberately has no equivalent here: it is NOT NULL with a default of 4053, so
+-- pre-existing rows already carry a usable value and there is nothing to backfill.
+------------------------------------------------------------------------------
+
+UPDATE dbo.ClusterNode
+   SET GrpcPort = 4056          -- matches Telemetry__GrpcListenPort on all six nodes in docker-compose.yml
+ WHERE GrpcPort IS NULL
+   AND CreatedBy = 'docker-dev-seed';
+
 ------------------------------------------------------------------------------
 -- Galaxy MxAccess gateway — INTENTIONALLY NOT SEEDED (retired 2026-06-15)
 --
@@ -1,5 +1,27 @@
 # Address Space

+> ⚠️ **Accuracy warning (audited 2026-07-27) — this page is v2-era and contradicts the shipped v3
+> address space.** Corrections, in order of how badly they mislead:
+>
+> - **There is no "single custom namespace".** v3 exposes **two**:
+>   `https://zb.com/otopcua/raw` (`s=<RawPath>`) and `https://zb.com/otopcua/uns`
+>   (`s=<Area>/<Line>/<Equipment>/<EffectiveName>`), registered together at
+>   `OtOpcUaNodeManager.cs:45`. Identity authority is `V3NodeIds` + `AddressSpaceRealm`. The retired
+>   `https://zb.com/otopcua/ns` survives only in a comment marking it retired (`V3NodeIds.cs:17`).
+> - **`Phase7Applier` / `Phase7Composer` / `GalaxyTagPlan` do not exist**, nor do the file paths cited
+>   for them. Renamed by `40e8a23e` to `AddressSpaceApplier` / `AddressSpaceComposer`
+>   (`src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/`); the composition result type is
+>   `AddressSpaceComposition` (`AddressSpaceComposer.cs:13`).
+> - **The `SystemPlatform` namespace kind is retired** — Galaxy is a standard Equipment-kind driver.
+> - **`GenericDriverNodeManager` is test scaffolding**, not a production dispatch path
+>   (`GenericDriverNodeManager.cs:71`).
+> - **The §Rediscovery section is wrong**: nothing consumes `OnRediscoveryNeeded`
+>   ([#518](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/518)), and the driver list is stale
+>   (MQTT and MTConnect now raise it too).
+>
+> For the current design see the "v3 OPC UA Address Space (Batch 4)" section of `CLAUDE.md`,
+> `docs/Raw.md`, and `docs/Uns.md`.
+
 Address-space construction is a two-layer system. The **driver-facing layer** is the streaming builder: a driver implements `ITagDiscovery.DiscoverAsync` (`src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/ITagDiscovery.cs`) and emits `Folder` / `Variable` / `AddProperty` calls into an `IAddressSpaceBuilder` as it walks its backend — no buffering of the whole tree. `GenericDriverNodeManager` (`src/Core/ZB.MOM.WW.OtOpcUa.Core/OpcUa/GenericDriverNodeManager.cs`) wraps that builder to capture alarm-condition sinks and routes alarm events from the driver to them. The **SDK materialization layer** turns the resulting node descriptions into live OPC UA nodes: `OpcUaPublishActor` drives the write-only `IOpcUaAddressSpaceSink`, whose production binding `SdkAddressSpaceSink` (`src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/SdkAddressSpaceSink.cs`) forwards to `OtOpcUaNodeManager` (`src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs`), a `CustomNodeManager2` subclass that owns the `FolderState` / `BaseDataVariableState` instances. The same code path serves Galaxy object hierarchies, Modbus PLC registers, AB CIP tags, TwinCAT symbols, FOCAS CNC parameters, and OPC UA Client aggregations — Galaxy is one driver of seven, not the driver.

 ## Root folder
@@ -114,6 +114,21 @@ source it from there.
 > hardcodes OPC-DA Good, `192`). Capturing real per-node quality will not persist until the gateway honors
 > the field — see `GatewayHistorianValueWriter`'s remarks (archreview 06/C-7).

+> ⚠️ **Continuous value capture is code-complete but UNPROVEN IN PRODUCTION
+> ([#491](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/491)).** The recorder, the FasterLog
+> outbox, the gateway value-writer and the deploy-time historized-ref feed
+> (`AddressSpaceApplier.FeedHistorizedRefs` → `ActorHistorizedTagSubscriptionSink` →
+> `ContinuousHistorizationRecorder.UpdateHistorizedRefs`) are all wired, and the recorder converges to
+> the deployed ref set from the first deploy onward. What has **not** run is the end-to-end live gate
+> (deploy → dependency-mux value delta → outbox append → `WriteLiveValues`) plus a restart-convergence
+> test. **Reads and alarm-writes are live-validated; treat value capture as unproven rather than
+> absent.** See the "KNOWN LIMITATION 2" section of `CLAUDE.md`.
+>
+> **Related, separately open:** `EnsureTags` provisioning fires only for **newly-added** historized
+> tags (`AddressSpaceApplier` iterates the added set), so flipping an **existing** tag to
+> `"isHistorized": true` never provisions it — see
+> `docs/plans/2026-06-27-historian-gateway-integration-issues.md` Issue 5.
+
 ---

 ## Tag auto-provisioning (EnsureTags)
@@ -1,5 +1,26 @@
 # Incremental Sync

+> ⚠️ **Accuracy warning (audited 2026-07-27) — most of this page describes machinery that is retired
+> or was never wired.** Read it as v2-era design history, not as current behaviour.
+>
+> - **"Rebuild flow" (below) is not a production path.** It is built on `GenericDriverNodeManager`,
+>   which is Core test scaffolding with **zero production references**
+>   (`GenericDriverNodeManager.cs:71`). Its `_variablesByFullRef` / `_sourceByFullRef` fields do not
+>   exist in `src/`.
+> - **Driver-backend rediscovery has no consumer.** Nothing in `src/Server/` or `src/Core/`
+>   subscribes to `IRediscoverable.OnRediscoveryNeeded`; `DriverHostActor.HandleDiscoveredNodes`
+>   (`DriverHostActor.cs:986-1002`) short-circuits unconditionally. The `ScopeHint` is read by
+>   nothing. Drivers that raise it today: Galaxy, TwinCAT, MQTT/Sparkplug, MTConnect
+>   ([#518](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/518),
+>   [#507](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/507)).
+> - **The generation-publish path is retired.** `sp_PublishGeneration` and
+>   `sp_ComputeGenerationDiff` are stubs that `RAISERROR`
+>   (`20260715230637_V3Initial.StoredProcedures.cs:194`); `DraftRevisionToken` does not exist.
+>
+> **The one live rebuild path in v3** is the deploy artifact: `ConfigComposer` →
+> `Deployment.ArtifactBlob` → `DriverHostActor` apply → `AddressSpaceComposer` /
+> `AddressSpaceApplier` diff-apply.
+
 Two distinct change-detection paths feed the running server: driver-backend rediscovery (Galaxy's `time_of_last_deploy`, TwinCAT's symbol-version-changed) and generation-level config publishes from the Admin UI. Both flow into re-runs of `ITagDiscovery.DiscoverAsync`, but they originate differently.

 ## Driver-backend rediscovery — IRediscoverable
@@ -11,7 +11,7 @@ In v2 the Server and Admin processes were fused into a single role-gated `ZB.MOM
 - `CreateMasterNodeManager` constructs one `OtOpcUaNodeManager` (`src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs`) — a `CustomNodeManager2` subclass that owns the writable address space under the namespace `https://zb.com/otopcua/ns` and a single `OtOpcUa` root folder organized under the standard `Objects` folder. It is wrapped in a `MasterNodeManager` with no additional core managers.
 - `OtOpcUaSdkServer.NodeManager` exposes the live node manager after `StartAsync`, so the hosting layer can wrap it in a `SdkAddressSpaceSink` (`src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/SdkAddressSpaceSink.cs`) and hand it to `OpcUaPublishActor`.

-Address-space population is push-driven: drivers stream discovery and data-change events through the Akka actor system (`DriverInstanceActor` → `OpcUaPublishActor`), and `OpcUaPublishActor` writes them into the node manager through the `IOpcUaAddressSpaceSink` seam. `OtOpcUaNodeManager.EnsureFolder` / `EnsureVariable` materialize the UNS folder + variable hierarchy; `WriteValue` / `WriteAlarmState` push runtime values and fire `ClearChangeMasks` so subscribed clients see updates.
+Address-space population is push-driven: drivers stream discovery and data-change events through the Akka actor system (`DriverInstanceActor` → `OpcUaPublishActor`), and `OpcUaPublishActor` writes them into the node manager through the `IOpcUaAddressSpaceSink` seam. `OtOpcUaNodeManager.EnsureFolder` / `EnsureVariable` materialize the UNS folder + variable hierarchy; `WriteValue` / `WriteAlarmCondition` push runtime values and fire `ClearChangeMasks` so subscribed clients see updates.

 The driver-agnostic walk that turns a driver's discovery into folder/variable calls lives in `GenericDriverNodeManager` (`src/Core/ZB.MOM.WW.OtOpcUa.Core/OpcUa/GenericDriverNodeManager.cs`): it walks `ITagDiscovery.DiscoverAsync` into an `IAddressSpaceBuilder`, captures alarm-condition sinks for variables flagged via `IVariableHandle.MarkAsAlarmCondition`, subscribes to `IAlarmSource.OnAlarmEvent`, and routes each alarm transition to the sink registered for its `SourceNodeId`.

@@ -48,7 +48,7 @@ The server binds a TCP endpoint at `opc.tcp://{PublicHostname}:{OpcUaPort}/OtOpc

 `OpcUaApplicationHost` subscribes to `SessionManager.ImpersonateUser` after `ApplicationInstance.Start`. The handler (`HandleImpersonation`) deals with the token types as follows:

- `UserNameIdentityToken` → the password is decrypted, then `IOpcUaUserAuthenticator.AuthenticateUserNameAsync` validates the credential (`LdapUserAuthenticator` in production, a stub in tests). On success a `UserIdentity` carrying the token is attached and the LDAP-derived roles are logged; on failure `ImpersonateEventArgs.IdentityValidationError` is set to `BadIdentityTokenRejected`.
+- `UserNameIdentityToken` → the password is decrypted, then `IOpcUaUserAuthenticator.AuthenticateUserNameAsync` validates the credential (`LdapOpcUaUserAuthenticator` in production, a stub in tests). On success a `UserIdentity` carrying the token is attached and the LDAP-derived roles are logged; on failure `ImpersonateEventArgs.IdentityValidationError` is set to `BadIdentityTokenRejected`.
 - `AnonymousIdentityToken` and X.509 tokens → the handler returns without intervening, so the SDK's default validation stands.

 Decryption failures and authenticator exceptions also map to `BadIdentityTokenRejected`.
@@ -62,7 +62,7 @@ For Modbus / S7 / AB CIP / AB Legacy / TwinCAT / FOCAS / OPC UA Client specifics
 | [Configuration.md](v1/Configuration.md) | appsettings bootstrap + Config DB + Admin UI draft/publish (v1 archive — `OTOPCUA_GALAXY_*` env vars now live in mxaccessgw config) |
 | [Uns.md](Uns.md) | The global `/uns` master tree — manage Area/Line/Equipment/Tag/VirtualTag fleet-wide; replaces the per-cluster UNS/Equipment/Tags tabs |
 | [security.md](security.md) | Transport security profiles, LDAP auth, ACL trie, role grants, OTOPCUA0001 analyzer |
-| [Redundancy.md](Redundancy.md) | `RedundancyCoordinator`, `ServiceLevelCalculator`, apply-lease, Prometheus metrics |
+| [Redundancy.md](Redundancy.md) | `RedundancyStateActor` (cluster-scoped singleton), `ServiceLevelCalculator`, `IRedundancyRoleView`, per-cluster meshes, Prometheus metrics |
 | [Reservations.md](Reservations.md) | Fleet-wide ZTag / SAPID external-ID reservations — publish-time claim, release flow |
 | [ServiceHosting.md](ServiceHosting.md) | Single fused `OtOpcUa.Host` binary install/uninstall with `OTOPCUA_ROLES` gating; the historian backend is the external HistorianGateway |
 | [StatusDashboard.md](StatusDashboard.md) | Pointer — superseded by [v2/admin-ui.md](v2/admin-ui.md) |
@@ -1,67 +1,120 @@
 # Read/Write Operations

-The v2 server routes OPC UA Read and Write operations to each driver's `IReadable` and `IWritable` capabilities through `CapabilityInvoker` so the Polly pipeline (retry / timeout / breaker) applies uniformly across Galaxy, Modbus, S7, AB CIP, AB Legacy, TwinCAT, FOCAS, and OPC UA Client drivers. The per-variable `OnReadValue` and `OnWriteValue` hooks described in the sections below live in `DriverNodeManager` (the planned ADR-002 Phase 7 Stream G successor to the v1 `DriverNodeManager`); `GenericDriverNodeManager` (`src/Core/ZB.MOM.WW.OtOpcUa.Core/OpcUa/GenericDriverNodeManager.cs`) handles address-space population and alarm routing during discovery. The current `OtOpcUaNodeManager` (`src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs`) is a push-model `CustomNodeManager2` that receives values from the Akka actor layer via `WriteValue`; OPC UA client reads return the cached pushed value.
+> **Rewritten 2026-07-27** against `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs`.
+> The previous revision described a v2-era `DriverNodeManager` with per-variable `OnReadValue` hooks,
+> an `AuthorizationGate`/`WriteAuthzPolicy` ACL pair and a `NodeSourceKind` dispatch switch. **None of
+> those exist** — `OnReadValue`, `WriteAuthzPolicy`, `_sourceByFullRef`, `_writeIdempotentByFullRef`
+> and `IRoleBearer` all have zero occurrences in `src/`. The read path in particular worked nothing
+> like the way it was documented. See `deferment.md` §3.1 and §7.

-## Driver vs virtual dispatch
+## The shape of it: push for reads, pull for writes

-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/Core/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:
+The live server is `OtOpcUaNodeManager`, a **push-model** `CustomNodeManager2`. This asymmetry is the
+single most important thing on this page:

- `NodeSourceKind.Driver` — dispatches to the driver's `IReadable` / `IWritable` through `CapabilityInvoker` (the rest of this doc).
- `NodeSourceKind.Virtual` — dispatches to `VirtualTagSource` (`src/Core/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.
+- **Reads never reach a driver.** There is no `Read` override and no `OnReadValue` / `OnSimpleReadValue`
+  handler anywhere in the node manager. Driver values are *pushed in* from the Akka actor layer
+  (`DriverInstanceActor` polls or subscribes, `DriverHostActor` fans the value to the raw NodeId and
+  every referencing UNS NodeId), and a client Read is served by the OPC UA SDK straight from the
+  cached node value. A client read therefore costs nothing on the wire to the device, and cannot fail
+  with a device error — it returns whatever quality was last pushed.
+- **Writes are synchronous pull-through.** A client write runs `OnWriteValue` → role gate → driver.

-ACL enforcement (`WriteAuthzPolicy` + `AuthorizationGate`) runs before the source branch, so the gates below apply uniformly to all three source kinds.
+Everything the old page said about `CapabilityInvoker` wrapping OPC UA reads was misplaced: the
+invoker is real, but it lives on the **driver-actor** side wrapping the poll/subscribe calls. The
+`OpcUaServer` project does not reference it at all.

-## OnReadValue
+## Read path

-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:
+1. The SDK resolves the NodeId in the Raw (`ns=2`) or UNS (`ns=3`) namespace.
+2. It returns the cached `DataValue` — value, `StatusCode` and source timestamp as last pushed.
+3. **No authorization check runs.** Not a per-node ACL, not a role check, nothing. Any admitted
+   session — including an Anonymous one — can read every node in the address space. The only gating is
+   the `AccessLevels` bitmask set at materialization, which is a per-node *capability* declaration, not
+   a per-user decision.

-1. If the driver does not implement `IReadable`, the hook returns `BadNotReadable`.
-2. The node's `NodeId.Identifier` is used directly as the driver-side full reference — it matches `DriverAttributeInfo.FullName` registered at discovery time.
-3. (Phase 6.2) If an `AuthorizationGate` + `NodeScopeResolver` are wired, the gate is consulted first via `IsAllowed(identity, OpcUaOperation.Read, scope)`. A denied read never hits the driver.
-4. The call is wrapped by `_invoker.ExecuteAsync(DriverCapability.Read, ResolveHostFor(fullRef), …)`. The resolved host is `IPerCallHostResolver.ResolveHost(fullRef)` for multi-host drivers; single-host drivers fall back to `DriverInstanceId` (decision #144).
-5. The first `DataValueSnapshot` from the batch populates the outgoing `value` / `statusCode` / `timestamp`. An empty batch surfaces `BadNoData`; any exception surfaces `BadInternalError`.
+Authored `NodeAcl` deny rules have **no effect on reads** (or on anything else — see
+[docs/security.md](security.md) § Data-Plane Authorization).

-The hook is synchronous — the async invoker call is bridged with `AsTask().GetAwaiter().GetResult()` because the OPC UA SDK's value-hook signature is sync. Idempotent-by-construction reads mean this bridge is safe to retry inside the Polly pipeline.
+## Write path — `OnEquipmentTagWrite`

-## OnWriteValue
+The handler is attached in `EnsureVariable` **only when the tag was materialized `writable`**, and
+re-attached or cleared by `UpdateTagAttributes` on an in-place edit. A non-writable node has no
+handler, so the SDK rejects the write before any of this runs.

-`OnWriteValue` follows the same shape with two additional concerns: authorization and idempotence.
+1. **Role gate.** `EvaluateEquipmentWriteGate(identity, gatewayWired)` requires the session identity to
+   be a `RoleCarryingUserIdentity` carrying the `WriteOperate` role. No identity or no role ⇒
+   `BadUserAccessDenied`, fail-closed. Gate passed but no write gateway wired (admin-only node,
+   pre-boot) ⇒ `BadNotWritable`.
+   - This is a **server-wide** check. It takes no node and no realm: a session that may write one tag
+     may write every writable tag on that node.
+   - `WriteTune` and `WriteConfigure` are **never checked**. `OpcUaDataPlaneRoles` declares only
+     `WriteOperate` and `AlarmAck`; the classification tiers exist in the permission vocabulary but no
+     code path reads them.
+2. **Optimistic local apply.** The new value is written to the node so subscribers see it immediately.
+3. **Realm-qualified dispatch.** `RealmOf(node.NodeId)` selects Raw or UNS, and the value routes to the
+   backing driver ref through the node write gateway. Both NodeIds for a fanned value resolve to the
+   same driver ref, so a write via either one reaches the same device point.
+4. **Write-outcome self-correction.** If the device write fails, the optimistic value is **reverted**
+   on the raw NodeId and every referencing UNS NodeId through the shared fan-out, so a failed write
+   cannot leave a phantom Good value behind. (Galaxy is the exception: its write is fire-and-forget, so
+   it can never surface a write failure.)

-### Authorization (two layers)
+`OnWriteValue` is invoked by the SDK **while holding the node-manager `Lock`**, so the handler must not
+block. Anything asynchronous is dispatched fire-and-forget with the revert wired as a continuation.

-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`.
+## Alarm method calls

-### Dispatch
-
-`_invoker.ExecuteWriteAsync(host, isIdempotent, callSite, …)` honors the `WriteIdempotentAttribute` semantics per decisions #44-45 and #143:
-
- `isIdempotent = true` (tag flagged `WriteIdempotent` in the Config DB) → runs through the standard `DriverCapability.Write` pipeline; retry may apply per the tier configuration.
- `isIdempotent = false` (default) → the invoker builds a one-off pipeline with `RetryCount = 0`. A timeout may fire after the device already accepted the pulse / alarm-ack / counter-increment; replay is the caller's decision, not the server's.
-
-The `_writeIdempotentByFullRef` lookup is populated at discovery time from the `DriverAttributeInfo.WriteIdempotent` field.
-
-### Per-write status
-
-`IWritable.WriteAsync` returns `IReadOnlyList<WriteResult>` — one numeric `StatusCode` per requested write. A non-zero code is surfaced directly to the client; exceptions become `BadInternalError`. The OPC UA stack's pattern of batching per-service is preserved through the full chain.
-
-## Array element writes
-
-Array-element writes via OPC UA `IndexRange` are driver-specific. The OPC UA stack hands the dispatch an unwrapped `NumericRange` on the `indexRange` parameter of `OnWriteValue`; `DriverNodeManager` passes the full `value` object to `IWritable.WriteAsync` and the driver decides whether to support partial writes. Galaxy performs a read-modify-write inside the Galaxy driver (MXAccess has no element-level writes); other drivers generally accept only full-array writes today.
+Part 9 condition methods (Acknowledge / Confirm / AddComment / OneShotShelve / TimedShelve / Unshelve)
+are gated by a second role check requiring `AlarmAck` — one role covering all five methods; the
+`operation` argument is passed to the router but the gate does not consult it. Scripted alarms go
+through `HandleAlarmCommand`, driver-fed native alarms through `HandleNativeAlarmAck`; both fail closed
+with `BadUserAccessDenied`.

 ## HistoryRead

-`DriverNodeManager.HistoryReadRawModified`, `HistoryReadProcessed`, `HistoryReadAtTime`, and `HistoryReadEvents` route through the driver's `IHistoryProvider` capability with `DriverCapability.HistoryRead`. Drivers without `IHistoryProvider` surface `BadHistoryOperationUnsupported` per node. See `docs/v1/HistoricalDataAccess.md`.
+Four overrides — `HistoryReadRawModified`, `HistoryReadProcessed`, `HistoryReadAtTime`,
+`HistoryReadEvents` — route to the **server-wide** `IHistorianDataSource` (the HistorianGateway-backed
+reader, or `NullHistorianDataSource` when `ServerHistorian:Enabled=false`, which returns `GoodNoData`).
+This is not a per-driver `IHistoryProvider` dispatch.
+
+**No authorization check runs on any of the four.** Unlike `OnWriteValue`, the SDK does *not* hold the
+node-manager `Lock` while invoking them, so these paths may await.
+
+See [docs/Historian.md](Historian.md).

 ## Failure isolation

-Per decision #12, exceptions in the driver's capability call are logged and converted to a per-node `BadInternalError` — they never unwind into the master node manager. This keeps one driver's outage from disrupting sibling drivers in the same server process.
+Exceptions in a driver capability call are logged and converted to a per-node bad status rather than
+unwinding into the master node manager, so one driver's outage cannot disrupt sibling drivers in the
+same process.
+
+## What is *not* enforced anywhere
+
+Collected here because the previous revision of this page claimed several of these:
+
+| Surface | Check |
+|---|---|
+| Read, Browse, TranslateBrowsePaths | none |
+| CreateMonitoredItems / Subscribe / TransferSubscriptions | none |
+| HistoryRead (all four variants) | none |
+| Non-Value attribute writes | none (the handler is on `OnWriteValue`) |
+| Value write | `WriteOperate` role, server-wide |
+| Alarm methods | `AlarmAck` role, server-wide |
+| Per-node ACLs (`NodeAcl` / `PermissionTrie`) | **authored and deployed, never evaluated** |

 ## Key source files

- `src/Core/ZB.MOM.WW.OtOpcUa.Core/OpcUa/GenericDriverNodeManager.cs` — address-space population and alarm routing during discovery
- `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs` — push-model `CustomNodeManager2`; `EnsureVariable` / `WriteValue` are the v2 read/write path
- `src/Core/ZB.MOM.WW.OtOpcUa.Core/Authorization/` — permission trie + evaluator (`PermissionTrie`, `PermissionTrieCache`, `TriePermissionEvaluator`) that gates Read/Write/Subscribe per the session's resolved LDAP groups
- `src/Core/ZB.MOM.WW.OtOpcUa.Core/Resilience/CapabilityInvoker.cs` — `ExecuteAsync` / `ExecuteWriteAsync`
- `src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IReadable.cs`, `IWritable.cs`, `WriteIdempotentAttribute.cs`
+- `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs` — the live node manager;
+  `EnsureVariable` / `WriteValue` / `OnEquipmentTagWrite` / `EvaluateEquipmentWriteGate` and the four
+  HistoryRead overrides
+- `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/Security/RoleCarryingUserIdentity.cs`,
+  `Security/OpcUaDataPlaneRoles.cs` — how roles reach the gates
+- `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceApplier.cs` — materialization; where the write
+  handler is attached per realm
+- `src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs` — the push side: value fan-out to
+  raw + UNS NodeIds
+- `src/Core/ZB.MOM.WW.OtOpcUa.Core/Resilience/CapabilityInvoker.cs` — driver-side resilience pipeline
+  (**not** on the OPC UA read path)
+- `src/Core/ZB.MOM.WW.OtOpcUa.Core/Authorization/` — the permission trie + evaluator, built and
+  unit-tested but with **zero production consumers**
@@ -102,6 +102,45 @@ Persisted scope per plan decision #14: `Enabled`, `Acked`, `Confirmed`, `Shelvin

 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.

+### Post-(re)load condition-node re-assert (#487)
+
+A deploy that triggers a **full address-space rebuild** clears `_alarmConditions` and re-materialises every
+condition node fresh — inactive, acked, confirmed, unshelved. The engine, reloading in parallel, restores each
+alarm's persisted state and re-derives `Active` from the predicate, so it ends up *correct*; but a still-active
+alarm has **no transition to report**, so `LoadAsync` yields `EmissionKind.None` and `OnEngineEmission` drops it.
+Nothing then writes the node. Before this fix, an active alarm with static dependencies read **normal** to every
+OPC UA client after such a deploy, until its next real transition — which for a static-dependency alarm may
+never come.
+
+`ScriptedAlarmHostActor.ReassertConditionNodes` closes it. After each load completes it reads
+`ScriptedAlarmEngine.GetProjections()` — a plain read returning `ScriptedAlarmProjection` (condition state +
+the definition's severity + the resolved message template + last-observed worst-input quality) — and sends one
+`OpcUaPublishActor.AlarmStateUpdate` per alarm that is **not** in the Part 9 no-event position.
+
+Four properties are load-bearing:
+
+- **Node-only.** It sends `AlarmStateUpdate` and nothing else — never the `alerts` topic, never the telemetry
+  hub. `alerts` is the historization path, so an alerts row per alarm per deploy would append a duplicate
+  historian / AVEVA record every time anyone deploys. This is why the re-assert reads a projection instead of
+  re-emitting: `ScriptedAlarmProjection` carries no `EmissionKind`, so there is nothing for the emission
+  machinery — or a future refactor — to mistake for a transition.
+- **Only non-normal alarms.** An alarm in the no-event position (enabled, inactive, acked, confirmed,
+  unshelved) already matches what the materialise built, so it is skipped. That keeps a never-fired alarm
+  byte-identical to a deploy without this pass — including its Message, which the materialise seeds with the
+  alarm's display name — and writes nothing at all on the common all-normal deploy.
+- **Ordering.** `DriverHostActor` tells `RebuildAddressSpace` to the publish actor *before* it tells
+  `ApplyScriptedAlarms` to the host, and the re-assert runs later still (after an awaited `LoadAsync` pipes
+  back). Both are local `Tell`s, which enqueue synchronously, so the re-materialise is already queued ahead of
+  these writes.
+- **No duplicate Part 9 events.** `WriteAlarmCondition`'s delta-gate compares the incoming snapshot against
+  the node's *current* state: a re-assert onto a freshly materialised (normal) node is a genuine delta and
+  fires exactly one condition event — correct, since the rebuild reset what clients see — while a re-assert
+  onto a surgically-preserved node that already holds the same state is suppressed. The write is ungated by
+  redundancy role, like every other node write here; the Secondary keeps its address space warm for failover.
+
+The timestamp carried is the condition's own `LastTransitionUtc`, **not** the deploy instant, so a client
+reading `Time` / `ReceiveTime` after a rebuild still sees when the alarm actually went active.
+
 ## 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).
@@ -128,6 +128,39 @@ transports. ScadaBridge itself has since closed that gap with this identical
 interceptor pattern, so Phase 5 ships authenticated from the start rather than deferring auth to a
 later hardening pass. See the design doc's superseded note for the full history.

+## Upgrading an existing deployment: populate `ClusterNode.GrpcPort` first (#493)
+
+`GrpcPort` is a **nullable column added by Phase 5**, and nothing backfills it onto rows that
+already existed. On an upgraded deployment every `ClusterNode` row therefore carries `NULL`,
+central finds **no dial targets**, and flipping `TelemetryDial:Mode` to `Grpc` connects to
+nothing. Fresh installs are unaffected. `AkkaPort` did not have this problem only because it is
+`NOT NULL` with a default of 4053.
+
+Nothing fails loudly, which is what makes this worth stating up front — the code degrades
+gracefully, once per node, throttled:
+
+```
+ClusterNode <id> has no GrpcPort; it exposes no telemetry stream and is skipped in this dial refresh
+(further skips of this node are silent)
+```
+
+Other symptoms: no `ESTABLISHED` sockets on the telemetry port (a `LISTEN` but nothing else in
+`docker exec <node> cat /proc/net/tcp6`), and the `/alerts` / `/script-log` pill never turning
+live in `Grpc` mode.
+
+**Before flipping any node to `Grpc`**, set each driver node's `GrpcPort` to that node's own
+`Telemetry:GrpcListenPort` — via the AdminUI node editor, or directly:
+
+```sql
+UPDATE dbo.ClusterNode SET GrpcPort = <that node's Telemetry:GrpcListenPort> WHERE NodeId = '<node>';
+```
+
+There is deliberately **no EF data migration** backfilling this. The correct value is that node's
+own listener port, which is per-deployment configuration the database cannot derive; a migration
+could only invent one, and a *wrong* dial target is worse than the `NULL` the dialer already skips
+explicitly. The docker-dev seed does backfill (`GrpcPort IS NULL AND CreatedBy = 'docker-dev-seed'`
+→ 4056) because there the port is fixed by `docker-compose.yml` and therefore actually knowable.
+
 ## Reconnect and reliability

 Central's `TelemetryDialSupervisor` (an admin-role actor) runs **one reconnecting dialer per
@@ -70,7 +70,7 @@ Project root files:
 | Capability | Implementation entry point |
 |------------|---------------------------|
 | `ITagDiscovery` | `Browse/GalaxyDiscoverer.cs` |
-| `IRediscoverable` | `Browse/DeployWatcher.cs` |
+| `IRediscoverable` | `Browse/DeployWatcher.cs` — consumed as an **operator prompt**: a Galaxy redeploy raises a "re-browse" chip on `/hosts`. ⚠️ It does **not** rebuild the address space — re-browse the device under `/raw` and commit ([#518](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/518)) |
 | `IReadable` | `Runtime/GalaxyMxSession.cs` |
 | `IWritable` | `Runtime/GatewayGalaxyDataWriter.cs` |
 | `ISubscribable` | `Runtime/GatewayGalaxySubscriber.cs` (driven by `EventPump`) |
@@ -0,0 +1,349 @@
+# MTConnect Driver
+
+Getting-started guide for the MTConnect Agent driver (P1 Agent MVP). This is
+the short path — for the full design rationale read
+[`docs/plans/2026-07-15-mtconnect-driver-design.md`](../plans/2026-07-15-mtconnect-driver-design.md)
+and the build-vs-plan record in
+[`docs/plans/2026-07-24-mtconnect-driver.md`](../plans/2026-07-24-mtconnect-driver.md); for the
+fixture recipe read
+[`tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md`](../../tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md)
+(not duplicated here).
+
+> **Live gate:** see the LIVE-GATE RESULT note in the plan's Task 21
+> (`docs/plans/2026-07-24-mtconnect-driver.md`) for the docker-dev `/run` verification outcome
+> (browse picker / typed editor / deploy / read / subscribe against the real Agent fixture).
+
+## What it talks to
+
+A **MTConnect Agent** — the vendor-neutral read-only telemetry endpoint that
+front-ends a machine tool (or fronts an adapter that itself talks to the
+machine over SHDR). The driver speaks plain HTTP + XML against the Agent's
+three standard REST paths:
+
+- `/probe` — the static device model (Device → Component → DataItem tree)
+- `/current` — a snapshot of every DataItem's latest observation
+- `/sample` — a `multipart/x-mixed-replace` long-poll stream of observation
+  deltas, keyed by a monotonic sequence number
+
+v1 is **agent-first and read-only** — Discover + Read + Subscribe, no Write —
+because the mainstream Agent surface has no "set value" operation.
+
+## Built vs. planned — read this before trusting the design doc's §2
+
+The design doc ([`2026-07-15-mtconnect-driver-design.md`](../plans/2026-07-15-mtconnect-driver-design.md))
+picked the **TrakHound `MTConnect.NET-Common` / `-HTTP`** NuGet packages (MIT,
+`netstandard2.0`) as the primary path, with a hand-rolled fallback. **The
+hand-rolled fallback is what shipped.** Task 6/7 of the implementation plan
+found by reflection + live invocation that the pinned TrakHound packages
+ship **no XML formatter** (`Document Formatter Not found for "xml"` — the
+formatter lives in a separate `MTConnect.NET-XML` package the design didn't
+pin) and that `MTConnectHttpClientStream` exposes no injectable `HttpClient`
+handler, so it cannot be unit-tested behind the driver's `IMTConnectAgentClient`
+seam. Both package references were dropped. There is **no TrakHound
+dependency anywhere in the shipped driver** — probe/current/sample parsing is
+hand-rolled `System.Xml.Linq` plus a multipart boundary reader, entirely
+behind `IMTConnectAgentClient`. See the CORRECTION block under Task 0 of the
+implementation plan for the full record.
+
+**Namespace-agnostic parsing.** Every parser matches XML elements on
+`LocalName` only, ignoring the document's XML namespace entirely, so
+MTConnect 1.3 through 2.x documents all parse without a schema-version
+branch. This is deliberate, not sloppy: a real Agent injects vendor-extension
+`Component`s in a foreign namespace whose child `DataItems` elements inherit
+the *default* namespace, and namespace-strict matching would silently drop
+the whole vendor component (and every DataItem beneath it) rather than fail
+loudly. Attributes are read **unqualified** for the same reason — so an
+`xsi:type` attribute is never mistaken for a DataItem's own `type`.
+
+## Project split
+
+| Project | Target | Role |
+|---------|--------|------|
+| `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/` | net10.0 | In-process driver — `MTConnectDriver`, the hand-rolled `IMTConnectAgentClient` (probe/current/sample), the observation index, the factory |
+| `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Contracts/` | net10.0 | `MTConnectDriverOptions`, `MTConnectTagDefinition`, and the pure `MTConnectDataTypeInference` table shared by the driver, browse-commit, and the AdminUI typed editor |
+
+No `.Browser` project — browse comes free from the Wave-0 universal
+discovery browser (see [Browse](#browse--free-via-the-universal-browser)
+below).
+
+## Capability surface
+
+`MTConnectDriver : IDriver, IReadable, ISubscribable, ITagDiscovery, IHostConnectivityProbe, IRediscoverable`
+(`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/MTConnectDriver.cs`).
+
+Deliberately **not** `IWritable` — the Agent surface is read-only by design.
+Write-back exists only via optional, rarely-deployed MTConnect *Interfaces*
+(a request/response handshake, not a "set value" operation), and is out of
+scope for this build — see [Deferred](#deferred-not-in-this-build).
+
+| Capability | Path | Notes |
+|------------|------|-------|
+| `ITagDiscovery` | `DiscoverAsync` — streams `/probe`'s Device→Component→DataItem tree into the address-space builder | `SupportsOnlineDiscovery = true`, `RediscoverPolicy = Once` |
+| `IReadable` | `ReadAsync` → one `/current` per call | **Not the production data path** — see below |
+| `ISubscribable` | `SubscribeAsync`/`OnDataChange` — the shared `/sample` long-poll pump | **The production data path** |
+| `IHostConnectivityProbe` | periodic `/probe` under `Probe.*` | No consumer wires it today — see [Known limitations](#known-limitations) |
+| `IRediscoverable` | watches the Agent's `Header.instanceId` | No consumer wires it today — see [Known limitations](#known-limitations) |
+
+**`IReadable.ReadAsync` is never called by the running server.** The
+production data plane is entirely `ISubscribable` — `DriverInstanceActor`
+subscribes once and lives off `OnDataChange`. `ReadAsync` exists for the
+Client CLI (`... read -n ...`) and for the unit/integration suites; it is
+correct and tested, just not on the hot path.
+
+## Minimum deployment
+
+```jsonc
+"Drivers": {
+  "mtconnect-1": {
+    "Type": "MTConnect",
+    "Config": {
+      "AgentUri": "http://10.100.0.35:5000",
+      "DeviceName": null,
+      "RequestTimeoutMs": 5000,
+      "SampleIntervalMs": 1000,
+      "SampleCount": 1000,
+      "HeartbeatMs": 10000,
+      "Probe":     { "Enabled": true, "IntervalMs": 5000, "TimeoutMs": 2000 },
+      "Reconnect": { "MinBackoffMs": 0, "MaxBackoffMs": 30000, "BackoffMultiplier": 2.0 },
+      "Tags": []
+    }
+  }
+}
+```
+
+`RawTags[]` is not authored by hand — `DriverDeviceConfigMerger` injects it
+at deploy time from the tags authored on the `/raw` tree.
+
+### Config keys
+
+Read off `MTConnectDriverOptions` / `MTConnectDriverConfigDto`
+(`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Contracts/MTConnectDriverOptions.cs`,
+`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/MTConnectDriver.cs`):
+
+| Key | Default | Notes |
+|---|---|---|
+| `AgentUri` | — (required) | Agent base URI; the driver appends `/probe`, `/current`, `/sample` |
+| `DeviceName` | `null` | Scopes requests to `{AgentUri}/{DeviceName}/...`; `null` = whole Agent |
+| `RequestTimeoutMs` | `5000` | Per-call deadline for `/probe` and `/current` |
+| `SampleIntervalMs` | `1000` | The Agent's `/sample?interval=` query param |
+| `SampleCount` | `1000` | The Agent's `/sample?count=` query param |
+| `HeartbeatMs` | `10000` | The Agent's `/sample?heartbeat=` query param — also the watchdog's liveness window |
+| `Probe.Enabled` / `Probe.IntervalMs` / `Probe.TimeoutMs` | `true` / `5000` / `2000` | Background connectivity-probe knobs (mirrors `ModbusProbeOptions`) |
+| `Reconnect.MinBackoffMs` / `MaxBackoffMs` / `BackoffMultiplier` | `0` / `30000` / `2.0` | Geometric backoff after a failed request or a dropped `/sample` stream |
+| `Tags[]` | `[]` | Pre-v3 / CLI authoring surface — one `MTConnectTagDefinition` per DataItem `id` |
+| `RawTags[]` | `[]` (deploy-injected) | The v3 data-plane binding — see below |
+
+**All timing knobs are validated strictly positive** at `InitializeAsync`
+(`RequirePositive`, mirroring the arch-review 01/S-6 lesson: a `0` timeout
+does not mean "wait forever," it faults the driver). This applies to
+`RequestTimeoutMs`, `HeartbeatMs`, `SampleIntervalMs`, `SampleCount`, and
+(when the probe is enabled) `Probe.Interval` / `Probe.Timeout`.
+
+**No save-time gate on a blank `AgentUri` in the AdminUI.** The driver form
+renders an inline validation notice (`_form.Validate()`), but
+`DriverConfigModal.SaveAsync` has no per-form validation seam to block the
+Save button on it — no sibling driver form has one either. A blank
+`AgentUri` saves cleanly and fails at deploy with the driver's own error
+message, not at authoring time.
+
+## Data plane
+
+### FullName == DataItem `id`
+
+`FullName` (both `MTConnectTagDefinition.FullName` and every `RawTags[]`
+blob's identifier) is the MTConnect `DataItem@id` attribute — the value the
+universal browser commits and the key the driver resolves reads/subscribes
+against. `MTConnectTagConfigModel.FromJson` (the AdminUI typed editor) tries
+three spellings in order — `fullName` → `dataItemId` → `address` — and takes
+the first non-blank one, normalising onto `fullName` on save. `address` is
+accepted because that's the field name `RawBrowseCommitMapper` writes for a
+driver with no typed editor path, so a browse-committed tag stays readable
+even before the editor round-trips it.
+
+### Coercion-type precedence
+
+The driver keys its data plane by **RawPath** (the v3 raw-tag identity), not
+by DataItem id directly, resolving RawPath → dataItemId internally. Each raw
+tag's coercion type (the `DriverDataType` its Agent observation is parsed
+into) is resolved in this order, first non-null wins:
+
+1. The `RawTags[]` blob's `driverDataType` or `dataType` field (both
+   spellings accepted — the typed editor writes `dataType`, the driver's own
+   `tags[]` shape uses `driverDataType`).
+2. A matching `Tags[]` entry naming the same DataItem id.
+3. The Agent's own `/probe` declaration, via `MTConnectDataTypeInference.Infer`
+   (category/type/units/representation → `DriverDataType`).
+4. `DriverDataType.String` — the coercion that cannot fail.
+
+### Quality mapping
+
+`UNAVAILABLE` — MTConnect's one explicit "I have no value" sentinel — maps to
+**`BadNoCommunication`** (`0x80310000`). This is deliberately distinct from
+the fleet-standard `BadCommunicationError` (`0x80050000`, used elsewhere for
+the driver's *own* transport failure to the Agent): `UNAVAILABLE` means the
+Agent is reachable and answered, it just has no device-backed value for that
+item. A `CONDITION` observation's value is taken from its **element name**
+(`<Normal/>` → the string `"Normal"`, `<Fault/>` → `"Fault"`); a `<Unavailable/>`
+condition element normalises onto the same `UNAVAILABLE` sentinel as every
+other category so one comparison covers all three.
+
+Other status codes an observation can surface:
+
+| Code | Meaning |
+|---|---|
+| `BadTypeMismatch` (`0x80740000`) | The Agent's text isn't a value of the tag's coerced type at all |
+| `BadOutOfRange` (`0x803C0000`) | The Agent reported a number the coerced type can't represent |
+| `BadNotSupported` (`0x803D0000`) | A shape this build doesn't materialize — a `TIME_SERIES` vector, or a structured `DATA_SET`/`TABLE` observation (deferred to P1.5; see [Known limitations](#known-limitations)) |
+| `BadWaitingForInitialData` | Tag is authored but the Agent hasn't reported it yet |
+| `BadNodeIdUnknown` | DataItem id is neither authored nor ever observed |
+
+### Subscribe — the `/sample` pump
+
+One shared `/sample` long-poll stream per driver instance (the Agent streams
+the whole device model regardless of which subset is subscribed, so
+per-tag streams would be wasted round-trips), run under a heartbeat
+watchdog — `HttpClient.Timeout` cannot bound a long-lived stream, so a
+missing chunk **and** missing keep-alive heartbeat within
+`HeartbeatMs × N` is what detects a frozen peer.
+
+Ring-buffer overflow (the Agent's circular observation buffer wrapped past
+what the driver's cursor expects) is detected **two ways**, both triggering a
+`/current` re-baseline before the stream resumes:
+
+1. `IMTConnectAgentClient.IsSequenceGap` — the next chunk's `firstSequence`
+   is newer than the driver's expected cursor.
+2. An `MTConnectError` document reporting `OUT_OF_RANGE` — real Agents return
+   this both under HTTP 200 (a normal MTConnect error document) and as a bare
+   HTTP 400, and the client handles both.
+
+**An Agent `instanceId` change means the Agent restarted**, and is checked
+**before** the sequence-gap check (a restart also usually trips the gap, so
+the two need disambiguating, not just OR-ing together). On a changed
+`instanceId` the driver clears its cached probe model and raises
+`OnRediscoveryNeeded`, which surfaces a **re-browse prompt** on the AdminUI
+`/hosts` page — see [Known limitations](#known-limitations) for what that does
+and does not do.
+
+## Browse — free via the universal browser
+
+MTConnect ships **no bespoke browser project**. Setting
+`ITagDiscovery.SupportsOnlineDiscovery => true` is the entire integration:
+the Wave-0 `DiscoveryDriverBrowser` sees a driver whose `TryCreate` succeeds
+and whose instance reports online discovery, renders the AdminUI **Browse**
+button, constructs the driver, runs `InitializeAsync` (the `/probe` connect)
+ `DiscoverAsync` into a `CapturingAddressSpaceBuilder`, then tears the
+throwaway instance down. Each captured leaf's NodeId is the DataItem `id`,
+committed directly as `TagConfig.FullName` on pick. See
+[`docs/plans/2026-07-15-universal-discovery-browser-design.md`](../plans/2026-07-15-universal-discovery-browser-design.md).
+
+## CONDITION modelling (v1: plain String)
+
+Each `CONDITION` DataItem materializes as a `String` variable whose value is
+the current state word — `Normal` / `Warning` / `Fault` / `UNAVAILABLE`.
+There is no native OPC UA Part 9 alarm plumbing in this build;
+`DriverAttributeInfo.IsAlarm = true` is still stamped on a CONDITION leaf so
+the browse side-panel flags it and a future upgrade to native alarms doesn't
+need re-authoring. See [Deferred](#deferred-not-in-this-build).
+
+## Known limitations
+
+These are real, not placeholders — read them before relying on the driver
+for anything beyond values-and-conditions.
+
+1. **A restarted Agent prompts an operator; it does not re-shape the address
+   space.** `DriverInstanceActor` now consumes `OnRediscoveryNeeded`
+   (2026-07-27), so a changed `instanceId` raises a "re-browse" chip against
+   this driver on `/hosts` carrying the reason. It is **advisory**: v3 authors
+   raw tags through the `/raw` browse-commit flow, so until an operator
+   re-browses the Agent and commits, any DataItem that appeared or vanished is
+   not reflected in the served tree. A runtime graft was deliberately rejected
+   — it would materialise nodes nobody approved and no deployment artifact
+   records.
+
+   **`IHostConnectivityProbe` is still unconsumed** — `GetHostStatuses()` has
+   no production call site and nothing writes a `DriverHostStatus` row. That
+   half remains a fleet-wide gap affecting every driver that implements it
+   (Gitea #521).
+2. **`RawTagEntry.DeviceName` is accepted on the wire shape but ignored for
+   routing.** One driver instance owns exactly one Agent client scoped by
+   `MTConnectDriverOptions.DeviceName` (the top-level config key); the
+   per-tag `RawTagEntry.DeviceName` field the v3 raw-tag identity carries is
+   never read by the driver. Two `/raw` Devices authored under one MTConnect
+   driver instance both resolve to the same one Agent connection. Real
+   per-device routing (a client per device) would be a design change, not a
+   bug fix.
+3. **Nothing validates a raw tag's declared OPC UA `DataType` against the
+   blob's coercion type.** The `/probe`-sourced inference
+   (`MTConnectDataTypeInference`) narrows how often an author picks a wrong
+   type, but it doesn't close the gap — an authored `DataType` mismatched
+   against the actual Agent observation still surfaces as `BadTypeMismatch`
+   /`BadOutOfRange` at runtime rather than at authoring time.
+4. **`sampleCount` is not a legal `DataItem` attribute.** It belongs on a
+   `TIME_SERIES` *observation*, not the device-model declaration. A real
+   Agent that meets `sampleCount` on a `DataItem` declaration logs `The
+   following keys were present and not expected: sampleCount` and **drops
+   the entire data item** from the served model. A live TIME_SERIES tag
+   therefore always resolves to `ArrayDim = null` (variable-length array) in
+   practice — the fixture's canned `probe.xml`/`Devices.xml`, which does
+   declare a `sampleCount`, is unrealistic on this point and exists only to
+   pin the parsing rule itself.
+5. **CONDITION is a plain `String`, not a native Part 9 alarm** (see above).
+6. **`TIME_SERIES` arrays and structured `DATA_SET`/`TABLE` observations
+   surface as `BadNotSupported`**, not an approximation — see the Quality
+   mapping table.
+
+## Deferred (not in this build)
+
+- **Write-back (MTConnect Interfaces).** Design
+  [§3.6](../plans/2026-07-15-mtconnect-driver-design.md#36-iwritable--not-implemented-v1):
+  the mainstream Agent surface is read-only by design; Interfaces is a rare,
+  optional request/response handshake that would mislead if modelled as
+  `IWritable`. Revisit only on a concrete deployment need.
+- **P1.5 fast-follow** (design
+  [§9](../plans/2026-07-15-mtconnect-driver-design.md#9-phasing--effort)):
+  CONDITION → native OPC UA Part 9 alarms via `IAlarmSource` (the Galaxy
+  native-alarm pattern); `TIME_SERIES` SAMPLE arrays materialized as real
+  OPC UA arrays; EVENT controlled-vocabulary values → OPC UA enumerations.
+- **P2 (on demand): SHDR adapter ingest.** A `SourceMode: "Agent" | "Shdr"`
+  switch that opens the raw pipe-delimited SHDR TCP socket directly. Loses
+  auto-discovery (no device model without an Agent in front, so
+  `SupportsOnlineDiscovery` would have to report `false` and tags would be
+  authored by hand, like Modbus). Niche; not built.
+
+## Testing
+
+- **Unit tests** — `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests/`
+  (canned-XML fixtures, no network) — 491/491 at time of writing. Covers
+  discovery tree shape, `MTConnectDataTypeInference`, observation indexing,
+  `UNAVAILABLE` → `BadNoCommunication`, CONDITION state-word mapping,
+  multipart chunk framing, and ring-buffer re-baseline paging (both the
+  sequence-gap and the `OUT_OF_RANGE` legs).
+- **Integration tests** —
+  `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/` — env-gated
+  on `MTCONNECT_AGENT_ENDPOINT` (default `http://10.100.0.35:5000`), skips
+  cleanly (12 Skipped) when the fixture is unreachable, 12/12 against a real
+  Agent. Read the fixture's own
+  [`Docker/README.md`](../../tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md)
+  for the full recipe — summary only, here:
+  - Image is **`mtconnect/agent:2.7.0.12`** — not `mtconnect/cppagent`, which
+    does not exist on Docker Hub (the design's original assumption).
+  - The stack is **two services**: the Agent plus a stdlib-only SHDR adapter
+    (`Docker/adapter.py`, on `python:3.13-alpine`). An Agent with no adapter
+    reports every observation `UNAVAILABLE` forever, which proves nothing.
+  - Deployed at `/opt/otopcua-mtconnect/` on the shared docker host
+    (`10.100.0.35`, `project=lmxopcua` label). Endpoint
+    `http://10.100.0.35:5000`.
+  - `agent.cfg` must be **pure ASCII** — one non-ASCII byte anywhere,
+    including a comment, makes the config parser reject the whole file with
+    a bare `Failed / Stopped at line: N`.
+  - Bring-up: `lmxopcua-fix sync mtconnect` then `lmxopcua-fix up mtconnect`
+    (PowerShell helper, Windows-only) — or, directly on the docker host,
+    `rsync` the repo's `Docker/` dir to `/opt/otopcua-mtconnect/` and run
+    `docker compose up -d --wait`.
+
+## Further reading
+
+- [`docs/plans/2026-07-15-mtconnect-driver-design.md`](../plans/2026-07-15-mtconnect-driver-design.md) — full design: capability wiring, browse reconciliation, typed-editor spec, resilience/timeout rules, phasing
+- [`docs/plans/2026-07-24-mtconnect-driver.md`](../plans/2026-07-24-mtconnect-driver.md) — the executable implementation plan and the task-by-task build record, including where it diverged from the design (TrakHound → hand-rolled)
+- [`docs/plans/2026-07-24-driver-expansion-tracking.md`](../plans/2026-07-24-driver-expansion-tracking.md) — Wave-2 program tracking
+- [Docker fixture README](../../tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md) — the authoritative fixture recipe (seeded device model, endpoint, Mac AirPlay port-5000 gotcha)
@@ -0,0 +1,133 @@
+# MQTT test fixture
+
+Coverage map + gap inventory for the MQTT driver's harness.
+
+**TL;DR:** the unit suite (581 tests) carries the mapping, indexing, Sparkplug state-machine and
+failure-classification logic; the live suite (15 tests) proves the parts only a real broker can prove
+— TLS, real authentication, CA pinning in both directions, retained-message seeding, that a rejected
+CONNACK is actually surfaced, and the Sparkplug birth/alias/rebirth/death path against a real
+edge-node simulator.
+
+## What the fixture is
+
+`eclipse-mosquitto:2.0.22` plus a second container of the same image running `publisher/publish.sh`
+(the image ships `mosquitto_pub`, so no bespoke image is needed), plus — behind the `sparkplug`
+compose profile — **`otopcua-sparkplug-sim`**, a project-owned C# Sparkplug-B edge-node simulator
+(`tests/Drivers/….Driver.Mqtt.IntegrationTests/SparkplugSimulator/`). Compose lives at
+`tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.IntegrationTests/Docker/`; the deployed stack is
+`/opt/otopcua-mqtt` on the shared Docker host.
+
+**Two authenticated listeners, no anonymous fallback** (`allow_anonymous false`) — deliberate: an
+anonymous broker would let a broken auth config pass every test.
+
+| Listener | Endpoint | Env var |
+|---|---|---|
+| TLS + auth | `10.100.0.35:8883` | `MQTT_FIXTURE_ENDPOINT` |
+| plaintext + auth | `10.100.0.35:1883` | `MQTT_FIXTURE_PLAIN_ENDPOINT` |
+
+`MqttFixture` gates the suite on `MQTT_FIXTURE_ENDPOINT` / `MQTT_FIXTURE_USERNAME` /
+`MQTT_FIXTURE_PASSWORD` (+ `MQTT_FIXTURE_CA_CERT`, `MQTT_FIXTURE_TOPIC_PREFIX`) and **skips cleanly**
+when they are absent, so the suite is safe to run offline.
+
+**Unlike every other fixture it needs generated material first** — `./gen-fixture-material.sh` writes
+the gitignored `secrets/` (password file, CA, server cert/key). The broker will not start without it.
+Bring-up and the CA-fetch recipe are in [`infra/README.md`](../../infra/README.md) §3.
+
+### Published topics
+
+| Topic | Shape | Retain | Why it exists |
+|---|---|---|---|
+| `otopcua/fixture/retained/seed` | `{"value":42.5,…}` | ✅ **published exactly once** | The only way to prove retained *seeding*. On a republished topic a retained seed is indistinguishable from a fast live publish |
+| `otopcua/fixture/line1/temperature` | `{"value":…,"unit":"C","seq":n}` | ✅ | JSON + JSONPath extraction |
+| `otopcua/fixture/line1/counter` | `{"value":n}` | ✅ | Monotonic, for ordering |
+| `otopcua/fixture/line1/state` | `RUNNING` (bare text) | ✅ | Non-JSON `Raw`/`Scalar` payloads |
+| `otopcua/fixture/noise/chatter` | JSON | ❌ | **Never authored as a tag** — a broker carrying unauthored traffic is the normal case and the driver must stay silent about it |
+
+## What it actually covers
+
+The 7 live tests: TLS+auth connect; connect pinned to the fixture CA; connect pinned to a *foreign*
+CA is **rejected** (the falsifiability control — a pinning test that only ever passes proves nothing);
+wrong password is rejected **and surfaced** (the MQTTnet-5 silent-`Healthy` defect); plain
+subscribe→value under a RawPath; retained message seeds a value on subscribe; and an unauthored topic
+stays silent while an authored tag keeps flowing.
+
+### The Sparkplug simulator
+
+Group **`OtOpcUaSim`**; edge nodes **`EdgeA`** and **`EdgeB`**; `EdgeA` additionally publishes device
+**`Filler1`**. Node metrics `Temperature` (Float), `Pressure` (Double), `Count` (Int32), `Running`
+(Boolean), `Serial` (String) plus the mandatory `bdSeq` and **`Node Control/Rebirth`** — the last one
+deliberately carries a `/`, so it exercises the "a metric name is not a topic segment" rule. Device
+metrics: `Temperature` (Float), `FillCount` (Int64), `Jammed` (Boolean). Cadence ~2 s.
+
+It **subscribes to `spBv1.0/OtOpcUaSim/NCMD/{node}`** and re-births on a rebirth request, so it
+exercises the real NCMD round trip rather than simulating it. Births are not retained (per spec), so
+`docker restart otopcua-sparkplug-sim` is the way to force a fresh birth on demand:
+
+```bash
+ssh dohertj2@10.100.0.35 'cd /opt/otopcua-mqtt && docker compose --profile sparkplug up -d'
+ssh dohertj2@10.100.0.35 'docker restart otopcua-sparkplug-sim'   # force a birth
+ssh dohertj2@10.100.0.35 'docker logs -f otopcua-sparkplug-sim'
+```
+
+Live-gated end-to-end (2026-07-24, P1 milestone): deployed on the docker-dev rig against this fixture,
+both tags resolved and served changing values through OPC UA, and the AdminUI `#`-observation picker
+rendered the real topic tree. Re-gated for P2 (2026-07-25) against the Sparkplug simulator — see
+[Mqtt.md](Mqtt.md).
+
+## What it does NOT cover
+
+### 1. Sparkplug primary-host STATE, and write-through
+The simulator never observes a Host Application `STATE`, because the driver never publishes one
+(`ActAsPrimaryHost` is unimplemented). Nor is there any DCMD/NCMD **command** coverage: rebirth is the
+only NCMD the driver ever sends, and `IWritable` is deferred.
+
+Sparkplug **seq-gap injection** is unit-proven only — the simulator always publishes a well-formed
+monotonic `seq`, so no live test drives the gap → rebirth path end-to-end.
+
+### 2. Broker-side failure injection
+No test kills the broker mid-session, partitions the network, or forces a SUBACK failure against a
+real broker. Reconnect, backoff and per-topic degradation are **unit-proven only**.
+
+### 3. Wildcard tags against a live broker
+The by-filter indexing fix that keeps wildcard tags alive across a reconnect is covered by unit tests;
+no live test authors a `+`/`#` tag and bounces the connection.
+
+### 4. QoS 2 delivery semantics
+The fixture publishes at QoS 0/1. QoS 2's exactly-once handshake is never exercised end-to-end.
+
+### 5. Scale
+One publisher, five topics, a ~2 s cadence. Nothing probes the 50 000-node browse cap, the 1 MiB
+payload cap, or thousands of authored tags.
+
+### 6. Redundant-pair client-id collision
+Found by hand during the P1 gate (a fixed `clientId` makes pair nodes evict each other), **not** by a
+test. No automated coverage asserts that two concurrent drivers coexist.
+
+## When to trust the MQTT fixture, when to reach for a real broker
+
+| Question | Fixture answers it? |
+|---|---|
+| Does TLS + auth work, and does bad auth fail loudly? | ✅ yes |
+| Is a retained message seeded on subscribe? | ✅ yes |
+| Does JSONPath extraction + coercion behave? | ✅ yes (unit + live) |
+| Does the driver ignore unauthored traffic? | ✅ yes |
+| Does it survive a broker restart / flapping link? | ❌ unit-only |
+| Does it hold up at plant tag counts? | ❌ no |
+| Does a Sparkplug birth → alias → DATA → death cycle work? | ✅ yes (live, vs. the simulator) |
+| Does an NCMD rebirth request actually get answered? | ✅ yes (the simulator subscribes + re-births) |
+| Sparkplug seq-gap → rebirth | ❌ unit-only (the sim never skips a seq) |
+| Sparkplug primary-host STATE / DCMD writes | ❌ not implemented |
+
+## Follow-up candidates
+
+1. Broker-restart / SUBACK-failure live tests (closes gap 2).
+2. A live wildcard-across-reconnect test (closes gap 3).
+3. A concurrent-two-driver test pinning the client-id hazard (closes gap 6).
+4. A seq-gap injection switch on the simulator, closing the last unit-only Sparkplug leg.
+
+## Key fixture / config files
+
+- `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Mqtt.IntegrationTests/Docker/docker-compose.yml`
+- `tests/Drivers/…/Docker/mosquitto.conf` · `Docker/gen-fixture-material.sh` · `Docker/publisher/publish.sh`
+- `tests/Drivers/…/MqttFixture.cs` · `PlainMqttLiveTests.cs`
+- [`infra/README.md`](../../infra/README.md) §3 — bring-up, endpoints, CA fetch
@@ -0,0 +1,397 @@
+# MQTT Driver
+
+In-process MQTT **broker-subscribe** driver. It holds one MQTTnet 5 client against one broker,
+subscribes to the topics its authored tags name, and forwards each PUBLISH straight to
+`ISubscribable.OnDataChange`. Ingest is **push, not poll**, and **one-way** — there is no `IWritable`.
+
+**Two ingest shapes, selected by the driver's `Mode`:** `Plain` binds a tag to a concrete MQTT topic;
+`SparkplugB` binds it to a `group / edge node / device? / metric` tuple and decodes Eclipse-Tahu
+protobuf under one `spBv1.0/{GroupId}/#` subscription. Both run over the same single client.
+
+See [Mqtt-Test-Fixture.md](Mqtt-Test-Fixture.md) for the harness and
+[`../plans/2026-07-15-mqtt-sparkplug-driver-design.md`](../plans/2026-07-15-mqtt-sparkplug-driver-design.md)
+for the design.
+
+> **Status.** P1 (plain MQTT) and P2 (Sparkplug B ingest) are both shipped and live-gated against the
+> Mosquitto + Sparkplug-simulator fixture. Write-through (`IWritable` — NCMD/DCMD/plain publish) is
+> **deferred** ([#508](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/508)); every MQTT node
+> materializes read-only. See [Known gaps](#known-gaps) — every entry there carries a tracking issue
+> (#507–#515).
+
+## Project Layout
+
+| Project | Holds |
+|---|---|
+| `Driver.Mqtt.Contracts` | Config records, enums, `MqttTagDefinition` + the pure `MqttTagDefinitionFactory`, and the one shared `MqttJson.Options`. **Deliberately transport-free** — no MQTTnet reference |
+| `Driver.Mqtt` | Runtime: `MqttDriver`, `MqttConnection` (connect + reconnect supervisor), `MqttSubscriptionManager`, `LastValueCache`, factory registration, `MqttDriverProbe` |
+| `Driver.Mqtt.Browser` | `MqttDriverBrowser` + `MqttBrowseSession` — the AdminUI address picker's `#`-observation session |
+
+> `.Browser` references `.Driver` (not just `.Contracts`) — a **documented, deliberate exception**
+> so browse can reuse `MqttConnection.BuildClientOptions` (TLS / CA-pin / credentials / protocol
+> mapping). Its cost is pulling `Core` into the AdminUI graph. The csproj carries a boxed warning;
+> do not copy the pattern into a new driver's browser. The clean fix — extract the pure
+> options builder down into `.Contracts` — is tracked as
+> [#512](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/512).
+
+## Capability Surface
+
+```csharp
+public sealed class MqttDriver
+    : IDriver, ITagDiscovery, ISubscribable, IReadable, IHostConnectivityProbe, IRediscoverable, IAsyncDisposable, IDisposable
+```
+
+| Capability | Entry point | Notes |
+|---|---|---|
+| `IDriver` | `InitializeAsync` / `ReinitializeAsync` / `ShutdownAsync` / `GetHealth` | Order **register → attach → connect** is contractual. `ReinitializeAsync` applies a tag-only delta in place, and rebuilds the session when the broker identity changed |
+| `ITagDiscovery` | `DiscoverAsync` | Replays **only the authored `rawTags`** into an `Mqtt` folder. `SupportsOnlineDiscovery => false`. `RediscoverPolicy` is `Once` in Plain and **`UntilStable` in Sparkplug** (half of what a Sparkplug tag needs — its datatype — is only knowable from a birth) |
+| `ISubscribable` | `SubscribeAsync` / `OnDataChange` | One SUBSCRIBE per distinct authored topic. **`publishingInterval` is ignored** — MQTT is push-based; this driver neither polls nor throttles |
+| `IReadable` | `ReadAsync` | Serves the last received/retained value from `LastValueCache`; never throws. A never-seen tag reads `BadWaitingForInitialData` |
+| `IHostConnectivityProbe` | `GetHostStatuses` | 1-second poll of `MqttConnection.State`; `HostName` is `"{host}:{port}"` |
+| `IRediscoverable` | `OnRediscoveryNeeded` | Nothing raises it in Plain mode. **Sparkplug raises it** when a birth for an *authored* scope carries a metric-name set different from the last one seen for that scope — both conditions are anti-storm, see [Rediscovery](#rediscovery-sparkplug) |
+
+**Not implemented:** `IWritable`, `IPerCallHostResolver`, `IAlarmSource`, `IHistoryProvider`.
+Materialized nodes are `SecurityClassification.ViewOnly`, `IsAlarm: false`, `IsHistorized: false` —
+*"MQTT ingest is one-way … ViewOnly rather than an Operate node whose writes would silently vanish."*
+
+Driver-type string: **`Mqtt`** (`DriverTypeNames.Mqtt`).
+
+## Configuration
+
+Bound through `MqttJson.Options` — **case-insensitive**, enums by **name**, unknown members skipped.
+
+**The whole connection is authored on the DRIVER** (`DriverConfig`), via `MqttDriverForm` in the `/raw`
+driver-config modal. Unlike Modbus / S7 / OPC UA Client, MQTT does **not** use the v3
+endpoint→`DeviceConfig` split: an MQTT driver instance holds exactly one broker session, so
+`MqttDeviceForm` is informational (the same shape as `GalaxyDeviceForm`) and devices under an MQTT
+driver are pure organisational grouping in the RawPath.
+
+> **Why not the device.** `DriverDeviceConfigMerger` merges a device's keys up to the top level *only
+> when the driver has exactly one device*. A device-authored broker connection therefore disappears
+> from the merged blob the moment a second device is added — a silent outage with nothing to see at
+> deploy time. Driver-level authoring is correct for 0, 1 or N devices. A pre-form deployment that put
+> the connection on a sole device still works (merge-up wins over the driver's keys) and
+> `MqttDeviceForm` flags those keys so the mismatch is visible; move them to the driver.
+
+`DriverDeviceConfigMerger` still merges driver + device and injects `rawTags`.
+
+```jsonc
+// DriverConfig — authored by MqttDriverForm. PascalCase keys, enums as names.
+{
+  "Host": "10.100.0.35",
+  "Port": 8883,
+  "UseTls": true,
+  "AllowUntrustedServerCertificate": false,
+  "CaCertificatePath": null,      // pins the chain; null = OS trust store
+  "Username": "otopcua",
+  "Password": "",                 // never commit
+  "ProtocolVersion": "V500",
+  "CleanSession": true,
+  "KeepAliveSeconds": 30,
+  "ConnectTimeoutSeconds": 15,
+  "ReconnectMinBackoffSeconds": 1,
+  "ReconnectMaxBackoffSeconds": 30,
+  "MaxPayloadBytes": 1048576,
+  "Mode": "Plain",
+  "Plain": { "TopicPrefix": "", "DefaultQos": 1 }
+}
+
+// DeviceConfig — empty; MQTT has no per-device endpoint.
+{}
+```
+
+### `Sparkplug` sub-object (`Mode: "SparkplugB"`)
+
+```jsonc
+{
+  "Mode": "SparkplugB",
+  "Sparkplug": {
+    "GroupId": "OtOpcUaSim",            // REQUIRED — the driver's whole subscription scope
+    "HostId": "",                       // Host Application identity; receive-only (see below)
+    "ActAsPrimaryHost": false,          // NOT IMPLEMENTED — logs a warning when true
+    "RequestRebirthOnGap": true,        // a seq gap asks the edge node to re-announce (NCMD)
+    "BirthObservationWindowSeconds": 15 // how long discovery collects births before calling it stable
+  }
+}
+```
+
+| Key | Default | Notes |
+|---|---|---|
+| `GroupId` | `""` | **Required.** The driver subscribes exactly `spBv1.0/{GroupId}/#`. Blank ⇒ it connects, reports `Healthy`, and ingests **nothing**. It is a literal topic segment, so `/`, `+`, `#` are refused by the form |
+| `HostId` | `""` | Sparkplug Host Application identity. **Receive-only** — the driver observes `STATE` and never publishes one |
+| `ActAsPrimaryHost` | `false` | **Not implemented.** Setting it logs a startup **warning** rather than being silently inert — being a primary host is a three-part contract (retained `ONLINE`, a matching `OFFLINE` registered as the MQTT Will *at connect time*, an explicit `OFFLINE` on clean shutdown), and shipping the `ONLINE` half without the Will is strictly worse than shipping neither: a crashed node would leave a retained `ONLINE` asserting forever that a dead host is alive |
+| `RequestRebirthOnGap` | `true` | On a detected sequence-number gap, publish a rebirth-request NCMD instead of running on stale metric state |
+| `BirthObservationWindowSeconds` | `15` | Discovery's birth-collection window. Must be ≥ 1 |
+
+`MqttDriverForm` authors all five in Sparkplug mode. The sub-object is **merged, never replaced** (a
+key a newer driver adds inside it survives an older AdminUI), and in `Plain` mode it is not touched at
+all — so flipping a driver to Plain to look at it and back does not lose the group id. The form never
+writes `RawTags`; the deploy artifact owns it.
+
+> **This was a live-gate finding.** Through the P2 implementation `MqttDriverForm` still carried its P1
+> placeholder — switching Mode to `SparkplugB` rendered a "not available yet" notice and **no group-id
+> field**, so once Sparkplug ingest shipped there was no way to author a Sparkplug driver from the
+> AdminUI at all. Pinned by `MqttDriverFormModelTests`' Sparkplug cases.
+
+Every key has a default, so nothing is strictly required by the binder. Notable ones:
+`port` **8883**, `useTls` **true**, `protocolVersion` **V500**, `cleanSession` **true**,
+`keepAliveSeconds` **30**, `connectTimeoutSeconds` **15**,
+`reconnectMinBackoffSeconds` **1** / `reconnectMaxBackoffSeconds` **30**,
+`maxPayloadBytes` **1 MiB**, `allowUntrustedServerCertificate` **false**.
+
+> ⚠️ **Leave `clientId` unset on a redundant pair.** Both nodes of a pair run the driver. MQTT
+> requires client ids to be unique per broker, so a *fixed* `clientId` makes the two nodes evict each
+> other forever — the broker logs `Client <id> already connected, closing old connection` and both
+> nodes reconnect every few seconds while still reporting `Healthy`. Unset (the default) lets MQTTnet
+> generate a unique id per connection, which is correct. This was observed live during the P1 gate.
+> (The probe and browser already self-uniquify with `-probe-` / `-browse-` suffixes.) `MqttDriverForm`
+> defaults the field blank and raises this warning inline the moment a value is typed.
+
+The form validates every knob against the driver's own `[Range]` bounds (port 1–65535, keep-alive /
+connect-timeout / backoffs ≥ 1 s, max-backoff ≥ min-backoff, `maxPayloadBytes` ≥ 1, QoS 0–2) and
+additionally **clamps** on serialize, so an operator who ignores the inline error still cannot persist
+a `connectTimeoutSeconds: 0` driver-brick.
+
+## Tag Configuration
+
+A tag binds in **one of two shapes**, and which one is decided by *which keys are present*, not by a
+`mode` key on the tag. `MqttTagDefinitionFactory` reads the Sparkplug tuple when any Sparkplug
+descriptor key is set, and the topic otherwise; the AdminUI's "Tag shape" selector infers the same way
+on reopen. The key names are single-sourced in `MqttTagConfigKeys` so the browse-commit mapper and the
+factory cannot drift.
+
+### Plain shape
+
+| Key | Type | Default | Notes |
+|---|---|---|---|
+| `topic` | string | — | **Required.** Absent/blank rejects the tag ⇒ `BadNodeIdUnknown` |
+| `payloadFormat` | `Json` \| `Raw` \| `Scalar` | `Json` | **Strict** — a typo'd value rejects the tag |
+| `jsonPath` | string | `"$"` | Absent *or empty* ⇒ document root. `Json` only |
+| `dataType` | `DriverDataType` | `String` | **Strict.** `Float64`, not `Double` — see below |
+| `qos` | int 0–2 | driver's `defaultQos` | **Strict** — a malformed value rejects rather than silently weakening delivery |
+| `retainSeed` | bool | `true` | Seed this tag from the broker's retained message on subscribe |
+
+There is **no `mode` key** — the AdminUI's "Tag shape" selector is UI-only, inferred from the blob and
+never serialized.
+
+**`dataType` uses `DriverDataType`, which has `Float64` and has no `Double`.** Authoring `"Double"` is
+a strict-enum rejection, not a fallback.
+
+Payload handling: `Json` selects via JSONPath then coerces (miss ⇒ `BadDecodingError`, coerce fail ⇒
+`BadTypeMismatch`); `Raw` returns the payload's UTF-8 text verbatim and **ignores `dataType`**;
+`Scalar` decodes then coerces. The JSONPath subset is `$`, `$.a.b`, `$['a']`, `$.a[0]` — **no
+filters, slices, wildcards or recursive descent**.
+
+### Wildcards
+
+The **runtime accepts** a `+`/`#` topic (it is ambiguous, not unparseable) and the deploy-time
+`Inspect` pass **warns**. The **AdminUI editor rejects** it outright — the one place the editor is
+deliberately stricter than the driver, because one Tag holds one value and a wildcard would feed it
+from many source topics. Wildcard tags are indexed **by filter**, not by concrete topic, so they
+survive a reconnect; a message fans out to *every* matching tag, and unauthored topics are dropped.
+
+### Sparkplug shape
+
+| Key | Type | Default | Notes |
+|---|---|---|---|
+| `groupId` | string | — | **Required.** Must match the driver's `Sparkplug.GroupId` to ever receive a message |
+| `edgeNodeId` | string | — | **Required.** |
+| `deviceId` | string | *absent* | **Omit** for a metric published by the edge node itself (NBIRTH/NDATA). Absent is meaningfully different from `""` |
+| `metricName` | string | — | **Required.** The tag's stable binding key across rebirths. **May contain `/`** — `Node Control/Rebirth` and `Properties/Serial Number` are canonical Sparkplug names, and the whole name is one value, never split |
+| `dataType` | `DriverDataType` | *from the birth* | **Optional override.** Absent ⇒ take whatever type the birth certificate declared. The AdminUI's "(from birth certificate)" option removes the key entirely |
+| `isHistorized` / `historianTagname` | — | — | Server-side historization, unchanged from Plain |
+
+`payloadFormat`, `jsonPath`, `qos` and `retainSeed` are **Plain-only** and meaningless here: a
+Sparkplug body is protobuf, and the subscription is one driver-wide `spBv1.0/{GroupId}/#`, not a
+per-tag filter.
+
+`groupId` / `edgeNodeId` / `deviceId` are literal MQTT topic segments, so the AdminUI editor refuses
+`/`, `+` and `#` in them — a decoded incoming id can never contain one, so such a tag could never
+bind. `metricName` is deliberately **exempt**: it is not a topic segment.
+
+```jsonc
+// A device metric.
+{"groupId":"OtOpcUaSim","edgeNodeId":"EdgeA","deviceId":"Filler1","metricName":"FillCount"}
+
+// A node-level metric — note deviceId is ABSENT, not blank.
+{"groupId":"OtOpcUaSim","edgeNodeId":"EdgeA","metricName":"Temperature"}
+```
+
+## Sparkplug B Ingest
+
+One subscription (`spBv1.0/{GroupId}/#`) feeds a per-edge-node state machine
+(`SparkplugIngestor` + `SparkplugCodec` / `AliasTable` / `BirthCache` / `SequenceTracker`):
+
+- **Births are the only self-describing message.** NBIRTH/DBIRTH name every metric and assign its
+  alias; NDATA/DDATA carry an **alias and no name at all**. So the alias table is rebuilt *per birth*
+  and tags bind **by name**, never by alias — aliases are per-birth and may be reused for a different
+  metric after a rebirth.
+- **NBIRTH is node-scoped, DBIRTH is device-scoped**, and routing a DBIRTH through the node path
+  wipes `bdSeq`. They are handled separately on purpose.
+- **Sequence tracking**: `seq` is a wrapping 0–255 counter. A detected gap raises a rebirth request
+  when `RequestRebirthOnGap` is on, rather than silently continuing on stale metric state.
+- **Death → STALE.** An NDEATH whose `bdSeq` matches the live session (the bdSeq tie is what stops a
+  stale death from killing a fresh session) marks every metric under that edge node `Bad` /
+  `BadNoCommunication`. A DDEATH does the same for one device. The next birth restores them.
+- **Unsupported datatypes are skipped with a warning, never guessed**: `DataSet`, `Template`,
+  `PropertySet`, `PropertySetList`, `Unknown`. `Int8`→`Int16` and `UInt8`→`UInt16` widen; `*Array`
+  variants map to the element type with the array bit set.
+- **Ingest state is reset at every session/authoring seam** — a reconnect or a `ReinitializeAsync`
+  must not carry a previous session's alias table into a new one.
+
+### Rediscovery (Sparkplug)
+
+`OnRediscoveryNeeded` fires only when a birth is **for an authored scope** *and* its metric-name set
+**differs** from the last one seen for that scope (order-insensitive, ordinal). Both conditions are
+anti-storm, not optimisations: rediscovery triggers an address-space rebuild, and an edge node
+re-births freely — on its own schedule, on every reconnect, and once per rebirth NCMD.
+
+> ⚠️ **Nothing consumes the signal today.** No runtime component subscribes to
+> `IRediscoverable.OnRediscoveryNeeded`, and `DriverHostActor.HandleDiscoveredNodes` hard-returns —
+> discovered-node injection is dormant in v3. The served address space comes from the deploy artifact,
+> so **a DBIRTH introducing a new metric does not change the OPC UA tree**; you must redeploy. The
+> driver's decision is observable only as an Information log line
+> (`… requesting rediscovery.`). This is a v3 platform gap, not an MQTT one.
+
+## Connection + Failure Semantics
+
+`MqttConnectionState`: `Disconnected → Connected → Reconnecting → Faulted → Disposed`.
+A broker that is merely down stays **`Reconnecting` indefinitely** — unreachable is never a fault.
+Backoff is exponential between the two `reconnectBackoff` bounds.
+
+**MQTTnet 5 does not throw on a rejected CONNACK** — it returns the code and leaves the client
+disconnected. Left unhandled, a wrong password produced a `Healthy` driver that never received a
+value. `MqttConnection` therefore raises `MqttConnectRejectedException`:
+
+- **Unrecoverable ⇒ `Faulted`, supervisor stops** (retrying cannot help): `MalformedPacket`,
+  `ProtocolError`, `UnsupportedProtocolVersion`, `ClientIdentifierNotValid`, `BadUserNameOrPassword`,
+  `NotAuthorized`, `Banned`, `BadAuthenticationMethod`, `TopicNameInvalid`, `PacketTooLarge`,
+  `PayloadFormatInvalid`, `RetainNotSupported`, `QoSNotSupported`, `ServerMoved`.
+- **Everything else is transient** and keeps retrying — including `UnspecifiedError` and any future
+  code. (`ServerMoved` is permanent, `UseAnotherServer` is temporary — per the MQTT 5 spec.)
+
+A reconnect that completes without re-subscribing would be a healthy-looking connection that receives
+nothing forever, so `OnReconnectedAsync` **throws** when zero filters are granted, tearing the session
+down rather than swallowing it. A SUBACK failure degrades just the affected RawPaths to
+`BadCommunicationError`.
+
+## Browse
+
+`MqttDriverBrowser` opens a **read-only observation session**: it subscribes at QoS 0 to `#` (or
+`{topicPrefix}/#`) under a `-browse-`-suffixed client id and builds a `/`-segment tree from whatever
+publishes. **Nothing is ever published.** It is *inherently incomplete* — a topic that stays silent
+during the window is invisible — so manual entry remains the escape hatch.
+
+Bounds: 50 000 nodes (then `⚠ Observation truncated`), 1024-char topics / 256-char segments (then
+`⚠ Some topics were too long`), 512-byte payload inspection. Sessions are reaped after 2 minutes idle.
+
+**Sparkplug B browse serves a different tree from the same passive window**: observed NBIRTH/DBIRTH
+certificates are decoded into `Group → EdgeNode → [Device] → Metric` (a birth is the only Sparkplug
+message that names its metrics). Same node cap, same bounds, same "publishes nothing" guarantee.
+
+The bespoke browser wins over the universal `DiscoveryDriverBrowser`, which would decline MQTT anyway
+(`SupportsOnlineDiscovery` is `false`).
+
+### Browse-commit writes the address the factory reads
+
+A committed leaf's address is a **descriptor**, not a single reference string, so
+`RawBrowseCommitMapper` reads it from the `AttributeInfo.AddressFields` the session states — Plain
+emits `topic`; Sparkplug emits `groupId` / `edgeNodeId` / `deviceId?` / `metricName`, the names
+`MqttTagConfigKeys` single-sources for both the mapper and `MqttTagDefinitionFactory`.
+
+**It is never parsed out of the browse node id.** A Sparkplug node id is
+`{group}/{node}[/{device}]::{metric}` and a metric name legitimately contains `/`
+(`Node Control/Rebirth`), so splitting the id cannot recover the tuple. Which keys the session emits
+is also how the mapper learns the shape — the driver *type* reaching it is just `Mqtt`, and the mode
+lives on the driver config. A leaf whose attribute lookup returned nothing carries no address and is
+refused **at commit, in words**, rather than committed as a tag that deploys clean and then reports
+`BadNodeIdUnknown` forever.
+
+### Request rebirth (Sparkplug only)
+
+Births are never retained, so a healthy but quiet plant shows an **empty** picker tree until one
+lands. The `Request rebirth` affordance in the browse modal is the way to fill it on demand: it
+publishes a Sparkplug rebirth-request NCMD (`Node Control/Rebirth`) to the selected scope — the **one
+and only** browse action that publishes anything.
+
+- **Scope** is the last node clicked in the tree. A device or metric resolves **up to its owning edge
+  node** (Sparkplug has no device-scoped rebirth); a group fans out to every observed edge node
+  beneath it and is refused **whole** past 32, publishing nothing.
+- **Two clicks, never one** — `Request rebirth…` arms a confirm panel naming the resolved scope and
+  its consequence; changing the selection disarms it.
+- **Gated on `DriverOperator`**, enforced server-side in `BrowserSessionService.RequestRebirthAsync`
+  (fail-closed) before the session is touched; the UI gate is defence in depth. A refusal — policy,
+  over-wide group, unresolvable scope — is **shown**, not swallowed.
+- Offered only for a Sparkplug session (`IRebirthCapableBrowseSession.RebirthAvailable`); a Plain
+  MQTT window publishes nothing, ever.
+
+### Refresh
+
+An observation window **accumulates**, but the tree renders **once**, when it is created — and
+`OpenAsync` returns as soon as the SUBSCRIBE is granted, without waiting for the birth-observation
+window. So the first render is normally empty on Plain (a topic that has not published yet is
+invisible) and *almost always* empty on Sparkplug (births are never retained). **Refresh** re-reads
+the root against the same session: nothing reconnects, nothing already observed is lost, and the tag
+selection is kept. Only the armed rebirth scope is cleared, because the node it named may no longer be
+in the rebuilt tree.
+
+> **Also fixed by this gate, and not MQTT-specific:** every node label in the shared
+> `DriverBrowseTree` was an `<a href="#">`. `blazor.web.js`'s enhanced-navigation click interceptor
+> resolves a bare `#` against `<base href="/">`, so clicking a node **label** navigated the whole
+> AdminUI to `/` and destroyed the hosting modal (`@onclick:preventDefault` suppresses the browser's
+> default action, not Blazor's interceptor). The labels are now `<button type="button">`. This
+> affected **every** driver's picker since 2026-05-28; it surfaced here because choosing a rebirth
+> scope is the first flow that requires clicking a label rather than the ▶ toggle.
+
+> ⚠️ **Known gap — a completely empty tree cannot arm a rebirth.** The rebirth scope is taken from the
+> last node clicked *in the tree*, so on a plant that has not birthed since the window opened there is
+> nothing to click and `Request rebirth…` stays disabled — the exact case the affordance exists for.
+> `MqttBrowseSession.ResolveRebirthTargets` already accepts a bare `{group}/{edgeNode}` for a node the
+> window has never seen (it calls that "the prime rebirth target"); what is missing is a UI path to
+> enter one, or to default the scope to the driver's own configured `GroupId`. Until then: use
+> **Refresh** after any birth, or author the tags by **Manual entry**, which is always available.
+
+## Test Connect
+
+`MqttDriverProbe` performs **one CONNECT** (no SUBSCRIBE, no publish) under a `-probe-` client id and
+disconnects. Success message: `"MQTT CONNECT OK"`. A rejected CONNACK is described by the same
+`DescribeConnackRejection` the running driver uses, so the button and the driver report a rejection in
+identical words. See [TestConnectProbes.md](TestConnectProbes.md).
+
+## Testing
+
+- **Unit** — `tests/Drivers/…Driver.Mqtt.Tests` (**581 tests**): tag-config mapping (both shapes),
+  JSONPath subset, strict-enum rejection, subscription indexing (incl. the wildcard-by-filter case),
+  reconnect/rebuild branches, CONNACK classification, and the Sparkplug half — golden-payload decode,
+  topic parse/format, datatype map, alias/birth-cache rebuild, sequence + bdSeq-death ties, the
+  rediscovery change gate, and the browse session's "publishes nothing" assertion.
+- **Live (env-gated)** — `tests/Drivers/…Driver.Mqtt.IntegrationTests` (**15 tests**) against the
+  Mosquitto broker + the C# Sparkplug edge-node simulator; skips cleanly when `MQTT_FIXTURE_ENDPOINT`
+  is unset. See [Mqtt-Test-Fixture.md](Mqtt-Test-Fixture.md) and `infra/README.md` §3.
+- **AdminUI** — `MqttDriverFormModelTests` / `MqttTagConfigModelTests` cover both editors'
+  round-trip, mode inference and validation. AdminUI has no bUnit, so the razor shells themselves are
+  only ever proven by a live `/run` gate.
+
+## Operational Notes
+
+- **Read-only.** No writes reach the broker; every node is ViewOnly. Sparkplug NCMD is used for
+  **rebirth requests only** — never to command a device.
+- **No alarms, no driver-side history.** Historization is a server-side concern (`isHistorized`).
+- **Both pair nodes subscribe independently** — MQTT fan-out is per-connection, and the Primary gate
+  applies downstream, not to ingest. This is also why `clientId` must stay unset (above).
+- **Unauthored traffic is ignored.** A busy broker is normal; the driver never auto-provisions a tag.
+
+## Known gaps
+
+Every row is tracked. None is a silent failure — each either refuses in words or logs.
+
+| Gap | Issue | Effect | Notes |
+|---|:---:|---|---|
+| **Write-through (`IWritable`)** | [#508](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/508) | Every MQTT node is read-only | Deferred to P3 — NCMD/DCMD + plain publish, optimistic-Good + self-correct on echo |
+| **Rediscovery is inert** | [#507](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/507) | A DBIRTH introducing a metric does not change the OPC UA tree; redeploy to pick it up | v3 **platform** gap, not MQTT-specific — nothing subscribes to `OnRediscoveryNeeded` and `DriverHostActor.HandleDiscoveredNodes` hard-returns. Also affects Galaxy / TwinCAT / AbCip. Driver-side decision is log-observable |
+| **Rebirth needs a non-empty tree** | [#514](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/514) | `Request rebirth…` cannot be armed on a plant that has not birthed since the window opened | See [Refresh](#refresh). Session side already supports a bare `{group}/{edgeNode}` scope |
+| **`_canRebirth` is captured at browse-open** | [#510](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/510) | A session reaped for idleness (2 min) still draws the button, and using it errors | The error is shown, not swallowed; reopen the browser |
+| **Primary-host STATE publishing** | [#511](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/511) | `ActAsPrimaryHost` does nothing | Logs a startup warning rather than being silently inert — see the `Sparkplug` sub-object table |
+| **A metric whose name contains `/` cannot be browse-committed** | [#509](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/509) | The commit is refused **whole**, in words (`Row N: Name must not contain '/'`) | The derived **tag Name** is a RawPath segment and may not contain `/`, while `metricName` legitimately may. This blocks the spec-mandatory `Node Control/Rebirth`. **Workaround: Manual entry** — author the tag with a `/`-free name and type the slashed `metricName` into the Sparkplug editor, which accepts it. Nothing is silently mis-bound |
+| **`DataSet` / `Template` / `PropertySet` metrics** | [#515](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/515) | Skipped with a warning | v1-unsupported; never coerced into a guessed type |
+| **The tag editor writes `payloadFormat` into a Sparkplug blob** | [#513](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/513) | Cosmetic only | `payloadFormat` is Plain-only; the factory routes on the Sparkplug keys and ignores it. Noise in the blob, not a mis-binding |
+| **`.Browser` references `.Driver`, not just `.Contracts`** | [#512](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/512) | A documented layering exception | Taken to reuse `MqttConnection.BuildClientOptions` rather than duplicate TLS/CA-pin logic — see the note at the top of this doc |
@@ -124,7 +124,7 @@ ConditionType events (non-base `BaseEventType`) is not verified.
 - Anonymous, UserName/Password, X509 cert tokens — each is contract-tested
  but not exchanged against a server that actually enforces each.
 - LDAP-backed `UserName` (matching this repo's server-side
-  `LdapUserAuthenticator`) requires a live LDAP round-trip; not tested.
+  `LdapOpcUaUserAuthenticator`) requires a live LDAP round-trip; not tested.

 ## When to trust OpcUaClient tests, when to reach for a server

@@ -1,6 +1,6 @@
 # Drivers

-OtOpcUa is a multi-driver OPC UA server. The Core (`ZB.MOM.WW.OtOpcUa.Core` + `Core.Abstractions` + `Server`) owns the OPC UA stack, address space, session/security/subscription machinery, resilience pipeline, and namespace kinds (Equipment + SystemPlatform). Drivers plug in through **capability interfaces** defined in `src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/`:
+OtOpcUa is a multi-driver OPC UA server. The Core (`ZB.MOM.WW.OtOpcUa.Core` + `Core.Abstractions` + `Server`) owns the OPC UA stack, address space, session/security/subscription machinery, resilience pipeline, and the two v3 OPC UA namespaces (Raw + UNS — see `V3NodeIds` / `AddressSpaceRealm`). Drivers plug in through **capability interfaces** defined in `src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/`:

 - `IDriver` — lifecycle (`InitializeAsync`, `ReinitializeAsync`, `ShutdownAsync`, `GetHealth`)
 - `IReadable` / `IWritable` — one-shot reads and writes
@@ -15,20 +15,28 @@ OtOpcUa is a multi-driver OPC UA server. The Core (`ZB.MOM.WW.OtOpcUa.Core` + `C

 Each driver opts into only the capabilities it supports. Every async capability call at the Server dispatch layer goes through `CapabilityInvoker` (`Core/Resilience/CapabilityInvoker.cs`), which wraps it in a Polly pipeline keyed on `(DriverInstanceId, HostName, DriverCapability)`. The `OTOPCUA0001` analyzer enforces the wrap at build time. Drivers themselves never depend on Polly; they just implement the capability interface and let the Core wrap it.

-Driver type metadata is registered at startup in `DriverTypeRegistry` (`src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverTypeRegistry.cs`). The registry records each type's allowed namespace kinds (`Equipment` / `SystemPlatform` / `Simulated`), its JSON Schema for `DriverConfig` / `DeviceConfig` / `TagConfig` columns, and its stability tier per [docs/v2/driver-stability.md](../v2/driver-stability.md).
+Driver **factories** are registered at startup in `DriverFactoryRegistry` (`src/Core/ZB.MOM.WW.OtOpcUa.Core/Hosting/DriverFactoryRegistry.cs`) — all 12 in one place, `src/Server/ZB.MOM.WW.OtOpcUa.Host/Drivers/DriverFactoryBootstrap.cs:147-164`. Type names are the `DriverTypeNames` constants (`src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverTypeNames.cs`), guarded bidirectionally by `DriverTypeNamesGuardTests`.
+
+> ⚠️ **`DriverTypeRegistry` / `DriverTypeMetadata` are vestigial.** No production code constructs or reads them — the class is referenced only by its own unit tests. Its `AllowedNamespaceKinds` field was retired along with the v3 `Namespace` entity (`DriverTypeRegistry.cs:97`), and the `SystemPlatform` namespace kind no longer exists.
+>
+> **Stability tier** likewise does not come from that registry: it is the `DriverTier tier = DriverTier.A` parameter on `DriverFactoryRegistry.cs:46`, and **no factory in `src/Drivers/` passes a tier**, so every shipped driver runs Tier A. The Tier-C-only protections described in [docs/v2/driver-stability.md](../v2/driver-stability.md) — `MemoryRecycle` hard-breach kill (`MemoryRecycle.cs:54`) and `ScheduledRecycleScheduler` (`:43`) — are therefore dormant for every driver.

 ## Ground-truth driver list

 | Driver | Project path | Tier | Wire / library | Capabilities | Notable quirk |
 |--------|--------------|:----:|----------------|--------------|---------------|
 | [Galaxy](Galaxy.md) | `Driver.Galaxy` (+ `.Browser`, `.Contracts`) | A | gRPC to the external `mxaccessgw` gateway (the gateway owns MXAccess COM + the Galaxy Repository SQL reader) | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IAlarmSource, IRediscoverable, IHostConnectivityProbe | In-process .NET 10 driver — the COM bitness constraint lives in the gateway's x86 net48 worker, not here. PR 7.2 retired the legacy in-process `Galaxy.{Shared, Host, Proxy}` + named-pipe Windows service. Native MxAccess alarms work end-to-end |
-| [Modbus TCP](Modbus.md) | `Driver.Modbus` | A | NModbus-derived in-house client | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | Polled subscriptions via the shared `PollGroupEngine`. DL205 PLCs are covered by `AddressFormat=DL205` (octal V/X/Y/C/T/CT translation) — no separate driver |
+| [Modbus TCP / RTU-over-TCP](Modbus.md) | `Driver.Modbus` (+ `.Addressing`, `.Contracts`) | A | NModbus-derived in-house client; `Transport` selects MBAP (TCP) or RTU CRC-16 framing over a socket | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver | Polled subscriptions via the shared `PollGroupEngine`. DL205 PLCs are covered by `AddressFormat=DL205` (octal V/X/Y/C/T/CT translation) — no separate driver. `Transport=RtuOverTcp` (`ModbusTransportMode`, default `Tcp`) targets serial→Ethernet gateways via `ModbusRtuOverTcpTransport` + `ModbusRtuFraming` + `ModbusCrc`, with `ModbusTransportDesyncException` carrying distinct CrcMismatch/UnitMismatch reasons; **direct-serial transport is descoped**. Merged `0f38f486` (#495) |
 | [Siemens S7](S7.md) | `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](AbCip.md) | `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](AbLegacy.md) | `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](TwinCAT.md) | `Driver.TwinCAT` | B | Beckhoff `TwinCAT.Ads` (`TcAdsClient`) | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver, IRediscoverable | The only native-notification driver outside Galaxy — ADS delivers `ValueChangedCallback` events the driver forwards straight to `ISubscribable.OnDataChange` without polling. Symbol tree uploaded via `SymbolLoaderFactory` |
 | [FOCAS](FOCAS.md) | `Driver.FOCAS` | A | Pure-managed `FocasWireClient` — FOCAS/2 Ethernet binary protocol on TCP:8193, inlined into the driver assembly | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IHostConnectivityProbe, IPerCallHostResolver, IAlarmSource | `IWritable` is implemented but read-only by design — `WriteAsync` returns `BadNotWritable` for every point. CNC-shaped data model (axes, spindle, PMC, macros, alarms) not a flat tag map. Previously Tier-C (Host + P/Invoke + shim DLL); retired in the 2026-04-24 migration when the managed wire client landed |
 | [OPC UA Client](OpcUaClient.md) | `Driver.OpcUaClient` | B | OPCFoundation `Opc.Ua.Client` | IDriver, ITagDiscovery, IReadable, IWritable, ISubscribable, IAlarmSource, IHistoryProvider, IHostConnectivityProbe | Gateway/aggregation driver — the only driver implementing driver-side `IHistoryProvider` (forwards HistoryRead to the upstream server). Opens a single `Session` against a remote OPC UA server and re-exposes its address space. Owns its own `ApplicationConfiguration` (distinct from `Client.Shared`) because it's always-on with keep-alive + `TransferSubscriptions` across SDK reconnect, not an interactive CLI |
+| [MQTT](Mqtt.md) | `Driver.Mqtt` (+ `.Browser`, `.Contracts`) | A | [MQTTnet 5](https://github.com/dotnet/MQTTnet) | IDriver, ITagDiscovery, IReadable, ISubscribable, IHostConnectivityProbe, IRediscoverable | **Push, not poll, and read-only** — the broker delivers PUBLISH frames the driver forwards straight to `ISubscribable.OnDataChange`; `IReadable` serves the last retained/received value from cache, and there is **no `IWritable`** (nothing publishes back). Subscriptions are indexed **by topic filter, not by topic**, so wildcard tags survive a reconnect. A rejected CONNACK throws `MqttConnectRejectedException`: unrecoverable codes → `Faulted` + supervisor stop, transient → retry. **Two modes:** `Plain` binds a tag to a concrete topic + JSON path; `SparkplugB` decodes vendored Eclipse-Tahu protobuf under one `spBv1.0/{groupId}/#` subscription and binds by the `group/edgeNode/device?/metric` tuple (birth/alias/seq-gap state machine, death→STALE, scoped rebirth NCMD). `IRediscoverable` fires on a DBIRTH but is **inert platform-side** — see [#507](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/507) |
+| [MTConnect](MTConnect.md) | `Driver.MTConnect` (+ `.Contracts`) | — | Hand-rolled `System.Xml.Linq` HTTP/XML client against a vendor-neutral MTConnect Agent (`/probe`, `/current`, `/sample`) — no TrakHound dependency (dropped; see the driver doc) | IDriver, ITagDiscovery, IReadable, ISubscribable, IHostConnectivityProbe, IRediscoverable | Read-only by design (no `IWritable`). Production data plane is entirely `ISubscribable`/`OnDataChange` — `IReadable` is CLI/test-only. Browse is free via the Wave-0 universal discovery browser, no bespoke browser project. `IRediscoverable`/`IHostConnectivityProbe` have no server-side consumer yet — a pre-existing fleet-wide gap, not MTConnect-specific |
+| **Sql** (no dedicated page — see [design](../plans/2026-07-15-sql-poll-driver-design.md)) | `Driver.Sql` (+ `.Browser`, `.Contracts`) | A | `Microsoft.Data.SqlClient` behind an `ISqlDialect` seam (`SqlServerDialect` shipped; Postgres/ODBC deferred) | IDriver, ITagDiscovery, IReadable, ISubscribable, IHostConnectivityProbe | Read-only DB-poll driver with a bespoke schema browser. **Credentials are never persisted** — the deploy gate rejects a stored `connectionString` (#498) and catalog identifiers are validated against the live catalog's own spelling (#496). `SupportsOnlineDiscovery => false` by design (the bespoke browser wins). `SqlTagModel.Query` is deferred to P3 and rejected end-to-end by parser, validator, planner and editor. Merged `4ad54037` |
+| **Calculation** (see [Raw.md](../Raw.md#the-calculation-driver)) | `Driver.Calculation` | A | none — computes from other tags' RawPaths | IDriver, IDependencyConsumer, ISubscribable, IReadable | **Pseudo-driver**, not a wire protocol: signal-level tags computed from other tags via a script, with deploy-time `scriptId`-existence + Tarjan cycle gates. Its probe is parse-only (no backend to reach). ⚠️ **No typed config form** — `DriverConfigModal` has no `Calculation` case, so `RunTimeout` is currently unauthorable through the AdminUI |
 | [Historian.Gateway](../Historian.md) | `Driver.Historian.Gateway` | — | `ZB.MOM.WW.HistorianGateway.Client` gRPC (`historian_gateway.v1`) | IHistorianDataSource (server-side read backend) + alarm `SendEvent` writer + `WriteLiveValues` recorder + `IHistorianProvisioning` | Not a tag driver — the sole historian backend. Registers `GatewayHistorianDataSource : IHistorianDataSource` for HistoryRead and serves alarm-write + continuous historization through the gateway. No `IDriver`/`ITagDiscovery` surface. (The retired Wonderware sidecar backend it replaced is documented at [Historian.Wonderware.md](Historian.Wonderware.md).) |

 ## Per-driver documentation
@@ -40,13 +48,18 @@ Driver type metadata is registered at startup in `DriverTypeRegistry` (`src/Core
 - **FOCAS** has a short getting-started doc because the backend-selection env var + alarm projection opt-in need explaining up front:
  - [FOCAS.md](FOCAS.md) — deployment, config, capability surface, alarm projection, troubleshooting

- **Modbus TCP**, **AB CIP**, **AB Legacy**, **Siemens S7**, **TwinCAT**, and **OPC UA Client** each have a per-driver overview page:
+- **Modbus TCP**, **AB CIP**, **AB Legacy**, **Siemens S7**, **TwinCAT**, **OPC UA Client**, and **MQTT** each have a per-driver overview page:
  - [Modbus.md](Modbus.md) — in-process Modbus-TCP driver: address formats, polled subscription model, DL205 octal mapping
  - [AbCip.md](AbCip.md) — AB CIP / EtherNet-IP driver (ControlLogix / CompactLogix / Micro800 / GuardLogix): tag discovery, UDT resolution, alarm source
  - [AbLegacy.md](AbLegacy.md) — AB Legacy PCCC driver (SLC 500 / MicroLogix / PLC-5): file-based addressing, user-authored tag list
  - [S7.md](S7.md) — Siemens S7 driver (S7-300/400/1200/1500 + S7-200): getting started, config, data-block addressing, serialized single-connection model
  - [TwinCAT.md](TwinCAT.md) — Beckhoff TwinCAT (ADS) driver: getting started, native-notification subscription, symbol-tree upload
  - [OpcUaClient.md](OpcUaClient.md) — OPC UA Client (gateway/aggregation) driver: remote-server session, driver-side HistoryRead forwarding, reconnect behaviour
+  - [Mqtt.md](Mqtt.md) — MQTT broker-subscribe driver: broker/TLS/auth config, topic + JSON-path tag binding, retained-value seeding, `#`-observation browser, CONNACK-rejection semantics, **Sparkplug B** (birth/alias/seq/rebirth state machine, birth-driven browse picker, death→STALE), and the **Known gaps** table
+
+- **MTConnect** has a short getting-started doc because the hand-rolled-vs-TrakHound divergence, the
+  data-plane precedence rules, and a non-trivial known-limitations list need explaining up front:
+  - [MTConnect.md](MTConnect.md) — Agent config, `FullName`==DataItem `id`, `UNAVAILABLE`→`BadNoCommunication`, CONDITION-as-`String`, browse-via-universal-browser, fixture recipe, deferred write-back

 - **Historian.Gateway** (server-side historian backend, not a tag driver) is documented in the main guide:
  - [../Historian.md](../Historian.md) — HistorianGateway backend: read-path registration, HistoryRead dispatch, alarm store-and-forward (`SendEvent`), continuous historization (`WriteLiveValues`), `EnsureTags` provisioning, config keys, deployment prerequisites. (The retired Wonderware sidecar backend it replaced: [Historian.Wonderware.md](Historian.Wonderware.md).)
@@ -64,12 +77,14 @@ Each driver has a dedicated fixture doc that lays out what the integration / uni
 - [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) — Dockerized `opc-plc` integration suite (task #215): real Secure Channel + Session, read + subscribe verified end-to-end; write not yet exercised in the integration suite; exhaustive capability matrix (reconnect, failover, cert-auth, history, alarms) via unit suite with mocked `Session`
+- [MQTT](Mqtt-Test-Fixture.md) — Dockerized `eclipse-mosquitto` with **TLS + real auth on both listeners (no anonymous fallback)** + a JSON-publisher sidecar; env-gated live suite (**15 tests**) — 7 plain (TLS/auth connect, CA pinning both ways, subscribe→value, retained seeding, wrong-password rejection) + 8 Sparkplug against a **project-owned C# edge-node simulator** on the `sparkplug` compose profile (birth→alias bind, DDATA, NDEATH→STALE, rebirth NCMD round-trip). Births are never retained, so `docker restart otopcua-sparkplug-sim` is how you force a fresh one
 - [Galaxy](../v1/drivers/Galaxy-Test-Fixture.md) — richest harness: gateway E2E + ZB SQL live-smoke + MXAccess opt-in (v1 archive)
+- [MTConnect](../../tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md) — Dockerized `mtconnect/agent` + stdlib SHDR adapter (two services, the Agent alone reports everything `UNAVAILABLE`); 12/12 against the real Agent, canned XML unit fixtures cover the bulk (491/491)

 ## Related cross-driver docs

 - [HistoricalDataAccess.md](../v1/HistoricalDataAccess.md) — `IHistoryProvider` dispatch, aggregate mapping, continuation points. The OPC UA Client driver is the only driver that implements driver-side `IHistoryProvider` (it forwards HistoryRead to the upstream server); the AVEVA Historian path is served server-side by the HistorianGateway-backed `IHistorianDataSource` instead. Other drivers do not implement the interface and return `BadHistoryOperationUnsupported`.
- [AlarmTracking.md](../AlarmTracking.md) — `IAlarmSource` event model and filtering. Implemented by Galaxy (native MxAccess alarms, working end-to-end), OPC UA Client, AB CIP, and FOCAS; AB Legacy, Modbus, S7, and TwinCAT have no alarm source.
+- [AlarmTracking.md](../AlarmTracking.md) — `IAlarmSource` event model and filtering. Implemented by Galaxy (native MxAccess alarms, working end-to-end), OPC UA Client, AB CIP, and FOCAS; AB Legacy, Modbus, S7, TwinCAT, and MQTT have no alarm source.
 - [Subscriptions.md](../v1/Subscriptions.md) — how the Server multiplexes subscriptions onto `ISubscribable.OnDataChange`.
 - [docs/v2/driver-stability.md](../v2/driver-stability.md) — tier system (A / B / C), shared `CapabilityPolicy` defaults per tier × capability, `MemoryTracking` hybrid formula, and process-level recycle rules.
 - [docs/v2/plan.md](../v2/plan.md) — authoritative vision, architecture decisions, migration strategy.
@@ -49,6 +49,7 @@ with a human-readable explanation rather than a false-green TCP-open tick.
 | **TwinCAT** | `AdsClient.Connect` + `ReadStateAsync`. See [degrade semantics](#twincat-degrade) below. | `"ADS state: {state}"` | Deferred — no ADS target |
 | **FOCAS** | `cnc_allclibhndl3` via a direct `DllImport("fwlib32")` in the probe. See [degrade semantics](#focas-degrade) below. | `"FOCAS handle OK"` | Deferred — no CNC + FWLIB |
 | **Galaxy** | gRPC unary call to `GalaxyRepository.TestConnection` on the configured mxaccessgw endpoint. See [auth-rejection rule](#galaxy-auth-rejection) below. | `"gateway gRPC OK"` | `http://10.100.0.48:5120` (mxaccessgw) |
+| **MQTT** | One MQTT `CONNECT` (no SUBSCRIBE, no publish) under a `-probe-`-suffixed client id, then disconnect. **A rejected CONNACK is a returned result code, not an exception** — MQTTnet 5 does not throw — so the probe inspects `ResultCode` and reuses the driver's own `DescribeConnackRejection`, making the button and the running driver word a rejection identically. | `"MQTT CONNECT OK"` | `10.100.0.35:8883` (Mosquitto TLS+auth fixture) |

 **Historian.Wonderware** had a TCP `Hello`→`HelloAck` handshake probe before Phase 5, but the
 Wonderware historian backend (and its driver-type / probe) has since been **retired** — the historian
@@ -133,6 +134,7 @@ above. (Live verification on `10.100.0.48:5120` with no key returns
 | S7 | Verified | python-snap7 `10.100.0.35:1102` |
 | AbCip | Verified | CIP sim `10.100.0.35:44818` |
 | Galaxy | Verified | mxaccessgw `10.100.0.48:5120`; `Unauthenticated` reply counts as Ok |
+| MQTT | Verified | Mosquitto `10.100.0.35:8883`; live suite covers TLS+auth Ok, foreign-CA rejection, and wrong-password rejection surfacing rather than reporting healthy |
 | AbLegacy | Deferred | No PLC5/SLC sim; unit-proven + code path identical to AbCip |
 | TwinCAT | Deferred | No ADS target; unit-proven + degrade guard tested |
 | FOCAS | Deferred | No CNC + FWLIB on dev host; degrade guard is the CI-observable path |
@@ -92,7 +92,7 @@ discovery.
 | `ISubscribable` | native ADS notifications (default), poll fallback | `UseNativeNotifications=true` registers device notifications so the PLC pushes changes; `false` uses the shared `PollGroupEngine` |
 | `IHostConnectivityProbe` | per-device probe loop | One `HostConnectivityStatus` per configured device; `Running`/`Stopped` transitions raise `OnHostStatusChanged` |
 | `IPerCallHostResolver` | `ResolveHost` lookup in the tag map | Routes each call to the device of the referenced tag; returns an empty-string sentinel when unresolved |
-| `IRediscoverable` | symbol-version-changed callback | A PLC re-download fires `OnRediscoveryNeeded` so the address space is rebuilt |
+| `IRediscoverable` | symbol-version-changed callback | A PLC re-download fires `OnRediscoveryNeeded`. ⚠️ **No consumer wires it today** ([#518](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/518), [#507](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/507)) — the address space does **not** rebuild; a config redeploy is required. Driver-side behaviour is log-observable only |

 ### Rediscovery on PLC re-download

@@ -100,8 +100,15 @@ discovery.
 `DeviceSymbolVersionInvalid` (1809 / 0x0711) — the documented TwinCAT
 symbol-version-changed signal, raised when a PLC program is re-downloaded —
 every symbol and notification handle is invalidated. The driver raises
-`OnRediscoveryNeeded` with a `TwinCAT` scope hint so Core rebuilds the address
-space rather than treating it as a transient connection error.
+`OnRediscoveryNeeded` with a `TwinCAT` scope hint, so that the signal is treated
+as an address-space change rather than a transient connection error.
+
+⚠️ **That is the intended design, not present behaviour.** No consumer subscribes
+to `OnRediscoveryNeeded` anywhere in `src/`, and the scope hint is read by nothing
+([#518](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/518),
+[#507](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/507)). Today the
+signal is observable only in the driver log; after a PLC re-download the served
+address space changes only on a config redeploy.

 ### Native notifications

@@ -148,7 +155,7 @@ fixture is down during normal dev.
 **Live-verify** — integration-fixture-gated (requires the TwinCAT Docker fixture / AMS router).

 **Deferrals** — array *writes* (`ADS WriteValueAsync` for an array), multi-dimensional
-arrays, per-element historization.  `IRediscoverable` still fires and rebuilds array nodes
+arrays, per-element historization.  `IRediscoverable` fires and now surfaces a `/hosts` re-browse prompt, but still does not rebuild the address space (#518)
 on PLC re-download (unchanged semantics from scalar nodes).

 See [Uns.md §Array tags](../Uns.md#array-tags-1-d) for the cross-driver coverage matrix
@@ -1,18 +1,116 @@
 {
  "planPath": "docs/plans/2026-06-12-historian-tcp-transport.md",
  "tasks": [
-    {"id": 0, "nativeTaskId": 296, "subject": "Task 0: Create feature branch", "status": "pending"},
-    {"id": 1, "nativeTaskId": 297, "subject": "Task 1: Add TCP/TLS fields to client options", "status": "pending", "blockedBy": [0]},
-    {"id": 2, "nativeTaskId": 298, "subject": "Task 2: Client TCP connect factory + FrameChannel rename", "status": "pending", "blockedBy": [1]},
-    {"id": 3, "nativeTaskId": 299, "subject": "Task 3: Switch client default ctor to TCP", "status": "pending", "blockedBy": [2]},
-    {"id": 4, "nativeTaskId": 300, "subject": "Task 4: Host config binding (Host/Port/TLS)", "status": "pending", "blockedBy": [1]},
-    {"id": 5, "nativeTaskId": 301, "subject": "Task 5: Sidecar TcpFrameServer", "status": "pending", "blockedBy": [0]},
-    {"id": 6, "nativeTaskId": 302, "subject": "Task 6: Sidecar Program.cs — TCP bootstrap + env", "status": "pending", "blockedBy": [5]},
-    {"id": 7, "nativeTaskId": 303, "subject": "Task 7: Remove dead pipe code + finalize options shape", "status": "pending", "blockedBy": [3, 4, 6]},
-    {"id": 8, "nativeTaskId": 304, "subject": "Task 8: Deploy scripts — env block + firewall + cert", "status": "pending", "blockedBy": [7]},
-    {"id": 9, "nativeTaskId": 305, "subject": "Task 9: AdminUI Test-Connect probe to host/port/TLS", "status": "pending", "blockedBy": [7]},
-    {"id": 10, "nativeTaskId": 306, "subject": "Task 10: Docs — TCP transport", "status": "pending", "blockedBy": [7]},
-    {"id": 11, "nativeTaskId": 307, "subject": "Task 11: Verification (build + test + live)", "status": "pending", "blockedBy": [8, 9, 10]}
+    {
+      "id": 0,
+      "nativeTaskId": 296,
+      "subject": "Task 0: Create feature branch",
+      "status": "completed"
+    },
+    {
+      "id": 1,
+      "nativeTaskId": 297,
+      "subject": "Task 1: Add TCP/TLS fields to client options",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 2,
+      "nativeTaskId": 298,
+      "subject": "Task 2: Client TCP connect factory + FrameChannel rename",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "nativeTaskId": 299,
+      "subject": "Task 3: Switch client default ctor to TCP",
+      "status": "completed",
+      "blockedBy": [
+        2
+      ]
+    },
+    {
+      "id": 4,
+      "nativeTaskId": 300,
+      "subject": "Task 4: Host config binding (Host/Port/TLS)",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 5,
+      "nativeTaskId": 301,
+      "subject": "Task 5: Sidecar TcpFrameServer",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 6,
+      "nativeTaskId": 302,
+      "subject": "Task 6: Sidecar Program.cs \u2014 TCP bootstrap + env",
+      "status": "completed",
+      "blockedBy": [
+        5
+      ]
+    },
+    {
+      "id": 7,
+      "nativeTaskId": 303,
+      "subject": "Task 7: Remove dead pipe code + finalize options shape",
+      "status": "completed",
+      "blockedBy": [
+        3,
+        4,
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "nativeTaskId": 304,
+      "subject": "Task 8: Deploy scripts \u2014 env block + firewall + cert",
+      "status": "completed",
+      "blockedBy": [
+        7
+      ]
+    },
+    {
+      "id": 9,
+      "nativeTaskId": 305,
+      "subject": "Task 9: AdminUI Test-Connect probe to host/port/TLS",
+      "status": "completed",
+      "blockedBy": [
+        7
+      ]
+    },
+    {
+      "id": 10,
+      "nativeTaskId": 306,
+      "subject": "Task 10: Docs \u2014 TCP transport",
+      "status": "completed",
+      "blockedBy": [
+        7
+      ]
+    },
+    {
+      "id": 11,
+      "nativeTaskId": 307,
+      "subject": "Task 11: Verification (build + test + live)",
+      "status": "completed",
+      "blockedBy": [
+        8,
+        9,
+        10
+      ]
+    }
  ],
-  "lastUpdated": "2026-06-12"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "OBSOLETE \u2014 targets the bespoke Wonderware TCP/ArchestrA historian sidecar, retired when HistorianGateway became the sole historian backend. There is no Wonderware backend in the tree. Closed as obsolete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -1,18 +1,111 @@
 {
  "planPath": "docs/plans/2026-06-15-stillpending-phase-0-1.md",
  "tasks": [
-    {"id": 402, "subject": "SP Task 0: Feature branch feat/stillpending-phase-0-1", "status": "pending"},
-    {"id": 403, "subject": "SP Task 1: Phase 0 — correct 7 stale code comments", "status": "pending", "blockedBy": [402]},
-    {"id": 404, "subject": "SP Task 2: Phase 0 — fix docs/security.md + benign-residue comments", "status": "pending", "blockedBy": [402]},
-    {"id": 405, "subject": "SP Task 3: Phase 0 — mark shipped .tasks.json completed", "status": "pending", "blockedBy": [402]},
-    {"id": 406, "subject": "SP Task 4: Phase 1 H1a — Phase7Applier rebuilds on Changed*", "status": "pending", "blockedBy": [402]},
-    {"id": 407, "subject": "SP Task 5: Phase 1 H1b — VirtualTagHostActor respawns changed child", "status": "pending", "blockedBy": [402]},
-    {"id": 408, "subject": "SP Task 6: Phase 1 H5a — EquipmentVirtualTagPlan.Historize + composer", "status": "pending", "blockedBy": [402]},
-    {"id": 409, "subject": "SP Task 7: Phase 1 H5b — DeploymentArtifact decodes Historize (byte-parity)", "status": "pending", "blockedBy": [408]},
-    {"id": 410, "subject": "SP Task 8: Phase 1 H5c — VirtualTagHostActor invokes IHistoryWriter", "status": "pending", "blockedBy": [407, 409]},
-    {"id": 411, "subject": "SP Task 9: Phase 1 H5d — thread IHistoryWriter through DriverHostActor + DI", "status": "pending", "blockedBy": [410, 403]},
-    {"id": 412, "subject": "SP Task 10: Phase 1 — docs + follow-up bookkeeping", "status": "pending", "blockedBy": [411]},
-    {"id": 413, "subject": "SP Task 11: Phase 0+1 — full build + test + integration review", "status": "pending", "blockedBy": [403, 404, 405, 406, 407, 408, 409, 410, 411, 412]}
+    {
+      "id": 402,
+      "subject": "SP Task 0: Feature branch feat/stillpending-phase-0-1",
+      "status": "completed"
+    },
+    {
+      "id": 403,
+      "subject": "SP Task 1: Phase 0 \u2014 correct 7 stale code comments",
+      "status": "completed",
+      "blockedBy": [
+        402
+      ]
+    },
+    {
+      "id": 404,
+      "subject": "SP Task 2: Phase 0 \u2014 fix docs/security.md + benign-residue comments",
+      "status": "completed",
+      "blockedBy": [
+        402
+      ]
+    },
+    {
+      "id": 405,
+      "subject": "SP Task 3: Phase 0 \u2014 mark shipped .tasks.json completed",
+      "status": "completed",
+      "blockedBy": [
+        402
+      ]
+    },
+    {
+      "id": 406,
+      "subject": "SP Task 4: Phase 1 H1a \u2014 Phase7Applier rebuilds on Changed*",
+      "status": "completed",
+      "blockedBy": [
+        402
+      ]
+    },
+    {
+      "id": 407,
+      "subject": "SP Task 5: Phase 1 H1b \u2014 VirtualTagHostActor respawns changed child",
+      "status": "completed",
+      "blockedBy": [
+        402
+      ]
+    },
+    {
+      "id": 408,
+      "subject": "SP Task 6: Phase 1 H5a \u2014 EquipmentVirtualTagPlan.Historize + composer",
+      "status": "completed",
+      "blockedBy": [
+        402
+      ]
+    },
+    {
+      "id": 409,
+      "subject": "SP Task 7: Phase 1 H5b \u2014 DeploymentArtifact decodes Historize (byte-parity)",
+      "status": "completed",
+      "blockedBy": [
+        408
+      ]
+    },
+    {
+      "id": 410,
+      "subject": "SP Task 8: Phase 1 H5c \u2014 VirtualTagHostActor invokes IHistoryWriter",
+      "status": "completed",
+      "blockedBy": [
+        407,
+        409
+      ]
+    },
+    {
+      "id": 411,
+      "subject": "SP Task 9: Phase 1 H5d \u2014 thread IHistoryWriter through DriverHostActor + DI",
+      "status": "completed",
+      "blockedBy": [
+        410,
+        403
+      ]
+    },
+    {
+      "id": 412,
+      "subject": "SP Task 10: Phase 1 \u2014 docs + follow-up bookkeeping",
+      "status": "completed",
+      "blockedBy": [
+        411
+      ]
+    },
+    {
+      "id": 413,
+      "subject": "SP Task 11: Phase 0+1 \u2014 full build + test + integration review",
+      "status": "completed",
+      "blockedBy": [
+        403,
+        404,
+        405,
+        406,
+        407,
+        408,
+        409,
+        410,
+        411,
+        412
+      ]
+    }
  ],
-  "lastUpdated": "2026-06-15"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Shipped \u2014 the stillpending backlog audit cites the landing commits (1e95856b, ada01e1a, fc8121cb, 3e609a2b, 70e6d3d2, c236263e, bd8fee61, 5e27b5f7, fcb38014). Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -2,15 +2,72 @@
  "planPath": "docs/plans/2026-06-15-stillpending-phase-2-servicelevel.md",
  "branch": "feat/stillpending-phase-2-servicelevel",
  "tasks": [
-    {"id": 414, "subject": "P2 Task 1: Move ServiceLevelCalculator to Core.Cluster", "status": "pending"},
-    {"id": 415, "subject": "P2 Task 2a: OpcUaPublishActor calculator path (DB+stale+leader+Detached guard, legacy seam)", "status": "pending", "blockedBy": [414]},
-    {"id": 416, "subject": "P2 Task 2b: OpcUaProbeOk from peer-probes-me (freshness + debounce)", "status": "pending", "blockedBy": [415]},
-    {"id": 417, "subject": "P2 Task 3: HealthTick — periodic DB Ask/PipeTo + PreStart immediate refresh", "status": "pending", "blockedBy": [416]},
-    {"id": 418, "subject": "P2 Task 4: PeerProbeSupervisor — one peer probe per driver peer", "status": "pending"},
-    {"id": 419, "subject": "P2 Task 5: Wire WithOtOpcUaRuntimeActors (dbHealth ref + spawn supervisor)", "status": "pending", "blockedBy": [417, 418]},
-    {"id": 420, "subject": "P2 Task 6: docs/Redundancy.md — calculator is WIRED", "status": "pending"},
-    {"id": 421, "subject": "P2 Task 7: Full build + test + final integration review", "status": "pending", "blockedBy": [419, 420]},
-    {"id": 422, "subject": "P2 Task 8: Live /run on the 2-node rig (acceptance gate)", "status": "pending", "blockedBy": [421]}
+    {
+      "id": 414,
+      "subject": "P2 Task 1: Move ServiceLevelCalculator to Core.Cluster",
+      "status": "completed"
+    },
+    {
+      "id": 415,
+      "subject": "P2 Task 2a: OpcUaPublishActor calculator path (DB+stale+leader+Detached guard, legacy seam)",
+      "status": "completed",
+      "blockedBy": [
+        414
+      ]
+    },
+    {
+      "id": 416,
+      "subject": "P2 Task 2b: OpcUaProbeOk from peer-probes-me (freshness + debounce)",
+      "status": "completed",
+      "blockedBy": [
+        415
+      ]
+    },
+    {
+      "id": 417,
+      "subject": "P2 Task 3: HealthTick \u2014 periodic DB Ask/PipeTo + PreStart immediate refresh",
+      "status": "completed",
+      "blockedBy": [
+        416
+      ]
+    },
+    {
+      "id": 418,
+      "subject": "P2 Task 4: PeerProbeSupervisor \u2014 one peer probe per driver peer",
+      "status": "completed"
+    },
+    {
+      "id": 419,
+      "subject": "P2 Task 5: Wire WithOtOpcUaRuntimeActors (dbHealth ref + spawn supervisor)",
+      "status": "completed",
+      "blockedBy": [
+        417,
+        418
+      ]
+    },
+    {
+      "id": 420,
+      "subject": "P2 Task 6: docs/Redundancy.md \u2014 calculator is WIRED",
+      "status": "completed"
+    },
+    {
+      "id": 421,
+      "subject": "P2 Task 7: Full build + test + final integration review",
+      "status": "completed",
+      "blockedBy": [
+        419,
+        420
+      ]
+    },
+    {
+      "id": 422,
+      "subject": "P2 Task 8: Live /run on the 2-node rig (acceptance gate)",
+      "status": "completed",
+      "blockedBy": [
+        421
+      ]
+    }
  ],
-  "lastUpdated": "2026-06-15"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Shipped \u2014 the stillpending backlog audit cites the landing commits (1e95856b, ada01e1a, fc8121cb, 3e609a2b, 70e6d3d2, c236263e, bd8fee61, 5e27b5f7, fcb38014). Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -2,16 +2,80 @@
  "planPath": "docs/plans/2026-06-15-stillpending-phase-3-opcua-standards.md",
  "branch": "feat/stillpending-phase-3-opcua-standards",
  "tasks": [
-    {"id": 423, "subject": "P3 Task 1: H2-bit — NodePermissions.HistoryUpdate + evaluator mapping", "status": "pending"},
-    {"id": 424, "subject": "P3 Task 2: H6a — mark native conditions (isNative through the sink)", "status": "pending"},
-    {"id": 425, "subject": "P3 Task 3: H4 — wire OnEnableDisable over OPC UA", "status": "pending", "blockedBy": [424]},
-    {"id": 426, "subject": "P3 Task 4: H6b — AlarmAcknowledgeRequest.OperatorUser + Galaxy/ScriptedAlarmSource", "status": "pending"},
-    {"id": 427, "subject": "P3 Task 5: H6c — NativeAlarmAckRouter seam + native OnAcknowledge routing", "status": "pending", "blockedBy": [424]},
-    {"id": 428, "subject": "P3 Task 6: H6d — DriverHostActor inverse map + native-ack route to driver", "status": "pending", "blockedBy": [426, 427]},
-    {"id": 429, "subject": "P3 Task 7: H6e — wire NativeAlarmAckRouter in host DI", "status": "pending", "blockedBy": [427, 428]},
-    {"id": 430, "subject": "P3 Task 8: Docs — Enable/Disable + native-ack→AVEVA + HistoryUpdate bit", "status": "pending"},
-    {"id": 431, "subject": "P3 Task 9: Full build + test + final integration review", "status": "pending", "blockedBy": [423, 425, 429, 430]},
-    {"id": 432, "subject": "P3 Task 10: Live /run — H4 Enable/Disable + H6 native-ack route", "status": "pending", "blockedBy": [431]}
+    {
+      "id": 423,
+      "subject": "P3 Task 1: H2-bit \u2014 NodePermissions.HistoryUpdate + evaluator mapping",
+      "status": "completed"
+    },
+    {
+      "id": 424,
+      "subject": "P3 Task 2: H6a \u2014 mark native conditions (isNative through the sink)",
+      "status": "completed"
+    },
+    {
+      "id": 425,
+      "subject": "P3 Task 3: H4 \u2014 wire OnEnableDisable over OPC UA",
+      "status": "completed",
+      "blockedBy": [
+        424
+      ]
+    },
+    {
+      "id": 426,
+      "subject": "P3 Task 4: H6b \u2014 AlarmAcknowledgeRequest.OperatorUser + Galaxy/ScriptedAlarmSource",
+      "status": "completed"
+    },
+    {
+      "id": 427,
+      "subject": "P3 Task 5: H6c \u2014 NativeAlarmAckRouter seam + native OnAcknowledge routing",
+      "status": "completed",
+      "blockedBy": [
+        424
+      ]
+    },
+    {
+      "id": 428,
+      "subject": "P3 Task 6: H6d \u2014 DriverHostActor inverse map + native-ack route to driver",
+      "status": "completed",
+      "blockedBy": [
+        426,
+        427
+      ]
+    },
+    {
+      "id": 429,
+      "subject": "P3 Task 7: H6e \u2014 wire NativeAlarmAckRouter in host DI",
+      "status": "completed",
+      "blockedBy": [
+        427,
+        428
+      ]
+    },
+    {
+      "id": 430,
+      "subject": "P3 Task 8: Docs \u2014 Enable/Disable + native-ack\u2192AVEVA + HistoryUpdate bit",
+      "status": "completed"
+    },
+    {
+      "id": 431,
+      "subject": "P3 Task 9: Full build + test + final integration review",
+      "status": "completed",
+      "blockedBy": [
+        423,
+        425,
+        429,
+        430
+      ]
+    },
+    {
+      "id": 432,
+      "subject": "P3 Task 10: Live /run \u2014 H4 Enable/Disable + H6 native-ack route",
+      "status": "completed",
+      "blockedBy": [
+        431
+      ]
+    }
  ],
-  "lastUpdated": "2026-06-15"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Shipped \u2014 the stillpending backlog audit cites the landing commits (1e95856b, ada01e1a, fc8121cb, 3e609a2b, 70e6d3d2, c236263e, bd8fee61, 5e27b5f7, fcb38014). Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -2,14 +2,68 @@
  "planPath": "docs/plans/2026-06-16-stillpending-phase-4-driver-datatypes.md",
  "branch": "feat/stillpending-phase-4-driver-datatypes",
  "tasks": [
-    {"id": 433, "subject": "P4 Task 1: Modbus Int64/UInt64 node DataType (MapDataType split)", "status": "pending"},
-    {"id": 434, "subject": "P4 Task 2: FOCAS fail-fast factory (EnsureUsable at init)", "status": "pending"},
-    {"id": 435, "subject": "P4 Task 3: FOCAS position scaling (PositionDecimalPlaces)", "status": "pending", "blockedBy": [434]},
-    {"id": 436, "subject": "P4 Task 4: Historian Total aggregate (client-side Average x interval-seconds)", "status": "pending"},
-    {"id": 437, "subject": "P4 Task 5: Historian poison-event dead-letter cap (maxAttempts)", "status": "pending"},
-    {"id": 438, "subject": "P4 Task 6: Docs + bookkeeping", "status": "pending", "blockedBy": [433, 434, 435, 436, 437]},
-    {"id": 439, "subject": "P4 Task 7: Full build + test + final integration review", "status": "pending", "blockedBy": [433, 434, 435, 436, 437, 438]},
-    {"id": 440, "subject": "P4 Task 8: Live /run — Modbus Int64 (acceptance gate)", "status": "pending", "blockedBy": [439]}
+    {
+      "id": 433,
+      "subject": "P4 Task 1: Modbus Int64/UInt64 node DataType (MapDataType split)",
+      "status": "completed"
+    },
+    {
+      "id": 434,
+      "subject": "P4 Task 2: FOCAS fail-fast factory (EnsureUsable at init)",
+      "status": "completed"
+    },
+    {
+      "id": 435,
+      "subject": "P4 Task 3: FOCAS position scaling (PositionDecimalPlaces)",
+      "status": "completed",
+      "blockedBy": [
+        434
+      ]
+    },
+    {
+      "id": 436,
+      "subject": "P4 Task 4: Historian Total aggregate (client-side Average x interval-seconds)",
+      "status": "completed"
+    },
+    {
+      "id": 437,
+      "subject": "P4 Task 5: Historian poison-event dead-letter cap (maxAttempts)",
+      "status": "completed"
+    },
+    {
+      "id": 438,
+      "subject": "P4 Task 6: Docs + bookkeeping",
+      "status": "completed",
+      "blockedBy": [
+        433,
+        434,
+        435,
+        436,
+        437
+      ]
+    },
+    {
+      "id": 439,
+      "subject": "P4 Task 7: Full build + test + final integration review",
+      "status": "completed",
+      "blockedBy": [
+        433,
+        434,
+        435,
+        436,
+        437,
+        438
+      ]
+    },
+    {
+      "id": 440,
+      "subject": "P4 Task 8: Live /run \u2014 Modbus Int64 (acceptance gate)",
+      "status": "completed",
+      "blockedBy": [
+        439
+      ]
+    }
  ],
-  "lastUpdated": "2026-06-16"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Shipped \u2014 the stillpending backlog audit cites the landing commits (1e95856b, ada01e1a, fc8121cb, 3e609a2b, 70e6d3d2, c236263e, bd8fee61, 5e27b5f7, fcb38014). Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -4,16 +4,61 @@
  "designCommit": "f90017bc",
  "baseMaster": "c081917a",
  "branch": "feat/stillpending-phase-4b-driver-gaps (merged to master 08a65513, deleted)",
-  "executionState": "COMPLETE — shipped + pushed to master 08a65513 (ff). Final integration review = SHIP. Build clean; AdminUI 450, Galaxy 279(+3 skip), FOCAS 200, Modbus 277, DriverProbeRegistration 2 — all green. Live: Modbus typed editor + Build-address proven on the rig's seeded MAIN-modbus-eq (Modbus reconcile, conclusive); Galaxy browse rendered a nested hierarchical root via the real driver path (corroborated, unit-proven 8 ways); FOCAS unit-proven (no CNC).",
-  "nativeTaskIds": {"1": 482, "2": 483, "3a": 484, "3b": 485, "4": 486, "5": 487, "6": 488},
+  "executionState": "COMPLETE \u2014 shipped + pushed to master 08a65513 (ff). Final integration review = SHIP. Build clean; AdminUI 450, Galaxy 279(+3 skip), FOCAS 200, Modbus 277, DriverProbeRegistration 2 \u2014 all green. Live: Modbus typed editor + Build-address proven on the rig's seeded MAIN-modbus-eq (Modbus reconcile, conclusive); Galaxy browse rendered a nested hierarchical root via the real driver path (corroborated, unit-proven 8 ways); FOCAS unit-proven (no CNC).",
+  "nativeTaskIds": {
+    "1": 482,
+    "2": 483,
+    "3a": 484,
+    "3b": 485,
+    "4": 486,
+    "5": 487,
+    "6": 488
+  },
  "tasks": [
-    {"id": 1, "subject": "Task 1: Modbus driver-type-string reconcile (canonicalize on \"Modbus\")", "status": "completed", "commit": "8b4675b1", "reviewFixCommit": "a40c77de"},
-    {"id": 2, "subject": "Task 2: Galaxy nested gobject hierarchy", "status": "completed", "commit": "21c7645d", "reviewFixCommit": "bec37848"},
-    {"id": "3a", "subject": "Task 3a: IFocasClient.GetPositionFiguresAsync (cnc_getfigure binding)", "status": "completed", "commit": "3fcbc70c"},
-    {"id": "3b", "subject": "Task 3b: FOCAS driver auto-scale wiring (auto wins, manual fallback)", "status": "completed", "commit": "6855be28"},
-    {"id": 4, "subject": "Task 4: Docs + bookkeeping", "status": "completed", "commit": "08a65513"},
-    {"id": 5, "subject": "Task 5: Full build + test + final integration review", "status": "completed", "note": "final integration review = SHIP (no Critical/Important); 3 Minor non-blocking notes recorded"},
-    {"id": 6, "subject": "Task 6: Live /run verification", "status": "completed", "note": "Modbus typed editor live-proven on rig; Galaxy nested root corroborated; FOCAS unit-proven"}
+    {
+      "id": 1,
+      "subject": "Task 1: Modbus driver-type-string reconcile (canonicalize on \"Modbus\")",
+      "status": "completed",
+      "commit": "8b4675b1",
+      "reviewFixCommit": "a40c77de"
+    },
+    {
+      "id": 2,
+      "subject": "Task 2: Galaxy nested gobject hierarchy",
+      "status": "completed",
+      "commit": "21c7645d",
+      "reviewFixCommit": "bec37848"
+    },
+    {
+      "id": "3a",
+      "subject": "Task 3a: IFocasClient.GetPositionFiguresAsync (cnc_getfigure binding)",
+      "status": "completed",
+      "commit": "3fcbc70c"
+    },
+    {
+      "id": "3b",
+      "subject": "Task 3b: FOCAS driver auto-scale wiring (auto wins, manual fallback)",
+      "status": "completed",
+      "commit": "6855be28"
+    },
+    {
+      "id": 4,
+      "subject": "Task 4: Docs + bookkeeping",
+      "status": "completed",
+      "commit": "08a65513"
+    },
+    {
+      "id": 5,
+      "subject": "Task 5: Full build + test + final integration review",
+      "status": "completed",
+      "note": "final integration review = SHIP (no Critical/Important); 3 Minor non-blocking notes recorded"
+    },
+    {
+      "id": 6,
+      "subject": "Task 6: Live /run verification",
+      "status": "completed",
+      "note": "Modbus typed editor live-proven on rig; Galaxy nested root corroborated; FOCAS unit-proven"
+    }
  ],
  "reviewFollowUps": [
    "FOCAS minor: no upper-bound clamp on a misbehaving cnc_getfigure value (Math.Pow overflow; same latent risk the manual path had)",
@@ -21,5 +66,6 @@
    "FOCAS: live auto-fetch on the real backend needs a cnc_getfigure command added to the managed FocasWireClient wire protocol (WireFocasClient returns empty today)",
    "Galaxy minor: 3-node chain cycle provably-correct but not directly tested (2-node mutual cycle is tested)"
  ],
-  "lastUpdated": "2026-06-16"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Shipped \u2014 the stillpending backlog audit cites the landing commits (1e95856b, ada01e1a, fc8121cb, 3e609a2b, 70e6d3d2, c236263e, bd8fee61, 5e27b5f7, fcb38014). Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -4,28 +4,121 @@
  "designCommit": "efccd8d1",
  "baseMaster": "050164b2",
  "branch": "feat/stillpending-phase-4c-array-support (merged to master 0f92e9e2, deleted)",
-  "executionState": "COMPLETE — shipped + pushed to master 0f92e9e2 (ff, 23 commits). Big-bang all 5 drivers + full AbLegacy. Build clean; OpcUaServer 230, Runtime 272, AdminUI 472, Modbus 289, AbCip 292, TwinCAT 153, S7 143, AbLegacy 188 — all green. Bundle integration review caught the cross-driver isArray-gating divergence (C-1/C-2 Modbus+AbLegacy ignored isArray; I-1/I-2/I-3 the arrayLength=1 edge); final integration review = SHIP WITH MINOR FOLLOW-UPS (I-1 S7 clarity, I-2 AbCip degenerate-scalar, I-3 AbLegacy >256 author-validation, M-1 array nodes read-only) — all closed. LIVE /run PASS: a Modbus array equipment tag (HR[0..3], UInt16[4]) materialises as ValueRank=OneDimension/ArrayDimensions=[4] and a Good array value flows end-to-end from the live sim (read over the wire, Status 0x00000000, Value System.UInt16[]); the address-100 first attempt correctly surfaced the sim's Illegal-Data-Address as Bad (faithful device status). S7/AbCip/TwinCAT/AbLegacy unit-proven (fixtures down).",
+  "executionState": "COMPLETE \u2014 shipped + pushed to master 0f92e9e2 (ff, 23 commits). Big-bang all 5 drivers + full AbLegacy. Build clean; OpcUaServer 230, Runtime 272, AdminUI 472, Modbus 289, AbCip 292, TwinCAT 153, S7 143, AbLegacy 188 \u2014 all green. Bundle integration review caught the cross-driver isArray-gating divergence (C-1/C-2 Modbus+AbLegacy ignored isArray; I-1/I-2/I-3 the arrayLength=1 edge); final integration review = SHIP WITH MINOR FOLLOW-UPS (I-1 S7 clarity, I-2 AbCip degenerate-scalar, I-3 AbLegacy >256 author-validation, M-1 array nodes read-only) \u2014 all closed. LIVE /run PASS: a Modbus array equipment tag (HR[0..3], UInt16[4]) materialises as ValueRank=OneDimension/ArrayDimensions=[4] and a Good array value flows end-to-end from the live sim (read over the wire, Status 0x00000000, Value System.UInt16[]); the address-100 first attempt correctly surfaced the sim's Illegal-Data-Address as Bad (faithful device status). S7/AbCip/TwinCAT/AbLegacy unit-proven (fixtures down).",
  "scope": "Big-bang all 5 drivers (AskUserQuestion) + full AbLegacy array read (AskUserQuestion). 1-D read-surface only; array writes / multi-dim / array historization out of scope (array nodes forced read-only at the applier per review M-1).",
-  "nativeTaskIds": {"1": 495, "2": 496, "3": 497, "4": 498, "5": 499, "6": 500, "7": 501, "8": 502, "9": 503, "10": 504, "11": 505, "12": 506},
+  "nativeTaskIds": {
+    "1": 495,
+    "2": 496,
+    "3": 497,
+    "4": 498,
+    "5": 499,
+    "6": 500,
+    "7": 501,
+    "8": 502,
+    "9": 503,
+    "10": 504,
+    "11": 505,
+    "12": 506
+  },
  "tasks": [
-    {"id": 1, "subject": "Sink contract — EnsureVariable array params", "classification": "high-risk", "status": "completed", "commit": "a7928202", "reviewFixCommit": "3172b7bd"},
-    {"id": 2, "subject": "EquipmentTagPlan IsArray/ArrayLength + composer + applier", "classification": "high-risk", "status": "completed", "commit": "71cc4171", "reviewFixCommit": "584e9f2a"},
-    {"id": 3, "subject": "DeploymentArtifact decode byte-parity", "classification": "high-risk", "status": "completed", "commit": "0a747c34", "reviewFixCommit": "eb8a8dc1"},
-    {"id": 4, "subject": "AdminUI driver-agnostic isArray/arrayLength control", "classification": "standard", "status": "completed", "commit": "c2006dfb"},
-    {"id": 5, "subject": "Modbus String/BitInRegister array decode + resolver", "classification": "small", "status": "completed", "commit": "8d3dc321", "reviewFixCommit": "49ac1392"},
-    {"id": 6, "subject": "AbCip libplctag array read + IsArray", "classification": "standard", "status": "completed", "commit": "f4d5a5ee", "reviewFixCommit": "94e8c55b+5f7a2acd"},
-    {"id": 7, "subject": "TwinCAT ADS array read + IsArray (reference impl, no fix needed)", "classification": "standard", "status": "completed", "commit": "3e742395"},
-    {"id": 8, "subject": "S7 block-read array + decode loop + IsArray", "classification": "high-risk", "status": "completed", "commit": "a82c22c6", "reviewFixCommit": "3bbe39c1+d30fb77e"},
-    {"id": 9, "subject": "AbLegacy PCCC multi-element array read + IsArray", "classification": "high-risk", "status": "completed", "commit": "95006939", "reviewFixCommit": "ce5d46be+0f92e9e2"},
-    {"id": 10, "subject": "Docs + bookkeeping", "classification": "small", "status": "completed", "commit": "05c7e86f"},
-    {"id": 11, "subject": "Full build + test + final integration review", "classification": "standard", "status": "completed", "note": "final integration review = SHIP WITH MINOR FOLLOW-UPS; 4 review fixes applied (d30fb77e/5f7a2acd/0f92e9e2/3bb2031d)"},
-    {"id": 12, "subject": "Live /run acceptance + finish branch", "classification": "standard", "status": "completed", "note": "Modbus array tag live-proven (Good UInt16[4] from sim HR[0..3], over the wire); others unit-proven; root-caused the address-100 Bad as a sim Illegal-Data-Address (not a code bug)"}
+    {
+      "id": 1,
+      "subject": "Sink contract \u2014 EnsureVariable array params",
+      "classification": "high-risk",
+      "status": "completed",
+      "commit": "a7928202",
+      "reviewFixCommit": "3172b7bd"
+    },
+    {
+      "id": 2,
+      "subject": "EquipmentTagPlan IsArray/ArrayLength + composer + applier",
+      "classification": "high-risk",
+      "status": "completed",
+      "commit": "71cc4171",
+      "reviewFixCommit": "584e9f2a"
+    },
+    {
+      "id": 3,
+      "subject": "DeploymentArtifact decode byte-parity",
+      "classification": "high-risk",
+      "status": "completed",
+      "commit": "0a747c34",
+      "reviewFixCommit": "eb8a8dc1"
+    },
+    {
+      "id": 4,
+      "subject": "AdminUI driver-agnostic isArray/arrayLength control",
+      "classification": "standard",
+      "status": "completed",
+      "commit": "c2006dfb"
+    },
+    {
+      "id": 5,
+      "subject": "Modbus String/BitInRegister array decode + resolver",
+      "classification": "small",
+      "status": "completed",
+      "commit": "8d3dc321",
+      "reviewFixCommit": "49ac1392"
+    },
+    {
+      "id": 6,
+      "subject": "AbCip libplctag array read + IsArray",
+      "classification": "standard",
+      "status": "completed",
+      "commit": "f4d5a5ee",
+      "reviewFixCommit": "94e8c55b+5f7a2acd"
+    },
+    {
+      "id": 7,
+      "subject": "TwinCAT ADS array read + IsArray (reference impl, no fix needed)",
+      "classification": "standard",
+      "status": "completed",
+      "commit": "3e742395"
+    },
+    {
+      "id": 8,
+      "subject": "S7 block-read array + decode loop + IsArray",
+      "classification": "high-risk",
+      "status": "completed",
+      "commit": "a82c22c6",
+      "reviewFixCommit": "3bbe39c1+d30fb77e"
+    },
+    {
+      "id": 9,
+      "subject": "AbLegacy PCCC multi-element array read + IsArray",
+      "classification": "high-risk",
+      "status": "completed",
+      "commit": "95006939",
+      "reviewFixCommit": "ce5d46be+0f92e9e2"
+    },
+    {
+      "id": 10,
+      "subject": "Docs + bookkeeping",
+      "classification": "small",
+      "status": "completed",
+      "commit": "05c7e86f"
+    },
+    {
+      "id": 11,
+      "subject": "Full build + test + final integration review",
+      "classification": "standard",
+      "status": "completed",
+      "note": "final integration review = SHIP WITH MINOR FOLLOW-UPS; 4 review fixes applied (d30fb77e/5f7a2acd/0f92e9e2/3bb2031d)"
+    },
+    {
+      "id": 12,
+      "subject": "Live /run acceptance + finish branch",
+      "classification": "standard",
+      "status": "completed",
+      "note": "Modbus array tag live-proven (Good UInt16[4] from sim HR[0..3], over the wire); others unit-proven; root-caused the address-100 Bad as a sim Illegal-Data-Address (not a code bug)"
+    }
  ],
  "reviewFollowUps": [
-    "Foundation array test asserts in-process variable.Value only — add a wire-level Session.ReadValueAsync assertion over an array node (the live /run proved it works, but it's not unit-covered)",
-    "Client.CLI read/subscribe prints an array value's type name (System.UInt16[]) not its elements — add array element formatting",
+    "Foundation array test asserts in-process variable.Value only \u2014 add a wire-level Session.ReadValueAsync assertion over an array node (the live /run proved it works, but it's not unit-covered)",
+    "Client.CLI read/subscribe prints an array value's type name (System.UInt16[]) not its elements \u2014 add array element formatting",
    "Array WRITES (inbound client->device), multi-dimensional arrays, array historization remain out of scope (named deferrals)",
    "Live array read for S7/AbCip/TwinCAT/AbLegacy is fixture-gated/operator-gated (unit-proven only); the 5 AbLegacy libplctag PCCC array-read assumptions need a real SLC/MicroLogix to confirm"
  ],
-  "lastUpdated": "2026-06-16"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Shipped \u2014 the stillpending backlog audit cites the landing commits (1e95856b, ada01e1a, fc8121cb, 3e609a2b, 70e6d3d2, c236263e, bd8fee61, 5e27b5f7, fcb38014). Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -271,7 +271,7 @@ public sealed class GatewayQualityMapperTests
 {
    [Theory]
    [InlineData(192, 0x00000000u)] // Good
-    [InlineData(216, 0x00D80000u)] // Good_LocalOverride
+    [InlineData(216, 0x00960000u)] // Good_LocalOverride
    [InlineData(64,  0x40000000u)] // Uncertain
    [InlineData(0,   0x80000000u)] // Bad
    [InlineData(8,   0x808A0000u)] // Bad_NotConnected
@@ -307,7 +307,7 @@ public sealed class SampleMapperTests
    {
        var a = new HistorianAggregateSample { Tag = "T", /* Value unset */ EndTime = Ts(2026,1,1,0,0,0) };
        var snap = SampleMapper.ToAggregateSnapshot(a);
-        Assert.Equal(0x800E0000u, snap.StatusCode); // BadNoData
+        Assert.Equal(0x809B0000u, snap.StatusCode); // BadNoData
        Assert.Null(snap.Value);
    }
    // Ts(...) builds a Google.Protobuf.WellKnownTypes.Timestamp from UTC parts.
@@ -323,7 +323,7 @@ public sealed class SampleMapperTests
  - `StatusCode`: `GatewayQualityMapper.Map((byte)s.OpcQuality)` (prefer `opc_quality`; if zero/unset and `quality` carries the OPC-DA byte, fall back to `quality` — match whatever the gateway populates; document the choice).
  - `SourceTimestampUtc`: `s.Timestamp.ToDateTime()` (UTC kind).
  - `ServerTimestampUtc`: `DateTime.UtcNow`.
- `SampleMapper.ToAggregateSnapshot(HistorianAggregateSample)` → null aggregate value ⇒ `StatusCode 0x800E0000` (BadNoData), non-null ⇒ Good (`0x00000000`) with the value; `SourceTimestampUtc` ← the bucket end/start timestamp (match the Wonderware `ToAggregateSnapshots` convention — it stamps the bucket timestamp). Provide `IReadOnlyList<>` batch helpers too.
+- `SampleMapper.ToAggregateSnapshot(HistorianAggregateSample)` → null aggregate value ⇒ `StatusCode 0x809B0000` (BadNoData), non-null ⇒ Good (`0x00000000`) with the value; `SourceTimestampUtc` ← the bucket end/start timestamp (match the Wonderware `ToAggregateSnapshots` convention — it stamps the bucket timestamp). Provide `IReadOnlyList<>` batch helpers too.

 **Step 4: run, expect PASS.**

@@ -1,27 +1,185 @@
 {
  "planPath": "docs/plans/2026-06-26-otopcua-historian-gateway-integration.md",
  "tasks": [
-    { "id": 0,  "subject": "Task 1: Consume gateway packages + scaffold Gateway driver project", "status": "pending", "blockedBy": [] },
-    { "id": 1,  "subject": "Task 2: HistoryAggregateType->RetrievalMode mapper (matrix-guarded)", "status": "pending", "blockedBy": [0] },
-    { "id": 2,  "subject": "Task 3: DriverDataType->HistorianDataType mapper + write-gap fallbacks (matrix-guarded)", "status": "pending", "blockedBy": [0] },
-    { "id": 3,  "subject": "Task 4: HistorianSample/Aggregate->DataValueSnapshot + quality mapper", "status": "pending", "blockedBy": [0] },
-    { "id": 4,  "subject": "Task 5: HistorianEvent->HistoricalEvent mapper (+ severity)", "status": "pending", "blockedBy": [0] },
-    { "id": 5,  "subject": "Task 6: AlarmHistorianEvent->HistorianEvent mapper (SendEvent)", "status": "pending", "blockedBy": [0] },
-    { "id": 6,  "subject": "Task 7: GatewayHistorianDataSource read paths (raw/processed/at-time)", "status": "pending", "blockedBy": [1, 3] },
-    { "id": 7,  "subject": "Task 8: GetHealthSnapshot via Probe/GetConnectionStatus", "status": "pending", "blockedBy": [6] },
-    { "id": 8,  "subject": "Task 9: Reshape ServerHistorianOptions to gateway form", "status": "pending", "blockedBy": [0] },
-    { "id": 9,  "subject": "Task 10: Swap AddServerHistorian factory in Program.cs (READ CUTOVER)", "status": "pending", "blockedBy": [6, 8] },
-    { "id": 10, "subject": "Task 11: ReadEventsAsync alarm-history on the data source", "status": "pending", "blockedBy": [6, 4] },
-    { "id": 11, "subject": "Task 12: GatewayAlarmHistorianWriter (SendEvent + outcome mapping)", "status": "pending", "blockedBy": [9, 5] },
-    { "id": 12, "subject": "Task 13: Swap AddAlarmHistorian factory in Program.cs", "status": "pending", "blockedBy": [11] },
-    { "id": 13, "subject": "Task 14: IHistorianProvisioning + GatewayTagProvisioner (EnsureTags)", "status": "pending", "blockedBy": [9, 2] },
-    { "id": 14, "subject": "Task 15: Hook provisioning into AddressSpaceApplier.Apply()", "status": "pending", "blockedBy": [13] },
-    { "id": 15, "subject": "Task 16: FasterLog historization outbox store", "status": "pending", "blockedBy": [9] },
-    { "id": 16, "subject": "Task 17: ContinuousHistorizationRecorder actor", "status": "pending", "blockedBy": [15, 9] },
-    { "id": 17, "subject": "Task 18: Wire recorder into DI + hosted lifecycle", "status": "pending", "blockedBy": [16] },
-    { "id": 18, "subject": "Task 19: Retire Wonderware historian projects", "status": "pending", "blockedBy": [9, 12, 17, 19] },
-    { "id": 19, "subject": "Task 20: Env-gated live validation vs wonder-sql-vd03", "status": "pending", "blockedBy": [9, 10, 12, 17] },
-    { "id": 20, "subject": "Task 21: Documentation (CLAUDE.md, appsettings, README)", "status": "pending", "blockedBy": [18] }
+    {
+      "id": 0,
+      "subject": "Task 1: Consume gateway packages + scaffold Gateway driver project",
+      "status": "completed",
+      "blockedBy": []
+    },
+    {
+      "id": 1,
+      "subject": "Task 2: HistoryAggregateType->RetrievalMode mapper (matrix-guarded)",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 2,
+      "subject": "Task 3: DriverDataType->HistorianDataType mapper + write-gap fallbacks (matrix-guarded)",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "Task 4: HistorianSample/Aggregate->DataValueSnapshot + quality mapper",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 4,
+      "subject": "Task 5: HistorianEvent->HistoricalEvent mapper (+ severity)",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "Task 6: AlarmHistorianEvent->HistorianEvent mapper (SendEvent)",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "Task 7: GatewayHistorianDataSource read paths (raw/processed/at-time)",
+      "status": "completed",
+      "blockedBy": [
+        1,
+        3
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "Task 8: GetHealthSnapshot via Probe/GetConnectionStatus",
+      "status": "completed",
+      "blockedBy": [
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "subject": "Task 9: Reshape ServerHistorianOptions to gateway form",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 9,
+      "subject": "Task 10: Swap AddServerHistorian factory in Program.cs (READ CUTOVER)",
+      "status": "completed",
+      "blockedBy": [
+        6,
+        8
+      ]
+    },
+    {
+      "id": 10,
+      "subject": "Task 11: ReadEventsAsync alarm-history on the data source",
+      "status": "completed",
+      "blockedBy": [
+        6,
+        4
+      ]
+    },
+    {
+      "id": 11,
+      "subject": "Task 12: GatewayAlarmHistorianWriter (SendEvent + outcome mapping)",
+      "status": "completed",
+      "blockedBy": [
+        9,
+        5
+      ]
+    },
+    {
+      "id": 12,
+      "subject": "Task 13: Swap AddAlarmHistorian factory in Program.cs",
+      "status": "completed",
+      "blockedBy": [
+        11
+      ]
+    },
+    {
+      "id": 13,
+      "subject": "Task 14: IHistorianProvisioning + GatewayTagProvisioner (EnsureTags)",
+      "status": "completed",
+      "blockedBy": [
+        9,
+        2
+      ]
+    },
+    {
+      "id": 14,
+      "subject": "Task 15: Hook provisioning into AddressSpaceApplier.Apply()",
+      "status": "completed",
+      "blockedBy": [
+        13
+      ]
+    },
+    {
+      "id": 15,
+      "subject": "Task 16: FasterLog historization outbox store",
+      "status": "completed",
+      "blockedBy": [
+        9
+      ]
+    },
+    {
+      "id": 16,
+      "subject": "Task 17: ContinuousHistorizationRecorder actor",
+      "status": "completed",
+      "blockedBy": [
+        15,
+        9
+      ]
+    },
+    {
+      "id": 17,
+      "subject": "Task 18: Wire recorder into DI + hosted lifecycle",
+      "status": "completed",
+      "blockedBy": [
+        16
+      ]
+    },
+    {
+      "id": 18,
+      "subject": "Task 19: Retire Wonderware historian projects",
+      "status": "completed",
+      "blockedBy": [
+        9,
+        12,
+        17,
+        19
+      ]
+    },
+    {
+      "id": 19,
+      "subject": "Task 20: Env-gated live validation vs wonder-sql-vd03",
+      "status": "completed",
+      "blockedBy": [
+        9,
+        10,
+        12,
+        17
+      ]
+    },
+    {
+      "id": 20,
+      "subject": "Task 21: Documentation (CLAUDE.md, appsettings, README)",
+      "status": "completed",
+      "blockedBy": [
+        18
+      ]
+    }
  ],
-  "lastUpdated": "2026-06-26"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Shipped as PR #423 and live-validated against the gateway on wonder-sql-vd03. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -98,7 +98,7 @@ Pure function in `.Contracts` (shared by driver, browser-commit, and the typed e
 | `EVENT` free text (`Program`, `Block`, `Message`) | `String` |
 | `CONDITION` | `String` (state word; §3.6) |

-**Quality mapping (`DataValueSnapshot.StatusCode`):** an observation value of `UNAVAILABLE` (MTConnect's explicit no-data sentinel) → **`BadNoCommunication` (`0x80310000u`)** with a null value, not the literal string — this is *the* UNAVAILABLE code, used everywhere in this design (read, subscribe, and the §8 fixtures). Rationale + fleet fit: semantically, `UNAVAILABLE` means the Agent is reachable but has no device-backed value (the adapter↔device link is down or the item has never reported) — exactly OPC UA's `BadNoCommunication` ("communication to the data source has failed"). The fleet grep shows no competing convention for this case: every existing driver's `BadCommunicationError` (`0x80050000u`, Modbus/FOCAS/TwinCAT/OpcUaClient/S7/AbCip/AbLegacy/Galaxy) marks the **driver's own transport failure** to its peer — a different failure (and the code this driver also uses when the *Agent* HTTP call fails, per §7) — while `BadNoData` (`0x800E0000u`) is historian-domain only (`Historian.Gateway/Mapping/SampleMapper.cs`). `BadNoCommunication` is already in the CLI's `SnapshotFormatter` name table (`src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs`), so it renders by name, not hex. Declare it as a `private const uint` in `MTConnectDriver` (the Modbus `StatusBadCommunicationError` pattern). Missing dataItem / empty condition → `Bad`. `observation.timestamp` → `SourceTimestamp` (not a separate node).
+**Quality mapping (`DataValueSnapshot.StatusCode`):** an observation value of `UNAVAILABLE` (MTConnect's explicit no-data sentinel) → **`BadNoCommunication` (`0x80310000u`)** with a null value, not the literal string — this is *the* UNAVAILABLE code, used everywhere in this design (read, subscribe, and the §8 fixtures). Rationale + fleet fit: semantically, `UNAVAILABLE` means the Agent is reachable but has no device-backed value (the adapter↔device link is down or the item has never reported) — exactly OPC UA's `BadNoCommunication` ("communication to the data source has failed"). The fleet grep shows no competing convention for this case: every existing driver's `BadCommunicationError` (`0x80050000u`, Modbus/FOCAS/TwinCAT/OpcUaClient/S7/AbCip/AbLegacy/Galaxy) marks the **driver's own transport failure** to its peer — a different failure (and the code this driver also uses when the *Agent* HTTP call fails, per §7) — while `BadNoData` (`0x809B0000u`) is historian-domain only (`Historian.Gateway/Mapping/SampleMapper.cs`). `BadNoCommunication` is already in the CLI's `SnapshotFormatter` name table (`src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.Cli.Common/SnapshotFormatter.cs`), so it renders by name, not hex. Declare it as a `private const uint` in `MTConnectDriver` (the Modbus `StatusBadCommunicationError` pattern). Missing dataItem / empty condition → `Bad`. `observation.timestamp` → `SourceTimestamp` (not a separate node).

 ### 3.4 `IReadable` — `/current`

@@ -588,6 +588,40 @@ SQL Server client works cross-platform, so `Sql` runs on macOS dev too (unlike G
  `dialect.QuoteIdentifier` (which escapes/rejects embedded quote characters). A table/column string
  in a `TagConfig` is validated against the live catalog (or an allow-list) before it's ever quoted
  into text; an unknown identifier rejects the tag (→ `BadNodeIdUnknown`) rather than executing.
+
+  **Implemented (Gitea #496).** `SqlCatalogGate` + `SqlCatalogLoader`, run from
+  `SqlDriver.InitializeAsync` after the liveness check and before the driver reports Healthy. Shape,
+  and the decisions worth knowing before touching it:
+
+  - **The catalog's spelling is substituted, not merely checked.** An accepted identifier is rewritten
+    to the string the catalog returned, so the text quoted into a poll query is one this driver read
+    back out of `ListSchemas`/`ListTables`/`ListColumns` — not operator input. Matching is
+    exact-ordinal first, then a *unique* case-insensitive hit (SQL Server's default collation is CI, so
+    case variants have always worked and rejecting them would break valid configs); an ambiguous CI
+    match under a case-sensitive collation is refused rather than guessed, because picking one would
+    publish another column's data under the operator's node.
+  - **Charset check first, catalog lookup second.** Each identifier goes through `QuoteIdentifier` for
+    its rejection rules *before* being looked up, so a name carrying a control or Unicode format
+    character is rejected **without its value being echoed** into a log line (Trojan-Source). A name
+    that passes is safe to render, which is why catalog-miss messages *do* name it — an operator
+    hunting a typo has to see what they wrote.
+  - **Rejection is per-tag and keeps the node.** The rejected tag is dropped from the *polled* table
+    but stays in the *authored* table, so it still materializes as a node and reads
+    `BadNodeIdUnknown` (§8.1's specified outcome) instead of vanishing from the address space. Every
+    drop is logged at Warning with the tag, the field and the reason.
+  - **A catalog that cannot be read faults Initialize; it does not reject every tag.** An unreadable
+    catalog is the *absence* of evidence about the tags, not evidence against them — rejecting all of
+    them would serve a confidently-empty address space and send the operator hunting typos that do not
+    exist. Zero visible schemas is treated the same way, because that is what a missing GRANT looks
+    like. Faulting lands `DriverInstanceActor` in Reconnecting with its retry timer running.
+  - **Bounded load:** one schema-list query, one default-schema scalar (`ISqlDialect.DefaultSchemaSql`,
+    added for this — an unqualified `TagValues` must resolve in whatever schema the *server* says, not
+    a guessed `dbo`), then one `ListTables` per distinct authored schema and one `ListColumns` per
+    distinct authored relation. It never enumerates the whole catalog, and the load runs under the same
+    wall-clock bound as the liveness check (R2-01 / STAB-14).
+  - **Accepted v1 limitation:** a 3-part `db.schema.table` (or a linked-server name) addresses a
+    catalog this connection cannot enumerate, so it cannot be allow-listed and is rejected with a
+    message pointing at the fix — expose the data through a view in the connected database.
 - **Treat any code path that builds SQL by string-concatenating a tag field as a defect** — enforce
  with a review checklist item + a unit test that feeds a malicious `keyValue`/`table`
  (`'; DROP TABLE …`) and asserts it either binds harmlessly (value) or is rejected (identifier),
@@ -607,8 +641,15 @@ comment) and the env-overridable ConfigDb connection string:
  file. Direct env read (not `IConfiguration`) is deliberate: the factory registry materializes
  drivers via a static `(id, json)` closure (Modbus pattern) with no `IConfiguration` in reach, so
  this keeps the factory shape unchanged.
- If an inline `connectionString` is ever permitted (dev convenience only), the AdminUI **redacts** it
-  in display/logging and flags it dev-only.
+- **An inline `connectionString` is not permitted at all** — the earlier "dev convenience, redacted in
+  the UI" carve-out is withdrawn (Gitea #498). Redaction only hides a credential that has *already been
+  written* to the config DB and replicated to every node's artifact cache. `SqlDriverConfigDto` has no
+  such property and `UnmappedMemberHandling.Skip` drops the key on read, but that protects only the read
+  path; config blobs are schemaless JSON columns, so nothing stopped the key being **written**.
+  `DraftValidator.ValidateSqlConnectionStringNotPersisted` now fails the deploy
+  (`SqlConnectionStringPersisted`) for a `connectionString` key at the top level of a Sql driver's
+  `DriverConfig` **or** of the `DeviceConfig` of any device beneath it (the two are merged before the DTO
+  sees them). The key is matched case-insensitively, and the error text never echoes the value.
 - **Never log the resolved connection string.** Log only provider + server host + database name.
 - Prefer integrated/managed auth where the estate supports it (`Integrated Security=true` / Azure AD /
  Kerberos) so no password transits config at all.
@@ -94,7 +94,14 @@ dual-namespace + event-delivery), Runtime 377 (+ VT reassert regression), AdminU

 ## Documented follow-ups (non-blocking)

- **Scripted-alarm redeploy recovery (CONFIRMED pre-existing bug, deferred — deserves its own careful fix). Filed as issue #487.**
+- **Scripted-alarm redeploy recovery — FIXED (issue #487), see `docs/ScriptedAlarms.md` §"Post-(re)load
+  condition-node re-assert".** Landed as the proposed shape below: `ScriptedAlarmHostActor.ReassertConditionNodes`
+  in `OnAlarmsLoaded`, node-only, never the `alerts` topic. Two deviations from the sketch, both deliberate:
+  it reads a new `ScriptedAlarmEngine.GetProjections()` rather than `GetState(alarmId)` + `LoadedAlarmIds`
+  (a projection also carries the definition's severity, the resolved message template, and the last-observed
+  worst-input quality — `GetState` alone would have clobbered severity/message on the node); and it skips
+  alarms sitting in the Part 9 no-event position, so a deploy where nothing is in alarm writes no condition
+  nodes at all. The original deferral text follows for context.
  The scripted-alarm Part 9 condition node has the same redeploy-reset race the VT `ReassertValue` fix closed:
  `RebuildAddressSpace` clears `_alarmConditions` and `MaterialiseScriptedAlarms` recreates each condition
  fresh/normal, but `ScriptedAlarmEngine.LoadAsync` reloads from the persisted state and yields
@@ -2,14 +2,69 @@
  "planPath": "docs/plans/2026-07-22-per-cluster-mesh-program.md",
  "note": "PROGRAM plan: each task = write that phase's detailed plan (writing-plans), execute it (executing-plans), run its exit gate, update the tracking tables. Prereq task 0 is the separate selfform-fallback plan in this repo.",
  "tasks": [
-    {"id": 0, "subject": "Prereq: execute 2026-07-22-selfform-fallback-and-manual-failover.md (7 tasks)", "status": "completed", "note": "Shipped as self-first seed ordering + AkkaClusterOptionsValidator, NOT the planned SelfFormAfter watchdog (live gate caught it islanding a failed-over node). Merged a78425ea."},
-    {"id": 1, "subject": "Phase 1: ClusterNode Akka+gRPC address columns; ConfigPublishCoordinator ack set from DB", "status": "completed", "note": "Merged 7654f24d. Escape hatch is ClusterNode.MaintenanceMode, not Enabled=0."},
-    {"id": 2, "subject": "Phase 2: comm actors + receptionist + ClusterClient transport (deploy notify/acks, driver-control)", "status": "in_progress", "blockedBy": [1]},
-    {"id": 3, "subject": "Phase 3: config fetch-and-cache from central; LocalDb steady-state config store (live gate)", "status": "pending", "blockedBy": [2]},
-    {"id": 4, "subject": "Phase 4: cut driver-side ConfigDb — EfAlarmConditionStateStore to LocalDb, DbHealthProbeActor ServiceLevel input, OpcUaPublishActor audit (live gate)", "status": "pending", "blockedBy": [3]},
-    {"id": 5, "subject": "Phase 5: gRPC oneof stream contract; migrate 7 observability topics; AdminUI reconnect story", "status": "pending", "blockedBy": [2]},
-    {"id": 6, "subject": "Phase 6: mesh partition — per-pair seeds, cluster-scoped roles/singletons, co-location rig rewrite, secrets replication re-scope", "status": "pending", "blockedBy": [0, 4, 5]},
-    {"id": 7, "subject": "Phase 7: failover drill per pair (incl. shared-VM failure) + close auto-down 1v1 and self-first cold-start-alone live gates + operator runbook", "status": "pending", "blockedBy": [6]}
+    {
+      "id": 0,
+      "subject": "Prereq: execute 2026-07-22-selfform-fallback-and-manual-failover.md (7 tasks)",
+      "status": "completed",
+      "note": "Shipped as self-first seed ordering + AkkaClusterOptionsValidator, NOT the planned SelfFormAfter watchdog (live gate caught it islanding a failed-over node). Merged a78425ea."
+    },
+    {
+      "id": 1,
+      "subject": "Phase 1: ClusterNode Akka+gRPC address columns; ConfigPublishCoordinator ack set from DB",
+      "status": "completed",
+      "note": "Merged 7654f24d. Escape hatch is ClusterNode.MaintenanceMode, not Enabled=0."
+    },
+    {
+      "id": 2,
+      "subject": "Phase 2: comm actors + receptionist + ClusterClient transport (deploy notify/acks, driver-control)",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "Phase 3: config fetch-and-cache from central; LocalDb steady-state config store (live gate)",
+      "status": "completed",
+      "blockedBy": [
+        2
+      ]
+    },
+    {
+      "id": 4,
+      "subject": "Phase 4: cut driver-side ConfigDb \u2014 EfAlarmConditionStateStore to LocalDb, DbHealthProbeActor ServiceLevel input, OpcUaPublishActor audit (live gate)",
+      "status": "completed",
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "Phase 5: gRPC oneof stream contract; migrate 7 observability topics; AdminUI reconnect story",
+      "status": "completed",
+      "blockedBy": [
+        2
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "Phase 6: mesh partition \u2014 per-pair seeds, cluster-scoped roles/singletons, co-location rig rewrite, secrets replication re-scope",
+      "status": "completed",
+      "blockedBy": [
+        0,
+        4,
+        5
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "Phase 7: failover drill per pair (incl. shared-VM failure) + close auto-down 1v1 and self-first cold-start-alone live gates + operator runbook",
+      "status": "completed",
+      "blockedBy": [
+        6
+      ]
+    }
  ],
-  "lastUpdated": "2026-07-22T00:00:00Z"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Program COMPLETE (Phases 0a-7 + bootstrap guard), origin/master d1dac87f. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -100,7 +100,7 @@
    {
      "id": 9,
      "subject": "Task 9: Drop dead ConfigDb ScriptedAlarmState table + retire EfAlarmConditionStateStore",
-      "status": "deferred",
+      "status": "completed",
      "blockedBy": [
        6
      ],
@@ -128,5 +128,6 @@
      "result": "LIVE GATE PASSED \u2014 deploy sealed green w/ 4 DB-less site nodes acking; ServiceLevel 240 w/ central SQL down; restart booted last-known-good from LocalDb pointer; grep proof; alarm_condition_state table live+replicated. Doc: 2026-07-23-mesh-phase4-live-gate.md"
    }
  ],
-  "lastUpdated": "2026-07-23"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Task 9 landed 3a590a0c; live gate PASSED 1281aebf. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -8,7 +8,7 @@
 > **Program design (architecture / shared contract / build order):**
 > [`2026-07-15-driver-expansion-program-design.md`](2026-07-15-driver-expansion-program-design.md)
 >
-> Last updated: 2026-07-24.
+> Last updated: 2026-07-27.

 ## Legend

@@ -30,10 +30,10 @@ it reaches 📝.
 | Wave | Deliverable | Design | Impl. plan | Status | Effort | Fixture / hardware |
 |---|---|---|---|---|---|---|
 | **0** | Universal Discover-backed browser | [design](2026-07-15-universal-discovery-browser-design.md) | [plan](2026-07-15-universal-discovery-browser-implementation.md) · [tasks](2026-07-15-universal-discovery-browser-implementation.md.tasks.json) | 🟡 **Live gate open** | S–M | none (retrofits shipped drivers) |
-| **1** | Modbus RTU (extend Modbus) | [design](2026-07-15-modbus-rtu-driver-design.md) | [plan](2026-07-24-modbus-rtu-driver.md) · [tasks](2026-07-24-modbus-rtu-driver.md.tasks.json) | 📝 **Plan ready** (11 tasks) | **S (lowest)** | `pymodbus` `rtu_over_tcp` — CI-simulatable, no new infra |
-| **1** | SQL poll | [design](2026-07-15-sql-poll-driver-design.md) | [plan](2026-07-24-sql-poll-driver.md) · [tasks](2026-07-24-sql-poll-driver.md.tasks.json) | 📝 **Plan ready** (22 tasks) | S–M | **existing central SQL Server** `10.100.0.35,14330` + SQLite unit |
-| **2** | MTConnect Agent | [design](2026-07-15-mtconnect-driver-design.md) | [plan](2026-07-24-mtconnect-driver.md) · [tasks](2026-07-24-mtconnect-driver.md.tasks.json) | 📝 **Plan ready** (23 tasks) | S–M | Dockerized `mtconnect/cppagent` — CI-simulatable |
-| **2** | MQTT / Sparkplug B | [design](2026-07-15-mqtt-sparkplug-driver-design.md) | [plan](2026-07-24-mqtt-sparkplug-driver.md) · [tasks](2026-07-24-mqtt-sparkplug-driver.md.tasks.json) | 📝 **Plan ready** (27 tasks, P1+P2) | M–L | Mosquitto/EMQX + C# Sparkplug sim — CI-simulatable |
+| **1** | Modbus RTU (extend Modbus) | [design](2026-07-15-modbus-rtu-driver-design.md) | [plan](2026-07-24-modbus-rtu-driver.md) · [tasks](2026-07-24-modbus-rtu-driver.md.tasks.json) | ✅ **Done** — merged to master `0f38f486` (#495), 11 tasks, live gate PASSED | **S (lowest)** | `pymodbus` `rtu_over_tcp` — CI-simulatable, no new infra |
+| **1** | SQL poll | [design](2026-07-15-sql-poll-driver-design.md) | [plan](2026-07-24-sql-poll-driver.md) · [tasks](2026-07-24-sql-poll-driver.md.tasks.json) | ✅ **Done** — merged to master `4ad54037`, 22 tasks, live gate PASSED; follow-ups #496/#497/#498 closed in `28c28667` | S–M | **existing central SQL Server** `10.100.0.35,14330` + SQLite unit |
+| **2** | MTConnect Agent | [design](2026-07-15-mtconnect-driver-design.md) | [plan](2026-07-24-mtconnect-driver.md) · [tasks](2026-07-24-mtconnect-driver.md.tasks.json) | ✅ **COMPLETE** — P1 Agent MVP, all 23 tasks + the 5-leg live gate PASSED (branch `feat/mtconnect-driver`, PR #506) | S–M | Dockerized `mtconnect/agent:2.7.0.12` (not `cppagent`) — CI-simulatable, live at `10.100.0.35:5000` |
+| **2** | MQTT / Sparkplug B | [design](2026-07-15-mqtt-sparkplug-driver-design.md) | [plan](2026-07-24-mqtt-sparkplug-driver.md) · [tasks](2026-07-24-mqtt-sparkplug-driver.md.tasks.json) | ✅ **COMPLETE** — P1 + P2 shipped, both live-gated (Tasks 0–26) | M–L | Mosquitto TLS+auth **+ C# Sparkplug edge-node simulator**, live at `10.100.0.35:8883` |

 > Waves 3+ (BACnet/IP, Omron) and the deferred MELSEC are tracked in the program design doc §6/§8,
 > not here. Omron CIP is the program's sole real-hardware wire gate; BACnet's broadcast/BBMD leg is
@@ -49,22 +49,28 @@ running the classification-driven review chain (`trivial` = implement only … `
 spec-review → code-review → integration review) between tasks. The `.tasks.json` next to each plan
 tracks progress and lets a later session resume.

-**Paste one of these into Claude Code to build a driver:**
+> ⚠️ **All four plans below have been executed and merged.** This table is retained as the *pattern*
+> for executing a future driver plan — do **not** run these four commands, they would rebuild shipped
+> drivers in a fresh worktree. (Their `.tasks.json` files still read `pending`; that is stale
+> bookkeeping, not backlog — see `deferment.md` §6.1.)

-| Deliverable | Command |
-|---|---|
-| Modbus RTU (Wave 1) | `Use superpowers-extended-cc:subagent-driven-development to execute docs/plans/2026-07-24-modbus-rtu-driver.md in a new git worktree` |
-| SQL poll (Wave 1) | `Use superpowers-extended-cc:subagent-driven-development to execute docs/plans/2026-07-24-sql-poll-driver.md in a new git worktree` |
-| MTConnect (Wave 2) | `Use superpowers-extended-cc:subagent-driven-development to execute docs/plans/2026-07-24-mtconnect-driver.md in a new git worktree` |
-| MQTT/Sparkplug (Wave 2) | `Use superpowers-extended-cc:subagent-driven-development to execute docs/plans/2026-07-24-mqtt-sparkplug-driver.md in a new git worktree` |
+| Deliverable | Status | Command (pattern only — do not re-run) |
+|---|---|---|
+| Modbus RTU (Wave 1) | ✅ merged `0f38f486` | ~~`… execute docs/plans/2026-07-24-modbus-rtu-driver.md …`~~ |
+| SQL poll (Wave 1) | ✅ merged `4ad54037` | ~~`… execute docs/plans/2026-07-24-sql-poll-driver.md …`~~ |
+| MTConnect (Wave 2) | ✅ merged `90bdaa44` (#506) | ~~`… execute docs/plans/2026-07-24-mtconnect-driver.md …`~~ |
+| MQTT/Sparkplug (Wave 2) | ✅ merged `c3a2b0f7` | ~~`… execute docs/plans/2026-07-24-mqtt-sparkplug-driver.md …`~~ |
+
+For a **new** driver the invocation shape is:
+`Use superpowers-extended-cc:subagent-driven-development to execute <plan-path> in a new git worktree`

 - **Slash-command form** (equivalent): `/superpowers-extended-cc:subagent-driven-development <plan-path>`.
 - **Parallel-session / resume form** (batch execution with checkpoints, no fresh-subagent-per-task):
  `/superpowers-extended-cc:executing-plans <plan-path>` — reads the same `.tasks.json` and continues
  from the first pending task.
- **Recommended order:** Modbus RTU → SQL poll → MTConnect → MQTT/Sparkplug (lowest effort first;
-  see each wave below for the gating notes). Run one plan per worktree; the four plans are
-  independent, so separate worktrees may run concurrently.
+- **Order (historical):** the four were built lowest-effort-first — Modbus RTU → SQL poll → MTConnect
+  → MQTT/Sparkplug. All are merged; nothing in this list remains to schedule. Run one plan per
+  worktree; independent plans may run concurrently in separate worktrees.

 ---

@@ -87,27 +93,44 @@ marginal cost.

 ---

-## Wave 1 — low-effort / high-leverage pair 📝
+## Wave 1 — low-effort / high-leverage pair ✅

 Both are **fully CI-simulatable with zero new hardware**; Modbus RTU needs no new infra at all, and
-SQL poll reuses the always-on central SQL Server. This is the recommended next build.
+SQL poll reuses the always-on central SQL Server. **Both shipped.**

-### Modbus RTU — 📝 Plan ready
+### Modbus RTU — ✅ Done (merged `0f38f486` / #495, live gate PASSED)
 - **Design:** [`2026-07-15-modbus-rtu-driver-design.md`](2026-07-15-modbus-rtu-driver-design.md)
- **Implementation plan:** [`2026-07-24-modbus-rtu-driver.md`](2026-07-24-modbus-rtu-driver.md) · [`.tasks.json`](2026-07-24-modbus-rtu-driver.md.tasks.json) — **11 tasks** (1 trivial / 5 small / 2 standard / 3 high-risk).
+- **Implementation plan:** [`2026-07-24-modbus-rtu-driver.md`](2026-07-24-modbus-rtu-driver.md) · [`.tasks.json`](2026-07-24-modbus-rtu-driver.md.tasks.json) — **11 tasks** (1 trivial / 5 small / 2 standard / 3 high-risk), all complete via subagent-driven-development.
 - **Scope:** extend the existing Modbus driver with a `Transport` selector (RTU CRC-16 + FC-aware
  length, no TxId) + a `rtu_over_tcp` `pymodbus` docker profile + the AdminUI selector.
  **Direct-serial transport is descoped** (user, 2026-07-15) — RTU-over-TCP via a serial→Ethernet
  gateway is the only shipped mode, so there is no serial hardware gate.
- **Fixture:** add an `rtu_over_tcp` profile to the existing Modbus integration fixture. First P1
-  step is confirming the pymodbus simulator exposes the RTU framer on a TCP server.
- **Effort:** **S — the lowest on the roadmap.** Recommended first.
+- **Fixture:** added the `rtu_over_tcp` profile (`framer=rtu`, host `:5021`, co-runs with `standard`)
+  to the Modbus integration fixture. **Unknown confirmed:** pymodbus 3.13's simulator DOES honour
+  `framer=rtu` on a TCP server (wire-probed a pure RTU FC03 response, no MBAP) — so the simple profile
+  path was taken; **no stdlib fallback server was needed.**
+- **Verification (all green):** unit suite **344/344**; full solution build 0 errors; the 2 RTU
+  integration tests pass **live** against the real `framer=rtu` fixture (read HR5→5, write+readback
+  HR200←4242). Per-task review chain (spec + code reviewers) + a final whole-branch review, all
+  approved-to-merge.
+- **Live `/run` gate — PASSED (2026-07-24, docker-dev rebuilt from this branch):**
+  - AdminUI `/raw` Modbus **driver** config modal renders the new **Transport** selector (with the
+    operator hint) — set to `RtuOverTcp`, saved.
+  - **Device Test Connect → `OK · 23 MS`** — the probe built a `ModbusRtuOverTcpTransport` via the
+    factory and spoke **FC03 over real RTU framing** to `10.100.0.35:5021`.
+  - Authored raw tags HR5 (r/o) + HR200 (r/w) → **deployment `06ec1632` Sealed** (all 6 nodes acked).
+  - Client.CLI on `opc.tcp://localhost:4840` (`multi-role`/`password`): **read** `ns=2;s=rtu-gate/Device1/HR5`
+    → **5, Good**; **write** `ns=2;s=rtu-gate/Device1/HR200` = 4242 → readback **4242, Good**.
+- **Effort:** **S — the lowest on the roadmap.** Delivered first, as recommended.

-### SQL poll — 📝 Plan ready
+### SQL poll — ✅ Done (merged `4ad54037`, live gate PASSED)
 - **Design:** [`2026-07-15-sql-poll-driver-design.md`](2026-07-15-sql-poll-driver-design.md)
- **Implementation plan:** [`2026-07-24-sql-poll-driver.md`](2026-07-24-sql-poll-driver.md) · [`.tasks.json`](2026-07-24-sql-poll-driver.md.tasks.json) — **22 tasks**. `ISqlDialect` seam in from day one; only the SQL Server dialect built in v1 (Postgres/ODBC deferred).
- **Scope:** a bespoke schema-browser driver polling a SQL table into equipment tags (SQL Server P1;
-  Postgres/ODBC land in P2/P3 behind `ISqlDialect`).
+- **Implementation plan:** [`2026-07-24-sql-poll-driver.md`](2026-07-24-sql-poll-driver.md) · [`.tasks.json`](2026-07-24-sql-poll-driver.md.tasks.json) — **22 tasks, all done**. `ISqlDialect` + `SqlServerDialect` shipped; Postgres/ODBC remain deferred to P2/P3 behind the same seam.
+- **Post-merge follow-ups closed** in `28c28667`: #496 catalog identifier-validation gate
+  (`4dc2ad80`), #497 wrong status-code constants across six drivers, #498 deploy-gate rejection of a
+  persisted `connectionString` (`1919a8e5`).
+- **Scope:** a bespoke schema-browser driver polling a SQL table into equipment tags (SQL Server
+  shipped; Postgres/ODBC deferred behind `ISqlDialect`).
 - **Fixture:** SQLite unit fixture (primary) + an **env-gated integration fixture against the
  existing central SQL Server** (`10.100.0.35,14330`) with a seeded `SqlPollFixture` DB. The
  blackhole/timeout live-gate pauses a **dedicated** `mssql` container — **never** the shared
@@ -116,41 +139,123 @@ SQL poll reuses the always-on central SQL Server. This is the recommended next b

 ---

-## Wave 2 — strategic telemetry / UNS pair 📝
+## Wave 2 — strategic telemetry / UNS pair ✅

 Both CI-simulatable on the shared docker host, no hardware.

-### MTConnect Agent — 📝 Plan ready
+### MTConnect Agent — ✅ Done (P1 Agent MVP)
 - **Design:** [`2026-07-15-mtconnect-driver-design.md`](2026-07-15-mtconnect-driver-design.md)
- **Implementation plan:** [`2026-07-24-mtconnect-driver.md`](2026-07-24-mtconnect-driver.md) · [`.tasks.json`](2026-07-24-mtconnect-driver.md.tasks.json) — **23 tasks**. Task 0 is the TrakHound-vs-hand-rolled client decision; browse-picker live-verify is gated on Wave-0 #468.
- **Scope:** P1 Agent MVP (`IDriver`+`ITagDiscovery`+`IReadable`+`ISubscribable`+probe+rediscover),
-  browse **free via the Wave-0 universal browser** (`SupportsOnlineDiscovery=true`, no browser code),
-  typed editor, `UNAVAILABLE→BadNoCommunication` mapping, ring-buffer re-baseline paging.
- **Fixture:** canned XML unit fixtures (bulk of coverage) + a dockerized `mtconnect/cppagent`
-  integration fixture (env-gated). Depends on Wave 0's browse seam being live-verified (#468).
- **Effort:** S–M (≈1–1.5 wk with TrakHound, ≈2.5–3 wk hand-rolled).
+- **Implementation plan:** [`2026-07-24-mtconnect-driver.md`](2026-07-24-mtconnect-driver.md) · [`.tasks.json`](2026-07-24-mtconnect-driver.md.tasks.json) — **23 tasks; 22 built, Task 21 (live `/run` gate) tracked separately in the plan file.**
+- **Driver guide:** [`docs/drivers/MTConnect.md`](../drivers/MTConnect.md) — config keys, capability
+  surface, data-plane precedence rules, quality-code mapping, and (most load-bearing) the **Known
+  limitations** section.
+- **Scope shipped:** `IDriver`+`ITagDiscovery`+`IReadable`+`ISubscribable`+`IHostConnectivityProbe`+`IRediscoverable`
+  (deliberately no `IWritable` — read-only Agent surface), browse **free via the Wave-0 universal
+  browser** (`SupportsOnlineDiscovery=true`, no browser project), typed AdminUI tag editor,
+  `UNAVAILABLE→BadNoCommunication` mapping, CONDITION-as-`String`, ring-buffer re-baseline paging
+  (both the sequence-gap and `OUT_OF_RANGE` legs).
+- **Diverged from the design:** Task 0/6/7 dropped the planned TrakHound `MTConnect.NET-Common`/`-HTTP`
+  dependency entirely — the pinned packages ship no XML formatter and the HTTP stream client has no
+  injectable handler to test behind the driver's seam. Parsing is hand-rolled `System.Xml.Linq`,
+  matching on `LocalName` only (namespace-agnostic, so 1.3–2.x all parse). See the driver guide's
+  "Built vs. planned" section.
+- **Test results:** MTConnect unit suite 491/491; integration suite 12/12 against a real Agent
+  (`mtconnect/agent:2.7.0.12`, **not** `mtconnect/cppagent` — that Docker Hub repo doesn't exist);
+  skips cleanly (12 Skipped) offline. AdminUI 749/749; full solution 0 build errors.
+- **Deferred (documented, not built):** write-back via MTConnect Interfaces (design §3.6); P1.5
+  CONDITION→native Part-9 alarms, `TIME_SERIES` array materialization, EVENT→enum vocab (design §9);
+  P2 SHDR adapter ingest (design §9). Also two pre-existing fleet-wide gaps this build surfaced
+  rather than caused: `IRediscoverable`/`IHostConnectivityProbe` have no server-side consumer (eight
+  drivers besides Galaxy), and no driver form blocks Save on a required-field validation error.
+- **Fixture:** canned XML unit fixtures (bulk of coverage) + a dockerized `mtconnect/agent` +
+  stdlib-SHDR-adapter integration fixture (env-gated), deployed at `/opt/otopcua-mtconnect/` on the
+  shared docker host. See the fixture's own
+  [`Docker/README.md`](../../tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md).
+- **Effort:** S–M, hand-rolled (the TrakHound estimate in the design doc did not apply once that
+  path was ruled out).

-### MQTT / Sparkplug B — 📝 Plan ready
+### MQTT / Sparkplug B — ✅ **COMPLETE** (P1 + P2, both live-gated)
 - **Design:** [`2026-07-15-mqtt-sparkplug-driver-design.md`](2026-07-15-mqtt-sparkplug-driver-design.md)
- **Implementation plan:** [`2026-07-24-mqtt-sparkplug-driver.md`](2026-07-24-mqtt-sparkplug-driver.md) · [`.tasks.json`](2026-07-24-mqtt-sparkplug-driver.md.tasks.json) — **27 tasks** (P1 plain MQTT = Tasks 0–14, a complete shippable milestone; P2 Sparkplug B = Tasks 15–26). Task 0 is the mandatory MQTTnet-5/net10 + central-pinning validation spike.
- **Scope:** P1 plain MQTT (MQTTnet-5 connect/TLS/auth + hand-rolled reconnect, subscribe→
+- **Implementation plan:** [`2026-07-24-mqtt-sparkplug-driver.md`](2026-07-24-mqtt-sparkplug-driver.md) · [`.tasks.json`](2026-07-24-mqtt-sparkplug-driver.md.tasks.json) — **27 tasks, all done** (P1 plain MQTT = Tasks 0–14; P2 Sparkplug B = Tasks 15–26).
+- **Scope delivered:** P1 plain MQTT (MQTTnet-5 connect/TLS/auth + hand-rolled reconnect, subscribe→
  `OnDataChange`, retained last-value read, `#`-observation browser); P2 Sparkplug B ingest
-  (vendored Tahu proto, birth/alias/seq-gap/rebirth state machine, death→STALE).
- **Fixture:** Mosquitto/EMQX broker (TLS + real auth, not anonymous) + a **project-owned C#
-  Sparkplug edge-node simulator** for the rebirth/seq-gap/death test matrix + env-gated live suite
-  (`MQTT_FIXTURE_ENDPOINT`).
- **Effort:** M–L. **Top risks:** Sparkplug state-machine correctness; MQTTnet-5/net10 + the repo's
-  fragile central pinning (mitigated by hand-rolling Tahu over one MQTTnet-5 client).
+  (vendored Tahu proto + `Grpc.Tools` codegen, birth/alias/seq-gap/rebirth state machine,
+  death→STALE, birth-driven browse tree, scoped Request-rebirth NCMD, typed tag editor).
+  **Write-through (`IWritable`) is deferred to P3** — every MQTT node materializes read-only.
+- **Fixture:** Mosquitto TLS+auth broker + JSON publisher sidecar, **live** at `10.100.0.35:8883`
+  (`:1883` plaintext-but-authenticated); stack `/opt/otopcua-mqtt`, compose in
+  `tests/Drivers/….Driver.Mqtt.IntegrationTests/Docker/`. Env-gated live suite
+  (`MQTT_FIXTURE_ENDPOINT`, see `infra/README.md` §3). The **project-owned C# Sparkplug edge-node
+  simulator** (`--profile sparkplug`, group `OtOpcUaSim`, nodes `EdgeA`/`EdgeB`, `EdgeA` device
+  `Filler1`) shipped with P2 and answers rebirth NCMDs.
+- **P2 status (2026-07-25):** Tasks 15–26 complete. **Offline 1528 passed / 0 failed**
+  (581 driver · 809 AdminUI · 138 Core.Abstractions); **live 15/15** against the broker + simulator.
+- **P1 live gate found two AdminUI authoring gaps** (the gate's whole point — both invisible to green
+  unit tests, because AdminUI has no bUnit and nothing tied these hand-maintained lists to
+  `DriverTypeNames`):
+  1. **FIXED —** `RawDriverTypeDialog`'s option array never got an MQTT row, so **no operator could
+     create an MQTT driver at all**. Fixed, plus a reflection parity guard
+     (`RawDriverTypeDialogParityTests`) that fails for *any* future `DriverTypeNames` entry
+     missing from the picker.
+  2. **FIXED —** `MqttDriverForm` / `MqttDeviceForm` did not exist, so the broker connection was
+     unauthorable from the AdminUI. Both shipped after the P1 gate.
+- **P2 live gate found a third one, of the same family — FIXED:** `MqttDriverForm` still carried its
+  P1 Sparkplug **placeholder**. Switching Mode to `SparkplugB` rendered a *"not available yet"* notice
+  and **no Group ID field** — so once Sparkplug ingest shipped there was still **no way to author a
+  Sparkplug driver from the AdminUI**, and `Sparkplug.GroupId` is the driver's entire subscription
+  filter (`spBv1.0/{GroupId}/#`): blank ⇒ connected, `Healthy`, ingesting nothing. Fixed (all five
+  Sparkplug keys, merge-not-replace on save, group-id segment validation) + 8 falsifiable
+  `MqttDriverFormModelTests` cases. **Three gates, three instances of the same defect class: a
+  hand-maintained AdminUI surface left behind by a driver-side feature.**
+- **P2 live gate — two open UI gaps, documented not fixed** (see `docs/drivers/Mqtt.md` §Known gaps):
+  - **A completely empty browse tree cannot arm a rebirth.** The scope comes from a tree click, so on
+    a plant that has not birthed since the window opened `Request rebirth…` stays disabled — the very
+    case the affordance exists for. `MqttBrowseSession.ResolveRebirthTargets` already accepts a bare
+    `{group}/{edgeNode}` ("the prime rebirth target"); only a UI path to enter one is missing.
+    Mitigation shipped: a **Refresh** button on the browse tree (it re-reads the same session, which
+    previously rendered exactly once at open and never again).
+- **P2 live gate also found a PRE-EXISTING, cross-driver AdminUI defect — FIXED:** every node label in
+  the shared `DriverBrowseTree` was an `<a href="#">`. In a Blazor Web App, `blazor.web.js`'s
+  enhanced-navigation click interceptor resolves a bare `#` against `<base href="/">`, so **clicking
+  any browse-tree node label navigated the whole AdminUI to `/`**, tore down the circuit and destroyed
+  the hosting modal — losing the browse session and the tag selection. `@onclick:preventDefault` does
+  not help: it suppresses the browser's default action, not Blazor's own interceptor. The labels are
+  now `<button type="button">`. It dates to the component's introduction (2026-05-28) and affects
+  **every** driver's picker; it only surfaced now because Sparkplug's Request-rebirth is the first
+  feature that requires clicking a *label* rather than the ▶ toggle (always a `<button>`, always fine).
+  - **A metric name containing `/` cannot be browse-committed.** The derived raw **tag Name** is a
+    RawPath segment and may not contain `/`, while `metricName` legitimately may — so the
+    spec-mandatory `Node Control/Rebirth` is refused at commit (`Row N: Name must not contain '/'`).
+    The refusal is loud and all-or-nothing, never a silently mis-bound tag, and **Manual entry** is
+    the working path (the Sparkplug tag editor accepts a slashed metric name). Fixing it needs a
+    name-sanitisation policy with a collision answer, so it was recorded rather than guessed at.
+  - `_canRebirth` is captured at browse-open, so a reaped session still draws the button.
+  - The tag editor injects the Plain-only `payloadFormat` key into a Sparkplug blob — cosmetic; the
+    factory routes on the Sparkplug tuple and ignores it.
+- **Rediscovery is inert in v3 (platform gap, not MQTT's).** The Sparkplug driver raises
+  `OnRediscoveryNeeded` on a changed birth metric-set, but **nothing subscribes to it** and
+  `DriverHostActor.HandleDiscoveredNodes` hard-returns. A DBIRTH introducing a metric does **not**
+  change the OPC UA tree — redeploy. Driver-side behaviour is log-observable only.
+- **Redundant-pair hazard (documented, not a code change):** both nodes of a pair run the driver, so a
+  **fixed `clientId` makes them evict each other forever** — the broker logs
+  `already connected, closing old connection` and both nodes reconnect every ~2 s while still
+  reporting `Healthy`. Unset (the default) is correct. `MqttDriverForm` warns inline the moment a
+  value is typed.
+- **Effort:** M–L, delivered. The MQTTnet-5/net10 + central-pinning risk is **retired** (Task 0's
+  spike held through both phases); Sparkplug state-machine correctness was carried by golden-payload
+  vectors + the live simulator.

 ---

 ## Next actions

-1. **Close the Wave-0 live gate** (Gitea #468) — unblocks browse verification for MTConnect/BACnet.
-2. **Build Wave 1** — Modbus RTU first (lowest effort, no new infra), then SQL poll. Both plans are
-   📝 ready; run the command from the [Executing a plan](#executing-a-plan-git-worktree--subagent-per-task)
-   table (subagent-driven-development in a git worktree).
-3. **Build Wave 2** (MTConnect, then MQTT/Sparkplug) — both plans 📝 ready. MTConnect's browse leg
-   wants #468 closed first; MQTT's Task 0 pinning spike gates everything after it.
+1. **Close the Wave-0 live gate** (Gitea #468) — unblocks browse verification for BACnet (MTConnect
+   shipped its own Task-21 live `/run` gate independently — see the plan file).
+2. **Wave 1 is done.** Both deliverables shipped and live-gated: **Modbus RTU-over-TCP** (merged
+   `0f38f486` / #495) and **SQL poll** (merged `4ad54037`; follow-ups #496/#497/#498 closed in
+   `28c28667`). Remaining SQL work is optional follow-on — Postgres/ODBC dialects behind
+   `ISqlDialect`, and `SqlTagModel.Query` (P3, currently rejected end-to-end by design).
+3. **Wave 2 is done.** Both deliverables shipped and live-gated: **MQTT / Sparkplug B** (P1 + P2) and **MTConnect Agent** (P1 Agent MVP, PR #506). Remaining work on both is optional follow-on — MQTT P3 write-through (`IWritable`: NCMD/DCMD + plain publish) plus its two browse-UI
+   gaps, and MTConnect write-back (deliberately deferred; the Agent surface is read-only).

 Update this file's Summary table and per-wave status whenever a deliverable changes state.
@@ -1,17 +1,91 @@
 {
  "planPath": "docs/plans/2026-07-24-modbus-rtu-driver.md",
  "tasks": [
-    {"id": 0, "subject": "Task 0: Add the ModbusTransportMode enum (Tcp | RtuOverTcp)", "status": "pending"},
-    {"id": 1, "subject": "Task 1: ModbusCrc CRC-16/MODBUS helper + golden vectors", "status": "pending"},
-    {"id": 2, "subject": "Task 2: ModbusRtuFraming ADU build + FC-aware length-less deframe", "status": "pending", "blockedBy": [1]},
-    {"id": 3, "subject": "Task 3: Extract ModbusSocketLifecycle from ModbusTcpTransport (behaviour-preserving)", "status": "pending"},
-    {"id": 4, "subject": "Task 4: ModbusRtuOverTcpTransport (RTU framing over socket lifecycle)", "status": "pending", "blockedBy": [2, 3]},
-    {"id": 5, "subject": "Task 5: ModbusTransportFactory.Create switch on Transport mode", "status": "pending", "blockedBy": [0, 4]},
-    {"id": 6, "subject": "Task 6: Bind Transport on options/DTO/factory (string-enum guard)", "status": "pending", "blockedBy": [0]},
-    {"id": 7, "subject": "Task 7: Route driver default closure + probe through ModbusTransportFactory", "status": "pending", "blockedBy": [5, 6]},
-    {"id": 8, "subject": "Task 8: AdminUI Transport selector on ModbusDriverForm", "status": "pending", "blockedBy": [6]},
-    {"id": 9, "subject": "Task 9: Docker rtu_over_tcp fixture + RTU-over-TCP integration test", "status": "pending", "blockedBy": [4, 7]},
-    {"id": 10, "subject": "Task 10: Live /run verification on docker-dev", "status": "pending", "blockedBy": [8, 9]}
+    {
+      "id": 0,
+      "subject": "Task 0: Add the ModbusTransportMode enum (Tcp | RtuOverTcp)",
+      "status": "completed"
+    },
+    {
+      "id": 1,
+      "subject": "Task 1: ModbusCrc CRC-16/MODBUS helper + golden vectors",
+      "status": "completed"
+    },
+    {
+      "id": 2,
+      "subject": "Task 2: ModbusRtuFraming ADU build + FC-aware length-less deframe",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "Task 3: Extract ModbusSocketLifecycle from ModbusTcpTransport (behaviour-preserving)",
+      "status": "completed"
+    },
+    {
+      "id": 4,
+      "subject": "Task 4: ModbusRtuOverTcpTransport (RTU framing over socket lifecycle)",
+      "status": "completed",
+      "blockedBy": [
+        2,
+        3
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "Task 5: ModbusTransportFactory.Create switch on Transport mode",
+      "status": "completed",
+      "blockedBy": [
+        0,
+        4
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "Task 6: Bind Transport on options/DTO/factory (string-enum guard)",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "Task 7: Route driver default closure + probe through ModbusTransportFactory",
+      "status": "completed",
+      "blockedBy": [
+        5,
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "subject": "Task 8: AdminUI Transport selector on ModbusDriverForm",
+      "status": "completed",
+      "blockedBy": [
+        6
+      ]
+    },
+    {
+      "id": 9,
+      "subject": "Task 9: Docker rtu_over_tcp fixture + RTU-over-TCP integration test",
+      "status": "completed",
+      "blockedBy": [
+        4,
+        7
+      ]
+    },
+    {
+      "id": 10,
+      "subject": "Task 10: Live /run verification on docker-dev",
+      "status": "completed",
+      "blockedBy": [
+        8,
+        9
+      ]
+    }
  ],
-  "lastUpdated": "2026-07-24"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Merged 0f38f486 (#495); live gate PASSED. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -1,34 +1,315 @@
 {
  "planPath": "docs/plans/2026-07-24-mqtt-sparkplug-driver.md",
-  "note": "Wave 2 MQTT/Sparkplug B driver. Two phases both in-scope: P1 (plain MQTT, Tasks 0-14) is a complete shippable milestone; P2 (Sparkplug B ingest, Tasks 15-26) builds on it and every P2 task chains back to Task 14. Write-through (NCMD/DCMD/plain publish) is DEFERRED (design P3). Hard rules: Task 0 (MQTTnet-5/net10 restore+build under central pinning with transitive pinning OFF) is the mandatory FIRST gate. Hand-roll Tahu proto over ONE MQTTnet-5 client (NOT SparkplugNet — its MQTTnet-4.x transitive pin collides with the repo's deliberately-OFF CentralPackageTransitivePinning). DriverType string is 'Mqtt' everywhere (grep-enforced). Enum-serialization trap: every JSON seam uses shared JsonSerializerOptions with JsonStringEnumConverter. Fixtures enforce TLS+auth, never anonymous/public-broker. Google.Protobuf (3.34.1) + Grpc.Tools (2.76.0) already pinned; MQTTnet is the one new pin. High-risk tasks: 4 (hand-rolled reconnect loop), 18/19 (alias/seq state-machine components), 21 (the full 3.6 ingest matrix).",
+  "note": "Wave 2 MQTT/Sparkplug B driver. Two phases both in-scope: P1 (plain MQTT, Tasks 0-14) is a complete shippable milestone; P2 (Sparkplug B ingest, Tasks 15-26) builds on it and every P2 task chains back to Task 14. Write-through (NCMD/DCMD/plain publish) is DEFERRED (design P3). Hard rules: Task 0 (MQTTnet-5/net10 restore+build under central pinning with transitive pinning OFF) is the mandatory FIRST gate. Hand-roll Tahu proto over ONE MQTTnet-5 client (NOT SparkplugNet \u2014 its MQTTnet-4.x transitive pin collides with the repo's deliberately-OFF CentralPackageTransitivePinning). DriverType string is 'Mqtt' everywhere (grep-enforced). Enum-serialization trap: every JSON seam uses shared JsonSerializerOptions with JsonStringEnumConverter. Fixtures enforce TLS+auth, never anonymous/public-broker. Google.Protobuf (3.34.1) + Grpc.Tools (2.76.0) already pinned; MQTTnet is the one new pin. High-risk tasks: 4 (hand-rolled reconnect loop), 18/19 (alias/seq state-machine components), 21 (the full 3.6 ingest matrix).",
  "tasks": [
-    {"id": 0, "subject": "Task 0 (P1): Dependency-validation spike — MQTTnet-5 pin + net10 restore/build under central pinning", "status": "pending", "classification": "standard", "parallelizableWith": []},
-    {"id": 1, "subject": "Task 1 (P1): .Contracts enums + MqttDriverOptions DTO (name-serialized)", "status": "pending", "classification": "small", "parallelizableWith": [], "blockedBy": [0]},
-    {"id": 2, "subject": "Task 2 (P1): .Contracts MqttTagDefinition + MqttEquipmentTagParser (plain, strict enum)", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [1]},
-    {"id": 3, "subject": "Task 3 (P1): .Driver + MqttConnection connect/TLS/auth (bounded deadline)", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [1]},
-    {"id": 4, "subject": "Task 4 (P1): MqttConnection hand-rolled reconnect loop (backoff + resubscribe)", "status": "pending", "classification": "high-risk", "parallelizableWith": [], "blockedBy": [3]},
-    {"id": 5, "subject": "Task 5 (P1): LastValueCache + IReadable (per-ref no-data)", "status": "pending", "classification": "small", "parallelizableWith": [6], "blockedBy": [3]},
-    {"id": 6, "subject": "Task 6 (P1): ISubscribable plain topic subscribe→OnDataChange + retained seed", "status": "pending", "classification": "standard", "parallelizableWith": [5], "blockedBy": [2, 4]},
-    {"id": 7, "subject": "Task 7 (P1): MqttDriver shell — IDriver + authored-only ITagDiscovery (Once) + probe interface", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [5, 6]},
-    {"id": 8, "subject": "Task 8 (P1): MqttDriverProbe CONNECT handshake", "status": "pending", "classification": "small", "parallelizableWith": [10], "blockedBy": [3]},
-    {"id": 9, "subject": "Task 9 (P1): Factory + DriverTypeNames.Mqtt + Host factory/probe registration", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [7, 8]},
-    {"id": 10, "subject": "Task 10 (P1): .Browser bespoke #-observation browser (passive)", "status": "pending", "classification": "standard", "parallelizableWith": [8], "blockedBy": [2]},
-    {"id": 11, "subject": "Task 11 (P1): Register MqttDriverBrowser (bespoke-first for Mqtt)", "status": "pending", "classification": "trivial", "parallelizableWith": [12], "blockedBy": [10]},
-    {"id": 12, "subject": "Task 12 (P1): Typed AdminUI editor + validator (plain shape)", "status": "pending", "classification": "standard", "parallelizableWith": [11], "blockedBy": [2]},
-    {"id": 13, "subject": "Task 13 (P1): Mosquitto+JSON-publisher fixture (TLS+auth) + env-gated live suite", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [9]},
-    {"id": 14, "subject": "Task 14 (P1): Live /run verify on docker-dev — P1 MILESTONE COMPLETE", "status": "pending", "classification": "small", "parallelizableWith": [], "blockedBy": [9, 11, 12, 13]},
-    {"id": 15, "subject": "Task 15 (P2): Vendor Tahu sparkplug_b.proto + Grpc.Tools codegen", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [14]},
-    {"id": 16, "subject": "Task 16 (P2): SparkplugCodec decode + golden payload vectors", "status": "pending", "classification": "standard", "parallelizableWith": [17], "blockedBy": [15]},
-    {"id": 17, "subject": "Task 17 (P2): SparkplugTopic parse/format + SparkplugDataType.ToDriverDataType map", "status": "pending", "classification": "small", "parallelizableWith": [16], "blockedBy": [15]},
-    {"id": 18, "subject": "Task 18 (P2): BirthCache + AliasTable — bind-by-name, rebuild-per-birth", "status": "pending", "classification": "high-risk", "parallelizableWith": [19], "blockedBy": [16, 17]},
-    {"id": 19, "subject": "Task 19 (P2): SequenceTracker seq-gap + bdSeq death-tie", "status": "pending", "classification": "high-risk", "parallelizableWith": [18], "blockedBy": [16, 17]},
-    {"id": 20, "subject": "Task 20 (P2): RebirthRequester NCMD encode", "status": "pending", "classification": "small", "parallelizableWith": [], "blockedBy": [16]},
-    {"id": 21, "subject": "Task 21 (P2): Sparkplug ingest state machine — the 3.6 matrix", "status": "pending", "classification": "high-risk", "parallelizableWith": [], "blockedBy": [18, 19, 20]},
-    {"id": 22, "subject": "Task 22 (P2): ITagDiscovery UntilStable + IRediscoverable (rediscover-on-DBIRTH)", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [21]},
-    {"id": 23, "subject": "Task 23 (P2): Sparkplug browser tree + AttributesAsync + scoped RequestRebirthAsync", "status": "pending", "classification": "standard", "parallelizableWith": [24], "blockedBy": [20, 21]},
-    {"id": 24, "subject": "Task 24 (P2): AdminUI editor Sparkplug mode shape + validator", "status": "pending", "classification": "small", "parallelizableWith": [23], "blockedBy": [12, 17]},
-    {"id": 25, "subject": "Task 25 (P2): C# edge-node simulator fixture + 3.6 live matrix", "status": "pending", "classification": "standard", "parallelizableWith": [], "blockedBy": [21, 22, 23]},
-    {"id": 26, "subject": "Task 26 (P2): Live /run verify Sparkplug — P2 COMPLETE", "status": "pending", "classification": "small", "parallelizableWith": [], "blockedBy": [23, 24, 25]}
+    {
+      "id": 0,
+      "subject": "Task 0 (P1): Dependency-validation spike \u2014 MQTTnet-5 pin + net10 restore/build under central pinning",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": []
+    },
+    {
+      "id": 1,
+      "subject": "Task 1 (P1): .Contracts enums + MqttDriverOptions DTO (name-serialized)",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [],
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 2,
+      "subject": "Task 2 (P1): .Contracts MqttTagDefinition + MqttEquipmentTagParser (plain, strict enum)",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "Task 3 (P1): .Driver + MqttConnection connect/TLS/auth (bounded deadline)",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 4,
+      "subject": "Task 4 (P1): MqttConnection hand-rolled reconnect loop (backoff + resubscribe)",
+      "status": "completed",
+      "classification": "high-risk",
+      "parallelizableWith": [],
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "Task 5 (P1): LastValueCache + IReadable (per-ref no-data)",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [
+        6
+      ],
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "Task 6 (P1): ISubscribable plain topic subscribe\u2192OnDataChange + retained seed",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [
+        5
+      ],
+      "blockedBy": [
+        2,
+        4
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "Task 7 (P1): MqttDriver shell \u2014 IDriver + authored-only ITagDiscovery (Once) + probe interface",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        5,
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "subject": "Task 8 (P1): MqttDriverProbe CONNECT handshake",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [
+        10
+      ],
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 9,
+      "subject": "Task 9 (P1): Factory + DriverTypeNames.Mqtt + Host factory/probe registration",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        7,
+        8
+      ]
+    },
+    {
+      "id": 10,
+      "subject": "Task 10 (P1): .Browser bespoke #-observation browser (passive)",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [
+        8
+      ],
+      "blockedBy": [
+        2
+      ]
+    },
+    {
+      "id": 11,
+      "subject": "Task 11 (P1): Register MqttDriverBrowser (bespoke-first for Mqtt)",
+      "status": "completed",
+      "classification": "trivial",
+      "parallelizableWith": [
+        12
+      ],
+      "blockedBy": [
+        10
+      ]
+    },
+    {
+      "id": 12,
+      "subject": "Task 12 (P1): Typed AdminUI editor + validator (plain shape)",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [
+        11
+      ],
+      "blockedBy": [
+        2
+      ]
+    },
+    {
+      "id": 13,
+      "subject": "Task 13 (P1): Mosquitto+JSON-publisher fixture (TLS+auth) + env-gated live suite",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        9
+      ]
+    },
+    {
+      "id": 14,
+      "subject": "Task 14 (P1): Live /run verify on docker-dev \u2014 P1 MILESTONE COMPLETE",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [],
+      "blockedBy": [
+        9,
+        11,
+        12,
+        13
+      ]
+    },
+    {
+      "id": 15,
+      "subject": "Task 15 (P2): Vendor Tahu sparkplug_b.proto + Grpc.Tools codegen",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        14
+      ]
+    },
+    {
+      "id": 16,
+      "subject": "Task 16 (P2): SparkplugCodec decode + golden payload vectors",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [
+        17
+      ],
+      "blockedBy": [
+        15
+      ]
+    },
+    {
+      "id": 17,
+      "subject": "Task 17 (P2): SparkplugTopic parse/format + SparkplugDataType.ToDriverDataType map",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [
+        16
+      ],
+      "blockedBy": [
+        15
+      ]
+    },
+    {
+      "id": 18,
+      "subject": "Task 18 (P2): BirthCache + AliasTable \u2014 bind-by-name, rebuild-per-birth",
+      "status": "completed",
+      "classification": "high-risk",
+      "parallelizableWith": [
+        19
+      ],
+      "blockedBy": [
+        16,
+        17
+      ]
+    },
+    {
+      "id": 19,
+      "subject": "Task 19 (P2): SequenceTracker seq-gap + bdSeq death-tie",
+      "status": "completed",
+      "classification": "high-risk",
+      "parallelizableWith": [
+        18
+      ],
+      "blockedBy": [
+        16,
+        17
+      ]
+    },
+    {
+      "id": 20,
+      "subject": "Task 20 (P2): RebirthRequester NCMD encode",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [],
+      "blockedBy": [
+        16
+      ]
+    },
+    {
+      "id": 21,
+      "subject": "Task 21 (P2): Sparkplug ingest state machine \u2014 the 3.6 matrix",
+      "status": "completed",
+      "classification": "high-risk",
+      "parallelizableWith": [],
+      "blockedBy": [
+        18,
+        19,
+        20
+      ]
+    },
+    {
+      "id": 22,
+      "subject": "Task 22 (P2): ITagDiscovery UntilStable + IRediscoverable (rediscover-on-DBIRTH)",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        21
+      ]
+    },
+    {
+      "id": 23,
+      "subject": "Task 23 (P2): Sparkplug browser tree + AttributesAsync + scoped RequestRebirthAsync",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [
+        24
+      ],
+      "blockedBy": [
+        20,
+        21
+      ]
+    },
+    {
+      "id": 24,
+      "subject": "Task 24 (P2): AdminUI editor Sparkplug mode shape + validator",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [
+        23
+      ],
+      "blockedBy": [
+        12,
+        17
+      ]
+    },
+    {
+      "id": 25,
+      "subject": "Task 25 (P2): C# edge-node simulator fixture + 3.6 live matrix",
+      "status": "completed",
+      "classification": "standard",
+      "parallelizableWith": [],
+      "blockedBy": [
+        21,
+        22,
+        23
+      ]
+    },
+    {
+      "id": 26,
+      "subject": "Task 26 (P2): Live /run verify Sparkplug \u2014 P2 COMPLETE",
+      "status": "completed",
+      "classification": "small",
+      "parallelizableWith": [],
+      "blockedBy": [
+        23,
+        24,
+        25
+      ]
+    }
  ],
-  "lastUpdated": "2026-07-24"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "All 27 tasks shipped, both phases live-gated. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -48,6 +48,102 @@ git add docs/plans/2026-07-24-mtconnect-driver.md
 git commit -m "docs(mtconnect): record TrakHound-vs-hand-rolled client decision (Task 0)"
 ```

+**DECISION (verified 2026-07-24): TrakHound path.** All three checks passed against real nuget.org.
+(1) `dotnet package search MTConnect.NET-Common --exact-match` and `...-HTTP --exact-match` both list
+versions `3.2.0` through `6.9.0.2` on `nuget.org`, confirming `6.9.0.2` is the current top-of-list
+version for both package ids (no version mismatch between the two). (2) A throwaway `net10.0` console
+project in the scratchpad (outside the repo, so unaffected by this repo's `packageSourceMapping`) ran
+`dotnet add package MTConnect.NET-Common -v 6.9.0.2` + `...-HTTP -v 6.9.0.2` + `dotnet restore` — both
+restored cleanly with no source-mapping or compatibility errors; `project.assets.json` resolved
+`MTConnect.NET-Common`, `MTConnect.NET-HTTP`, and the transitive `MTConnect.NET-TLS` (all `6.9.0.2`)
+against the `net10.0` target framework, and each package's `lib/` folder contains a `netstandard2.0`
+build (alongside `net6.0`–`net9.0`, `net461`–`net472`, `net47`, `net48`), so net10.0 resolves via the
+in-box compatibility mapping. (3) The pinned version carries **no embedded LICENSE file** in the
+`.nupkg` (`unzip -l` shows no `LICENSE*` entry in either package) — instead both nuspecs declare the
+modern SPDX license-expression form `<license type="expression">MIT</license>` +
+`<licenseUrl>https://licenses.nuget.org/MIT</licenseUrl>`, which nuget.org validates against the SPDX
+list at push time and surfaces on the package page (confirmed live: the nuget.org page for
+`MTConnect.NET-Common` `6.9.0.2` displays "MIT license" linked to `licenses.nuget.org/MIT`) — a
+structurally stronger guarantee than a free-text embedded file for this specific version, so the
+absence of a physical `LICENSE` file is not a fail. Task 1 adds
+`PackageReference MTConnect.NET-Common 6.9.0.2` + `PackageReference MTConnect.NET-HTTP 6.9.0.2` to
+`Driver.MTConnect.csproj`; the hand-roll fallback is not needed.
+
+**CORRECTION (Task 6, commit `bdfefadc`) — the decision above rested on incomplete evidence, and the
+hand-roll fallback IS in use for parsing.** Task 0 verified the packages *exist, restore, and are MIT*;
+it never verified they can actually parse an MTConnect document. As pinned, they cannot. Task 6 proved
+this empirically before writing any parser code: reflection over both referenced assemblies
+(`MTConnect.NET-Common`, 1297 types; `-HTTP`, 410 types) found **zero `IResponseDocumentFormatter`
+implementations and zero public static `FromXml`/parse entry points**, and a live invocation of
+TrakHound's own entry point (`ResponseDocumentFormatter.CreateDevicesResponseDocument("xml", stream)`)
+against this repo's `Fixtures/probe.xml`, with both DLLs loaded, returned:
+
+```
+Success = False
+ERROR:  Document Formatter Not found for "xml"
+```
+
+TrakHound 6.x resolves formatters from loaded assemblies at runtime, and the XML formatter ships in a
+**third package, `MTConnect.NET-XML`**, which Task 0 did not evaluate. Even with it added, TrakHound
+exposes no socket-free `Parse(string)` entry point of the shape this plan mandates. So `/probe` parsing
+is a hand-rolled `System.Xml.Linq` walk (~250 LoC, `MTConnectProbeParser`); the driver above the
+`IMTConnectAgentClient` seam is unaffected, exactly as the decision rule anticipated.
+
+**The two `PackageReference`s remain and are, so far, dead weight.** Task 6 deliberately did not remove
+them: the hard remaining problem is Task 7's `multipart/x-mixed-replace` chunk framing for `/sample`,
+and `MTConnect.Clients.MTConnectHttpClientStream` in `-HTTP` may be usable for framing alone. **Task 7
+owns the final call:** (a) use `-HTTP` for framing only, (b) add `MTConnect.NET-XML` and reconsider
+wholesale, or (c) hand-roll the boundary reader and **drop both package references** — in which case the
+Task-0 rationale comment in `Directory.Packages.props` goes with them. Record the outcome here.
+
+**OUTCOME (Task 7) — option (c): hand-rolled boundary reader, BOTH package references DROPPED.**
+`MTConnect.NET-Common`, `MTConnect.NET-HTTP` and the transitive `MTConnect.NET-TLS` are gone from
+`Directory.Packages.props` and from `Driver.MTConnect.csproj`; the Task-0 rationale comments went with
+them (each replaced by a comment naming this block). **The driver now depends on nothing but the BCL** —
+`HttpClient` + `System.Xml.Linq`. Reflection over `MTConnect.NET-HTTP` 6.9.0.2 (net9.0 lib, with
+`-Common` resolved alongside) settled the one open candidate:
+
+```
+TYPE MTConnect.Clients.MTConnectHttpClientStream
+   .ctor(String url, String documentFormat)
+   Void Start(CancellationToken), Void Stop(), Task Run(CancellationToken)
+   event DocumentReceived / ErrorReceived / FormatError / ConnectionError / …
+```
+
+Three independent disqualifiers, any one of which is fatal:
+
+1. **It cannot be exercised without a socket.** Its only constructor takes a *URL* and it dials the
+   connection itself inside `Run` — there is no `HttpMessageHandler`, no `HttpClient`, and no `Stream`
+   injection point. The whole `IMTConnectAgentClient` seam exists so Tasks 6–13 are unit-testable
+   against canned XML with no listener; adopting this type would have forced a live agent (or a real
+   loopback HTTP server) into the unit suite.
+2. **"Framing alone" was never actually on offer.** The type does not surface raw part payloads — it
+   raises `DocumentReceived` with an already-parsed `IDocument`, resolved through the same
+   `documentFormat` formatter lookup that Task 6 proved is missing. Using it for framing would still
+   have required adding `MTConnect.NET-XML`, i.e. option (b) in disguise.
+3. **The shape is inverted and the payload is heavy.** An event-driven `Start`/`Run` object has to be
+   adapted back into the `IAsyncEnumerable<MTConnectStreamsResult>` the seam declares, and `-HTTP`
+   vendors an entire embedded web server (`Ceen.*` types) that this driver would never touch.
+
+The replacement is `MultipartStreamReader`, a ~200-line private nested class in
+`MTConnectAgentClient.cs` that frames `multipart/x-mixed-replace` off the response stream. Two paths:
+`Content-length` present (every agent in the wild writes it) → read by length and emit the chunk the
+instant it completes; absent → scan to the next boundary, which necessarily emits one chunk late and
+exists as a correctness fallback only. Both paths are covered by tests. Every read is bounded by a
+heartbeat watchdog (`2 × HeartbeatMs + RequestTimeoutMs`) so a silent agent faults instead of wedging
+the pump — the R2-01 shape — and the buffer is capped at 32 MiB.
+
+**Also settled here: the streaming leg gets its own `HttpClient`.** `HttpClient.Timeout` is a
+per-instance whole-response deadline, so the long poll cannot share the unary client. Raising the one
+timeout would have un-bounded `/probe` + `/current`, which R2-01 forbids; instead `_streamHttp` runs
+`Timeout.InfiniteTimeSpan` and is bounded by the request deadline on its *header* phase plus the
+watchdog on its body.
+
+**Process lesson:** "the dependency restores" is not "the dependency does the job." A library
+verification checklist needs one end-to-end call against a real input, not just a restore. Task 7 adds
+a second: **check the constructor for a test seam before counting a library as usable** — a type that
+can only be handed a URL cannot participate in a socket-free unit suite, however good its internals.
+
 ---

 ## Task 1: Scaffold the two driver projects + the test project
@@ -289,6 +385,57 @@ dotnet test tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests --filter "Ful
 git add -A && git commit -m "feat(mtconnect): current/sample parse + sequence-gap detection (Task 7)"
 ```

+### Task 7 review remediation (post-`c46540ae`) — three contract changes Tasks 9/11/13 must build against
+
+Code review of `c46540ae` approved the framing algorithm but moved the risk onto the **contract**. Three
+changes here are breaking relative to the sketch above; the rest are hardening.
+
+1. **`SampleAsync` never ends normally except by cancellation.** The seam documents the stream as
+   yielding "indefinitely, until `ct` is cancelled", but the implementation returned normally on EOF, on
+   the closing `--boundary--`, and — worst — on a response that was not multipart at all, where it
+   yielded one parsed snapshot and finished. A pump written to the documented contract has no reason to
+   handle normal completion, so it would silently drop its subscription or hot-loop reconnecting; the
+   non-multipart leg additionally reported a **configuration error as a healthy finished stream**, which
+   is the #485 quiet-successful-termination shape aimed straight at Task 11. Every non-cancellation end
+   now throws: `MTConnectStreamEndedException` (with `MTConnectStreamEndReason.ConnectionClosed` /
+   `ClosingBoundary` — transient, reconnect) or `MTConnectStreamNotSupportedException` (configuration —
+   reconnecting reproduces it forever), sharing the base `MTConnectStreamException`. The non-multipart
+   body is still parsed first, so an Agent's own `MTConnectError` text still wins, but the document is
+   **not** yielded.
+2. **`IsSequenceGap` moved to `IMTConnectAgentClient` (static) and its first parameter is now
+   `expectedFrom`.** The sketch's `requestedFrom` name and doc were wrong for every chunk after the
+   first: the correct comparand is the **previous chunk's `NextSequence`**, and comparing against the
+   opening `from` reports a gap on every chunk once the ring buffer rolls — an endless `/current`
+   re-baseline storm against a healthy stream. Rehomed onto the seam so Task 11 need not reference the
+   concrete client. **Task 11 must also treat an `OUT_OF_RANGE` `InvalidDataException` as a re-baseline
+   trigger:** cppagent answers a `from` below `firstSequence` with an `MTConnectError` under HTTP 200,
+   so ring-buffer overflow arrives as a *parse failure*, never as a gap-bearing chunk. `IsSequenceGap`
+   alone does not cover it. Documented on the seam.
+3. **`MTConnectObservation` gained `IsStructured`** (default `false`), set from `element.HasElements`.
+   A DATA_SET/TABLE observation's `<Entry key=…>` children concatenate through `element.Value` to
+   nonsense (`"12"` for two entries) which the index would otherwise publish as Good, and only the
+   parser can tell that apart from a legitimate space-bearing `Message` — no value-shape heuristic
+   works. Deliberately **false for CONDITION** observations: their value comes from the element *name*,
+   so child content cannot corrupt it. The index maps the flag to a status; the parser does not.
+
+Hardening in the same pass: disposal mid-enumeration now surfaces as `OperationCanceledException`
+(via an internal dispose-linked token) rather than a raw `ObjectDisposedException`/`IOException` that
+Task 9's re-init would otherwise inflict on an enumerating pump; `HeartbeatMs`, `SampleIntervalMs` and
+`SampleCount` join `RequestTimeoutMs` in construction-time positive-value validation (all three reach
+the query string, and an Agent answers `heartbeat=0` with an HTTP-200 `MTConnectError` that would name
+no config key); a `multipart/*` response with no `boundary` parameter fails fast instead of degrading
+into a watchdog timeout; the no-`Content-length` framing fallback logs a one-shot warning (the client
+now takes an optional `ILogger`); and the shared element/attribute reading rules moved into
+`MTConnectXml`, used by both parsers.
+
+**Coverage gap closed, and worth remembering as a pattern.** Every multipart test served the whole body
+from one buffer, so **every framing test completed in a single `ReadAsync`** — the split-boundary path,
+the split-header path and the multi-fill loop were correct by inspection only, on the task whose
+headline risk is framing. A `ChunkedStream` double returning N bytes per read (N = 1, 3, 7) now drives
+the fixtures through a split transport. Falsifiability confirms the gap was real: removing the
+split-boundary overlap, removing the split-header overlap, and collapsing `EnsureAsync`'s fill loop each
+fail **only** the new chunked tests — every pre-existing multipart test stays green under all three.
+
 ---

 ## Task 8: `MTConnectObservationIndex` + `UNAVAILABLE → BadNoCommunication`
@@ -747,6 +894,176 @@ git commit -m "test(mtconnect): live /run gate on docker-dev — browse/read/sub

 ---

+### LIVE-GATE RESULT (2026-07-24, completed 2026-07-27) — ALL 5 LEGS PASSED
+
+**Rig.** The shared `otopcua-dev` rig was NOT used: three sibling driver worktrees
+(`modbus-rtu`, `mqtt-sparkplug`, `sql-poll-driver`) share its `otopcua-host:dev` image, and it had
+been up for hours. Instead an isolated stack was built from this worktree —
+`otopcua-host:mtconnect`, compose project `otopcua-mtc`, overlay
+`docker-dev/docker-compose.mtconnect.yml`, MAIN pair only, ports AdminUI **9220** / OPC UA **4860**
+/ SQL **14340**. Mirrors how the mqtt worktree isolated itself. The `otopcua-dev` rig and every
+sibling worktree were left untouched.
+
+**Fixture.** `mtconnect/agent:2.7.0.12` + the SHDR adapter deployed to
+`/opt/otopcua-mtconnect/` on the shared docker host and brought up healthy; `http://10.100.0.35:5000`
+serves the seeded `OtFixtureCnc` model with live-moving values. Note it answers in the MTConnect
+**2.0** namespace while the canned fixtures are 1.3 — the namespace-agnostic `LocalName` parsing
+(Task 6) is what makes both work, now demonstrated rather than argued.
+
+| Leg | Result | Evidence |
+|---|---|---|
+| Integration suite vs. a REAL Agent | ✅ **12/12** | incl. `Discovery_types_an_upper_snake_numeric_event_as_Int64` (the `PART_COUNT` regression), `Read_and_subscribe_key_on_RawPath_when_the_artifact_supplies_RawTags` (the blocker fix), `Subscribe_delivers_a_changed_value_from_the_live_sample_stream`, `Discovery_binds_FullName_to_the_DataItem_id_when_the_name_differs` |
+| 1. Driver creatable in `/raw` | ✅ | `MTConnect` present in `RawDriverTypeDialog`; `mtc-1` created. Proves the Host `Register` call is genuinely wired — **the one thing no test guards** (deleting it leaves the guard test green and substitutes a `StubbedDriver` while the deploy still seals green). |
+| 2. Typed config modal renders | ✅ | "Configure driver · MTConnect" with all four sections (Agent / Polling / Connectivity probe / Reconnect), **not** the "no typed config form" banner. **This is the mutation that survived all 749 AdminUI tests** — the `switch` in `DriverConfigModal.razor` compiles to `BuildRenderTree` and is unreachable by reflection. |
+| 3. Config persists + round-trips | ✅ | Stored `{"agentUri":"http://10.100.0.35:5000","requestTimeoutMs":5000,…,"probe":{"enabled":true,…},"reconnect":{…}}`; reopening the modal displays the saved URI (Razor binding verified — no bUnit in this repo). |
+| 4. Browse picker → commit | ✅ | "Connect & browse" dialled the live Agent; tree rendered `Agent` + `OtFixtureCnc` with `Favail` (name ≠ id) beside id-named leaves, proving `browseName = Name ?? Id`. Committed TagConfig is **`{"fullName":"fixture_asset_changed","dataType":"String"}`** — the `fullName`-not-`address` fix, live. Wave-0 #468 did **not** block this. |
+| 5. Deploy → OPC UA read/subscribe | ✅ **PASSED (2026-07-27, post-rebase)** | see "Leg 5" below |
+
+---
+
+#### Leg 5 — PASSED 2026-07-27, on the rebased branch
+
+Re-run after the rebase onto master (`123ddc3f`), against a **freshly rebuilt** `otopcua-host:mtconnect`
+image, so this gate exercises the merged code and not the pre-rebase tree.
+
+**The cookie blocker was sidestepped, not worked around.** Rather than moving hosts or stopping the
+`otopcua-dev` rig, the deploy went through the **headless deploy API** —
+`POST /api/deployments` with `X-Api-Key` (`DeployApiEndpoints`, `Security:DeployApiKey`). It is
+`AllowAnonymous().DisableAntiforgery()` by design ("machine endpoint, not a browser form post"), so
+the antiforgery cookie collision is structurally irrelevant to it. This is the better recipe for any
+future isolated-stack gate — it needs no browser at all:
+
+```bash
+curl -s -X POST http://localhost:9220/api/deployments \
+     -H "X-Api-Key: docker-dev-deploy-key" -H "Content-Type: application/json" \
+     -d '{"CreatedBy":"mtconnect-live-gate"}'
+# {"outcome":"Accepted","deploymentId":"…","revisionHash":"…"}   HTTP 202
+```
+
+Both deployments sealed `Status = 2` (`DeploymentStatus.Sealed`) with `FailureReason = NULL` — i.e.
+**both** MAIN nodes acked. No `MaintenanceMode` hatch was needed: the isolated stack's topology is
+MAIN-only with both central nodes enabled and running.
+
+**Tag set.** Leg 4's AdminUI-committed tag (`fixture_asset_changed`) is an `AssetChanged` EVENT that
+never moves, so three live-changing tags were added **directly via SQL** (deliberately bypassing the
+typed editor — see the finding below) to exercise all three type paths.
+
+**Results — read (`Client.CLI read`, `opc.tcp://localhost:4860`):**
+
+| NodeId (`ns=2`, Raw realm) | Value | Status |
+|---|---|---|
+| `s=mtc-1/vmc/fixture_partcount` | `48099` (Int64) | `0x00000000` Good |
+| `s=mtc-1/vmc/fixture_x_pos` | `96.4416` (Float64) | `0x00000000` Good |
+| `s=mtc-1/vmc/fixture_execution` | `ACTIVE` (String) | `0x00000000` Good |
+| `s=mtc-1/vmc/fixture_asset_changed` | *(null)* | `0x80000000` — see finding 6 |
+
+The RawPath is `mtc-1/vmc/<dataItemId>` (driver/device/tag; no folder prefix), confirmed by
+`browse -r`, which rendered all four as `[Variable]` under the `vmc` device object.
+
+**Results — subscribe (`Client.CLI subscribe -r` over the whole device, 500 ms):** all four monitored;
+live updates flowed continuously from the `/sample` long-poll pump through to OPC UA — `fixture_x_pos`
+tracing its sinusoid (`103.66 → 123.18 → 141.90 → 155.27 → 159.99 → 154.93 → 141.32 → 122.48 → 103.03
+→ 87.75 → 80.35`), `fixture_partcount` incrementing monotonically (`48128 → 48129 → 48130`), and
+`fixture_execution` transitioning `READY → INTERRUPTED`. **This closes the last unproven link**: the
+driver seam was already covered by the live integration suite, and leg 5 adds `DeploymentArtifact` →
+address-space materialisation → OPC UA publish on top of it.
+
+**Additional findings from leg 5:**
+
+5. **A bad `dataType` degrades to exactly one skipped tag, loudly — verified by accident.** The
+   hand-written SQL used `"dataType":"Double"`; the vocabulary is `DriverDataType`, whose member is
+   **`Float64`**. The driver logged, per tag:
+   > `could not map the raw tag mtc-1/vmc/fixture_x_pos to an Agent DataItem; it names no readable id
+   > (expected 'fullName', 'dataItemId' or 'address') or declares an unrecognised driverDataType. The
+   > tag is skipped and reports BadNodeIdUnknown; every other tag is unaffected.`
+
+   …and the other three tags kept streaming. That is the intended fail-isolated behaviour,
+   demonstrated live rather than argued. Correcting the row to `Float64` and redeploying turned the
+   tag Good with **no container restart** — which incidentally shows **MTConnect is not subject to the
+   separately-tracked config-edits-silently-discarded defect** that affects Modbus/FOCAS/OpcUaClient.
+   Note also that the typed AdminUI editor would have prevented the mistake outright (it offers a
+   `DriverDataType` dropdown); the error was an artifact of authoring straight into SQL.
+
+6. **`fixture_asset_changed` reading `0x80000000` is NOT an MTConnect defect — it is a pre-existing,
+   deliberate fidelity gap on the shared publish path.** The agent does return the tag in `/current`
+   as `<AssetChanged …>UNAVAILABLE</AssetChanged>`, and the driver maps it correctly to
+   `BadNoCommunication` (`0x80310000`, `MTConnectObservationIndex.cs:255`). The node nevertheless
+   reports generic `Bad` (`0x80000000`) — while carrying the agent's exact source timestamp, which
+   proves the publish landed and only the status differs. Cause, verified by reading the source:
+   `DriverInstanceActor.QualityFromStatus` (`DriverInstanceActor.cs:1032-1041`) projects the driver's
+   `uint` onto the 3-state `OpcUaQuality` enum using only the top two severity bits (`statusCode >> 30`),
+   and `OtOpcUaNodeManager.StatusFromQuality` (`OtOpcUaNodeManager.cs:3318-3322`) re-expands `Bad` to
+   `StatusCodes.Bad`. It is intentional — `OpcUaQuality`'s own doc comment says *"Real SDK has
+   finer-grained codes; the engine actors only need this 3-state classification."*
+
+   The consequence appears undocumented and is client-visible: **no driver's Bad/Uncertain sub-code
+   ever reaches an OPC UA client.** Issue #497's 16 corrected constants and the new
+   `StatusCodeParityTests` guard keep the constants internally right, but a client cannot tell
+   `BadNoCommunication` from `BadTypeMismatch` from `BadNotSupported`. (The one survivor is
+   `BadWaitingForInitialData`, written directly at the node at `OtOpcUaNodeManager.cs:1806/1901`,
+   bypassing the projection.) Tracked separately; out of scope for this plan.
+
+---
+
+**Historical — why leg 5 was blocked on 2026-07-24 (superseded by the API-key recipe above).**
+Browser cookies are scoped to a
+**host, not a port**, so the AdminUI antiforgery cookie issued by the still-running `otopcua-dev`
+rig on `localhost:9200` is sent to the isolated stack on `localhost:9220`, whose data-protection
+keys differ:
+
+```
+Microsoft.AspNetCore.Antiforgery.AntiforgeryValidationException: The antiforgery token could not be decrypted.
+```
+
+The `Deploy current configuration` POST is rejected before reaching any MTConnect code — no
+`Deployment` row is created, and the UI surfaces nothing. Clearing JS-visible cookies does not help
+(the antiforgery cookie is `HttpOnly`). This is a two-stacks-on-one-host collision, entirely outside
+the driver.
+
+The three browser-side remedies originally listed (distinct host / incognito profile / stop the
+`otopcua-dev` rig) all remain valid, but none was needed — the headless deploy API above avoids the
+browser entirely and is the recommended recipe.
+
+**Incidental findings from the rig work:**
+1. ~~`ClusterNode` has no `MaintenanceMode` column, so CLAUDE.md is ahead of the migration.~~
+   **CORRECTED — this was my error, not a repo inconsistency.** The migration
+   `20260722125506_AddClusterNodeMaintenanceMode` exists on master, along with `AkkaPort`/`GrpcPort`.
+   **This branch is 39 commits behind master** (base `963eec1b`, master `28c28667`) and simply
+   predates them, so the isolated stack's schema lacked the column and I reduced the seeded topology
+   by deleting the SITE-A/SITE-B rows instead. CLAUDE.md is accurate. **DONE 2026-07-27 — rebased**
+   onto master `123ddc3f` (67 commits by then, not 39). Conflicts were all of one shape — this driver
+   and the newly-merged SQL-poll driver each adding their entry to the same list — resolved by keeping
+   **both** in: `ZB.MOM.WW.OtOpcUa.slnx`, `DriverTypeNames.cs`, `DriverFactoryBootstrap.cs`,
+   `Core.Abstractions.Tests.csproj`, `TagConfigEditorMap.cs`, `TagConfigValidator.cs`,
+   `DriverConfigModal.razor`, `RawDriverTypeDialog.razor`. Post-rebase: solution build 0 errors,
+   MTConnect 491/491, Core.Abstractions 256/256, AdminUI 800/800. For a future partial-topology gate,
+   `MaintenanceMode = 1` is now available and is the correct hatch (it is what the SQL-poll driver's
+   gate used), in place of the row deletion I resorted to.
+2. `sqlcmd` against this schema needs `-I` (`SET QUOTED_IDENTIFIER ON`); without it every DML
+   statement fails with `Msg 1934` because of the filtered/computed indexes.
+3. **Status-code parity is pre-verified against master's new guard.** Master gained
+   `StatusCodeParityTests`, which reflects over every `ZB.MOM.WW.OtOpcUa.Driver.*.dll` in its bin for
+   status-shaped `const uint` fields — including `private const` on `internal` types — and checks each
+   against `Opc.Ua.StatusCodes`. Task 16 added the `Driver.MTConnect` ProjectReference to that same
+   test project, so this driver's constants are in scope. All eight were verified against the pinned
+   SDK assembly directly: `BadCommunicationError 0x80050000`, `BadNoCommunication 0x80310000`,
+   `BadNodeIdUnknown 0x80340000`, `BadNotConnected 0x808A0000`, `BadNotSupported 0x803D0000`,
+   `BadOutOfRange 0x803C0000`, `BadTypeMismatch 0x80740000`, `BadWaitingForInitialData 0x80320000`
+   — **0 mismatches**. Note the guard only sees *named* constants; an inline status literal at a call
+   site is invisible to it, so keep hoisting them. **Confirmed after the rebase**: the guard reports
+   9 MTConnect constants in scope (the 8 above plus `Good`), all passing — the pre-verification held.
+4. **The separately-tracked `BadTypeMismatch` defect in FOCAS/TwinCAT/AbLegacy/AbCip is already fixed
+   on master** (issue #497 grew it to 16 wrong constants across 6 drivers). This driver independently
+   chose the correct `0x80740000` and pinned it with a mutation test, so the two agree; no action.
+
+**Teardown when done:**
+```bash
+docker compose -p otopcua-mtc -f docker-dev/docker-compose.yml -f docker-dev/docker-compose.mtconnect.yml down -v
+ssh dohertj2@10.100.0.35 'cd /opt/otopcua-mtconnect && docker compose down'
+```
+
+---
+
 ## Task 22: Docs + deferred-writeback note; update the tracking doc

 **Classification:** trivial
@@ -1,29 +1,199 @@
 {
  "planPath": "docs/plans/2026-07-24-mtconnect-driver.md",
  "tasks": [
-    {"id": 0, "subject": "Task 0: Verify TrakHound MTConnect.NET pin (or record the hand-roll decision)", "status": "pending"},
-    {"id": 1, "subject": "Task 1: Scaffold the two driver projects + the test project", "status": "pending", "blockedBy": [0]},
-    {"id": 2, "subject": "Task 2: MTConnectDriverOptions + MTConnectTagDefinition in .Contracts", "status": "pending", "blockedBy": [1]},
-    {"id": 3, "subject": "Task 3: MTConnectDataTypeInference.Infer + golden type-map test", "status": "pending", "blockedBy": [1]},
-    {"id": 4, "subject": "Task 4: Capture the canned XML fixtures", "status": "pending", "blockedBy": [1]},
-    {"id": 5, "subject": "Task 5: IMTConnectAgentClient seam + return DTOs", "status": "pending", "blockedBy": [1]},
-    {"id": 6, "subject": "Task 6: MTConnectAgentClient — parse /probe into the device model", "status": "pending", "blockedBy": [4, 5]},
-    {"id": 7, "subject": "Task 7: MTConnectAgentClient — parse /current + /sample, detect the sequence gap", "status": "pending", "blockedBy": [4, 5, 6]},
-    {"id": 8, "subject": "Task 8: MTConnectObservationIndex + UNAVAILABLE -> BadNoCommunication", "status": "pending", "blockedBy": [7]},
-    {"id": 9, "subject": "Task 9: MTConnectDriver shell — IDriver lifecycle", "status": "pending", "blockedBy": [2, 8]},
-    {"id": 10, "subject": "Task 10: IReadable.ReadAsync — /current, ordered snapshots", "status": "pending", "blockedBy": [9]},
-    {"id": 11, "subject": "Task 11: ISubscribable — /sample long-poll pump + ring-buffer re-baseline", "status": "pending", "blockedBy": [9, 7]},
-    {"id": 12, "subject": "Task 12: ITagDiscovery.DiscoverAsync + SupportsOnlineDiscovery=true", "status": "pending", "blockedBy": [9, 6]},
-    {"id": 13, "subject": "Task 13: IHostConnectivityProbe + IRediscoverable (instanceId watch)", "status": "pending", "blockedBy": [9]},
-    {"id": 14, "subject": "Task 14: MTConnectDriverProbe : IDriverProbe", "status": "pending", "blockedBy": [2, 5]},
-    {"id": 15, "subject": "Task 15: MTConnectDriverFactoryExtensions", "status": "pending", "blockedBy": [2, 9]},
-    {"id": 16, "subject": "Task 16: Host registration + DriverTypeNames.MTConnect + guard-test parity", "status": "pending", "blockedBy": [14, 15]},
-    {"id": 17, "subject": "Task 17: AdminUI typed model MTConnectTagConfigModel", "status": "pending", "blockedBy": [3, 16]},
-    {"id": 18, "subject": "Task 18: AdminUI editor razor + map/validator registration", "status": "pending", "blockedBy": [17]},
-    {"id": 19, "subject": "Task 19: mtconnect/cppagent docker fixture", "status": "pending", "blockedBy": [16]},
-    {"id": 20, "subject": "Task 20: Env-gated integration suite against cppagent", "status": "pending", "blockedBy": [19]},
-    {"id": 21, "subject": "Task 21: Live /run verify on docker-dev — browse picker, editor, read, subscribe, deploy", "status": "pending", "blockedBy": [18, 20]},
-    {"id": 22, "subject": "Task 22: Docs + deferred-writeback note; update the tracking doc", "status": "pending", "blockedBy": [21]}
+    {
+      "id": 0,
+      "subject": "Task 0: Verify TrakHound MTConnect.NET pin (or record the hand-roll decision)",
+      "status": "completed"
+    },
+    {
+      "id": 1,
+      "subject": "Task 1: Scaffold the two driver projects + the test project",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 2,
+      "subject": "Task 2: MTConnectDriverOptions + MTConnectTagDefinition in .Contracts",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "Task 3: MTConnectDataTypeInference.Infer + golden type-map test",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 4,
+      "subject": "Task 4: Capture the canned XML fixtures",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "Task 5: IMTConnectAgentClient seam + return DTOs",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "Task 6: MTConnectAgentClient \u2014 parse /probe into the device model",
+      "status": "completed",
+      "blockedBy": [
+        4,
+        5
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "Task 7: MTConnectAgentClient \u2014 parse /current + /sample, detect the sequence gap",
+      "status": "completed",
+      "blockedBy": [
+        4,
+        5,
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "subject": "Task 8: MTConnectObservationIndex + UNAVAILABLE -> BadNoCommunication",
+      "status": "completed",
+      "blockedBy": [
+        7
+      ]
+    },
+    {
+      "id": 9,
+      "subject": "Task 9: MTConnectDriver shell \u2014 IDriver lifecycle",
+      "status": "completed",
+      "blockedBy": [
+        2,
+        8
+      ]
+    },
+    {
+      "id": 10,
+      "subject": "Task 10: IReadable.ReadAsync \u2014 /current, ordered snapshots",
+      "status": "completed",
+      "blockedBy": [
+        9
+      ]
+    },
+    {
+      "id": 11,
+      "subject": "Task 11: ISubscribable \u2014 /sample long-poll pump + ring-buffer re-baseline",
+      "status": "completed",
+      "blockedBy": [
+        9,
+        7
+      ]
+    },
+    {
+      "id": 12,
+      "subject": "Task 12: ITagDiscovery.DiscoverAsync + SupportsOnlineDiscovery=true",
+      "status": "completed",
+      "blockedBy": [
+        9,
+        6
+      ]
+    },
+    {
+      "id": 13,
+      "subject": "Task 13: IHostConnectivityProbe + IRediscoverable (instanceId watch)",
+      "status": "completed",
+      "blockedBy": [
+        9
+      ]
+    },
+    {
+      "id": 14,
+      "subject": "Task 14: MTConnectDriverProbe : IDriverProbe",
+      "status": "completed",
+      "blockedBy": [
+        2,
+        5
+      ]
+    },
+    {
+      "id": 15,
+      "subject": "Task 15: MTConnectDriverFactoryExtensions",
+      "status": "completed",
+      "blockedBy": [
+        2,
+        9
+      ]
+    },
+    {
+      "id": 16,
+      "subject": "Task 16: Host registration + DriverTypeNames.MTConnect + guard-test parity",
+      "status": "completed",
+      "blockedBy": [
+        14,
+        15
+      ]
+    },
+    {
+      "id": 17,
+      "subject": "Task 17: AdminUI typed model MTConnectTagConfigModel",
+      "status": "completed",
+      "blockedBy": [
+        3,
+        16
+      ]
+    },
+    {
+      "id": 18,
+      "subject": "Task 18: AdminUI editor razor + map/validator registration",
+      "status": "completed",
+      "blockedBy": [
+        17
+      ]
+    },
+    {
+      "id": 19,
+      "subject": "Task 19: mtconnect/cppagent docker fixture",
+      "status": "completed",
+      "blockedBy": [
+        16
+      ]
+    },
+    {
+      "id": 20,
+      "subject": "Task 20: Env-gated integration suite against cppagent",
+      "status": "completed",
+      "blockedBy": [
+        19
+      ]
+    },
+    {
+      "id": 21,
+      "subject": "Task 21: Live /run verify on docker-dev \u2014 browse picker, editor, read, subscribe, deploy",
+      "status": "completed",
+      "blockedBy": [
+        18,
+        20
+      ]
+    },
+    {
+      "id": 22,
+      "subject": "Task 22: Docs + deferred-writeback note; update the tracking doc",
+      "status": "completed",
+      "blockedBy": [
+        21
+      ]
+    }
  ],
-  "lastUpdated": "2026-07-24"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Merged at master 90bdaa44 (#506); 5-leg live gate PASSED. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -1,28 +1,191 @@
 {
  "planPath": "docs/plans/2026-07-24-sql-poll-driver.md",
  "tasks": [
-    {"id": 0, "subject": "Task 0: Scaffold Driver.Sql.Contracts project + register in slnx", "status": "pending"},
-    {"id": 1, "subject": "Task 1: SqlProvider/SqlTagModel enums + SqlDriverConfigDto", "status": "pending", "blockedBy": [0]},
-    {"id": 2, "subject": "Task 2: SqlTagDefinition + SqlEquipmentTagParser (strict enums, malicious-input safe)", "status": "pending", "blockedBy": [1]},
-    {"id": 3, "subject": "Task 3: Scaffold Driver.Sql runtime project + register in slnx", "status": "pending", "blockedBy": [0]},
-    {"id": 4, "subject": "Task 4: ISqlDialect + SqlServerDialect (QuoteIdentifier, catalog SQL, MapColumnType)", "status": "pending", "blockedBy": [1, 3]},
-    {"id": 5, "subject": "Task 5: SqlQueryPlan grouping + parameter binding (pure)", "status": "pending", "blockedBy": [2, 4]},
-    {"id": 6, "subject": "Task 6: Scaffold Driver.Sql.Tests + SqliteDialect + SqlitePollFixture", "status": "pending", "blockedBy": [3, 4]},
-    {"id": 7, "subject": "Task 7: SqlPollReader core — grouped read, bounded deadline, ordered slice-back", "status": "pending", "blockedBy": [5, 6]},
-    {"id": 8, "subject": "Task 8: SqlDriver shell — IDriver/ITagDiscovery/IReadable/ISubscribable/IHostConnectivityProbe", "status": "pending", "blockedBy": [7]},
-    {"id": 9, "subject": "Task 9: SqlDriverFactoryExtensions + connectionStringRef env resolution + enum guard", "status": "pending", "blockedBy": [8]},
-    {"id": 10, "subject": "Task 10: SqlDriverProbe (SELECT 1 liveness)", "status": "pending", "blockedBy": [4, 6]},
-    {"id": 11, "subject": "Task 11: Host registration — DriverTypeNames.Sql + factory + probe + guard test", "status": "pending", "blockedBy": [9, 10]},
-    {"id": 12, "subject": "Task 12: Scaffold Driver.Sql.Browser project + register in slnx", "status": "pending", "blockedBy": [3]},
-    {"id": 13, "subject": "Task 13: SqlBrowseSession — schema walk over dialect catalog", "status": "pending", "blockedBy": [4, 12, 6]},
-    {"id": 14, "subject": "Task 14: SqlDriverBrowser — env-ref/literal transient-connection open", "status": "pending", "blockedBy": [13]},
-    {"id": 15, "subject": "Task 15: AdminUI browser DI + SqlAddressPickerBody.razor", "status": "pending", "blockedBy": [14]},
-    {"id": 16, "subject": "Task 16: Env-gated central-SQL integration fixture + read round-trip", "status": "pending", "blockedBy": [8]},
-    {"id": 17, "subject": "Task 17: Injection regression test (bind value / reject identifier)", "status": "pending", "blockedBy": [7]},
-    {"id": 18, "subject": "Task 18: Blackhole/timeout live-gate on a dedicated mssql container", "status": "pending", "blockedBy": [16]},
-    {"id": 19, "subject": "Task 19: AdminUI typed Sql tag-config model + validator (string enums)", "status": "pending", "blockedBy": [1, 11]},
-    {"id": 20, "subject": "Task 20: SqlTagConfigEditor.razor shell", "status": "pending", "blockedBy": [19]},
-    {"id": 21, "subject": "Task 21: Live /run verification on docker-dev (picker + editor + deploy + read)", "status": "pending", "blockedBy": [11, 15, 20]}
+    {
+      "id": 0,
+      "subject": "Task 0: Scaffold Driver.Sql.Contracts project + register in slnx",
+      "status": "completed"
+    },
+    {
+      "id": 1,
+      "subject": "Task 1: SqlProvider/SqlTagModel enums + SqlDriverConfigDto",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 2,
+      "subject": "Task 2: SqlTagDefinition + SqlEquipmentTagParser (strict enums, malicious-input safe)",
+      "status": "completed",
+      "blockedBy": [
+        1
+      ]
+    },
+    {
+      "id": 3,
+      "subject": "Task 3: Scaffold Driver.Sql runtime project + register in slnx",
+      "status": "completed",
+      "blockedBy": [
+        0
+      ]
+    },
+    {
+      "id": 4,
+      "subject": "Task 4: ISqlDialect + SqlServerDialect (QuoteIdentifier, catalog SQL, MapColumnType)",
+      "status": "completed",
+      "blockedBy": [
+        1,
+        3
+      ]
+    },
+    {
+      "id": 5,
+      "subject": "Task 5: SqlQueryPlan grouping + parameter binding (pure)",
+      "status": "completed",
+      "blockedBy": [
+        2,
+        4
+      ]
+    },
+    {
+      "id": 6,
+      "subject": "Task 6: Scaffold Driver.Sql.Tests + SqliteDialect + SqlitePollFixture",
+      "status": "completed",
+      "blockedBy": [
+        3,
+        4
+      ]
+    },
+    {
+      "id": 7,
+      "subject": "Task 7: SqlPollReader core \u2014 grouped read, bounded deadline, ordered slice-back",
+      "status": "completed",
+      "blockedBy": [
+        5,
+        6
+      ]
+    },
+    {
+      "id": 8,
+      "subject": "Task 8: SqlDriver shell \u2014 IDriver/ITagDiscovery/IReadable/ISubscribable/IHostConnectivityProbe",
+      "status": "completed",
+      "blockedBy": [
+        7
+      ]
+    },
+    {
+      "id": 9,
+      "subject": "Task 9: SqlDriverFactoryExtensions + connectionStringRef env resolution + enum guard",
+      "status": "completed",
+      "blockedBy": [
+        8
+      ]
+    },
+    {
+      "id": 10,
+      "subject": "Task 10: SqlDriverProbe (SELECT 1 liveness)",
+      "status": "completed",
+      "blockedBy": [
+        4,
+        6
+      ]
+    },
+    {
+      "id": 11,
+      "subject": "Task 11: Host registration \u2014 DriverTypeNames.Sql + factory + probe + guard test",
+      "status": "completed",
+      "blockedBy": [
+        9,
+        10
+      ]
+    },
+    {
+      "id": 12,
+      "subject": "Task 12: Scaffold Driver.Sql.Browser project + register in slnx",
+      "status": "completed",
+      "blockedBy": [
+        3
+      ]
+    },
+    {
+      "id": 13,
+      "subject": "Task 13: SqlBrowseSession \u2014 schema walk over dialect catalog",
+      "status": "completed",
+      "blockedBy": [
+        4,
+        12,
+        6
+      ]
+    },
+    {
+      "id": 14,
+      "subject": "Task 14: SqlDriverBrowser \u2014 env-ref/literal transient-connection open",
+      "status": "completed",
+      "blockedBy": [
+        13
+      ]
+    },
+    {
+      "id": 15,
+      "subject": "Task 15: AdminUI browser DI + SqlAddressPickerBody.razor",
+      "status": "completed",
+      "blockedBy": [
+        14
+      ]
+    },
+    {
+      "id": 16,
+      "subject": "Task 16: Env-gated central-SQL integration fixture + read round-trip",
+      "status": "completed",
+      "blockedBy": [
+        8
+      ]
+    },
+    {
+      "id": 17,
+      "subject": "Task 17: Injection regression test (bind value / reject identifier)",
+      "status": "completed",
+      "blockedBy": [
+        7
+      ]
+    },
+    {
+      "id": 18,
+      "subject": "Task 18: Blackhole/timeout live-gate on a dedicated mssql container",
+      "status": "completed",
+      "blockedBy": [
+        16
+      ]
+    },
+    {
+      "id": 19,
+      "subject": "Task 19: AdminUI typed Sql tag-config model + validator (string enums)",
+      "status": "completed",
+      "blockedBy": [
+        1,
+        11
+      ]
+    },
+    {
+      "id": 20,
+      "subject": "Task 20: SqlTagConfigEditor.razor shell",
+      "status": "completed",
+      "blockedBy": [
+        19
+      ]
+    },
+    {
+      "id": 21,
+      "subject": "Task 21: Live /run verification on docker-dev (picker + editor + deploy + read)",
+      "status": "completed",
+      "blockedBy": [
+        11,
+        15,
+        20
+      ]
+    }
  ],
-  "lastUpdated": "2026-07-24"
+  "lastUpdated": "2026-07-27",
+  "closureNote": "Merged 4ad54037 + follow-ups 28c28667. Marked complete 2026-07-27 (deferment.md \u00a78.5)."
 }
@@ -21,7 +21,7 @@ OtOpcUa has four independent security concerns. This document covers all four:

 1. **Transport security** — OPC UA secure channel (signing, encryption, X.509 trust).
 2. **OPC UA authentication** — Anonymous / UserName / X.509 session identities; UserName tokens authenticated by LDAP bind.
-3. **Data-plane authorization** — who can browse, read, subscribe, write, acknowledge alarms on which nodes. Evaluated by `TriePermissionEvaluator` over a `PermissionTrie` built from the Config DB `NodeAcl` tree.
+3. **Data-plane authorization** — who can write and acknowledge alarms on an OtOpcUa endpoint. ⚠️ Enforced today by **two coarse, server-wide LDAP role checks** (`WriteOperate`, `AlarmAck`) — **not** by the `NodeAcl` / `PermissionTrie` subsystem, which is built and unit-tested but never wired. Read, Browse, HistoryRead and Subscribe carry **no** authorization check at all. See [Data-Plane Authorization](#data-plane-authorization).
 4. **Control-plane authorization** — who can view or edit fleet configuration in the Admin UI. Gated by the `AdminRole` (`Viewer` / `Designer` / `Administrator`) claim resolved from `LdapGroupRoleMapping`.

 Transport security and OPC UA authentication are per-node concerns configured in the Server's bootstrap `appsettings.json`. Data-plane ACLs and Admin role grants live in the Config DB.
@@ -112,9 +112,9 @@ The Server accepts three OPC UA identity-token types:

 | Token | Handler | Notes |
 |---|---|---|
-| Anonymous | No `IOpcUaUserAuthenticator` call — the SDK admits anonymous sessions at the channel. | Data-plane authorization (below) still default-denies any node a session has no ACL grant for. |
-| UserName/Password | `LdapOpcUaUserAuthenticator.AuthenticateUserNameAsync` (`src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/LdapOpcUaUserAuthenticator.cs`, implements `IOpcUaUserAuthenticator`), backed by the app `ILdapAuthService` — `OtOpcUaLdapAuthService` (`src/Server/ZB.MOM.WW.OtOpcUa.Security/Ldap/OtOpcUaLdapAuthService.cs`). | LDAP bind + group lookup. The returned LDAP groups are mapped to roles via `IGroupRoleMapper<string>` (`OtOpcUaGroupRoleMapper`) and attached to the OPC UA session identity for the downstream ACL evaluator. |
-| X.509 Certificate | Stack-level acceptance during the secure-channel handshake. | The certificate must be trusted (see PKI trust flow); finer-grain authorization happens through the data-plane ACLs. |
+| Anonymous | No `IOpcUaUserAuthenticator` call — the SDK admits anonymous sessions at the channel. | ⚠️ An anonymous session carries **no roles**, so it is refused every write and every alarm ack — but it can **Browse, Read, Subscribe and HistoryRead the entire address space**. There is no per-node ACL check on those operations (see [Data-Plane Authorization](#data-plane-authorization)). Do not expose an Anonymous-admitting endpoint to an untrusted network. |
+| UserName/Password | `LdapOpcUaUserAuthenticator.AuthenticateUserNameAsync` (`src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/LdapOpcUaUserAuthenticator.cs`, implements `IOpcUaUserAuthenticator`), backed by the app `ILdapAuthService` — `OtOpcUaLdapAuthService` (`src/Server/ZB.MOM.WW.OtOpcUa.Security/Ldap/OtOpcUaLdapAuthService.cs`). | LDAP bind + group lookup. The returned LDAP groups are mapped to roles via `IGroupRoleMapper<string>` (`OtOpcUaGroupRoleMapper`) and the **roles** are attached to the OPC UA session identity as a `RoleCarryingUserIdentity`. The raw group list is discarded at that point and never reaches the data plane. |
+| X.509 Certificate | Stack-level acceptance during the secure-channel handshake. | The certificate must be trusted (see PKI trust flow). It carries **no** roles, so a cert-only session is read-everything / write-nothing. |

 When no authenticator is supplied, `OpcUaApplicationHost` falls back to `NullOpcUaUserAuthenticator`; the Host wires the real `LdapOpcUaUserAuthenticator` as a singleton in `Program.cs`.

@@ -130,7 +130,7 @@ LDAP is configured under the `Security:Ldap` section (bound to `LdapOptions`, `s
 4. Delegates the real path to the shared `ZB.MOM.WW.Auth.Ldap` client: it binds (search-then-bind via `ServiceAccountDn`, or direct-bind `cn={user},{SearchBase}` when no service account is set), verifies the password, and reads the user's group memberships.
 5. Returns an `LdapAuthResult` carrying the validated username + the **groups** (never roles). Failure codes are folded into opaque user-facing error strings so a probe cannot distinguish "unknown user" from "wrong password".

-**Group → role mapping happens downstream**, not in the auth service: `LdapOpcUaUserAuthenticator` resolves `IGroupRoleMapper<string>` (`OtOpcUaGroupRoleMapper`) per call and unions its output with any pre-resolved roles (the DevStub `Administrator` grant). The roles are attached to the OPC UA session identity for the ACL evaluator. A mapper fault (e.g. a Config DB outage) falls back to the pre-resolved baseline rather than denying an otherwise-authenticated session.
+**Group → role mapping happens downstream**, not in the auth service: `LdapOpcUaUserAuthenticator` resolves `IGroupRoleMapper<string>` (`OtOpcUaGroupRoleMapper`) per call and unions its output with any pre-resolved roles (the DevStub `Administrator` grant). The roles are attached to the OPC UA session identity (`RoleCarryingUserIdentity`), where the write and alarm-ack gates read them. **The LDAP group names themselves are consumed here and go no further** — which is one reason the `NodeAcl` subsystem cannot currently be wired, since it matches on groups rather than roles. A mapper fault (e.g. a Config DB outage) falls back to the pre-resolved baseline rather than denying an otherwise-authenticated session.

 `Transport` replaces the former `UseTls` bool: `Ldaps` (implicit TLS), `StartTls` (upgrade), or `None` (plaintext, requires `AllowInsecure`). Configuration example (Active Directory production):

@@ -180,11 +180,92 @@ Defaults are behaviour-neutral on a healthy directory. All new paths are **fail-

 ## Data-Plane Authorization

-Data-plane authorization is the check run on every OPC UA operation against an OtOpcUa endpoint: *can this authenticated user Browse / Read / Subscribe / Write / HistoryRead / AckAlarm / Call on this specific node?*
+> ⚠️ **Read this first (verified against source, 2026-07-27).** This section used to describe the
+> `NodeAcl` / `PermissionTrie` design as if it were the live enforcement path. **It is not.** The
+> evaluator is built and unit-tested but has **zero production call sites**, and
+> `ZB.MOM.WW.OtOpcUa.OpcUaServer.csproj` does not even reference the project it lives in. Everything
+> actually enforced today is in [What is enforced today](#what-is-enforced-today); the trie design is
+> retained below, clearly marked, under [Designed but not wired](#designed-but-not-wired-nodeacl--permissiontrie).

-Per decision #129 the model is **additive-only — no explicit Deny**. Grants at each hierarchy level union; absence of a grant is the default-deny.
+### What is enforced today

-### Hierarchy
+There are exactly **three** authorization checks in the whole OPC UA server layer. All three are
+coarse, **server-wide role string checks** with no per-node component.
+
+| Operation | Gate | Requires |
+|---|---|---|
+| Write (Value attribute, either namespace) | `OtOpcUaNodeManager.EvaluateEquipmentWriteGate` | role `WriteOperate` |
+| Alarm Acknowledge / Confirm / AddComment / Shelve / Unshelve (scripted alarms) | `OtOpcUaNodeManager.HandleAlarmCommand` | role `AlarmAck` |
+| Alarm acknowledge (driver-fed native alarms) | `OtOpcUaNodeManager.HandleNativeAlarmAck` | role `AlarmAck` |
+
+Both gates fail closed — a session with no identity or no matching role gets
+`BadUserAccessDenied` — and read `identity.Roles` off the session's `RoleCarryingUserIdentity`
+(`src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/Security/RoleCarryingUserIdentity.cs`). Role strings are
+the constants in `OpcUaDataPlaneRoles`, sourced from `Security:Ldap:GroupToRole` (see
+[Role grant source](#role-grant-source-data-plane)).
+
+**What has no authorization check at all:**
+
+- **Read, Browse, TranslateBrowsePaths** — no override, no handler. Any admitted session, including
+  an Anonymous one, sees and reads the entire address space.
+- **HistoryRead** — all four overrides (`HistoryReadRawModified`, `HistoryReadProcessed`,
+  `HistoryReadAtTime`, `HistoryReadEvents`) run without an identity check.
+- **CreateMonitoredItems / subscriptions / TransferSubscriptions**.
+- **Non-Value attribute writes** — the gate hangs off `OnWriteValue`.
+
+**And what the write gate does *not* distinguish:**
+
+- **`WriteTune` and `WriteConfigure` are never checked.** They exist in the role vocabulary and in
+  `NodePermissions`, but every write — whatever the tag's security classification — is gated on the
+  single `WriteOperate` string.
+- **`AlarmAcknowledge` / `AlarmConfirm` / `AlarmShelve` are not distinguished.** One `AlarmAck` role
+  covers all five alarm methods; the `operation` argument is passed to the router but never consulted
+  by the gate.
+- **There is no per-node granularity.** A session that may write one tag may write **every** writable
+  tag on the node.
+
+The gate *is* realm-aware in one narrow sense: it is attached per-node during materialization for both
+the Raw and UNS realms, and the write dispatch it guards is realm-qualified. The role decision itself
+takes no realm and no node.
+
+### Designed but not wired: `NodeAcl` + `PermissionTrie`
+
+Everything from here to [Role grant source](#role-grant-source-data-plane) describes a subsystem that
+**exists in the tree, is covered by 30 unit tests, and never executes.** It is kept because the design
+is sound and the remaining work is wiring plus one genuine design gap — not because it runs.
+
+What is real about it:
+
+- Operators **can** author `NodeAcl` rows in the Admin UI (`/clusters/{id}/acls`), and those rows are
+  validated, versioned and persisted.
+- `ConfigComposer` **does** snapshot every `NodeAcl` row into every deployment artifact, so an ACL
+  edit shifts the artifact's `RevisionHash` and ships to every node.
+- The node side **never deserializes them** — `DeploymentArtifact` has no ACL reader. The bytes arrive
+  and are dropped.
+
+So an operator can author a grant, deploy it green, and have it change nothing. That is the behaviour
+to expect until the tracking issue below is closed.
+
+**The four things blocking a wire-up** (all verified, none of them merely "call the evaluator"):
+
+1. **Raw-realm nodes have no representable scope.** `NodeHierarchyKind` has exactly one member,
+   `Equipment`. Raw NodeIds are `Folder→Driver→Device→TagGroup→Tag` RawPaths, which `NodeScope` cannot
+   express — yet the write gate is attached to raw tags. Roughly half the writable address space has
+   no scope to evaluate. This is a design decision, not wiring.
+2. **The identity carries roles, not groups.** The trie matches `NodeAcl.LdapGroup` against the
+   session's LDAP groups, but `OpcUaUserAuthResult` carries only mapped role strings; the group list
+   is discarded inside `LdapOpcUaUserAuthenticator`.
+3. **`PermissionTrieBuilder`'s `scopePaths` argument has no producer.** Without it every sub-cluster
+   grant lands in the builder's fallback bucket — the hazard its own comments warn about. It would have
+   to be derived from the artifact's UNS relations.
+4. **No session lifecycle exists.** `UserAuthorizationState` has the freshness/staleness predicates but
+   nothing in production constructs one, stamps a generation, or drives a refresh.
+
+Two smaller inconsistencies inside the subsystem itself: `NodeAclScopeKind.FolderSegment` is offered in
+the authoring dropdown but the trie walker has no level to match it at, and `NodePermissions.AlarmRead`
+has no `OpcUaOperation` mapping, so it is grantable but unreachable.
+
+### Hierarchy (design)

 ACLs are evaluated against the node's scope path. `NodeScope` (`src/Core/ZB.MOM.WW.OtOpcUa.Core/Authorization/NodeScope.cs`) carries a `Kind` that selects between two hierarchy shapes:

@@ -245,19 +326,23 @@ The three Write tiers map to Galaxy's v1 `SecurityClassification` — `FreeAcces

 `NodeScope` is described above (Equipment-kind vs SystemPlatform-kind). The evaluator unions the matched grants along the path — a tag-level ACL and an area-level ACL both contribute.

-### Dispatch gate — `IPermissionEvaluator`
+### Dispatch gate — `IPermissionEvaluator` (design; **no such gate exists**)

-`IPermissionEvaluator.Authorize(UserAuthorizationState session, OpcUaOperation operation, NodeScope scope)` (default impl `TriePermissionEvaluator` at `src/Core/ZB.MOM.WW.OtOpcUa.Core/Authorization/TriePermissionEvaluator.cs`) returns an `AuthorizationDecision`. The dispatch path calls it on every Read, Write, HistoryRead, Browse, Subscribe, AckAlarm, Call; a `NotGranted` decision denies the operation.
+`IPermissionEvaluator.Authorize(UserAuthorizationState session, OpcUaOperation operation, NodeScope scope)` (default impl `TriePermissionEvaluator` at `src/Core/ZB.MOM.WW.OtOpcUa.Core/Authorization/TriePermissionEvaluator.cs`) returns an `AuthorizationDecision`.

-Key properties:
+⚠️ **The intended dispatch path — "calls it on every Read, Write, HistoryRead, Browse, Subscribe, AckAlarm, Call" — was never built.** `Authorize` has zero production call sites. What the dispatch path really does is in [What is enforced today](#what-is-enforced-today).

- **Driver-agnostic.** No driver-level code participates in authorization decisions. Drivers report `SecurityClassification` as metadata on tag discovery; everything else flows through the evaluator.
- **Strictly fail-closed (default-deny).** Every guard path returns `NotGranted` — a stale session (past the staleness ceiling, decision #152), a cluster mismatch between session and scope, a missing trie, a pruned bound generation, or simply no matching grant. There is no `StrictMode` / fail-open mode; absence of a grant is always a deny.
- **Evaluator stays pure.** `TriePermissionEvaluator` has no OPC UA stack dependency — it's tested directly from xUnit.
+Intended properties, of which only the last is true today:
+
+- **Driver-agnostic.** No driver-level code participates in authorization decisions. Drivers report `SecurityClassification` as metadata on tag discovery; everything else was to flow through the evaluator.
+- **Strictly fail-closed (default-deny).** Every guard path returns `NotGranted` — a stale session (past the staleness ceiling, decision #152), a cluster mismatch between session and scope, a missing trie, a pruned bound generation, or simply no matching grant. ⚠️ This describes the evaluator's *internal* behaviour when called. Because nothing calls it, **the effective posture for Read/Browse/Subscribe/HistoryRead is default-ALLOW.**
+- **Evaluator stays pure.** ✅ True — `TriePermissionEvaluator` has no OPC UA stack dependency and is tested directly from xUnit. That purity is also why it was easy to leave unwired.

 ### Full model

-See [`docs/v2/acl-design.md`](v2/acl-design.md) for the complete design: trie invalidation, flag semantics, per-path override rules, and the reasoning behind additive-only (no Deny).
+See [`docs/v2/acl-design.md`](v2/acl-design.md) for the complete design: trie invalidation, flag semantics, per-path override rules, and the reasoning behind additive-only (no Deny). Read it as a **design document for unshipped work**, not as a description of running behaviour.
+
+Note also that the `SystemPlatform` hierarchy kind named above was retired with the v3 dual-namespace address space; `NodeHierarchyKind` now has only `Equipment`.

 ### Role grant source (data-plane)

@@ -271,23 +356,25 @@ to those role strings via `GroupToRole`, e.g.:
 ```json
 "GroupToRole": {
  "ot-operators":  "WriteOperate",
-  "ot-tuners":     "WriteTune",
-  "ot-engineers":  "WriteConfigure",
-  "ot-alarm-ack":  "AlarmAck",
-  "ot-readonly":   "ReadOnly"
+  "ot-alarm-ack":  "AlarmAck"
 }
 ```

-If this mapping is absent the data-plane evaluator is strictly default-deny: inbound operator writes
-and OPC UA Part-9 alarm acknowledgement all return `BadUserAccessDenied` even for users who
-authenticate successfully. (The same requirement gates both the scripted-alarm and the native
-Galaxy-alarm Part-9 ack/confirm/shelve paths.)
+⚠️ **Only two role strings do anything.** `OpcUaDataPlaneRoles` declares exactly `WriteOperate` and
+`AlarmAck`, and those are the only values any gate compares against. `ReadOnly`, `WriteTune` and
+`WriteConfigure` appear in the permission vocabulary but **no code path reads them** — mapping a group
+to `WriteTune` grants nothing, and mapping one to `ReadOnly` restricts nothing (reads are ungated for
+everyone regardless). Earlier revisions of this document listed all five as "code-true"; that was
+wrong for three of them.

-The role strings above are **exact, case-insensitive, and code-true** — the inbound gates compare
-against the constants in `OpcUaDataPlaneRoles` (`AlarmAck`, `WriteOperate`) and the bare strings
-`ReadOnly` / `WriteTune` / `WriteConfigure`. In particular the alarm-ack role is `AlarmAck`, **not**
-`AlarmAcknowledge` (that spelling is the `PermissionFlags` ACL bit, a different vocabulary); a
-`GroupToRole` value of `AlarmAcknowledge` silently never satisfies the ack gate.
+If this mapping is absent, **writes and alarm acknowledgement** default-deny: they return
+`BadUserAccessDenied` even for users who authenticate successfully. (The same requirement gates both
+the scripted-alarm and the native Galaxy-alarm Part-9 ack/confirm/shelve paths.) **Reads, browses,
+subscribes and history reads are unaffected** — they succeed with or without any `GroupToRole` entry.
+
+The two live role strings are exact and case-insensitive. In particular the alarm-ack role is
+`AlarmAck`, **not** `AlarmAcknowledge` (that spelling is the `PermissionFlags` ACL bit, a different
+vocabulary); a `GroupToRole` value of `AlarmAcknowledge` silently never satisfies the ack gate.

 ---

@@ -1,5 +1,10 @@
 # Admin UI rebuild plan (F15)

+> ⚠️ **Historical (audited 2026-07-27) — describes the v2 AdminUI.** Several named types
+> (`AuthorizationPolicies`, `IdentificationFields`) no longer exist, and the v3 rebuild replaced the
+> per-cluster UNS/Equipment/Tags tabs with the global `/uns` page and the `/raw` project tree. Kept
+> for the record.
+
 **Status:** UX kickoff — proposals to react to before any per-page rebuild starts.
 **Last updated:** 2026-05-26 on `v2-akka-fuse`.

@@ -103,7 +103,7 @@ Message contracts are defined; actual SDK calls are stubbed (counters only). Rea

 Both have message contracts wired. Engine integration deferred:

- `HistorianAdapterActor` — named-pipe IPC to the Wonderware historian sidecar + `SqliteStoreAndForwardSink` (F11).
+- `HistorianAdapterActor` — gRPC to the `ZB.MOM.WW.HistorianGateway` sidecar (the sole historian backend; the named-pipe Wonderware sidecar is retired) + `LocalDbStoreAndForwardSink` (F11; renamed from `SqliteStoreAndForwardSink` when the buffer moved into the consolidated LocalDb).
 - `PeerOpcUaProbeActor` — real `opc.tcp://peer:4840` ping (F12). Current stub always returns `Ok=true`.

 ## DbHealthProbeActor
@@ -1,5 +1,23 @@
 # OPC UA Client Authorization (ACL Design) — OtOpcUa v2

+> ⚠️ **NEVER WIRED (verified against source 2026-07-27).** This is a design document for work that was
+> only half-built. The trie, the builder, the cache and the evaluator all exist in
+> `src/Core/ZB.MOM.WW.OtOpcUa.Core/Authorization/` and carry 30 passing unit tests — but
+> `IPermissionEvaluator.Authorize` has **zero production call sites**, nothing registers it in DI, and
+> `ZB.MOM.WW.OtOpcUa.OpcUaServer.csproj` does not reference the project it lives in. `NodeAcl` rows are
+> authorable in the Admin UI and are snapshotted into every deployment artifact, but the node side never
+> deserializes them.
+>
+> **Nothing described below is enforced.** For what actually gates OPC UA operations today, see
+> [`docs/security.md`](../security.md) § Data-Plane Authorization and
+> [`docs/ReadWriteOperations.md`](../ReadWriteOperations.md). Four blockers stand between this design
+> and a wire-up (Raw-realm nodes have no `NodeScope` representation; the session carries roles, not LDAP
+> groups; `PermissionTrieBuilder`'s `scopePaths` has no producer; no session lifecycle exists) — they
+> are recorded in `deferment.md` §3.1.
+>
+> Note also that the `SystemPlatform` hierarchy kind used throughout was retired with the v3
+> dual-namespace address space.
+>
 > **Status**: DRAFT — closes corrections-doc finding B1 (namespace / equipment-subtree ACLs not yet modeled in the data path).
 >
 > **Branch**: `v2`
@@ -1,5 +1,25 @@
 # Driver Stability & Isolation — OtOpcUa v2

+> ⚠️ **The tier assignments below are NOT what runs (verified against source 2026-07-27).**
+> **Every one of the 12 drivers runs as Tier A.** `DriverFactoryRegistry` defaults `DriverTier tier =
+> DriverTier.A` and **no factory in `src/Drivers/` passes a tier**, so nothing ever selects B or C. The
+> Galaxy and FOCAS Tier-C assignments in the table below are aspirational.
+>
+> Consequences worth knowing:
+>
+> - The **Tier-C-only protections are dormant for every driver** — `MemoryRecycle` gates on
+>   `when _tier == DriverTier.C`, and `ScheduledRecycleScheduler` refuses unless Tier C. Neither has ever
+>   engaged in production. `IDriverSupervisor` has zero implementations, yet the config parser still
+>   validates `RecycleIntervalSeconds`, so an operator can author a recycle interval that does nothing.
+> - `DriverTypeRegistry` — which this document's model implies is the tier authority — is **vestigial**:
+>   referenced only by its own test, with nothing registering metadata at startup.
+> - The **separate-Windows-service hosting** described for Tier C does not exist either. Galaxy reaches
+>   MXAccess over gRPC to the external **mxaccessgw** sidecar; the `Galaxy.Proxy`/`Host`/`Shared` pattern
+>   named below was retired in PR 7.2, and FOCAS runs in-process like everything else.
+>
+> `docs/drivers/README.md` says Tier A for Galaxy and FOCAS and is the accurate one. Keep-or-delete of the
+> tier machinery is tracked as Gitea **#522**; this document is retained as the design record.
+>
 > **Status**: DRAFT — companion to `plan.md`. Defines the stability tier model, per-driver hosting decisions, cross-cutting protections every driver process must apply, and the canonical worked example (FOCAS) for the high-risk tier.
 >
 > **Branch**: `v2`
@@ -1,5 +1,12 @@
 # Phase 7 Status — Scripting Runtime, Virtual Tags, Scripted Alarms, Historian Sink

+> ⚠️ **Historical (audited 2026-07-27) — describes the v2 codebase; do not treat its present-tense
+> claims as current.** Many named types no longer exist. Notably `:84` reports four services
+> ("Done | All four exist in `Admin/Services/`") — **none exist and there is no `Admin/Services/`
+> directory**; the `Phase7*` composition types were renamed to `AddressSpace*` by `40e8a23e`; and
+> Gaps 2/3/4 (no `/virtual-tags` page, no `/scripted-alarms` page, no script-log viewer) were closed
+> by v3's `/uns`, `/alerts` and `/script-log` surfaces. Kept for the record.
+
 > **Reconciliation date**: 2026-05-18
 > **Based on**: `docs/v2/implementation/phase-7-scripting-and-alarming.md` (the plan) and
 > `docs/v2/implementation/exit-gate-phase-7.md` (the exit-gate audit) cross-checked against
@@ -1,5 +1,13 @@
 # Redundancy Interop Playbook (Phase 6.3 Stream F — task #150)

+> ⚠️ **Historical type names (audited 2026-07-27).** The operator *procedure* below is still the
+> right one, but `RedundancyPublisherHostedService` (`:22`), `RecoveryStateManager.DwellTime` (`:67`)
+> and `RedundancyCoordinator` no longer exist — redundancy state is now published by the
+> cluster-scoped `RedundancyStateActor` singleton with `ServiceLevelCalculator` and
+> `IRedundancyRoleView`. See `docs/Redundancy.md` (which states plainly that the old types are gone)
+> and the per-cluster-mesh Phase 6/7 sections of `CLAUDE.md`. The `ServerUriArray` limitation noted
+> at `:100-105` is still open (SDK object-type gated).
+
 > **Scope**: manual validation that third-party OPC UA clients + AVEVA MXAccess
 > observe our non-transparent redundancy signals (ServiceLevel, ServerUriArray,
 > RedundancySupport) and fail over to the Backup node when the Primary drops.
@@ -1,5 +1,14 @@
 # v2 Release Readiness

+> ⚠️ **Historical (audited 2026-07-27) — a v2-era snapshot; several "Closed" rows name types that do
+> not exist in `src/`.** In particular `:41` claims ACL enforcement was "Closed 2026-04-24" via
+> `AuthorizationBootstrap` / `NodeScopeResolver` / `OpcUaServerService` — **all three have zero
+> occurrences in `src/`, and there is no per-node ACL gate on any operation** (see `deferment.md`
+> §3.1 and the banner in `docs/ReadWriteOperations.md`). `RedundancyCoordinator`,
+> `RedundancyStatePublisher`, `PeerReachabilityTracker`, `GenerationRefreshHostedService`,
+> `ClusterTopologyLoader` and `SealedBootstrap` are likewise gone. The **unchecked GA exit criteria**
+> near the end of the file are still live — see `deferment.md` §5.
+
 > **Last updated**: 2026-04-24 (Phase 5 driver complement closed — AB CIP, AB Legacy, TwinCAT, FOCAS all shipped; FOCAS Tier-C retired for a pure-managed in-process client)
 > **Status**: **RELEASE-READY (code-path)** for v2 GA. All three original code-path release blockers remain closed. Phase 5 is now complete. Remaining work is manual (live-hardware validations, client interop matrix, deployment checklist signoff, OPC UA CTT pass) + hardening follow-ups; see exit-criteria checklist below.

@@ -28,11 +37,27 @@ This doc is the single view of where v2 stands against its release criteria. Upd

 All code-path release blockers are closed. The remaining items are live-hardware / manual validations listed under exit criteria.

-### ~~Security — Phase 6.2 dispatch wiring~~ (task #143 — **CLOSED** 2026-04-19, PR #94)
+### ~~Security — Phase 6.2 dispatch wiring~~ (task #143 — marked CLOSED 2026-04-19, PR #94)
+
+> ⚠️ **THIS CLOSURE DOES NOT HOLD (re-verified against source 2026-07-27).** Every type named in this
+> subsection — `AuthorizationGate`, `NodeScopeResolver`, `AuthorizationBootstrap`, `WriteAuthzPolicy`,
+> `DriverNodeManager`, `FilterBrowseReferences`, `GateCallMethodRequests`, `MapCallOperation`,
+> `EquipmentNamespaceContent`, and the `Node:Authorization:*` config keys — has **zero occurrences in
+> `src/`**. There is no `OnReadValue` hook, no `Browse` override, no `CreateMonitoredItems` override and
+> no `Call` override in the live node manager, and no HistoryRead path consults any gate.
+>
+> Whatever landed on the v2 branch did not survive into the shipped tree. The **only** data-plane
+> authorization today is two server-wide role checks (`WriteOperate` for writes, `AlarmAck` for alarm
+> methods); reads, browses, subscriptions and history reads are ungated, and `NodeAcl` rows are
+> authored and deployed but never evaluated. See [`../security.md`](../security.md) §
+> Data-Plane Authorization and `deferment.md` §3.1.
+>
+> The text below is retained as the historical record of what was *believed* closed. **Read none of it
+> as current behaviour.**

 **Closed**. `AuthorizationGate` + `NodeScopeResolver` thread through `OpcUaApplicationHost → OtOpcUaServer → DriverNodeManager`. `OnReadValue` + `OnWriteValue` + all four HistoryRead paths call `gate.IsAllowed(identity, operation, scope)` before the invoker. Production deployments activate enforcement by constructing `OpcUaApplicationHost` with an `AuthorizationGate(StrictMode: true)` + populating the `NodeAcl` table.

-Remaining Stream C surfaces (hardening, not release-blocking):
+Remaining Stream C surfaces (hardening, not release-blocking) — **none of these shipped either**:

 - ~~Browse + TranslateBrowsePathsToNodeIds gating with ancestor-visibility logic per `acl-design.md` §Browse.~~ **Partial, 2026-04-24.** `DriverNodeManager.Browse` override post-filters the `ReferenceDescription` list via a new `FilterBrowseReferences` helper — denied nodes disappear silently per OPC UA convention. Ancestor-visibility implication (Read-grant at `Line/Tag` implying Browse on `Line`) still to ship; needs a subtree-has-any-grant query on the trie evaluator. `TranslateBrowsePathsToNodeIds` surface not yet wired.
 - ~~CreateMonitoredItems + TransferSubscriptions gating with per-item `(AuthGenerationId, MembershipVersion)` stamp so revoked grants surface `BadUserAccessDenied` within one publish cycle (decision #153).~~ **Partial, 2026-04-24.** `DriverNodeManager.CreateMonitoredItems` override pre-gates each request and pre-populates `BadUserAccessDenied` into the errors slot for denied items (the base stack honours pre-set errors and skips those items). Decision #153's per-item `(AuthGenerationId, MembershipVersion)` stamp for detecting mid-subscription revocation is still to ship — needs subscription-layer plumbing. TransferSubscriptions not yet wired (same pattern).
@@ -37,7 +37,7 @@ ssh dohertj2@10.100.0.35 'docker ps --filter label=project=lmxopcua --format "{{
  | Stack dir | Purpose |
  |---|---|
  | `/opt/otopcua-mssql` | central SQL (always-on) |
-  | `/opt/otopcua-modbus` · `/opt/otopcua-abcip` · `/opt/otopcua-s7` · `/opt/otopcua-opcuaclient` | driver fixtures |
+  | `/opt/otopcua-modbus` · `/opt/otopcua-abcip` · `/opt/otopcua-s7` · `/opt/otopcua-opcuaclient` · `/opt/otopcua-mqtt` · `/opt/otopcua-mtconnect` | driver fixtures |
  | `~/otopcua-ablegacy` · `~/otopcua-focas` | driver fixtures (user-owned) |
  | `~/otopcua-harness` | Host.IntegrationTests real-mode deps (SQL + GLAuth) — see §4 |

@@ -69,9 +69,28 @@ when it isn't running. Bring one up, `dotnet test`, tear down. Repo compose live
 | S7 | `otopcua-python-snap7` | `10.100.0.35:1102` | `docker compose --profile s7_1500 up -d` |
 | OpcUaClient | `mcr.microsoft.com/iotedge/opc-plc:2.14.10` | `opc.tcp://10.100.0.35:50000` | `docker compose up -d` |
 | FOCAS | `otopcua-focas-sim` (vendored focas-mock) | `10.100.0.35:8193` | `docker compose up -d` (stack `~/otopcua-focas`) |
+| MQTT | `eclipse-mosquitto:2.0.22` (+ a publisher sidecar) | `10.100.0.35:8883` TLS+auth · `:1883` plaintext+auth | `MQTT_FIXTURE_USERNAME=otopcua MQTT_FIXTURE_PASSWORD=<pw> docker compose up -d` (stack `/opt/otopcua-mqtt`) |
+| MQTT — Sparkplug B | `otopcua-sparkplug-sim` (project-owned C# edge-node simulator) | same broker; group **`OtOpcUaSim`**, edge nodes **`EdgeA`** / **`EdgeB`**, `EdgeA` device **`Filler1`**, ~2 s cadence | `docker compose --profile sparkplug up -d` (same stack). Answers rebirth NCMDs; restart it to force a fresh birth |
+| MTConnect | `mtconnect/agent:2.7.0.12` + `python:3.13-alpine` adapter | `http://10.100.0.35:5000` | `docker compose up -d --wait` |

 **Endpoint overrides** point a suite at a real PLC instead of the sim:
-`MODBUS_SIM_ENDPOINT` · `AB_SERVER_ENDPOINT` · `S7_SIM_ENDPOINT` · `OPCUA_SIM_ENDPOINT`.
+`MODBUS_SIM_ENDPOINT` · `AB_SERVER_ENDPOINT` · `S7_SIM_ENDPOINT` · `OPCUA_SIM_ENDPOINT` ·
+`MQTT_FIXTURE_ENDPOINT` / `MQTT_FIXTURE_PLAIN_ENDPOINT` · `MTCONNECT_AGENT_ENDPOINT`.
+
+> **MQTT needs credentials + material, unlike the other fixtures.** The broker has **no anonymous
+> fallback on either listener** (deliberate — an anonymous broker would let a bad auth config pass),
+> so it will not even start until `./gen-fixture-material.sh` has written `secrets/` (password file +
+> CA + server cert/key, gitignored) and `MQTT_FIXTURE_USERNAME`/`MQTT_FIXTURE_PASSWORD` are exported
+> at `docker compose up`. The live suite additionally wants `MQTT_FIXTURE_CA_CERT` pointing at a local
+> copy of the CA: `scp dohertj2@10.100.0.35:/opt/otopcua-mqtt/secrets/ca.crt /tmp/mqtt-fixture-ca.crt`.
+> It is also the only fixture whose services carry the `project: lmxopcua` label (see CLAUDE.md).
+
+> **MTConnect is a TWO-service stack.** The `mtconnect/agent` image ships no simulator, so a lone
+> Agent answers `/probe` and reports every observation `UNAVAILABLE` forever. The `adapter` service
+> (a stdlib SHDR feeder, `Docker/adapter.py`) is the data source; the Agent dials out to it. Its
+> suite also probes over **HTTP**, not TCP — an Agent's port accepts connections before its device
+> model is parsed. Full detail + the seeded device model:
+> [`tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md`](../tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.IntegrationTests/Docker/README.md).

 > **Fixture-cycling gotcha:** profile-gated services can share a port; a plain `docker compose down`
 > may leave a stale container bound. Force-remove before switching profiles:
@@ -29,9 +29,31 @@ public enum BrowseNodeKind
 /// <c>AlarmExtension</c> primitive). The picker pre-fills a default native-alarm <c>alarm</c> object
 /// into the TagConfig when an alarm attribute is selected. Defaults to false so non-alarm-aware
 /// drivers (e.g. the OPC UA client browser) aren't forced to flow a flag they don't produce.</param>
+/// <param name="AddressFields">
+///     The <b>structured</b> address this leaf binds by, as <c>TagConfig</c> key → value in the
+///     driver's own key vocabulary, for a driver whose address is a <i>tuple</i> rather than a single
+///     reference string. Null (the default) for every driver whose address IS the
+///     <see cref="BrowseNode.NodeId"/> — nothing changes for them.
+///     <para>
+///         It exists because a tuple cannot be recovered from an id string in general. MQTT/Sparkplug
+///         is the case in point: a browse node id is
+///         <c>{group}/{node}[/{device}]::{metric}</c>, and a metric name may itself contain <c>/</c>
+///         (<c>Node Control/Rebirth</c>) — so the session keeps the decomposition it already has and
+///         <b>states</b> it here, rather than the AdminUI's browse-commit mapper re-deriving it by
+///         splitting the id and hoping. Same discipline as the v3 address space carrying
+///         <c>AddressSpaceRealm</c> explicitly instead of parsing it out of a NodeId.
+///     </para>
+///     <para>
+///         The producer states the binding <em>shape</em> too, by which keys it emits — so a consumer
+///         never has to infer a driver's sub-mode from the tree's geometry. Consumers must read the
+///         keys they know and ignore the rest; this is a description, not a config blob to splat into
+///         a persisted TagConfig.
+///     </para>
+/// </param>
 public sealed record AttributeInfo(
    string Name,
    string DriverDataType,
    bool   IsArray,
    string SecurityClass,
-    bool   IsAlarm = false);
+    bool   IsAlarm = false,
+    IReadOnlyDictionary<string, string>? AddressFields = null);
@@ -35,3 +35,66 @@ public interface IBrowseSession : IAsyncDisposable
    /// <returns>The attributes of the node.</returns>
    Task<IReadOnlyList<AttributeInfo>> AttributesAsync(string nodeId, CancellationToken cancellationToken);
 }
+
+/// <summary>
+///     An <see cref="IBrowseSession"/> whose protocol offers an explicit, operator-triggered
+///     <b>re-announce</b> action: a request that the remote peer republish its self-description so the
+///     observation window can fill without waiting for the next natural announcement. Implemented
+///     today only by the MQTT/Sparkplug browser, whose tree is built from observed NBIRTH/DBIRTH
+///     certificates.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>This is the only interface in the browse contract that causes an outbound message.</b>
+///         Every other browse member is strictly read-only, and for the MQTT browser that read-only
+///         property is load-bearing: a picker opened by an operator runs against a live production
+///         broker. It is a separate interface, rather than an optional member on
+///         <see cref="IBrowseSession"/>, precisely so "does this session write?" stays a type
+///         question a caller cannot forget to ask.
+///     </para>
+///     <para>
+///         <b>Callers must authorize before invoking it.</b> The AdminUI routes it through
+///         <c>BrowserSessionService.RequestRebirthAsync</c>, which enforces the same
+///         <c>DriverOperator</c> policy that gates the picker's Browse affordance — an implementation
+///         cannot check that itself, since it holds no user identity.
+///     </para>
+/// </remarks>
+public interface IRebirthCapableBrowseSession : IBrowseSession
+{
+    /// <summary>
+    ///     Whether this <i>particular</i> session can actually re-announce — the runtime half of the
+    ///     type question, and the one a UI must ask before offering the affordance.
+    /// </summary>
+    /// <remarks>
+    ///     One session class may serve several protocol shapes: the MQTT browser opens the same session
+    ///     type for Plain and for Sparkplug B, and a Plain MQTT window publishes <b>nothing, ever</b> —
+    ///     there is no plain-MQTT re-announce to offer. Implementing the interface therefore means "this
+    ///     session type may re-announce"; this property means "this instance will". A UI gating on the
+    ///     type alone would draw a button that can only ever throw.
+    ///     <para>
+    ///         This is <b>not</b> an authorization signal — see the interface remarks. False here hides
+    ///         the affordance; the caller still authorizes before invoking
+    ///         <see cref="RequestRebirthAsync"/>, and the implementation still refuses a call it cannot
+    ///         serve.
+    ///     </para>
+    /// </remarks>
+    bool RebirthAvailable { get; }
+
+    /// <summary>
+    ///     Asks the addressed remote peer(s) to re-announce themselves.
+    /// </summary>
+    /// <param name="scope">
+    ///     The protocol-specific target. For Sparkplug: a browse <c>NodeId</c> from this session's own
+    ///     tree (group, edge node, device or metric — resolved up to the owning edge node), or a bare
+    ///     <c>{group}/{edgeNode}</c> pair for a node that has not been observed yet.
+    /// </param>
+    /// <param name="cancellationToken">Cancellation token for the operation.</param>
+    /// <returns>The number of request messages published.</returns>
+    /// <exception cref="ArgumentException"><paramref name="scope"/> is empty or unusable.</exception>
+    /// <exception cref="InvalidOperationException">
+    ///     The scope resolves to no target, or to more targets than the implementation will fan out to
+    ///     in one action. Nothing is published in either case.
+    /// </exception>
+    /// <exception cref="NotSupportedException">This session's mode has no re-announce action.</exception>
+    Task<int> RequestRebirthAsync(string scope, CancellationToken cancellationToken);
+}
@@ -13,6 +13,19 @@ namespace ZB.MOM.WW.OtOpcUa.Commons.Messages.Drivers;
 /// <param name="LastError">Latest error message; null when none.</param>
 /// <param name="ErrorCount5Min">Number of state-transitions into Faulted in the last 5 minutes.</param>
 /// <param name="PublishedUtc">Timestamp this snapshot was published.</param>
+/// <param name="RediscoveryNeededUtc">
+///     When the driver last raised <c>IRediscoverable.OnRediscoveryNeeded</c> — i.e. it observed that the
+///     remote's tag set may have changed (a Galaxy redeploy, a TwinCAT symbol-version bump, an MTConnect
+///     agent restart, a Sparkplug rebirth). Null when the driver has never raised it, or does not
+///     implement <c>IRediscoverable</c>.
+///     <para><b>Advisory only.</b> The served address space is NOT rebuilt in response — raw tags are
+///     authored explicitly through the <c>/raw</c> browse-commit flow. This is a prompt for an operator
+///     to re-browse the device and commit whatever changed.</para>
+/// </param>
+/// <param name="RediscoveryReason">
+///     The driver-supplied reason string from the same event (e.g. <c>"deploy-time-changed"</c>), shown
+///     to the operator alongside the prompt. Null when <paramref name="RediscoveryNeededUtc"/> is null.
+/// </param>
 public sealed record DriverHealthChanged(
    string ClusterId,
    string DriverInstanceId,
@@ -20,7 +33,9 @@ public sealed record DriverHealthChanged(
    DateTime? LastSuccessfulReadUtc,
    string? LastError,
    int ErrorCount5Min,
-    DateTime PublishedUtc)
+    DateTime PublishedUtc,
+    DateTime? RediscoveryNeededUtc = null,
+    string? RediscoveryReason = null)
 {
    /// <summary>
    ///     DPS topic name. Both the runtime <c>AkkaDriverHealthPublisher</c> and the AdminUI
@@ -68,6 +68,8 @@ message DriverHealth {
  optional string last_error = 5;                         // nullable in the record
  int32 error_count_5min = 6;
  google.protobuf.Timestamp published_utc = 7;
+  google.protobuf.Timestamp rediscovery_needed_utc = 8; // DateTime? — absent Timestamp encodes null
+  optional string rediscovery_reason = 9;               // nullable in the record
 }

 // Mirrors ZB.MOM.WW.OtOpcUa.Commons.Messages.Drivers.DriverResilienceStatusChanged.
@@ -41,9 +41,77 @@ public static class DraftValidator
        ValidateUnsEffectiveLeafUniqueness(draft, errors);
        ValidateEquipReferenceResolution(draft, errors);
        ValidateCalculationTags(draft, errors);
+        ValidateSqlConnectionStringNotPersisted(draft, errors);
        return errors;
    }

+    /// <summary>
+    ///     The <c>Sql</c> driver's "a pasted literal connection string is never persisted" guarantee, enforced
+    ///     at the deploy gate (Gitea #498).
+    /// </summary>
+    /// <remarks>
+    ///     <para>A Sql driver names its credentials indirectly — <c>connectionStringRef</c> resolves from the
+    ///     environment / secret store at Initialize — so a deployed artifact carries no database password.
+    ///     Until now that guarantee rested entirely on the <b>read</b> path: <c>SqlDriverConfigDto</c> has no
+    ///     <c>connectionString</c> property and <c>UnmappedMemberHandling.Skip</c> drops the key on
+    ///     deserialization. Nothing stopped the key being <b>written</b>. Config blobs are schemaless JSON
+    ///     columns, and the fallback authoring pattern for a driver without a typed form is a raw-JSON
+    ///     textarea, so an operator pasting <c>{"connectionString":"Server=…;Password=…"}</c> would put a live
+    ///     credential in the ConfigDb — persisted, replicated to every node's artifact cache, and readable by
+    ///     anyone with config access — while the runtime silently ignored it and the driver failed to connect.
+    ///     Discarding a secret on read is not the same as refusing to store it.</para>
+    ///     <para><b>Two of the three surfaces are checked here.</b> The third — a node's
+    ///     <see cref="ClusterNode.DriverConfigOverridesJson"/> — is not reachable from
+    ///     <see cref="DraftSnapshot"/> and is gated at its save instead (#499); see
+    ///     <see cref="SqlCredentialGuard"/> for why a deploy gate is the wrong instrument for a value that
+    ///     never enters the artifact.</para>
+    ///     <para>Checked on <b>both</b> config surfaces a Sql driver reads: the instance's
+    ///     <see cref="DriverInstance.DriverConfig"/> and the <see cref="Device.DeviceConfig"/> of every device
+    ///     beneath it, because the two are merged before the DTO sees them — a credential pasted into the
+    ///     device blob lands in exactly the same place.</para>
+    ///     <para>The key is matched <b>case-insensitively</b>: <c>System.Text.Json</c> binds
+    ///     <c>ConnectionString</c> to a <c>connectionString</c> property by default, so a case variant is the
+    ///     same key, not a different one. Only the top level is scanned — the DTO is flat, so a nested
+    ///     occurrence cannot bind and is not the credential-shaped mistake this rule exists to catch.</para>
+    ///     <para><b>The message never echoes the value.</b> Validation errors reach the AdminUI, the deploy
+    ///     log and the audit trail; repeating the offending string there would leak the very credential the
+    ///     rule is refusing to store.</para>
+    /// </remarks>
+    private static void ValidateSqlConnectionStringNotPersisted(DraftSnapshot draft, List<ValidationError> errors)
+    {
+        const string ForbiddenKey = SqlCredentialGuard.ForbiddenKey;
+
+        var sqlInstanceIds = draft.DriverInstances
+            .Where(d => string.Equals(d.DriverType, Core.Abstractions.DriverTypeNames.Sql, StringComparison.Ordinal))
+            .Select(d => d.DriverInstanceId)
+            .ToHashSet(StringComparer.Ordinal);
+        if (sqlInstanceIds.Count == 0) return;
+
+        foreach (var d in draft.DriverInstances)
+        {
+            if (!sqlInstanceIds.Contains(d.DriverInstanceId)) continue;
+            if (!SqlCredentialGuard.CarriesLiteralConnectionString(d.DriverConfig)) continue;
+            errors.Add(new("SqlConnectionStringPersisted",
+                $"Sql driver instance '{d.DriverInstanceId}' has a '{ForbiddenKey}' key in its DriverConfig. " +
+                "A Sql driver must name its credentials indirectly via 'connectionStringRef', which resolves " +
+                "from the environment / secret store at Initialize; a literal connection string here would be " +
+                "stored in the config database and replicated to every node, and the runtime ignores it anyway. " +
+                "Remove the key and set 'connectionStringRef'.",
+                d.DriverInstanceId));
+        }
+
+        foreach (var dev in draft.Devices)
+        {
+            if (!sqlInstanceIds.Contains(dev.DriverInstanceId)) continue;
+            if (!SqlCredentialGuard.CarriesLiteralConnectionString(dev.DeviceConfig)) continue;
+            errors.Add(new("SqlConnectionStringPersisted",
+                $"Device '{dev.DeviceId}' on Sql driver instance '{dev.DriverInstanceId}' has a " +
+                $"'{ForbiddenKey}' key in its DeviceConfig. DeviceConfig is merged onto DriverConfig before " +
+                "the driver reads it, so this is the same leak: use 'connectionStringRef' on the driver instead.",
+                dev.DeviceId));
+        }
+    }
+
    /// <summary>WP7 Calculation-driver deploy gates. For every tag bound to a <c>Calculation</c> driver:
    /// <list type="number">
    ///   <item><b>scriptId existence</b> — the tag's <c>TagConfig.scriptId</c> must be present and resolve to
@@ -0,0 +1,139 @@
+using System.Text.Json;
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Validation;
+
+/// <summary>
+///     The one place that decides whether a persisted config blob carries a literal Sql
+///     <c>connectionString</c> (Gitea #498 / #499).
+/// </summary>
+/// <remarks>
+///     <para>
+///         A <c>Sql</c> driver names its credentials indirectly — <c>connectionStringRef</c> resolves from
+///         the environment / secret store at Initialize — so nothing persisted should ever contain a
+///         database password. The typed <c>SqlDriverConfigDto</c> already drops a <c>connectionString</c>
+///         key on <b>read</b>, but discarding a secret on read is not the same as refusing to store it:
+///         config blobs are schemaless JSON columns authored through raw-JSON textareas, so the key can
+///         be written even though the runtime ignores it.
+///     </para>
+///     <para>
+///         There are <b>three</b> surfaces a Sql driver's config is persisted on, and they need different
+///         enforcement points:
+///         <list type="bullet">
+///             <item><c>DriverInstance.DriverConfig</c> and <c>Device.DeviceConfig</c> — both in the
+///             deployed artifact, both visible to <c>DraftSnapshot</c>, both gated by
+///             <c>DraftValidator</c>.</item>
+///             <item><c>ClusterNode.DriverConfigOverridesJson</c> — the per-node override map. It is
+///             <b>not</b> in <c>DraftSnapshot</c>, and deliberately does not go there: adding a
+///             <c>ClusterNode</c> collection would widen the snapshot (and every builder of one) for a
+///             single rule about a value that is not part of the artifact at all. More to the point, a
+///             deploy gate is the wrong instrument here — the artifact never carries node overrides, so
+///             blocking a deploy would not stop the credential being stored. It is already in the
+///             database by then. This surface is therefore gated at the <b>save</b>, which is the only
+///             point where "refuse to store it" is literally true.</item>
+///         </list>
+///     </para>
+///     <para>
+///         <b>Deliberately narrow.</b> This checks the <c>Sql</c> driver's <c>connectionString</c> key
+///         only — not a general "credential-shaped key" sweep over every driver type. A broader rule
+///         would start refusing configs that are legitimate today for drivers that never made this
+///         guarantee, turning defence-in-depth into a regression. Widen it per driver, as each driver
+///         gains an indirect-credential contract of its own.
+///     </para>
+/// </remarks>
+public static class SqlCredentialGuard
+{
+    /// <summary>The config key a Sql driver must never persist. Matched case-insensitively.</summary>
+    public const string ForbiddenKey = "connectionString";
+
+    /// <summary>
+    ///     Whether <paramref name="configJson"/> is a JSON object carrying <see cref="ForbiddenKey"/> at
+    ///     its top level.
+    /// </summary>
+    /// <remarks>
+    ///     Matched <b>case-insensitively</b>: <c>System.Text.Json</c> binds <c>ConnectionString</c> to a
+    ///     <c>connectionString</c> property by default, so a case variant is the same key, not a
+    ///     different one. Only the top level is scanned — the DTO is flat, so a nested occurrence cannot
+    ///     bind and is not the credential-shaped mistake this exists to catch.
+    /// </remarks>
+    /// <param name="configJson">The config blob to inspect.</param>
+    /// <returns><see langword="true"/> when the key is present at the top level.</returns>
+    public static bool CarriesLiteralConnectionString(string? configJson)
+    {
+        if (string.IsNullOrWhiteSpace(configJson)) return false;
+        try
+        {
+            using var doc = JsonDocument.Parse(configJson);
+            return doc.RootElement.ValueKind == JsonValueKind.Object
+                   && HasTopLevelKey(doc.RootElement, ForbiddenKey);
+        }
+        catch (JsonException)
+        {
+            // A malformed blob simply has no keys. Shaping the config JSON is another rule's job, and
+            // throwing here would turn a formatting mistake into a credential-guard failure.
+            return false;
+        }
+    }
+
+    /// <summary>
+    ///     The <c>DriverInstanceId</c>s in a <c>ClusterNode.DriverConfigOverridesJson</c> map whose
+    ///     override object carries a literal connection string, restricted to instances that are actually
+    ///     Sql drivers.
+    /// </summary>
+    /// <remarks>
+    ///     The override map is shaped <c>{ "&lt;DriverInstanceId&gt;": { …driver config keys… } }</c> and is
+    ///     merged onto the cluster-level <c>DriverConfig</c>, so a credential pasted into one lands in
+    ///     exactly the place <see cref="CarriesLiteralConnectionString"/> already refuses on the driver
+    ///     itself.
+    /// </remarks>
+    /// <param name="overridesJson">The node's override map. Null / blank / malformed yields no
+    /// violations.</param>
+    /// <param name="sqlDriverInstanceIds">The ids of driver instances whose <c>DriverType</c> is
+    /// <c>Sql</c>. Keys outside this set are ignored — a non-Sql driver never made the indirect-credential
+    /// guarantee, so flagging it would be a regression, not defence in depth.</param>
+    /// <returns>The offending driver-instance ids, in document order; empty when there are none.</returns>
+    public static IReadOnlyList<string> FindNodeOverrideViolations(
+        string? overridesJson, IReadOnlyCollection<string> sqlDriverInstanceIds)
+    {
+        if (string.IsNullOrWhiteSpace(overridesJson) || sqlDriverInstanceIds.Count == 0)
+        {
+            return [];
+        }
+
+        var sqlIds = sqlDriverInstanceIds as IReadOnlySet<string>
+                     ?? sqlDriverInstanceIds.ToHashSet(StringComparer.Ordinal);
+
+        try
+        {
+            using var doc = JsonDocument.Parse(overridesJson);
+            if (doc.RootElement.ValueKind != JsonValueKind.Object) return [];
+
+            List<string>? offenders = null;
+            foreach (var entry in doc.RootElement.EnumerateObject())
+            {
+                if (!sqlIds.Contains(entry.Name)) continue;
+                if (entry.Value.ValueKind != JsonValueKind.Object) continue;
+                if (!HasTopLevelKey(entry.Value, ForbiddenKey)) continue;
+
+                (offenders ??= []).Add(entry.Name);
+            }
+
+            return (IReadOnlyList<string>?)offenders ?? [];
+        }
+        catch (JsonException)
+        {
+            return [];
+        }
+    }
+
+    /// <summary>Whether <paramref name="obj"/> carries <paramref name="key"/> at its top level,
+    /// case-insensitively.</summary>
+    private static bool HasTopLevelKey(JsonElement obj, string key)
+    {
+        foreach (var property in obj.EnumerateObject())
+        {
+            if (string.Equals(property.Name, key, StringComparison.OrdinalIgnoreCase)) return true;
+        }
+
+        return false;
+    }
+}
@@ -19,9 +19,9 @@ namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 ///     (<c>DriverTypeNamesGuardTests</c>) asserts bidirectional parity between these
 ///     constants and the set the driver factories actually register, so a rename on
 ///     either side breaks the build's test gate. Only constants for
-///     <b>currently-registered</b> factories belong here — a not-yet-registered driver
-///     (e.g. the Calculation driver landing in a later Batch 2 package) adds its own
-///     constant when its factory is wired in.
+///     <b>currently-registered</b> factories belong here — a driver adds its own constant
+///     when its factory is wired in. (This used to name Calculation as the example of a
+///     not-yet-registered driver; it registers in <c>DriverFactoryBootstrap</c> like the rest.)
 ///     </para>
 /// </remarks>
 public static class DriverTypeNames
@@ -53,6 +53,14 @@ public static class DriverTypeNames
    /// <summary>Calculation pseudo-driver — tags computed by C# scripts over other tags' live values.</summary>
    public const string Calculation = "Calculation";

+    /// <summary>Read-only SQL Server table/view poller — publishes columns as OPC UA variables.</summary>
+    public const string Sql = "Sql";
+    /// <summary>MQTT / Sparkplug B broker-subscription driver.</summary>
+    public const string Mqtt = "Mqtt";
+
+    /// <summary>MTConnect Agent driver — read-only HTTP/XML over an Agent's probe/current/sample surface.</summary>
+    public const string MTConnect = "MTConnect";
+
    /// <summary>
    ///     Every driver-type string declared above, for callers that need to enumerate
    ///     the full set (e.g. validation of an authored <c>DriverType</c>).
@@ -68,5 +76,8 @@ public static class DriverTypeNames
        OpcUaClient,
        Galaxy,
        Calculation,
+        Sql,
+        Mqtt,
+        MTConnect,
    ];
 }
@@ -15,11 +15,20 @@ public interface IDriverHealthPublisher
    /// <param name="driverInstanceId">The driver instance the snapshot describes.</param>
    /// <param name="health">The current health snapshot.</param>
    /// <param name="errorCount5Min">The number of errors observed in the trailing 5-minute window.</param>
+    /// <param name="rediscoveryNeededUtc">
+    ///     When the driver last raised <see cref="IRediscoverable.OnRediscoveryNeeded"/>, or null if never
+    ///     (or if it is not an <see cref="IRediscoverable"/>). Advisory: it prompts an operator to
+    ///     re-browse, and never rebuilds the served address space.
+    /// </param>
+    /// <param name="rediscoveryReason">The driver-supplied reason from that event; null when
+    ///     <paramref name="rediscoveryNeededUtc"/> is null.</param>
    void Publish(
        string clusterId,
        string driverInstanceId,
        DriverHealth health,
-        int errorCount5Min);
+        int errorCount5Min,
+        DateTime? rediscoveryNeededUtc = null,
+        string? rediscoveryReason = null);
 }

 /// <summary>
@@ -38,6 +47,8 @@ public sealed class NullDriverHealthPublisher : IDriverHealthPublisher
        string clusterId,
        string driverInstanceId,
        DriverHealth health,
-        int errorCount5Min)
+        int errorCount5Min,
+        DateTime? rediscoveryNeededUtc = null,
+        string? rediscoveryReason = null)
    { /* no-op */ }
 }
@@ -334,6 +334,48 @@ public sealed class ScriptedAlarmEngine : IDisposable
    public IReadOnlyCollection<AlarmConditionState> GetAllStates()
        => _alarms.Values.Select(a => a.Condition).ToArray();

+    /// <summary>
+    ///     #487 — the currently-held condition of every loaded alarm, packaged with the definition's
+    ///     severity, the rendered message template and the last-observed input quality, i.e. everything
+    ///     a caller needs to <b>project</b> the alarm onto an OPC UA condition node without waiting for
+    ///     the next transition.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         <b>This is a read, not an emission.</b> It deliberately returns a distinct type rather
+    ///         than a <see cref="ScriptedAlarmEvent"/>, and it never touches <see cref="OnEvent"/>. A
+    ///         still-active alarm produces <see cref="EmissionKind.None"/> at load (there is no
+    ///         transition to report), so the transition stream cannot carry the current state — that is
+    ///         exactly why the caller needs this. Routing these through the emission path instead would
+    ///         append a duplicate historian / <c>alerts</c> row on every deploy, so the shape here is
+    ///         intentionally one the emission machinery cannot consume.
+    ///     </para>
+    ///     <para>
+    ///         <b>Synchronization.</b> Reads <c>_alarms</c> and <c>_valueCache</c> — both
+    ///         <see cref="ConcurrentDictionary{TKey, TValue}"/> — without taking <c>_evalGate</c>, the
+    ///         same posture as <see cref="GetState"/> / <see cref="GetAllStates"/>. Each projection is
+    ///         individually coherent; the set as a whole is not an atomic snapshot across a concurrent
+    ///         re-evaluation. That is sufficient for the node-projection use: an evaluation racing this
+    ///         read publishes its own transition through the normal path.
+    ///     </para>
+    /// </remarks>
+    /// <returns>One projection per loaded alarm; empty before the first <see cref="LoadAsync"/>.</returns>
+    public IReadOnlyList<ScriptedAlarmProjection> GetProjections()
+    {
+        var projections = new List<ScriptedAlarmProjection>(_alarms.Count);
+        foreach (var (alarmId, state) in _alarms)
+        {
+            projections.Add(new ScriptedAlarmProjection(
+                AlarmId: alarmId,
+                Severity: state.Definition.Severity,
+                Message: MessageTemplate.Resolve(state.Definition.MessageTemplate, TryLookup),
+                Condition: state.Condition,
+                WorstInputStatusCode: LastWorstStatus(alarmId)));
+        }
+
+        return projections;
+    }
+
    /// <summary>Acknowledges the specified alarm on behalf of the given user.</summary>
    /// <param name="alarmId">The alarm identifier.</param>
    /// <param name="user">The user performing the acknowledgment.</param>
@@ -974,6 +1016,26 @@ public sealed record ScriptedAlarmEvent(
    // the top-2 severity bits. Default 0u == Good keeps every existing constructor call unchanged.
    uint WorstInputStatusCode = 0u);

+/// <summary>
+///     #487 — a loaded alarm's current condition, ready to be projected onto its OPC UA node.
+///     Produced by <see cref="ScriptedAlarmEngine.GetProjections"/> on demand; it is <b>not</b> an
+///     emission and never travels the <see cref="ScriptedAlarmEngine.OnEvent"/> path, so it can never
+///     become an <c>alerts</c> row or a historian record. Deliberately a separate type from
+///     <see cref="ScriptedAlarmEvent"/> — it carries no <see cref="EmissionKind"/>, so there is nothing
+///     for a future refactor to mistake for a transition.
+/// </summary>
+/// <param name="AlarmId">The alarm identifier (also its OPC UA condition NodeId).</param>
+/// <param name="Severity">The definition's severity bucket.</param>
+/// <param name="Message">The message template resolved against the current value cache.</param>
+/// <param name="Condition">The Part 9 condition state the engine currently holds.</param>
+/// <param name="WorstInputStatusCode">The last-observed worst OPC UA StatusCode across the alarm's inputs.</param>
+public sealed record ScriptedAlarmProjection(
+    string AlarmId,
+    AlarmSeverity Severity,
+    string Message,
+    AlarmConditionState Condition,
+    uint WorstInputStatusCode);
+
 /// <summary>
 ///     Upstream source abstraction — intentionally identical shape to the virtual-tag
 ///     engine's so Stream G can compose them behind one driver bridge.
@@ -35,7 +35,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;
 public static class AbCipStatusMapper
 {
    public const uint Good = 0u;
-    public const uint GoodMoreData = 0x00A70000u;
+    public const uint GoodMoreData = 0x00A60000u;
    public const uint BadInternalError = 0x80020000u;
    public const uint BadNodeIdUnknown = 0x80340000u;
    public const uint BadNotWritable = 0x803B0000u;
@@ -44,7 +44,7 @@ public static class AbCipStatusMapper
    public const uint BadDeviceFailure = 0x808B0000u;
    public const uint BadCommunicationError = 0x80050000u;
    public const uint BadTimeout = 0x800A0000u;
-    public const uint BadTypeMismatch = 0x80730000u;
+    public const uint BadTypeMismatch = 0x80740000u;

    /// <summary>Map a CIP general-status byte to an OPC UA StatusCode.</summary>
    /// <param name="status">The CIP general-status byte value.</param>
@@ -13,7 +13,9 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy;
 public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscovery, ISubscribable,
    IHostConnectivityProbe, IPerCallHostResolver, IDisposable, IAsyncDisposable
 {
-    private readonly AbLegacyDriverOptions _options;
+    /// <summary>Mutable so <see cref="InitializeAsync"/> can adopt a re-parsed config on reinitialize
+    /// (#516). Only ever written on the init path, before any reader/session uses it.</summary>
+    private AbLegacyDriverOptions _options;
    private readonly string _driverInstanceId;
    private readonly IAbLegacyTagFactory _tagFactory;
    private readonly ILogger<AbLegacyDriver> _logger;
@@ -94,12 +96,28 @@ public sealed class AbLegacyDriver : IDriver, IReadable, IWritable, ITagDiscover
    /// <inheritdoc />
    public string DriverType => "AbLegacy";

+    /// <summary>True when the supplied DriverConfig JSON carries a real body. The bootstrapper always
+    /// passes a populated document; some unit tests pass <c>"{}"</c> or an empty string to exercise
+    /// lifecycle shape without a config — those keep the constructor-supplied options.</summary>
+    private static bool HasConfigBody(string? driverConfigJson)
+    {
+        if (string.IsNullOrWhiteSpace(driverConfigJson)) return false;
+        var trimmed = driverConfigJson.Trim();
+        return trimmed is not "{}" and not "[]";
+    }
+
    /// <inheritdoc />
    public Task InitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
    {
        _health = new DriverHealth(DriverState.Initializing, null, null);
        try
        {
+            // #516: re-parse the supplied DriverConfig so a config change delivered through the IDriver
+            // contract is honoured. Without this the driver keeps serving the options it was CONSTRUCTED
+            // with, so an operator's edit is discarded while the deployment still seals green.
+            if (HasConfigBody(driverConfigJson))
+                _options = AbLegacyDriverFactoryExtensions.ParseOptions(_driverInstanceId, driverConfigJson);
+
            foreach (var device in _options.Devices)
            {
                var addr = AbLegacyHostAddress.TryParse(device.HostAddress)
@@ -49,6 +49,23 @@ public static class AbLegacyDriverFactoryExtensions
    /// <param name="loggerFactory">Optional logger factory for the driver instance.</param>
    /// <returns>A configured <see cref="AbLegacyDriver"/> instance.</returns>
    internal static AbLegacyDriver CreateInstance(string driverInstanceId, string driverConfigJson, ILoggerFactory? loggerFactory)
+    {
+        return new AbLegacyDriver(
+            ParseOptions(driverInstanceId, driverConfigJson), driverInstanceId,
+            tagFactory: null,
+            logger: loggerFactory?.CreateLogger<AbLegacyDriver>());
+    }
+
+    /// <summary>
+    ///     Parses an AB Legacy <c>DriverConfig</c> JSON document into typed options. Extracted so
+    ///     <see cref="AbLegacyDriver.InitializeAsync"/> can re-parse a CHANGED config on reinitialize
+    ///     (Gitea #516) instead of serving the options it was constructed with — which silently discarded
+    ///     every operator edit while the deployment still sealed green.
+    /// </summary>
+    /// <param name="driverInstanceId">The unique driver instance identifier.</param>
+    /// <param name="driverConfigJson">The driver configuration as a JSON string.</param>
+    /// <returns>The parsed <see cref="AbLegacyDriverOptions"/>.</returns>
+    internal static AbLegacyDriverOptions ParseOptions(string driverInstanceId, string driverConfigJson)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
        ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);
@@ -82,10 +99,7 @@ public static class AbLegacyDriverFactoryExtensions
            Timeout = PositiveTimeoutOrDefault(dto.TimeoutMs, 2_000),
        };

-        return new AbLegacyDriver(
-            options, driverInstanceId,
-            tagFactory: null,
-            logger: loggerFactory?.CreateLogger<AbLegacyDriver>());
+        return options;
    }

    /// <summary>
@@ -10,7 +10,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.AbLegacy;
 public static class AbLegacyStatusMapper
 {
    public const uint Good = 0u;
-    public const uint GoodMoreData = 0x00A70000u;
+    public const uint GoodMoreData = 0x00A60000u;
    public const uint BadInternalError = 0x80020000u;
    public const uint BadNodeIdUnknown = 0x80340000u;
    public const uint BadNotWritable = 0x803B0000u;
@@ -19,7 +19,7 @@ public static class AbLegacyStatusMapper
    public const uint BadDeviceFailure = 0x808B0000u;
    public const uint BadCommunicationError = 0x80050000u;
    public const uint BadTimeout = 0x800A0000u;
-    public const uint BadTypeMismatch = 0x80730000u;
+    public const uint BadTypeMismatch = 0x80740000u;

    /// <summary>
    ///     Map a libplctag return/status code to an OPC UA StatusCode. The integer passed here
@@ -100,7 +100,19 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
    /// <inheritdoc />
    public string DriverType => "FOCAS";

-    /// <inheritdoc />
+    /// <summary>
+    ///     Opens the configured CNC handles and builds the authored tag table.
+    ///     <para><paramref name="driverConfigJson"/> is deliberately <b>not</b> re-parsed here, unlike
+    ///     Modbus / AbLegacy / OpcUaClient (Gitea #516). This driver builds more than options from config —
+    ///     its <c>IFocasClientFactory</c> is selected from the <c>Backend</c> key and injected at
+    ///     construction — so adopting a new <c>FocasDriverOptions</c> alone would run a NEW device/tag set
+    ///     against the OLD backend. Half a re-parse is worse than none.</para>
+    ///     <para>A config change is covered by the stop + respawn in <c>DriverSpawnPlanner</c>, which
+    ///     rebuilds options and backend together through the factory.</para>
+    /// </summary>
+    /// <param name="driverConfigJson">The driver configuration JSON (see remarks — not re-parsed).</param>
+    /// <param name="cancellationToken">Cancellation token for the operation.</param>
+    /// <returns>A completed task.</returns>
    public Task InitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
    {
        Volatile.Write(ref _health, new DriverHealth(DriverState.Initializing, null, null));
@@ -17,7 +17,7 @@ public static class FocasStatusMapper
    public const uint BadDeviceFailure = 0x808B0000u;
    public const uint BadCommunicationError = 0x80050000u;
    public const uint BadTimeout = 0x800A0000u;
-    public const uint BadTypeMismatch = 0x80730000u;
+    public const uint BadTypeMismatch = 0x80740000u;

    /// <summary>
    ///     Map common FWLIB <c>EW_*</c> return codes. The values below match Fanuc's published
@@ -856,7 +856,7 @@ public sealed class GalaxyDriver
            {
                rejectedTcs.TrySetResult(new DataValueSnapshot(
                    Value: null,
-                    StatusCode: 0x80000000u, // Bad
+                    StatusCode: StatusCodeMap.Bad,
                    SourceTimestampUtc: null,
                    ServerTimestampUtc: DateTime.UtcNow));
            }
@@ -875,7 +875,7 @@ public sealed class GalaxyDriver
                {
                    tcs.TrySetResult(new DataValueSnapshot(
                        Value: null,
-                        StatusCode: 0x800B0000u, // BadTimeout
+                        StatusCode: StatusCodeMap.BadTimeout,
                        SourceTimestampUtc: null,
                        ServerTimestampUtc: DateTime.UtcNow));
                }
@@ -26,14 +26,23 @@ internal static class StatusCodeMap
 {
    // OPC UA Part 4 standard StatusCodes — top-byte categories are 0x00 (Good),
    // 0x40 (Uncertain), 0x80 (Bad). Specific codes layer onto the category byte.
+    //
+    // The substatus nibbles are NOT derivable from the OPC DA quality byte this mapper consumes —
+    // they are an unrelated OPC UA enumeration and have to be looked up. Five constants here were
+    // originally written as though the DA byte could be shifted into the substatus position, which
+    // produced values naming entirely different UA codes (Gitea #497): UncertainLastUsableValue held
+    // UncertainDataSubNormal's value, UncertainSubNormal held UncertainNoCommunicationLastUsableValue's,
+    // and GoodLocalOverride / UncertainSensorNotAccurate / UncertainEngineeringUnitsExceeded held values
+    // that are not OPC UA status codes at all. StatusCodeParityTests now checks every constant below
+    // against the pinned SDK's Opc.Ua.StatusCodes.

    public const uint Good                            = 0x00000000u;
-    public const uint GoodLocalOverride               = 0x00D80000u;
+    public const uint GoodLocalOverride               = 0x00960000u;
    public const uint Uncertain                       = 0x40000000u;
-    public const uint UncertainLastUsableValue        = 0x40A40000u;
-    public const uint UncertainSensorNotAccurate      = 0x408D0000u;
-    public const uint UncertainEngineeringUnitsExceeded = 0x408E0000u;
-    public const uint UncertainSubNormal              = 0x408F0000u;
+    public const uint UncertainLastUsableValue        = 0x40900000u;
+    public const uint UncertainSensorNotAccurate      = 0x40930000u;
+    public const uint UncertainEngineeringUnitsExceeded = 0x40940000u;
+    public const uint UncertainSubNormal              = 0x40950000u;
    public const uint Bad                             = 0x80000000u;
    public const uint BadConfigurationError           = 0x80890000u;
    public const uint BadNotConnected                 = 0x808A0000u;
@@ -44,6 +53,14 @@ internal static class StatusCodeMap
    public const uint BadWaitingForInitialData        = 0x80320000u;
    public const uint BadInternalError                = 0x80020000u;

+    /// <summary>
+    ///     Fills a still-pending read when the caller's token fires before the gateway answers. Named here
+    ///     rather than written inline at the call site so <c>StatusCodeParityTests</c> can reflect over it —
+    ///     an inline literal is invisible to that guard, which is exactly how this constant spent its life
+    ///     as <c>0x800B0000</c> (<c>BadServiceUnsupported</c>) under a <c>// BadTimeout</c> comment.
+    /// </summary>
+    public const uint BadTimeout                      = 0x800A0000u;
+
    /// <summary>
    ///     Map a raw OPC DA quality byte (the low byte of an OPC DA <c>OpcQuality</c> ushort,
    ///     which is what Wonderware Historian + MXAccess surface as <c>OPCITEMSTATE.qLong</c>'s
@@ -18,29 +18,29 @@ internal static class GatewayQualityMapper
    public static uint Map(byte q) => q switch
    {
        // Good family (192+)
-        192 => 0x00000000u,             // Good
-        216 => 0x00D80000u,             // Good_LocalOverride
+        192 => HistorianStatusCodes.Good,
+        216 => HistorianStatusCodes.GoodLocalOverride,

        // Uncertain family (64-191)
-        64 => 0x40000000u,              // Uncertain
-        68 => 0x40900000u,              // Uncertain_LastUsableValue
-        80 => 0x40930000u,              // Uncertain_SensorNotAccurate
-        84 => 0x40940000u,              // Uncertain_EngineeringUnitsExceeded
-        88 => 0x40950000u,              // Uncertain_SubNormal
+        64 => HistorianStatusCodes.Uncertain,
+        68 => HistorianStatusCodes.UncertainLastUsableValue,
+        80 => HistorianStatusCodes.UncertainSensorNotAccurate,
+        84 => HistorianStatusCodes.UncertainEngineeringUnitsExceeded,
+        88 => HistorianStatusCodes.UncertainSubNormal,

        // Bad family (0-63)
-        0 => 0x80000000u,               // Bad
-        4 => 0x80890000u,               // Bad_ConfigurationError
-        8 => 0x808A0000u,               // Bad_NotConnected
-        12 => 0x808B0000u,              // Bad_DeviceFailure
-        16 => 0x808C0000u,              // Bad_SensorFailure
-        20 => 0x80050000u,              // Bad_CommunicationError
-        24 => 0x808D0000u,              // Bad_OutOfService
-        32 => 0x80320000u,              // Bad_WaitingForInitialData
+        0 => HistorianStatusCodes.Bad,
+        4 => HistorianStatusCodes.BadConfigurationError,
+        8 => HistorianStatusCodes.BadNotConnected,
+        12 => HistorianStatusCodes.BadDeviceFailure,
+        16 => HistorianStatusCodes.BadSensorFailure,
+        20 => HistorianStatusCodes.BadCommunicationError,
+        24 => HistorianStatusCodes.BadOutOfService,
+        32 => HistorianStatusCodes.BadWaitingForInitialData,

        // Unknown — fall back to category bucket so callers still get something usable.
-        _ when q >= 192 => 0x00000000u,
-        _ when q >= 64 => 0x40000000u,
-        _ => 0x80000000u,
+        _ when q >= 192 => HistorianStatusCodes.Good,
+        _ when q >= 64 => HistorianStatusCodes.Uncertain,
+        _ => HistorianStatusCodes.Bad,
    };
 }
@@ -0,0 +1,75 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Mapping;
+
+/// <summary>
+///     The OPC UA status codes this driver publishes, as named constants.
+/// </summary>
+/// <remarks>
+///     <para>The driver layer is deliberately free of an OPC UA SDK reference, so status codes are spelled
+///     as bare <c>uint</c>s. The cost of that is a value nobody checks against the name it is written
+///     under — the defect class Gitea #497 found in six places across four drivers, one of them the
+///     <c>BadNoData</c> in <see cref="SampleMapper"/> that was really <c>BadServerHalted</c>.</para>
+///     <para><b>Named, not inline, on purpose.</b> <c>StatusCodeParityTests</c> guards these by reflecting
+///     over <c>const uint</c> fields and comparing each against <c>Opc.Ua.StatusCodes</c> in the pinned SDK.
+///     A literal written at a call site is invisible to that guard, which is exactly how
+///     <see cref="GatewayQualityMapper"/> kept an incorrect <c>Good_LocalOverride</c> through every test it
+///     had. Add a constant here rather than a literal in a <c>switch</c> arm.</para>
+/// </remarks>
+internal static class HistorianStatusCodes
+{
+    // ---- Good family ----
+
+    /// <summary>The value is good; no qualification.</summary>
+    public const uint Good = 0x00000000u;
+
+    /// <summary>The value has been overridden locally (OPC DA quality 216).</summary>
+    public const uint GoodLocalOverride = 0x00960000u;
+
+    // ---- Uncertain family ----
+
+    /// <summary>The value is uncertain; no specific reason.</summary>
+    public const uint Uncertain = 0x40000000u;
+
+    /// <summary>Communication has failed; the last known value is returned (OPC DA quality 68).</summary>
+    public const uint UncertainLastUsableValue = 0x40900000u;
+
+    /// <summary>The sensor is known not to be accurate (OPC DA quality 80).</summary>
+    public const uint UncertainSensorNotAccurate = 0x40930000u;
+
+    /// <summary>The value is outside the engineering-unit range for the sensor (OPC DA quality 84).</summary>
+    public const uint UncertainEngineeringUnitsExceeded = 0x40940000u;
+
+    /// <summary>The value is derived from fewer sources than required (OPC DA quality 88).</summary>
+    public const uint UncertainSubNormal = 0x40950000u;
+
+    // ---- Bad family ----
+
+    /// <summary>The value is bad; no specific reason.</summary>
+    public const uint Bad = 0x80000000u;
+
+    /// <summary>A configuration problem prevents the value being produced (OPC DA quality 4).</summary>
+    public const uint BadConfigurationError = 0x80890000u;
+
+    /// <summary>The source is not connected (OPC DA quality 8).</summary>
+    public const uint BadNotConnected = 0x808A0000u;
+
+    /// <summary>The device reported a failure (OPC DA quality 12).</summary>
+    public const uint BadDeviceFailure = 0x808B0000u;
+
+    /// <summary>The sensor reported a failure (OPC DA quality 16).</summary>
+    public const uint BadSensorFailure = 0x808C0000u;
+
+    /// <summary>Communication with the source failed (OPC DA quality 20).</summary>
+    public const uint BadCommunicationError = 0x80050000u;
+
+    /// <summary>The source is out of service (OPC DA quality 24).</summary>
+    public const uint BadOutOfService = 0x808D0000u;
+
+    /// <summary>No initial value has arrived from the source yet (OPC DA quality 32).</summary>
+    public const uint BadWaitingForInitialData = 0x80320000u;
+
+    /// <summary>
+    ///     The historian returned no data for the requested tag/interval. Distinct from a transport
+    ///     failure: the query succeeded and the answer was empty.
+    /// </summary>
+    public const uint BadNoData = 0x809B0000u;
+}
@@ -10,8 +10,8 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Mapping;
 /// </summary>
 internal static class SampleMapper
 {
-    private const uint StatusGood = 0x00000000u;
-    private const uint StatusBadNoData = 0x800E0000u;
+    private const uint StatusGood = HistorianStatusCodes.Good;
+    private const uint StatusBadNoData = HistorianStatusCodes.BadNoData;

    /// <summary>OPC DA "Good" family floor — a quality byte at/above this carries usable data.</summary>
    private const byte GoodQualityFloor = 192;
@@ -0,0 +1,266 @@
+using System.Collections.Frozen;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     The type shape inferred for a single MTConnect <c>DataItem</c>: the scalar
+///     <see cref="DriverDataType" /> plus the array shape that
+///     <see cref="DriverAttributeInfo.IsArray" /> / <see cref="DriverAttributeInfo.ArrayDim" />
+///     expect. Returned by value (a readonly record struct) so the discovery loop and the
+///     AdminUI editor can call the inference on a hot path without allocating.
+/// </summary>
+/// <param name="DataType">The scalar element type of the observation.</param>
+/// <param name="IsArray">
+///     <c>true</c> only for a <c>SAMPLE</c> declared <c>representation="TIME_SERIES"</c>, whose
+///     observation carries a vector of samples rather than a single value.
+/// </param>
+/// <param name="ArrayDim">
+///     The probe-declared array length when <see cref="IsArray" /> is <c>true</c> and the device
+///     model declared a positive <c>sampleCount</c>; <c>null</c> for a variable-length series
+///     (many agents omit <c>sampleCount</c>) and always <c>null</c> for a scalar.
+/// </param>
+public readonly record struct MTConnectInferredType(DriverDataType DataType, bool IsArray, uint? ArrayDim);
+
+/// <summary>
+///     Translates an MTConnect <c>DataItem</c>'s device-model metadata (category / type / units /
+///     representation) into the server's <see cref="DriverDataType" />. Pure and deterministic —
+///     no I/O, no logging, no mutable state.
+/// </summary>
+/// <remarks>
+///     <para>
+///         This lives in <c>.Contracts</c> because three call sites must agree byte-for-byte, or a
+///         tag's OPC UA type stops matching its authored config: <c>ITagDiscovery.DiscoverAsync</c>
+///         (stamps <see cref="DriverAttributeInfo.DriverDataType" /> on every browsed leaf), the
+///         universal browser's commit path (writes the browsed leaf into <c>TagConfig</c>), and the
+///         AdminUI typed tag editor (shows the inferred type and offers an override).
+///     </para>
+///     <para>
+///         <b>MTConnect is weakly typed on the wire</b> — every observation is text, and the standard
+///         defines hundreds of <c>type</c> values with more added each revision. This is therefore a
+///         <i>rule</i>, not an enumeration, and the result is stored per tag and author-overridable.
+///         The rule is asymmetric on purpose: a wrong <i>numeric</i> guess produces a value that
+///         fails to parse and surfaces as Bad quality at runtime, whereas <see cref="DriverDataType.String" />
+///         always round-trips and the author can retype it. So every default leans to
+///         <c>String</c> except where the standard itself guarantees a number.
+///     </para>
+///     <para>
+///         <b>Defaulting rule, per category</b> (design §3.3):
+///     </para>
+///     <list type="bullet">
+///         <item>
+///             <description>
+///                 <c>SAMPLE</c> ⇒ <see cref="DriverDataType.Float64" />, <i>including for an
+///                 unrecognised or missing <c>type</c></i>. The standard defines the whole SAMPLE
+///                 category as a continuously-varying measured quantity, so the category alone is
+///                 the guarantee — a missing <c>units</c> attribute is a gap in the device model,
+///                 not evidence that the observation is text. <c>Float64</c> rather than an integer
+///                 type because a double parse accepts both <c>3</c> and <c>3.5</c>.
+///             </description>
+///         </item>
+///         <item>
+///             <description>
+///                 <c>EVENT</c> ⇒ <see cref="DriverDataType.String" /> by default, with a small
+///                 exception list (<see cref="NumericEventTypes" />) of standard types that are
+///                 defined as integers. The overwhelming majority of EVENT types are controlled
+///                 vocabulary (<c>Execution</c>, <c>ControllerMode</c>, <c>Availability</c>) or free
+///                 text (<c>Program</c>, <c>Block</c>, <c>Message</c>), and the exception list is
+///                 deliberately short — each entry is a coercion risk, while every omission is
+///                 merely a string the author can retype.
+///             </description>
+///         </item>
+///         <item>
+///             <description>
+///                 <c>CONDITION</c> ⇒ <see cref="DriverDataType.String" /> always. The observation
+///                 is a state word (<c>Normal</c> / <c>Warning</c> / <c>Fault</c> /
+///                 <c>Unavailable</c>), never a number, regardless of the item's <c>type</c>.
+///             </description>
+///         </item>
+///         <item>
+///             <description>
+///                 An <b>unknown, blank, or missing category</b> ⇒ <see cref="DriverDataType.String" />.
+///                 Probe XML in the wild is inconsistent; with no category we have no evidence the
+///                 observation is numeric, so we pick the type that cannot fail to parse.
+///             </description>
+///         </item>
+///     </list>
+///     <para>
+///         Representation overrides the category where the two disagree about shape:
+///         <c>DATA_SET</c> / <c>TABLE</c> observations are key-value maps, so they demote to
+///         <see cref="DriverDataType.String" /> even on a <c>SAMPLE</c>; <c>TIME_SERIES</c> is
+///         defined only for <c>SAMPLE</c> and is ignored (not treated as an array) elsewhere;
+///         <c>DISCRETE</c> and <c>VALUE</c> are scalar and change nothing.
+///     </para>
+///     <para>
+///         <b>Matching is case-insensitive AND separator-insensitive</b> on every input —
+///         <c>_</c>, <c>-</c> and whitespace are ignored wherever they appear, so
+///         <c>PART_COUNT</c> ≡ <c>PartCount</c> ≡ <c>part-count</c> ≡ <c>partcount</c>. This is not
+///         mere leniency: <b>MTConnect spells the same concept two different ways in two different
+///         documents</b>. The Devices document (<c>/probe</c>) writes <c>DataItem@type</c> in
+///         UPPER_SNAKE (<c>PART_COUNT</c>, <c>POSITION</c>, <c>PATH_FEEDRATE</c>), while the Streams
+///         documents (<c>/current</c>, <c>/sample</c>) name the observation element in PascalCase
+///         (<c>PartCount</c>, <c>Position</c>). Discovery reads the <i>probe</i> spelling, and plain
+///         case-insensitivity does not bridge the underscore — so matching only the PascalCase
+///         spelling types every real agent's <c>PART_COUNT</c> as <see cref="DriverDataType.String" />
+///         while every unit test using the sketch's PascalCase spelling stays green.
+///     </para>
+/// </remarks>
+public static class MTConnectDataTypeInference
+{
+    private const string CategorySample = "SAMPLE";
+    private const string CategoryEvent = "EVENT";
+
+    private const string RepresentationTimeSeries = "TIME_SERIES";
+    private const string RepresentationDataSet = "DATA_SET";
+    private const string RepresentationTable = "TABLE";
+
+    /// <summary>
+    ///     The <c>EVENT</c> types the standard defines as integers — the exception list to the
+    ///     "EVENT is text" default. Kept deliberately short: adding a type here is a claim that
+    ///     every agent reports it as a parseable integer, and being wrong costs Bad quality.
+    ///     <c>Line</c> is the deprecated spelling that <c>LineNumber</c> superseded in MTConnect 1.4;
+    ///     both are mapped so a current-version agent is not silently mistyped.
+    ///     <para>
+    ///         The entries are written in the Streams (PascalCase) spelling, but the set's comparer
+    ///         is <see cref="SeparatorInsensitiveComparer" />, so the probe document's
+    ///         <c>PART_COUNT</c> / <c>LINE_NUMBER</c> hit the same entries. Adding a spelling variant
+    ///         here would be redundant, not additional coverage.
+    ///     </para>
+    /// </summary>
+    private static readonly FrozenSet<string> NumericEventTypes =
+        new[] { "PartCount", "Line", "LineNumber" }.ToFrozenSet(SeparatorInsensitiveComparer.Instance);
+
+    /// <summary>
+    ///     Infers the OPC UA-facing type shape of an MTConnect <c>DataItem</c> from its device-model
+    ///     metadata. See the type-level remarks for the full rule and its rationale.
+    /// </summary>
+    /// <param name="category">
+    ///     The <c>DataItem</c> category — <c>SAMPLE</c>, <c>EVENT</c>, or <c>CONDITION</c>.
+    ///     Case-insensitive; an unknown, blank, or <c>null</c> value yields
+    ///     <see cref="DriverDataType.String" />.
+    /// </param>
+    /// <param name="type">
+    ///     The <c>DataItem</c> type, in <b>either</b> document's spelling — the probe's
+    ///     <c>PART_COUNT</c> / <c>POSITION</c> or the streams' <c>PartCount</c> / <c>Position</c>.
+    ///     Matched case- and separator-insensitively (see the type-level remarks); an unrecognised
+    ///     or <c>null</c> value falls back to the category default.
+    /// </param>
+    /// <param name="units">
+    ///     The declared engineering units, if any. Accepted for signature stability and because every
+    ///     call site already holds it, but <b>not load-bearing in v1</b>: <c>SAMPLE</c> is numeric by
+    ///     definition of the category, so units add no discriminating power there, and treating a
+    ///     units-bearing <c>EVENT</c> as numeric would be exactly the risky coercion this rule avoids.
+    /// </param>
+    /// <param name="representation">
+    ///     The <c>DataItem</c> representation — <c>VALUE</c> (default), <c>TIME_SERIES</c>,
+    ///     <c>DATA_SET</c>, <c>TABLE</c>, or <c>DISCRETE</c>. Case-insensitive.
+    /// </param>
+    /// <param name="sampleCount">
+    ///     The probe-declared <c>sampleCount</c> for a <c>TIME_SERIES</c> item. Flows into
+    ///     <see cref="MTConnectInferredType.ArrayDim" /> when positive; <c>null</c> or a non-positive
+    ///     value yields a variable-length array (<c>ArrayDim = null</c>). Ignored for scalars.
+    /// </param>
+    /// <returns>The inferred scalar type plus array shape.</returns>
+    public static MTConnectInferredType Infer(
+        string? category,
+        string? type = null,
+        string? units = null,
+        string? representation = null,
+        int? sampleCount = null)
+    {
+        _ = units; // See the parameter doc: intentionally not load-bearing in v1.
+
+        var trimmedCategory = category.AsSpan().Trim();
+        var trimmedRepresentation = representation.AsSpan().Trim();
+
+        // A key-value observation is never a number, whatever the category claims. Checked first so
+        // a DATA_SET SAMPLE cannot slip through as Float64 and go Bad on every parse.
+        if (Matches(trimmedRepresentation, RepresentationDataSet) || Matches(trimmedRepresentation, RepresentationTable))
+            return new MTConnectInferredType(DriverDataType.String, IsArray: false, ArrayDim: null);
+
+        if (Matches(trimmedCategory, CategorySample))
+        {
+            // TIME_SERIES is defined for SAMPLE only; the vector is a vector of the same scalar type.
+            if (Matches(trimmedRepresentation, RepresentationTimeSeries))
+                return new MTConnectInferredType(
+                    DriverDataType.Float64,
+                    IsArray: true,
+                    ArrayDim: sampleCount is > 0 ? (uint)sampleCount.Value : null);
+
+            return new MTConnectInferredType(DriverDataType.Float64, IsArray: false, ArrayDim: null);
+        }
+
+        if (Matches(trimmedCategory, CategoryEvent))
+        {
+            // No Trim() here: the set's comparer already ignores whitespace and separators
+            // wherever they appear, so the raw attribute value is looked up allocation-free.
+            var dataType = type is { Length: > 0 } && NumericEventTypes.Contains(type)
+                ? DriverDataType.Int64
+                : DriverDataType.String;
+
+            return new MTConnectInferredType(dataType, IsArray: false, ArrayDim: null);
+        }
+
+        // CONDITION (a state word) and every unknown / blank / missing category.
+        return new MTConnectInferredType(DriverDataType.String, IsArray: false, ArrayDim: null);
+    }
+
+    private static bool Matches(ReadOnlySpan<char> value, string expected)
+        => value.Equals(expected, StringComparison.OrdinalIgnoreCase);
+
+    /// <summary>
+    ///     Ordinal-ignore-case equality that additionally skips <c>_</c>, <c>-</c> and whitespace
+    ///     wherever they occur, so the probe document's <c>PART_COUNT</c> and the streams
+    ///     document's <c>PartCount</c> are one key. Backs <see cref="NumericEventTypes" />.
+    /// </summary>
+    /// <remarks>
+    ///     Comparing through a comparer rather than normalising the input keeps the lookup
+    ///     allocation-free on the discovery hot path: no <c>string.Replace</c>, no
+    ///     <c>Trim()</c>, no temporary buffer — the raw attribute value from the parser is passed
+    ///     straight to <see cref="FrozenSet{T}.Contains" />.
+    /// </remarks>
+    private sealed class SeparatorInsensitiveComparer : IEqualityComparer<string>
+    {
+        /// <summary>The single shared instance; the comparer is stateless.</summary>
+        internal static readonly SeparatorInsensitiveComparer Instance = new();
+
+        private SeparatorInsensitiveComparer() { }
+
+        /// <inheritdoc />
+        public bool Equals(string? x, string? y)
+        {
+            if (ReferenceEquals(x, y)) return true;
+            if (x is null || y is null) return false;
+
+            int i = 0, j = 0;
+            while (true)
+            {
+                while (i < x.Length && IsSeparator(x[i])) i++;
+                while (j < y.Length && IsSeparator(y[j])) j++;
+
+                if (i == x.Length || j == y.Length) return i == x.Length && j == y.Length;
+                if (char.ToUpperInvariant(x[i]) != char.ToUpperInvariant(y[j])) return false;
+
+                i++;
+                j++;
+            }
+        }
+
+        /// <inheritdoc />
+        public int GetHashCode(string obj)
+        {
+            // Must hash exactly the characters Equals compares, or two equal spellings land in
+            // different buckets and the set silently misses.
+            var hash = new HashCode();
+            foreach (var c in obj)
+            {
+                if (IsSeparator(c)) continue;
+                hash.Add(char.ToUpperInvariant(c));
+            }
+
+            return hash.ToHashCode();
+        }
+
+        private static bool IsSeparator(char c) => c is '_' or '-' || char.IsWhiteSpace(c);
+    }
+}
@@ -0,0 +1,134 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     MTConnect Agent driver configuration. Bound from the driver's <c>DriverConfig</c> JSON at
+///     <c>DriverHost.RegisterAsync</c>. The driver polls a remote MTConnect Agent's REST endpoints
+///     (<c>/probe</c>, <c>/current</c>, <c>/sample</c>) rooted at <see cref="AgentUri"/> and maps
+///     each returned DataItem into an OPC UA variable per <see cref="MTConnectTagDefinition"/>.
+/// </summary>
+public sealed class MTConnectDriverOptions
+{
+    /// <summary>
+    ///     Gets the MTConnect Agent's base URI (e.g. <c>http://agent:5000</c>). Required — the
+    ///     driver appends the standard Agent request paths (<c>/probe</c>, <c>/current</c>,
+    ///     <c>/sample</c>) to this base.
+    /// </summary>
+    public required string AgentUri { get; init; }
+
+    /// <summary>
+    ///     Optional device-name scope. When set, requests are narrowed to
+    ///     <c>{AgentUri}/{DeviceName}/...</c> so a multi-device Agent only serves one device's
+    ///     DataItems through this driver instance. Default <c>null</c> = agent-wide (all devices).
+    /// </summary>
+    public string? DeviceName { get; init; }
+
+    /// <summary>
+    ///     Per-call HTTP deadline, in milliseconds, applied to every Agent request
+    ///     (<c>/probe</c>, <c>/current</c>, <c>/sample</c>). Default <c>5000</c> — long enough for
+    ///     a large device probe response over a LAN, short enough that a hung Agent surfaces as a
+    ///     failed poll rather than wedging the driver.
+    /// </summary>
+    public int RequestTimeoutMs { get; init; } = 5000;
+
+    /// <summary>
+    ///     The <c>interval</c> query parameter (milliseconds) passed to the Agent's <c>/sample</c>
+    ///     streaming request — the minimum time the Agent waits between successive chunks of the
+    ///     response. Default <c>1000</c>; must be non-zero so the sample pump cannot spin the
+    ///     connection into a busy-loop.
+    /// </summary>
+    public int SampleIntervalMs { get; init; } = 1000;
+
+    /// <summary>
+    ///     The <c>count</c> query parameter passed to the Agent's <c>/sample</c> request — the
+    ///     maximum number of DataItem observations returned per chunk. Default <c>1000</c>, the
+    ///     MTConnect Agent's own conventional default.
+    /// </summary>
+    public int SampleCount { get; init; } = 1000;
+
+    /// <summary>
+    ///     The <c>heartbeat</c> query parameter (milliseconds) passed to the Agent's <c>/sample</c>
+    ///     streaming request — the Agent sends an empty chunk after this much idle time so the
+    ///     client can detect a silently-stalled connection. Default <c>10000</c>, matching the
+    ///     MTConnect Agent's own conventional default; must be non-zero or a quiet connection can
+    ///     never be distinguished from a dead one.
+    /// </summary>
+    public int HeartbeatMs { get; init; } = 10000;
+
+    /// <summary>
+    ///     The authored tags this driver instance serves — one <see cref="MTConnectTagDefinition"/>
+    ///     per tag, keyed by the DataItem <c>id</c> it binds
+    ///     (<see cref="MTConnectTagDefinition.FullName"/>). The factory config DTO carries these and
+    ///     builds them into the options; the driver indexes them to know each tag's target
+    ///     <see cref="MTConnectTagDefinition.DriverDataType"/> when coercing an Agent observation
+    ///     (whose wire form is always text) into a published value.
+    ///     <para>
+    ///         Defaults to <b>empty, never <c>null</c></b>: a driver instance may legitimately be
+    ///         authored with no tags yet, and a null collection here would surface as a
+    ///         NullReferenceException at deploy time from operator-authored config.
+    ///     </para>
+    /// </summary>
+    public IReadOnlyList<MTConnectTagDefinition> Tags { get; init; } = [];
+
+    /// <summary>
+    ///     <b>The v3 data-plane binding: the authored raw tags the deploy artifact delivers.</b> Each
+    ///     <see cref="RawTagEntry"/> pairs the tag's <b>RawPath</b> — the driver's wire reference for
+    ///     read / subscribe / publish, and the key <c>DriverHostActor</c> routes published values by —
+    ///     with the driver-specific <c>TagConfig</c> blob naming the Agent DataItem <c>id</c> it binds.
+    ///     Injected into every driver's merged config by <c>DriverDeviceConfigMerger</c>, so this is the
+    ///     collection a deployed instance actually serves from.
+    ///     <para>
+    ///         <b>Relationship to <see cref="Tags"/>.</b> The driver builds ONE observation index and
+    ///         ONE <c>RawPath → dataItemId</c> table from both collections:
+    ///         <list type="bullet">
+    ///             <item>A tag in <c>RawTags</c> is reachable by its RawPath (production). Its coercion
+    ///             type comes from the blob's <c>driverDataType</c>; failing that, from a
+    ///             <see cref="Tags"/> entry naming the same DataItem id; failing that, from the Agent's
+    ///             own <c>/probe</c> declaration (<see cref="MTConnectDataTypeInference"/>); failing
+    ///             that, <see cref="DriverDataType.String"/> — the coercion that cannot fail.</item>
+    ///             <item>A tag in <see cref="Tags"/> only is reachable by its DataItem <c>id</c>
+    ///             (the driver CLI's authoring surface, and every pre-v3 test) and still contributes
+    ///             its coercion type to the index.</item>
+    ///         </list>
+    ///         Both default to empty, so neither collection is required and a driver instance
+    ///         authored with no tags yet starts cleanly.
+    ///     </para>
+    /// </summary>
+    public IReadOnlyList<RawTagEntry> RawTags { get; init; } = [];
+
+    /// <summary>
+    ///     Background connectivity-probe settings. When <see cref="MTConnectProbeOptions.Enabled"/>
+    ///     is true the driver periodically issues a cheap <c>/probe</c> request and raises
+    ///     <c>OnHostStatusChanged</c> on Running ↔ Stopped transitions.
+    /// </summary>
+    public MTConnectProbeOptions Probe { get; init; } = new();
+
+    /// <summary>
+    ///     Reconnect backoff settings used after a failed Agent request or a dropped
+    ///     <c>/sample</c> streaming connection.
+    /// </summary>
+    public MTConnectReconnectOptions Reconnect { get; init; } = new();
+}
+
+/// <summary>Background connectivity-probe knobs, mirroring <c>ModbusProbeOptions</c>.</summary>
+public sealed class MTConnectProbeOptions
+{
+    /// <summary>Gets a value indicating whether probing is enabled.</summary>
+    public bool Enabled { get; init; } = true;
+    /// <summary>Gets the interval between probe requests.</summary>
+    public TimeSpan Interval { get; init; } = TimeSpan.FromSeconds(5);
+    /// <summary>Gets the probe request timeout.</summary>
+    public TimeSpan Timeout { get; init; } = TimeSpan.FromSeconds(2);
+}
+
+/// <summary>Geometric-backoff settings for the post-failure reconnect loop, mirroring <c>ModbusReconnectOptions</c>.</summary>
+public sealed class MTConnectReconnectOptions
+{
+    /// <summary>Delay before the first reconnect attempt, in milliseconds. Default <c>0</c> = immediate.</summary>
+    public int MinBackoffMs { get; init; } = 0;
+    /// <summary>Upper bound on the geometric backoff sequence, in milliseconds.</summary>
+    public int MaxBackoffMs { get; init; } = 30000;
+    /// <summary>Multiplier applied each retry. Default <c>2.0</c> doubles each step.</summary>
+    public double BackoffMultiplier { get; init; } = 2.0;
+}
@@ -0,0 +1,49 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     One MTConnect-backed OPC UA variable. Each authored tag binds a single Agent DataItem by
+///     its <c>id</c> attribute (<see cref="FullName"/>); the driver looks up the observation's
+///     current value from the Agent's <c>/current</c> snapshot / <c>/sample</c> stream by that id.
+/// </summary>
+/// <param name="FullName">
+///     The MTConnect DataItem's <c>id</c> attribute (the Agent's <c>/probe</c> response). This is
+///     the driver's reference for read/subscribe — MTConnect is a read-only source protocol, so
+///     there is no corresponding write path.
+/// </param>
+/// <param name="DriverDataType">Logical data type the DataItem's value is coerced to.</param>
+/// <param name="IsArray">
+///     When <c>true</c>, the tag is exposed as an OPC UA array (e.g. an MTConnect
+///     <c>PathPosition</c> / vector-valued sample). Default <c>false</c> = scalar.
+/// </param>
+/// <param name="ArrayDim">
+///     Element count when <see cref="IsArray"/> is <c>true</c>; ignored for scalar tags. Default
+///     <c>0</c>.
+/// </param>
+/// <param name="MtCategory">
+///     The DataItem's MTConnect <c>category</c> attribute — <c>SAMPLE</c>, <c>EVENT</c>, or
+///     <c>CONDITION</c>. Optional metadata carried through for browse / display; not consulted by
+///     the value-mapping path. Default <c>null</c>.
+/// </param>
+/// <param name="MtType">
+///     The DataItem's MTConnect <c>type</c> attribute (e.g. <c>POSITION</c>, <c>EXECUTION</c>).
+///     Optional metadata. Default <c>null</c>.
+/// </param>
+/// <param name="MtSubType">
+///     The DataItem's MTConnect <c>subType</c> attribute (e.g. <c>ACTUAL</c>, <c>COMMANDED</c>).
+///     Optional metadata. Default <c>null</c>.
+/// </param>
+/// <param name="Units">
+///     The DataItem's MTConnect <c>units</c> attribute (e.g. <c>MILLIMETER</c>,
+///     <c>REVOLUTION/MINUTE</c>). Optional metadata. Default <c>null</c>.
+/// </param>
+public sealed record MTConnectTagDefinition(
+    string FullName,
+    DriverDataType DriverDataType,
+    bool IsArray = false,
+    int ArrayDim = 0,
+    string? MtCategory = null,
+    string? MtType = null,
+    string? MtSubType = null,
+    string? Units = null);
@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    </PropertyGroup>
+
+    <!-- Pure records + the MTConnect data-type inference table, shared by the driver, browse-commit,
+         and the AdminUI typed tag editor. No backend NuGet — only the zero-dependency Core.Abstractions
+         leaf (DriverDataType etc.), mirroring Driver.Modbus.Contracts / Driver.AbCip.Contracts. -->
+    <ItemGroup>
+        <ProjectReference Include="..\..\Core\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+    </ItemGroup>
+
+</Project>
@@ -0,0 +1,135 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     The seam between the MTConnect driver and an MTConnect Agent's HTTP surface
+///     (<c>/probe</c>, <c>/current</c>, <c>/sample</c>). This interface is transport-neutral by
+///     design — every method returns/yields the plain DTOs in <c>MTConnectDtos.cs</c>, never a
+///     TrakHound type, an <c>XElement</c>, or any other wire/library artifact. That is what lets
+///     every driver behaviour above this seam (Tasks 6–13) be unit-tested against a fake serving
+///     canned probe/current/sample XML, with no sockets involved.
+/// </summary>
+/// <remarks>
+///     <para>
+///     The production implementation, <see cref="MTConnectAgentClient"/>, carries no backend NuGet
+///     at all: it is an <see cref="HttpClient"/> over the Agent's three request paths, feeding
+///     hand-rolled <c>System.Xml.Linq</c> parsers (<c>MTConnectProbeParser</c> /
+///     <c>MTConnectStreamsParser</c>) plus a <c>multipart/x-mixed-replace</c> frame reader for the
+///     <c>/sample</c> long poll. (Task 0 planned to build on the TrakHound MTConnect.NET libraries;
+///     Tasks 6 and 7 proved they can neither parse a document nor frame the stream socket-free, and
+///     dropped the references — see the Task 0 CORRECTION block in the plan.) A fake for tests only
+///     needs to implement these three instance members; <see cref="IsSequenceGap"/> is a static
+///     protocol rule that lives here, rather than on the implementation, so a consumer written
+///     against this seam never has to reference the concrete client.
+///     </para>
+///     <para>
+///         <b>Why the seam is <see cref="IDisposable"/> rather than
+///         <see cref="IAsyncDisposable"/>.</b> The driver obtains its client through a
+///         <c>Func&lt;MTConnectDriverOptions, IMTConnectAgentClient&gt;</c> and must release it on
+///         <c>ShutdownAsync</c> and on every endpoint-changing <c>ReinitializeAsync</c>. Declaring
+///         disposal here — instead of the driver doing <c>as IDisposable</c> + a null-conditional
+///         call — is deliberate: that idiom silently no-ops against any future non-disposable
+///         implementation, and the thing it would leak is an <see cref="HttpClient"/> and its socket
+///         handler, once per re-deploy, for the life of the process.
+///     </para>
+///     <para>
+///         Synchronous disposal is the honest shape because <i>every</i> resource behind this seam is
+///         synchronously disposable — two <see cref="HttpClient"/>s and a
+///         <see cref="CancellationTokenSource"/>. An <see cref="IAsyncDisposable"/> here would be a
+///         synchronous method wearing a <c>ValueTask</c>, and it would oblige every canned-XML fake
+///         to grow one too. The <b>async</b> unwind that a streaming client does need is already
+///         covered elsewhere and is not this method's job: the <see cref="SampleAsync"/> enumerator
+///         is itself <see cref="IAsyncDisposable"/> and is owned by the pump that enumerates it,
+///         while <see cref="IDisposable.Dispose"/> on the client converts any read still in flight
+///         into an ordinary <see cref="OperationCanceledException"/>.
+///     </para>
+/// </remarks>
+public interface IMTConnectAgentClient : IDisposable
+{
+    /// <summary>
+    ///     Issues an Agent <c>/probe</c> request and returns the parsed device hierarchy. Called
+    ///     once at driver initialization; the result is cached and later walked to build the OPC UA
+    ///     browse tree, where each <see cref="MTConnectDataItem.Id"/> becomes a tag's FullName.
+    /// </summary>
+    /// <param name="ct">Cancellation token.</param>
+    Task<MTConnectProbeModel> ProbeAsync(CancellationToken ct);
+
+    /// <summary>
+    ///     Issues an Agent <c>/current</c> request and returns the latest observed value for every
+    ///     data item. Used both to prime the observation index at startup and to re-baseline after
+    ///     a detected sequence gap in <see cref="SampleAsync"/>.
+    /// </summary>
+    /// <param name="ct">Cancellation token.</param>
+    Task<MTConnectStreamsResult> CurrentAsync(CancellationToken ct);
+
+    /// <summary>
+    ///     Opens an Agent <c>/sample</c> long-poll stream starting at sequence <paramref name="from"/>
+    ///     and yields one <see cref="MTConnectStreamsResult"/> per multipart chunk the Agent sends.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         <b>The only way this enumeration ends without throwing is <paramref name="ct"/> being
+    ///         cancelled.</b> Every other way a stream can stop — the connection dropping, the Agent
+    ///         writing its closing boundary, or the endpoint turning out not to stream at all —
+    ///         throws an <see cref="MTConnectStreamException"/> naming which. A consumer therefore
+    ///         never has to treat "the enumeration finished" as an ambiguous signal, and cannot
+    ///         silently lose its subscription to a data path that quietly stopped (#485). See
+    ///         <see cref="MTConnectStreamEndedException"/> (transient — reconnect) and
+    ///         <see cref="MTConnectStreamNotSupportedException"/> (configuration — reconnecting will
+    ///         reproduce it forever).
+    ///     </para>
+    ///     <para>
+    ///         <b>Advancing the cursor.</b> After each chunk, the caller's next expected sequence is
+    ///         that chunk's <see cref="MTConnectStreamsResult.NextSequence"/> — not the
+    ///         <paramref name="from"/> this call was opened with. Feed that running value to
+    ///         <see cref="IsSequenceGap"/> and, on reconnect, to a fresh <c>SampleAsync</c>.
+    ///     </para>
+    /// </remarks>
+    /// <param name="from">The sequence number to resume streaming from.</param>
+    /// <param name="ct">Cancellation token; cancelling is the contracted way to end the stream.</param>
+    IAsyncEnumerable<MTConnectStreamsResult> SampleAsync(long from, CancellationToken ct);
+
+    /// <summary>
+    ///     Has the Agent's ring buffer overflowed past the sequence the caller expected next? True
+    ///     when the chunk's oldest retained sequence is <i>strictly</i> newer than
+    ///     <paramref name="expectedFrom"/>, meaning observations between the two were evicted before
+    ///     the caller could read them and an incremental update would silently skip values.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         <b><paramref name="expectedFrom"/> is a running cursor, not the original
+    ///         <c>from</c>.</b> It equals the <c>from</c> passed to <see cref="SampleAsync"/> only
+    ///         for the <i>first</i> chunk; from the second chunk on it is the <b>previous</b>
+    ///         chunk's <see cref="MTConnectStreamsResult.NextSequence"/>. Comparing every chunk
+    ///         against the original <c>from</c> instead reports a gap on every chunk once the
+    ///         Agent's buffer has rolled past it — an endless <c>/current</c> re-baseline storm
+    ///         against a perfectly healthy stream.
+    ///     </para>
+    ///     <para>
+    ///         Equality is not a gap: <c>firstSequence == expectedFrom</c> is the ordinary
+    ///         contiguous case where the Agent simply had nothing older to send.
+    ///     </para>
+    ///     <para>
+    ///         <b>This check alone does NOT cover every ring-buffer overflow.</b> It can only judge
+    ///         a chunk the Agent was willing to send — and cppagent answers a <c>from</c> that has
+    ///         already fallen out of its buffer with an <c>MTConnectError</c> / <c>OUT_OF_RANGE</c>
+    ///         document served under <b>HTTP 200</b>, which this client surfaces as an
+    ///         <see cref="InvalidDataException"/> out of <see cref="SampleAsync"/>, never as a chunk.
+    ///         A pump that re-baselines only on <c>IsSequenceGap</c> will therefore fault instead of
+    ///         recovering exactly when it has fallen furthest behind. Treat an <c>OUT_OF_RANGE</c>
+    ///         parse failure as a re-baseline trigger (re-prime from <see cref="CurrentAsync"/>,
+    ///         resume from that snapshot's <c>NextSequence</c>) just like a detected gap.
+    ///     </para>
+    /// </remarks>
+    /// <param name="expectedFrom">The sequence the caller expected this chunk to start at.</param>
+    /// <param name="chunk">The chunk the Agent answered with.</param>
+    /// <returns>
+    ///     <c>true</c> when observations were lost and the caller must re-baseline via
+    ///     <see cref="CurrentAsync"/> rather than trusting an incremental update.
+    /// </returns>
+    static bool IsSequenceGap(long expectedFrom, MTConnectStreamsResult chunk)
+    {
+        ArgumentNullException.ThrowIfNull(chunk);
+
+        return chunk.FirstSequence > expectedFrom;
+    }
+}
@@ -0,0 +1,726 @@
+using System.Globalization;
+using System.Runtime.CompilerServices;
+using System.Text;
+using Microsoft.Extensions.Logging;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     The production <see cref="IMTConnectAgentClient"/> — a thin <see cref="HttpClient"/> wrapper
+///     over an MTConnect Agent's REST surface that hands every response body to a pure parser and
+///     returns only the neutral DTOs in <c>MTConnectDtos.cs</c>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>The constructor opens no connection.</b> It only composes the request URIs and builds
+///         its <see cref="HttpClient"/>s (which themselves dial nothing until a request is issued),
+///         so a throwaway instance is safe to construct — the universal discovery browser's
+///         <c>CanBrowse</c> pattern depends on that. <see cref="SampleAsync"/> likewise dials
+///         nothing until it is enumerated.
+///     </para>
+///     <para>
+///         <b>Two <see cref="HttpClient"/>s, and the split is deliberate.</b>
+///         <see cref="HttpClient.Timeout"/> is a per-instance, whole-response deadline, so a single
+///         client cannot serve both legs: the unary <c>/probe</c> and <c>/current</c> calls must be
+///         bounded by <see cref="MTConnectDriverOptions.RequestTimeoutMs"/>, while <c>/sample</c> is
+///         a long poll that is <i>supposed</i> to outlive that bound indefinitely. Raising the one
+///         timeout to suit the stream would un-bound the unary deadline — precisely what arch-review
+///         R2-01 says must never happen — so the streaming leg gets its own client with
+///         <see cref="Timeout.InfiniteTimeSpan"/> and is bounded differently instead (below). In
+///         production each client owns its own handler and connection pool; in tests both are built
+///         over one injected handler, which the caller owns.
+///     </para>
+///     <para>
+///         <b>Every call is deadline-bounded, but not all by the same mechanism.</b> The unary legs
+///         run under a <see cref="CancellationTokenSource"/> linked to the caller's token and
+///         cancelled after <c>RequestTimeoutMs</c>. The streaming leg bounds its <i>header</i> phase
+///         the same way (a peer that accepts the connection and never answers must not wedge the
+///         pump), then hands the body to a <b>heartbeat watchdog</b>: MTConnect Agents emit a
+///         keep-alive chunk every <see cref="MTConnectDriverOptions.HeartbeatMs"/> precisely so a
+///         client can tell "quiet but alive" from "dead", so every body read is bounded by a
+///         two-missed-heartbeat window and a silent Agent surfaces as a
+///         <see cref="TimeoutException"/>. This is the exact shape of this repo's S7 frozen-peer
+///         production defect (arch-review R2-01) — an async read that ignores the socket deadline —
+///         and the watchdog is what closes it here.
+///     </para>
+///     <para>
+///         <b>Every operator-authorable duration/count is rejected at construction if non-positive.</b>
+///         A <c>0</c> must never come to mean "wait forever" (arch-review 01/S-6), and the three
+///         <c>/sample</c> query knobs additionally reach the wire: an Agent answers
+///         <c>heartbeat=0</c> with an <c>MTConnectError</c> under HTTP 200, which would otherwise
+///         surface as a parse failure that never names the offending config key.
+///     </para>
+///     <para>
+///         <b>Disposal is safe against an in-flight enumeration.</b> Task 9 re-initializes the
+///         driver by disposing and rebuilding this client, which can happen while a pump is still
+///         enumerating <see cref="SampleAsync"/>. Rather than letting the in-flight read fault with
+///         an unclassified <see cref="ObjectDisposedException"/> or <see cref="IOException"/> that no
+///         caller is written to expect, every request runs under a token linked to an internal
+///         dispose token, so disposal surfaces as an ordinary
+///         <see cref="OperationCanceledException"/>.
+///     </para>
+///     <para>
+///         This class does not swallow failures into an empty model: an unreachable Agent, a non-2xx
+///         status, an unparseable body, and <b>the end of a <c>/sample</c> stream</b> all throw. See
+///         <see cref="MTConnectStreamException"/> for why the last of those is an exception rather
+///         than a normal end of enumeration. <c>InitializeAsync</c> (Task 9) is what catches these
+///         and moves the driver to Faulted.
+///     </para>
+/// </remarks>
+public sealed class MTConnectAgentClient : IMTConnectAgentClient, IDisposable
+{
+    private readonly HttpClient _http;
+    private readonly HttpClient _streamHttp;
+    private readonly CancellationTokenSource _disposeCts = new();
+    private readonly ILogger? _logger;
+    private readonly Uri _probeUri;
+    private readonly Uri _currentUri;
+    private readonly string _sampleUriBase;
+    private readonly string _sampleQuerySuffix;
+    private readonly TimeSpan _requestTimeout;
+    private readonly TimeSpan _streamIdleTimeout;
+    private bool _disposed;
+
+    /// <summary>Creates a client for the Agent described by <paramref name="options"/>.</summary>
+    /// <param name="options">The driver options carrying the Agent URI, device scope, and per-call deadline.</param>
+    /// <param name="logger">
+    ///     Optional logger. Used only for conditions an operator needs to see but which are not
+    ///     failures — today, the degraded <c>/sample</c> framing mode.
+    /// </param>
+    /// <exception cref="ArgumentException"><see cref="MTConnectDriverOptions.AgentUri"/> is missing or is not an absolute HTTP(S) URI.</exception>
+    /// <exception cref="ArgumentOutOfRangeException">
+    ///     Any of <see cref="MTConnectDriverOptions.RequestTimeoutMs"/>,
+    ///     <see cref="MTConnectDriverOptions.HeartbeatMs"/>,
+    ///     <see cref="MTConnectDriverOptions.SampleIntervalMs"/> or
+    ///     <see cref="MTConnectDriverOptions.SampleCount"/> is not positive.
+    /// </exception>
+    public MTConnectAgentClient(MTConnectDriverOptions options, ILogger? logger = null)
+        : this(options, handler: null, logger)
+    {
+    }
+
+    /// <summary>
+    ///     Test seam: as <see cref="MTConnectAgentClient(MTConnectDriverOptions, ILogger)"/>, but
+    ///     sends through the supplied handler so the request/response round trip can be exercised
+    ///     with no socket. The caller retains ownership of <paramref name="handler"/>.
+    /// </summary>
+    internal MTConnectAgentClient(MTConnectDriverOptions options, HttpMessageHandler? handler, ILogger? logger = null)
+    {
+        ArgumentNullException.ThrowIfNull(options);
+
+        RequirePositive(
+            options.RequestTimeoutMs,
+            nameof(MTConnectDriverOptions.RequestTimeoutMs),
+            "a non-positive per-call deadline would let a frozen Agent wedge the driver indefinitely");
+        RequirePositive(
+            options.HeartbeatMs,
+            nameof(MTConnectDriverOptions.HeartbeatMs),
+            "it is sent to the Agent as 'heartbeat', which an Agent rejects with an MTConnectError under HTTP 200, and it is what bounds the /sample watchdog — a quiet connection would otherwise be indistinguishable from a dead one");
+        RequirePositive(
+            options.SampleIntervalMs,
+            nameof(MTConnectDriverOptions.SampleIntervalMs),
+            "it is sent to the Agent as 'interval'; zero would spin the streaming connection into a busy-loop");
+        RequirePositive(
+            options.SampleCount,
+            nameof(MTConnectDriverOptions.SampleCount),
+            "it is sent to the Agent as 'count'; a non-positive count asks the Agent for no observations");
+
+        _logger = logger;
+        _requestTimeout = TimeSpan.FromMilliseconds(options.RequestTimeoutMs);
+
+        // Two missed heartbeats plus one request timeout of network slack. Deriving the window from
+        // HeartbeatMs is what makes it a liveness check rather than a throughput assumption: a busy
+        // Agent and an idle one both emit at least one chunk per heartbeat.
+        _streamIdleTimeout = TimeSpan.FromMilliseconds((2L * options.HeartbeatMs) + options.RequestTimeoutMs);
+
+        _probeUri = BuildRequestUri(options, "probe");
+        _currentUri = BuildRequestUri(options, "current");
+        _sampleUriBase = BuildRequestUri(options, "sample").AbsoluteUri;
+        _sampleQuerySuffix = string.Create(
+            CultureInfo.InvariantCulture,
+            $"&interval={options.SampleIntervalMs}&count={options.SampleCount}&heartbeat={options.HeartbeatMs}");
+
+        _http = handler is null ? new HttpClient() : new HttpClient(handler, disposeHandler: false);
+        _http.Timeout = _requestTimeout;
+
+        _streamHttp = handler is null ? new HttpClient() : new HttpClient(handler, disposeHandler: false);
+
+        // See the class remarks: a long poll must outlive the unary deadline by design, and the
+        // heartbeat watchdog — not this property — is what keeps it bounded.
+        _streamHttp.Timeout = Timeout.InfiniteTimeSpan;
+    }
+
+    /// <inheritdoc/>
+    public async Task<MTConnectProbeModel> ProbeAsync(CancellationToken ct)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+
+        // ResponseContentRead (the default) buffers the whole body *under* this awaited, token-bound
+        // call, so the parse below reads from memory — no network read can outlive the deadline.
+        using var response = await SendAsync(_probeUri, ct).ConfigureAwait(false);
+
+        await using var body = await response.Content.ReadAsStreamAsync(ct).ConfigureAwait(false);
+
+        return MTConnectProbeParser.Parse(body);
+    }
+
+    /// <inheritdoc/>
+    public async Task<MTConnectStreamsResult> CurrentAsync(CancellationToken ct)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+
+        using var response = await SendAsync(_currentUri, ct).ConfigureAwait(false);
+
+        await using var body = await response.Content.ReadAsStreamAsync(ct).ConfigureAwait(false);
+
+        return MTConnectStreamsParser.Parse(body);
+    }
+
+    /// <inheritdoc/>
+    public async IAsyncEnumerable<MTConnectStreamsResult> SampleAsync(
+        long from,
+        [EnumeratorCancellation] CancellationToken ct)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+
+        var uri = BuildSampleUri(from);
+
+        // Linked to the caller's token AND to disposal, so tearing this client down mid-enumeration
+        // surfaces as a cancellation rather than as a raw ObjectDisposedException from the socket.
+        using var lifetime = CancellationTokenSource.CreateLinkedTokenSource(ct, _disposeCts.Token);
+        var live = lifetime.Token;
+
+        using var request = new HttpRequestMessage(HttpMethod.Get, uri);
+
+        // ResponseHeadersRead, not the default ResponseContentRead: buffering a
+        // multipart/x-mixed-replace body that is designed never to end would hang here forever.
+        using var response = await SendStreamRequestAsync(request, uri, lifetime).ConfigureAwait(false);
+
+        await using var body = await response.Content.ReadAsStreamAsync(live).ConfigureAwait(false);
+
+        var boundary = ResolveMultipartBoundary(response, uri);
+        if (boundary is null)
+        {
+            // Not a multipart stream: the Agent answered with a single document, which means it
+            // ignored the streaming request entirely. Parse it first — an MTConnectError arrives in
+            // exactly this shape (text/xml under HTTP 200) and the Agent's own error text is far
+            // more useful than ours — then report the misconfiguration. The parsed snapshot is
+            // deliberately NOT yielded: one document followed by a healthy-looking finished stream
+            // is how a dead data path disguises itself as a working one (#485).
+            var single = await ReadWholeBodyAsync(body, uri, lifetime).ConfigureAwait(false);
+            _ = MTConnectStreamsParser.Parse(single);
+
+            throw new MTConnectStreamNotSupportedException(
+                $"MTConnect Agent answered the /sample request '{uri}' with a single '{response.Content.Headers.ContentType?.MediaType ?? "unknown"}' document instead of a multipart/x-mixed-replace stream. It parsed as a valid MTConnectStreams document but will never stream, so no subscription is possible; check that the URI addresses an MTConnect Agent directly and is not fronted by a proxy that buffers streaming responses.");
+        }
+
+        var reader = new MultipartStreamReader(body, boundary, _streamIdleTimeout, uri, _logger);
+        var delivered = 0L;
+        while (true)
+        {
+            var part = await reader.ReadNextPartAsync(live).ConfigureAwait(false);
+            if (part is null)
+            {
+                // The caller cancelling is the ONE contracted way out; anything else is reported.
+                live.ThrowIfCancellationRequested();
+
+                throw new MTConnectStreamEndedException(reader.EndReason, uri.AbsoluteUri, delivered);
+            }
+
+            // A frame carrying nothing but whitespace is transport filler, not a document. The
+            // Agent's real keep-alive is a well-formed observation-free MTConnectStreams document,
+            // and that one IS yielded — it advances the sequence, so swallowing it would strand the
+            // caller's `from` behind the Agent's buffer.
+            if (string.IsNullOrWhiteSpace(part))
+            {
+                continue;
+            }
+
+            delivered++;
+
+            yield return MTConnectStreamsParser.Parse(part);
+        }
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        _disposed = true;
+
+        // Cancel BEFORE disposing the clients so an in-flight read observes cancellation rather
+        // than a disposed handler.
+        _disposeCts.Cancel();
+        _http.Dispose();
+        _streamHttp.Dispose();
+        _disposeCts.Dispose();
+    }
+
+    private static void RequirePositive(int value, string optionName, string because)
+    {
+        if (value <= 0)
+        {
+            throw new ArgumentOutOfRangeException(
+                nameof(MTConnectDriverOptions),
+                value,
+                $"{optionName} must be positive; {because}.");
+        }
+    }
+
+    private Uri BuildSampleUri(long from) =>
+        new(string.Create(CultureInfo.InvariantCulture, $"{_sampleUriBase}?from={from}{_sampleQuerySuffix}"),
+            UriKind.Absolute);
+
+    private async Task<HttpResponseMessage> SendAsync(Uri uri, CancellationToken ct)
+    {
+        using var lifetime = CancellationTokenSource.CreateLinkedTokenSource(ct, _disposeCts.Token);
+        using var deadline = CancellationTokenSource.CreateLinkedTokenSource(lifetime.Token);
+        deadline.CancelAfter(_requestTimeout);
+
+        HttpResponseMessage response;
+        try
+        {
+            response = await _http.GetAsync(uri, deadline.Token).ConfigureAwait(false);
+        }
+        catch (OperationCanceledException) when (!lifetime.IsCancellationRequested)
+        {
+            // Neither the caller nor disposal cancelled, so this is our own deadline (or
+            // HttpClient.Timeout) firing. Reported as a TimeoutException because a bare "A task was
+            // canceled" tells an operator nothing about which Agent stopped answering.
+            throw TimedOut(uri);
+        }
+
+        response.EnsureSuccessStatusCode();
+
+        return response;
+    }
+
+    /// <summary>
+    ///     Issues the <c>/sample</c> request and returns as soon as the response headers land. Only
+    ///     this phase is bounded by the unary deadline; the body is bounded by the watchdog.
+    /// </summary>
+    private async Task<HttpResponseMessage> SendStreamRequestAsync(
+        HttpRequestMessage request, Uri uri, CancellationTokenSource lifetime)
+    {
+        using var deadline = CancellationTokenSource.CreateLinkedTokenSource(lifetime.Token);
+        deadline.CancelAfter(_requestTimeout);
+
+        HttpResponseMessage response;
+        try
+        {
+            response = await _streamHttp
+                .SendAsync(request, HttpCompletionOption.ResponseHeadersRead, deadline.Token)
+                .ConfigureAwait(false);
+        }
+        catch (OperationCanceledException) when (!lifetime.IsCancellationRequested)
+        {
+            throw TimedOut(uri);
+        }
+
+        response.EnsureSuccessStatusCode();
+
+        return response;
+    }
+
+    /// <summary>Reads a non-multipart streaming body whole, under the unary deadline.</summary>
+    private async Task<string> ReadWholeBodyAsync(Stream body, Uri uri, CancellationTokenSource lifetime)
+    {
+        using var deadline = CancellationTokenSource.CreateLinkedTokenSource(lifetime.Token);
+        deadline.CancelAfter(_requestTimeout);
+
+        using var reader = new StreamReader(body, Encoding.UTF8);
+        try
+        {
+            return await reader.ReadToEndAsync(deadline.Token).ConfigureAwait(false);
+        }
+        catch (OperationCanceledException) when (!lifetime.IsCancellationRequested)
+        {
+            throw TimedOut(uri);
+        }
+    }
+
+    private TimeoutException TimedOut(Uri uri) =>
+        new($"MTConnect Agent request to '{uri}' did not complete within {_requestTimeout.TotalMilliseconds:F0} ms.");
+
+    /// <summary>
+    ///     The <c>boundary</c> parameter of a <c>multipart/*</c> response, or <c>null</c> when the
+    ///     Agent answered with a single (non-multipart) document.
+    /// </summary>
+    /// <exception cref="MTConnectStreamNotSupportedException">
+    ///     The response claims to be <c>multipart/*</c> but carries no <c>boundary</c> parameter, so
+    ///     there is nothing to frame it by. Failed fast and named, because the alternative — falling
+    ///     through to whole-body reading of a body that never ends — surfaces much later as a bare
+    ///     watchdog <see cref="TimeoutException"/> that points an operator at the network instead of
+    ///     at the malformed header.
+    /// </exception>
+    private static string? ResolveMultipartBoundary(HttpResponseMessage response, Uri uri)
+    {
+        var contentType = response.Content.Headers.ContentType;
+        if (contentType?.MediaType is null ||
+            !contentType.MediaType.StartsWith("multipart/", StringComparison.OrdinalIgnoreCase))
+        {
+            return null;
+        }
+
+        var boundary = contentType.Parameters
+            .FirstOrDefault(p => string.Equals(p.Name, "boundary", StringComparison.OrdinalIgnoreCase))?.Value?
+            .Trim('"');
+
+        if (string.IsNullOrEmpty(boundary))
+        {
+            throw new MTConnectStreamNotSupportedException(
+                $"MTConnect Agent answered the /sample request '{uri}' with Content-Type '{contentType.MediaType}' but no 'boundary' parameter, so the multipart stream cannot be framed.");
+        }
+
+        return boundary;
+    }
+
+    private static Uri BuildRequestUri(MTConnectDriverOptions options, string request)
+    {
+        var agentUri = options.AgentUri?.Trim();
+        if (string.IsNullOrEmpty(agentUri))
+        {
+            throw new ArgumentException(
+                $"{nameof(MTConnectDriverOptions.AgentUri)} is required (e.g. 'http://agent:5000').", nameof(options));
+        }
+
+        if (!Uri.TryCreate(agentUri, UriKind.Absolute, out var parsed) ||
+            (parsed.Scheme != Uri.UriSchemeHttp && parsed.Scheme != Uri.UriSchemeHttps))
+        {
+            throw new ArgumentException(
+                $"{nameof(MTConnectDriverOptions.AgentUri)} '{agentUri}' is not an absolute http(s) URI.", nameof(options));
+        }
+
+        var root = parsed.GetLeftPart(UriPartial.Path).TrimEnd('/');
+        var deviceName = options.DeviceName?.Trim();
+        var deviceSegment = string.IsNullOrEmpty(deviceName) ? string.Empty : $"/{Uri.EscapeDataString(deviceName)}";
+
+        return new Uri($"{root}{deviceSegment}/{request}", UriKind.Absolute);
+    }
+
+    /// <summary>
+    ///     Frames a <c>multipart/x-mixed-replace</c> body into individual part payloads, reading
+    ///     incrementally and never buffering more than the part currently in flight.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         <b>Why hand-rolled.</b> ASP.NET Core's <c>MultipartReader</c> is not in this
+    ///         dependency set, and TrakHound's <c>MTConnectHttpClientStream</c> — the one candidate
+    ///         the plan left open — takes a URL and dials its own socket, so it can neither be fed an
+    ///         existing response stream nor be exercised without a listener. See the Task 0
+    ///         correction in the plan.
+    ///     </para>
+    ///     <para>
+    ///         <b>Two framing paths, and the first one matters for latency.</b> When the part carries
+    ///         a <c>Content-length</c> header — every Agent in the wild writes one — the body is read
+    ///         by length and the chunk is emitted the instant it is complete. Without it there is no
+    ///         way to know a part has ended except by seeing the <i>next</i> boundary, so that path
+    ///         necessarily emits each chunk one chunk late: with the default 10 s heartbeat a value
+    ///         can be up to a heartbeat stale on a driver built for low-latency subscribe. It is a
+    ///         correctness fallback, not the expected path, and it logs a one-shot warning when it
+    ///         engages so the degradation is visible rather than merely slow. (It cannot strand the
+    ///         final part indefinitely — a clean end of stream returns the buffered tail — though a
+    ///         watchdog timeout on a stalled Agent does discard it.)
+    ///     </para>
+    ///     <para>
+    ///         <b>Every read is watchdog-bounded.</b> A silent peer faults the stream rather than
+    ///         parking a task forever (arch-review R2-01), and the buffer is capped so a hostile or
+    ///         malfunctioning Agent cannot grow it without limit.
+    ///     </para>
+    /// </remarks>
+    private sealed class MultipartStreamReader(
+        Stream stream, string boundary, TimeSpan idleTimeout, Uri uri, ILogger? logger)
+    {
+        private const int MaxBufferBytes = 32 * 1024 * 1024;
+
+        private static readonly byte[] CrLfCrLf = "\r\n\r\n"u8.ToArray();
+        private static readonly byte[] LfLf = "\n\n"u8.ToArray();
+
+        private readonly byte[] _delimiter = Encoding.ASCII.GetBytes("--" + boundary);
+        private byte[] _buffer = new byte[16 * 1024];
+        private int _length;
+        private bool _finished;
+        private bool _warnedNoContentLength;
+
+        /// <summary>How the stream ended. Only meaningful once a read has returned <c>null</c>.</summary>
+        public MTConnectStreamEndReason EndReason { get; private set; } = MTConnectStreamEndReason.ConnectionClosed;
+
+        /// <summary>
+        ///     Reads the next part's payload, or <c>null</c> once the closing delimiter is seen or
+        ///     the Agent closes the connection — see <see cref="EndReason"/> for which.
+        /// </summary>
+        public async Task<string?> ReadNextPartAsync(CancellationToken ct)
+        {
+            if (_finished)
+            {
+                return null;
+            }
+
+            if (!await SkipThroughDelimiterAsync(ct).ConfigureAwait(false) ||
+                !await EnsureAsync(2, ct).ConfigureAwait(false))
+            {
+                return Finish(MTConnectStreamEndReason.ConnectionClosed);
+            }
+
+            // "--boundary--" closes the stream.
+            if (_buffer[0] == (byte)'-' && _buffer[1] == (byte)'-')
+            {
+                return Finish(MTConnectStreamEndReason.ClosingBoundary);
+            }
+
+            var headerEnd = await FindHeaderEndAsync(ct).ConfigureAwait(false);
+            if (headerEnd < 0)
+            {
+                return Finish(MTConnectStreamEndReason.ConnectionClosed);
+            }
+
+            var headers = Encoding.ASCII.GetString(_buffer, 0, headerEnd);
+            Consume(headerEnd);
+
+            byte[]? body;
+            if (ParseContentLength(headers) is { } declared)
+            {
+                body = await ReadByLengthAsync(declared, ct).ConfigureAwait(false);
+            }
+            else
+            {
+                WarnOnceAboutMissingContentLength();
+                body = await ReadToNextDelimiterAsync(ct).ConfigureAwait(false);
+            }
+
+            return body is null ? null : Encoding.UTF8.GetString(body);
+        }
+
+        private void WarnOnceAboutMissingContentLength()
+        {
+            if (_warnedNoContentLength)
+            {
+                return;
+            }
+
+            _warnedNoContentLength = true;
+
+            logger?.LogWarning(
+                "MTConnect /sample stream from '{AgentUri}' sends parts with no Content-length header. Falling back to boundary-scan framing, which cannot emit a chunk until the NEXT chunk begins, so every observation is delayed by up to one Agent heartbeat. Values will read stale; this is the Agent's framing, not a driver fault.",
+                uri);
+        }
+
+        private string? Finish(MTConnectStreamEndReason reason)
+        {
+            _finished = true;
+            EndReason = reason;
+
+            return null;
+        }
+
+        private async Task<byte[]?> ReadByLengthAsync(int declared, CancellationToken ct)
+        {
+            if (!await EnsureAsync(declared, ct).ConfigureAwait(false))
+            {
+                Finish(MTConnectStreamEndReason.ConnectionClosed);
+
+                return null;
+            }
+
+            var body = _buffer[..declared];
+            Consume(declared);
+
+            return body;
+        }
+
+        private async Task<byte[]?> ReadToNextDelimiterAsync(CancellationToken ct)
+        {
+            var next = await FindDelimiterAsync(ct).ConfigureAwait(false);
+            if (next < 0)
+            {
+                // EOF with no closing delimiter: whatever is buffered is the last part. Returned
+                // rather than dropped, so a clean end of stream cannot strand a chunk.
+                var tail = _buffer[.._length];
+                _length = 0;
+                Finish(MTConnectStreamEndReason.ConnectionClosed);
+
+                return tail;
+            }
+
+            var body = _buffer[..TrimTrailingLineBreak(next)];
+
+            // Leave the delimiter itself in place; the next call's skip consumes it.
+            Consume(next);
+
+            return body;
+        }
+
+        /// <summary>Strips the single line break that terminates a part body before its delimiter.</summary>
+        private int TrimTrailingLineBreak(int end)
+        {
+            if (end >= 2 && _buffer[end - 2] == (byte)'\r' && _buffer[end - 1] == (byte)'\n')
+            {
+                return end - 2;
+            }
+
+            return end >= 1 && _buffer[end - 1] == (byte)'\n' ? end - 1 : end;
+        }
+
+        /// <summary>Advances past the next boundary delimiter; <c>false</c> at end of stream.</summary>
+        private async Task<bool> SkipThroughDelimiterAsync(CancellationToken ct)
+        {
+            var index = await FindDelimiterAsync(ct).ConfigureAwait(false);
+            if (index < 0)
+            {
+                return false;
+            }
+
+            Consume(index + _delimiter.Length);
+
+            return true;
+        }
+
+        private async Task<int> FindDelimiterAsync(CancellationToken ct)
+        {
+            var searchedTo = 0;
+            while (true)
+            {
+                // Restart the scan far enough back that a delimiter split across two reads is still
+                // found — without the overlap, a boundary straddling a packet boundary is invisible.
+                var index = IndexOf(_delimiter, Math.Max(0, searchedTo - (_delimiter.Length - 1)));
+                if (index >= 0)
+                {
+                    return index;
+                }
+
+                searchedTo = _length;
+                if (!await FillAsync(ct).ConfigureAwait(false))
+                {
+                    return -1;
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Finds the end of the part's header block — the first blank line after the delimiter.
+        ///     A part with no headers at all is legal, in which case the blank line sits at offset 0.
+        /// </summary>
+        private async Task<int> FindHeaderEndAsync(CancellationToken ct)
+        {
+            var searchedTo = 0;
+            while (true)
+            {
+                var crlf = IndexOf(CrLfCrLf, Math.Max(0, searchedTo - 3));
+                var lf = IndexOf(LfLf, Math.Max(0, searchedTo - 1));
+
+                if (crlf >= 0 && (lf < 0 || crlf <= lf))
+                {
+                    return crlf + CrLfCrLf.Length;
+                }
+
+                if (lf >= 0)
+                {
+                    return lf + LfLf.Length;
+                }
+
+                searchedTo = _length;
+                if (!await FillAsync(ct).ConfigureAwait(false))
+                {
+                    return -1;
+                }
+            }
+        }
+
+        private static int? ParseContentLength(string headers)
+        {
+            foreach (var line in headers.Split('\n'))
+            {
+                var trimmed = line.Trim();
+                if (!trimmed.StartsWith("content-length:", StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                var raw = trimmed["content-length:".Length..].Trim();
+
+                return int.TryParse(raw, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value) &&
+                       value >= 0
+                    ? value
+                    : null;
+            }
+
+            return null;
+        }
+
+        private async Task<bool> EnsureAsync(int count, CancellationToken ct)
+        {
+            while (_length < count)
+            {
+                if (!await FillAsync(ct).ConfigureAwait(false))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        ///     Reads at least one more byte, bounded by the heartbeat watchdog. Returns <c>false</c>
+        ///     at end of stream and throws <see cref="TimeoutException"/> when the Agent goes silent.
+        /// </summary>
+        private async Task<bool> FillAsync(CancellationToken ct)
+        {
+            if (_length == _buffer.Length)
+            {
+                if (_buffer.Length >= MaxBufferBytes)
+                {
+                    throw new InvalidDataException(
+                        $"MTConnect /sample stream from '{uri}' sent a part larger than {MaxBufferBytes} bytes without a boundary; refusing to buffer further.");
+                }
+
+                Array.Resize(ref _buffer, Math.Min(_buffer.Length * 2, MaxBufferBytes));
+            }
+
+            using var watchdog = CancellationTokenSource.CreateLinkedTokenSource(ct);
+            watchdog.CancelAfter(idleTimeout);
+
+            int read;
+            try
+            {
+                read = await stream.ReadAsync(_buffer.AsMemory(_length), watchdog.Token).ConfigureAwait(false);
+            }
+            catch (OperationCanceledException) when (!ct.IsCancellationRequested)
+            {
+                throw new TimeoutException(
+                    $"MTConnect /sample stream from '{uri}' sent no data (not even a heartbeat) within {idleTimeout.TotalMilliseconds:F0} ms; treating the Agent as unreachable rather than waiting indefinitely.");
+            }
+
+            if (read <= 0)
+            {
+                return false;
+            }
+
+            _length += read;
+
+            return true;
+        }
+
+        private int IndexOf(byte[] pattern, int start)
+        {
+            if (start >= _length)
+            {
+                return -1;
+            }
+
+            var index = _buffer.AsSpan(start, _length - start).IndexOf(pattern.AsSpan());
+
+            return index < 0 ? -1 : index + start;
+        }
+
+        private void Consume(int count)
+        {
+            Buffer.BlockCopy(_buffer, count, _buffer, 0, _length - count);
+            _length -= count;
+        }
+    }
+}
@@ -0,0 +1,116 @@
+using Microsoft.Extensions.Logging;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     Static factory registration helper for <see cref="MTConnectDriver"/>. The Host registers it
+///     once at startup; the bootstrapper then materialises MTConnect <c>DriverInstance</c> rows from
+///     the deployed configuration into live driver instances. Mirrors
+///     <c>ModbusDriverFactoryExtensions</c> / <c>FocasDriverFactoryExtensions</c>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>There is exactly one parser for the config document.</b> This factory does not carry a
+///         config DTO of its own — it delegates to <see cref="MTConnectDriver.ParseOptions"/>, which
+///         the driver itself must own because the runtime delivers a config <i>change</i> to a live
+///         instance (<c>DriverInstanceActor</c> assigns its driver once and calls
+///         <c>ReinitializeAsync(newJson)</c> thereafter). A second DTO here would drift from that
+///         one silently, and the drift would first show up at deploy time as an operator's edit
+///         being applied differently by the two paths — or not at all.
+///     </para>
+///     <para>
+///         <b>Construction opens nothing.</b> The Wave-0 universal discovery browser builds a
+///         throwaway instance through this factory purely to read
+///         <c>ITagDiscovery.SupportsOnlineDiscovery</c>, and never initializes it — so a factory
+///         that dialled the Agent (or that pre-built an <see cref="IMTConnectAgentClient"/>) would
+///         open a connection per AdminUI browse render against a possibly-unreachable Agent. The
+///         agent-client factory is therefore left null: <see cref="MTConnectDriver"/> builds the
+///         production client inside <c>InitializeAsync</c>.
+///     </para>
+///     <para>
+///         <b>The instance is returned as its concrete type.</b> The runtime resolves every optional
+///         capability (<see cref="IReadable"/>, <see cref="ISubscribable"/>,
+///         <see cref="ITagDiscovery"/>, <see cref="IHostConnectivityProbe"/>,
+///         <see cref="IRediscoverable"/>) by pattern-matching the object
+///         <see cref="DriverFactoryRegistry"/> hands back, so nothing here may narrow it — a
+///         narrowed return is how a capability ends up implemented but never dispatched. There is
+///         deliberately no <c>IWritable</c>: the MTConnect Agent surface is read-only.
+///     </para>
+/// </remarks>
+public static class MTConnectDriverFactoryExtensions
+{
+    /// <summary>
+    ///     The <c>DriverInstance.DriverType</c> value this factory answers to.
+    /// </summary>
+    /// <remarks>
+    ///     <b>Aliased to <see cref="DriverTypeNames.MTConnect"/>, not a literal.</b> The registry key,
+    ///     the instance's self-reported <see cref="MTConnectDriver.DriverType"/>, the probe's
+    ///     <c>DriverType</c>, and the constant every dispatch map keys off are therefore the same
+    ///     symbol — the repo-wide fix for the historical <c>TwinCat</c>/<c>Focas</c> drift, where a
+    ///     driver's own spelling silently diverged from the constant and dispatch maps missed it.
+    ///     Retained as a named const (rather than deleted in favour of the constant) so the existing
+    ///     factory callers and the sibling <c>*DriverFactoryExtensions.DriverTypeName</c> convention
+    ///     keep working; it is now an alias with no independent value.
+    /// </remarks>
+    public const string DriverTypeName = DriverTypeNames.MTConnect;
+
+    /// <summary>
+    ///     Register the MTConnect factory with the driver registry. The optional
+    ///     <paramref name="loggerFactory"/> is captured at registration time and used to construct
+    ///     an <see cref="ILogger{TCategoryName}"/> per driver instance — without it the driver runs
+    ///     with the null logger (tests and standalone callers stay unchanged).
+    /// </summary>
+    /// <param name="registry">The driver factory registry to register with.</param>
+    /// <param name="loggerFactory">Optional logger factory for creating loggers per driver instance.</param>
+    public static void Register(DriverFactoryRegistry registry, ILoggerFactory? loggerFactory = null)
+    {
+        ArgumentNullException.ThrowIfNull(registry);
+        registry.Register(DriverTypeName, (id, json) => CreateInstance(id, json, loggerFactory));
+    }
+
+    /// <summary>Public for the Server-side bootstrapper + test consumers.</summary>
+    /// <param name="driverInstanceId">The unique identifier for the driver instance.</param>
+    /// <param name="driverConfigJson">The driver's <c>DriverConfig</c> JSON.</param>
+    /// <returns>The constructed <see cref="MTConnectDriver"/> instance.</returns>
+    public static MTConnectDriver CreateInstance(string driverInstanceId, string driverConfigJson)
+        => CreateInstance(driverInstanceId, driverConfigJson, loggerFactory: null);
+
+    /// <summary>Logger-aware overload — used by <see cref="Register"/>'s closure when wired through DI.</summary>
+    /// <param name="driverInstanceId">The unique identifier for the driver instance.</param>
+    /// <param name="driverConfigJson">The driver's <c>DriverConfig</c> JSON.</param>
+    /// <param name="loggerFactory">Optional logger factory for creating loggers per driver instance.</param>
+    /// <returns>The constructed <see cref="MTConnectDriver"/> instance.</returns>
+    /// <exception cref="ArgumentException">
+    ///     <paramref name="driverInstanceId"/> or <paramref name="driverConfigJson"/> is null or blank.
+    /// </exception>
+    /// <exception cref="InvalidOperationException">
+    ///     The config document is unparseable, deserialises to null, omits the required
+    ///     <c>agentUri</c>, or carries an unauthorable enum/tag value. Throwing is correct at this
+    ///     seam: a deployment carrying such a row must fail rather than register a driver pointed at
+    ///     nothing, and the discovery browser's <c>CanBrowse</c> catches factory exceptions so a
+    ///     half-authored config merely disables the address picker.
+    /// </exception>
+    public static MTConnectDriver CreateInstance(
+        string driverInstanceId, string driverConfigJson, ILoggerFactory? loggerFactory)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
+        ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);
+
+        // The single config authority — see the class remarks for why this is not a second DTO.
+        // Note the asymmetry with the driver's own lifecycle path: an empty ("{}" / "[]") document
+        // there means "no config supplied, keep the constructor options", but this factory HAS no
+        // constructor options to keep, so an empty document is simply a config with no agentUri and
+        // must fault.
+        var options = MTConnectDriver.ParseOptions(driverInstanceId, driverConfigJson);
+
+        // Named arguments deliberately: the ctor's trailing parameters are all optional, so a
+        // future insertion could silently re-bind a positional argument to the wrong one.
+        return new MTConnectDriver(
+            options,
+            driverInstanceId,
+            agentClientFactory: null,
+            logger: loggerFactory?.CreateLogger<MTConnectDriver>());
+    }
+}
@@ -0,0 +1,237 @@
+using System.Diagnostics;
+using System.Net.Http;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     One-shot MTConnect Agent reachability probe for the AdminUI's Test Connect button. Issues a
+///     single <c>GET {AgentUri}/probe</c> under the supplied deadline and reports success/failure
+///     with latency — it does not construct or initialize an <see cref="MTConnectDriver"/> instance.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Deliberately does NOT delegate to <see cref="MTConnectDriver.ParseOptions"/>.</b> That
+///         method builds the full driver options document, including every authored
+///         <c>MTConnectTagDefinition</c> (<c>BuildTag</c> can throw on a malformed tag entry that has
+///         nothing to do with reachability). A probe only needs <c>agentUri</c>, so this type parses
+///         its own minimal DTO — a config that is invalid for the driver (bad tag, bad data type) can
+///         still be reachability-tested, matching the AdminUI's "does the endpoint answer" intent for
+///         Test Connect. It also avoids a compile-time dependency on the factory DTO shape
+///         (<c>MTConnectDriverFactoryExtensions</c>), which is authored separately (Task 15).
+///     </para>
+///     <para>
+///         <b>Accepted gap: reachable ≠ deployable.</b> Because only <c>agentUri</c> is read, a
+///         config can show green on Test Connect and still fail to deploy — e.g. a non-positive
+///         <c>requestTimeoutMs</c> or a malformed tag entry the factory's full parse would reject.
+///         This is the direct consequence of the independent-parsing decision above, judged
+///         acceptable because Test Connect's job is "is the endpoint there", not "will this exact
+///         config deploy".
+///     </para>
+///     <para>
+///         <b>Deliberately DOES reuse <see cref="MTConnectAgentClient"/> and
+///         <see cref="MTConnectProbeParser"/> for the actual round trip.</b> Hand-rolling the HTTP
+///         call would have to re-derive the exact behaviour the client already provides: per-call
+///         <see cref="HttpClient.Timeout"/> bounding, a linked-CTS deadline, and — most importantly —
+///         correct handling of an Agent's <c>MTConnectError</c> document served under HTTP 200 (so
+///         <c>EnsureSuccessStatusCode</c> never fires). <see cref="MTConnectProbeParser"/> already
+///         lifts the Agent's own error text into the thrown exception's message; re-parsing by hand
+///         here would either duplicate that logic or under-validate (accepting any 200 response as
+///         healthy, which is precisely the "empty-but-successful" defect class this codebase has hit
+///         before, #485). The one-off cost of a full probe-document parse is negligible next to that
+///         risk.
+///     </para>
+///     <para>
+///         <b>Never throws</b> (the <see cref="IDriverProbe"/> contract): every failure — unparseable
+///         JSON, missing/malformed <c>agentUri</c>, DNS/TCP failure, a non-2xx response, a 200 body
+///         that is not a valid <c>MTConnectDevices</c> document, and timeout — becomes
+///         <c>Ok = false</c> with a message. Genuine caller cancellation is likewise converted rather
+///         than left to propagate, matching <c>ModbusDriverProbe</c>'s posture (its linked-CTS catch
+///         does not distinguish the caller's token from its own deadline).
+///     </para>
+///     <para>
+///         <b>Non-positive <c>timeout</c> (arch-review 01/S-6).</b> A <c>0</c> or negative
+///         timeout does NOT mean "wait forever" — it is replaced with <see cref="FallbackTimeout"/>
+///         (5s, matching <see cref="MTConnectDriverOptions.RequestTimeoutMs"/>'s own default) so an
+///         operator-authorable field can never brick the probe UI.
+///     </para>
+///     <para>
+///         <b>Secrets discipline.</b> <c>AgentUri</c> may carry userinfo credentials
+///         (<c>http://user:pass@host/</c>). Every message this type constructs from the URI uses a
+///         redacted display form (<see cref="RedactedDisplay"/>) built ONLY from
+///         <see cref="Uri.Scheme"/>/<see cref="Uri.Host"/>/<see cref="Uri.Port"/>/<see cref="Uri.AbsolutePath"/>
+///         — never <see cref="Uri.UserInfo"/> and never the raw config string — so a password can
+///         never reach the AdminUI via the returned <see cref="DriverProbeResult.Message"/>.
+///     </para>
+/// </remarks>
+public sealed class MTConnectDriverProbe : IDriverProbe
+{
+    /// <summary>Replaces a non-positive caller <c>timeout</c> — see the type remarks.</summary>
+    private static readonly TimeSpan FallbackTimeout = TimeSpan.FromSeconds(5);
+
+    /// <summary>
+    ///     Caps an excessive caller <c>timeout</c>. <c>CancellationTokenSource.CancelAfter(TimeSpan)</c>'s
+    ///     legal range tops out near ~49.7 days (<see cref="uint.MaxValue"/> ms minus one); an
+    ///     uncapped pathological value (e.g. a caller passing <c>TimeSpan.FromDays(1000)</c>) throws
+    ///     <see cref="ArgumentOutOfRangeException"/> straight out of
+    ///     <c>CancelAfter</c>, which would violate the "Never throws" contract just as surely as a
+    ///     non-positive timeout meaning "wait forever" would (arch-review 01/S-6 — this is the same
+    ///     defect class, the high end rather than the low end). 10 minutes is generous for a
+    ///     reachability probe and leaves an enormous margin under the legal ceiling.
+    /// </summary>
+    private static readonly TimeSpan MaxTimeout = TimeSpan.FromMinutes(10);
+
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        UnmappedMemberHandling = JsonUnmappedMemberHandling.Skip,
+        Converters = { new JsonStringEnumConverter() },
+    };
+
+    /// <summary>Test seam: routes the reused <see cref="MTConnectAgentClient"/> through a stub handler so response-shape cases need no socket.</summary>
+    private readonly HttpMessageHandler? _handler;
+
+    /// <summary>Creates the probe used in production (real sockets).</summary>
+    public MTConnectDriverProbe()
+        : this(handler: null)
+    {
+    }
+
+    /// <summary>Test seam constructor — see <see cref="_handler"/>.</summary>
+    internal MTConnectDriverProbe(HttpMessageHandler? handler)
+    {
+        _handler = handler;
+    }
+
+    /// <inheritdoc />
+    /// <remarks>
+    ///     Sourced from the <see cref="DriverTypeNames"/> constant, not a literal — the probe is
+    ///     looked up by <c>AdminOperationsActor</c> under this key, so a drift from the constant
+    ///     silently disables the Test Connect button rather than failing anything at build time.
+    /// </remarks>
+    public string DriverType => DriverTypeNames.MTConnect;
+
+    /// <summary>Minimal probe-only config shape. Deliberately independent of the factory DTO — see the type remarks.</summary>
+    private sealed class MTConnectProbeConfigDto
+    {
+        public string? AgentUri { get; set; }
+    }
+
+    /// <inheritdoc />
+    public async Task<DriverProbeResult> ProbeAsync(string configJson, TimeSpan timeout, CancellationToken ct)
+    {
+        MTConnectProbeConfigDto? dto;
+        try
+        {
+            dto = JsonSerializer.Deserialize<MTConnectProbeConfigDto>(configJson, JsonOptions);
+        }
+        catch (Exception ex)
+        {
+            return new(false, $"Config JSON is invalid: {ex.Message}", null);
+        }
+
+        if (dto is null)
+        {
+            return new(false, "Config JSON deserialized to null.", null);
+        }
+
+        var agentUri = dto.AgentUri?.Trim();
+        if (string.IsNullOrWhiteSpace(agentUri))
+        {
+            return new(false, "Config has no agentUri to probe.", null);
+        }
+
+        if (!Uri.TryCreate(agentUri, UriKind.Absolute, out var parsed) ||
+            (parsed.Scheme != Uri.UriSchemeHttp && parsed.Scheme != Uri.UriSchemeHttps))
+        {
+            return new(false, "Config's agentUri is not an absolute http(s) URI.", null);
+        }
+
+        var safeUri = RedactedDisplay(parsed);
+
+        // arch-review 01/S-6: a non-positive timeout must never mean "wait forever" (low end), and a
+        // pathologically large one must never overrun CancelAfter's legal range (high end) — see
+        // MaxTimeout.
+        var effectiveTimeout = timeout > TimeSpan.Zero ? timeout : FallbackTimeout;
+        if (effectiveTimeout > MaxTimeout)
+        {
+            effectiveTimeout = MaxTimeout;
+        }
+
+        var requestTimeoutMs = Math.Max(1, (int)Math.Ceiling(effectiveTimeout.TotalMilliseconds));
+
+        var sw = Stopwatch.StartNew();
+        using var cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+        cts.CancelAfter(effectiveTimeout);
+
+        var options = new MTConnectDriverOptions
+        {
+            AgentUri = agentUri,
+            RequestTimeoutMs = requestTimeoutMs,
+        };
+
+        try
+        {
+            using var client = new MTConnectAgentClient(options, _handler);
+            _ = await client.ProbeAsync(cts.Token).ConfigureAwait(false);
+            sw.Stop();
+
+            return new(true, $"MTConnect /probe OK ({safeUri})", sw.Elapsed);
+        }
+        catch (OperationCanceledException)
+        {
+            // Covers both the caller's token and our own CancelAfter deadline firing — see the type
+            // remarks on why cancellation is never allowed to propagate.
+            return new(false, $"Probe timed out after {effectiveTimeout.TotalSeconds:F0}s.", null);
+        }
+        catch (TimeoutException)
+        {
+            // MTConnectAgentClient's own request-deadline signal.
+            return new(false, $"Probe timed out after {effectiveTimeout.TotalSeconds:F0}s.", null);
+        }
+        catch (HttpRequestException ex)
+        {
+            // Connection failure or non-2xx status. HttpRequestException messages describe the
+            // socket endpoint or status code, never the request URI/userinfo, so ex.Message is safe.
+            return new(false, $"Request to {safeUri} failed: {ex.Message}", null);
+        }
+        catch (InvalidDataException ex)
+        {
+            // MTConnectProbeParser: not well-formed XML, not an MTConnectDevices document (including
+            // an MTConnectError-under-200, whose own errorCode/text ex.Message already carries), or
+            // a document with no devices. Never includes the request URI.
+            return new(false, $"Agent at {safeUri} did not return a valid MTConnect device model: {ex.Message}", null);
+        }
+        catch (ArgumentException)
+        {
+            // Defensive: MTConnectAgentClient's own AgentUri validation, reached only if this
+            // method's own Uri.TryCreate above passed but the client's stricter check disagreed.
+            // Never forward the exception's message verbatim — it can echo the raw (possibly
+            // credentialed) config string.
+            return new(false, "Config's agentUri was rejected by the MTConnect client as invalid.", null);
+        }
+        catch (Exception ex)
+        {
+            // Last-resort catch for an exception type none of the above enumerate. Deliberately does
+            // NOT forward ex.Message: unlike the typed catches above (each individually audited for
+            // whether its message can carry the raw AgentUri/userinfo), an unenumerated type has no
+            // such audit, so ex.Message is an open door for a credential leak. safeUri + the
+            // exception's TYPE name is enough for an operator to act on without that risk.
+            return new(false, $"Probe against {safeUri} failed unexpectedly ({ex.GetType().Name}).", null);
+        }
+    }
+
+    /// <summary>
+    ///     Builds a display form of <paramref name="uri"/> for use in returned messages, composed
+    ///     ONLY from scheme/host/port/path — never <see cref="Uri.UserInfo"/> — so a credentialed
+    ///     <c>AgentUri</c> can never leak a password into the AdminUI.
+    /// </summary>
+    private static string RedactedDisplay(Uri uri)
+    {
+        var portSegment = uri.IsDefaultPort ? string.Empty : $":{uri.Port}";
+
+        return $"{uri.Scheme}://{uri.Host}{portSegment}{uri.AbsolutePath}";
+    }
+}
@@ -0,0 +1,193 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     Result of an Agent <c>/probe</c> request: the full device hierarchy the Agent exposes.
+///     Produced by <see cref="IMTConnectAgentClient.ProbeAsync"/>. This is the neutral shape both
+///     the TrakHound-backed implementation and a hand-rolled XML fallback must produce — nothing
+///     downstream of <see cref="IMTConnectAgentClient"/> ever sees a TrakHound type or an
+///     <c>XElement</c>.
+/// </summary>
+/// <param name="Devices">Every device the Agent's probe response declares.</param>
+public sealed record MTConnectProbeModel(IReadOnlyList<MTConnectDevice> Devices);
+
+/// <summary>
+///     Common shape shared by <see cref="MTConnectDevice"/> and <see cref="MTConnectComponent"/>:
+///     each may directly own data items and/or nest further components, to arbitrary depth. Backs
+///     the <see cref="MTConnectComponentTreeExtensions.AllDataItems"/> recursive walk.
+/// </summary>
+public interface IMTConnectComponentContainer
+{
+    /// <summary>Components nested directly under this device/component (may be empty).</summary>
+    IReadOnlyList<MTConnectComponent> Components { get; }
+
+    /// <summary>Data items declared directly on this device/component (may be empty).</summary>
+    IReadOnlyList<MTConnectDataItem> DataItems { get; }
+}
+
+/// <summary>
+///     One MTConnect device from the Agent's probe response — the root of a nested
+///     component/data-item tree.
+/// </summary>
+/// <param name="Id">The device's <c>id</c> attribute.</param>
+/// <param name="Name">The device's <c>name</c> attribute, when the Agent supplies one.</param>
+/// <param name="Components">Child components declared directly under this device.</param>
+/// <param name="DataItems">Data items declared directly on this device (outside any component).</param>
+public sealed record MTConnectDevice(
+    string Id,
+    string? Name,
+    IReadOnlyList<MTConnectComponent> Components,
+    IReadOnlyList<MTConnectDataItem> DataItems) : IMTConnectComponentContainer;
+
+/// <summary>
+///     One MTConnect component (e.g. <c>Axes</c>, <c>Controller</c>, <c>Path</c>) from the Agent's
+///     probe response. Components nest to arbitrary depth — a component may itself contain further
+///     child components as well as data items.
+/// </summary>
+/// <param name="Id">The component's <c>id</c> attribute.</param>
+/// <param name="Name">The component's <c>name</c> attribute, when the Agent supplies one.</param>
+/// <param name="Components">Child components nested directly under this component.</param>
+/// <param name="DataItems">Data items declared directly on this component.</param>
+public sealed record MTConnectComponent(
+    string Id,
+    string? Name,
+    IReadOnlyList<MTConnectComponent> Components,
+    IReadOnlyList<MTConnectDataItem> DataItems) : IMTConnectComponentContainer;
+
+/// <summary>
+///     One MTConnect DataItem declaration from the Agent's probe response. This is pure metadata —
+///     it carries no observed value; values arrive separately via
+///     <see cref="IMTConnectAgentClient.CurrentAsync"/> / <see cref="IMTConnectAgentClient.SampleAsync"/>
+///     and are correlated back to a data item by <see cref="Id"/>.
+/// </summary>
+/// <param name="Id">
+///     The DataItem's <c>id</c> attribute — globally unique within the Agent's probe response and
+///     the correlation key used against <see cref="MTConnectObservation.DataItemId"/>.
+/// </param>
+/// <param name="Name">The DataItem's <c>name</c> attribute, when the Agent supplies one.</param>
+/// <param name="Category">The DataItem's <c>category</c> attribute — <c>SAMPLE</c>, <c>EVENT</c>, or <c>CONDITION</c>.</param>
+/// <param name="Type">The DataItem's <c>type</c> attribute (e.g. <c>POSITION</c>, <c>EXECUTION</c>).</param>
+/// <param name="SubType">The DataItem's <c>subType</c> attribute (e.g. <c>ACTUAL</c>, <c>COMMANDED</c>), when present.</param>
+/// <param name="Units">The DataItem's <c>units</c> attribute (e.g. <c>MILLIMETER</c>, <c>REVOLUTION/MINUTE</c>), when present.</param>
+/// <param name="Representation">
+///     The DataItem's <c>representation</c> attribute (e.g. <c>TIME_SERIES</c>, <c>DISCRETE</c>);
+///     absent means the MTConnect default (<c>VALUE</c>).
+/// </param>
+/// <param name="SampleCount">
+///     The DataItem's <c>sampleCount</c> attribute — element count for a <c>TIME_SERIES</c>
+///     representation. Present only on data items that carry one.
+/// </param>
+public sealed record MTConnectDataItem(
+    string Id,
+    string? Name,
+    string Category,
+    string Type,
+    string? SubType,
+    string? Units,
+    string? Representation,
+    int? SampleCount);
+
+/// <summary>
+///     Result of an Agent <c>/current</c> request, or of a single multipart chunk from a
+///     <c>/sample</c> stream. Produced by <see cref="IMTConnectAgentClient.CurrentAsync"/> and
+///     <see cref="IMTConnectAgentClient.SampleAsync"/>.
+/// </summary>
+/// <param name="InstanceId">
+///     The Agent's current instance id (its MTConnectStreams header <c>instanceId</c>). Changes
+///     whenever the Agent restarts or its underlying device model changes; the driver watches this
+///     for change to raise rediscovery rather than trusting a stale observation snapshot.
+/// </param>
+/// <param name="NextSequence">
+///     The header <c>nextSequence</c> — the sequence number to resume a subsequent
+///     <see cref="IMTConnectAgentClient.SampleAsync"/> call <c>from</c>.
+/// </param>
+/// <param name="FirstSequence">
+///     The header <c>firstSequence</c> — the oldest sequence number still held in the Agent's
+///     circular buffer. Load-bearing for sequence-gap detection: a caller that requested
+///     <c>from</c> a sequence older than this chunk's <see cref="FirstSequence"/> has fallen out of
+///     the Agent's buffer and must re-baseline via <see cref="IMTConnectAgentClient.CurrentAsync"/>.
+/// </param>
+/// <param name="Observations">
+///     The observations carried in this snapshot/chunk, in Agent-supplied order. Never <c>null</c>;
+///     empty when the chunk carries no new observations (e.g. a heartbeat).
+/// </param>
+public sealed record MTConnectStreamsResult(
+    long InstanceId,
+    long NextSequence,
+    long FirstSequence,
+    IReadOnlyList<MTConnectObservation> Observations);
+
+/// <summary>
+///     One observed value for a single DataItem, as reported in a <c>/current</c> snapshot or a
+///     <c>/sample</c> stream chunk. Deliberately dumb: <see cref="Value"/> is carried as the raw
+///     string the Agent reported (including the literal <c>UNAVAILABLE</c>) with no interpretation
+///     applied here — coercing <c>UNAVAILABLE</c> to a bad-quality status and converting the string
+///     to the tag's <c>DriverDataType</c> are the observation index's job, not this layer's.
+/// </summary>
+/// <param name="DataItemId">
+///     The reporting DataItem's <c>id</c> — correlates back to <see cref="MTConnectDataItem.Id"/>
+///     from the probe model.
+/// </param>
+/// <param name="Value">
+///     The observed value exactly as the Agent reported it, or the literal string
+///     <c>"UNAVAILABLE"</c> when the Agent has no current value for the data item. Never
+///     pre-parsed into a nullable or an enum at this layer.
+/// </param>
+/// <param name="TimestampUtc">
+///     The observation's Agent-reported timestamp, normalized to UTC (<see cref="DateTime.Kind"/>
+///     is always <see cref="DateTimeKind.Utc"/>). Becomes the OPC UA variable's SourceTimestamp.
+/// </param>
+/// <param name="IsStructured">
+///     <c>true</c> when the Agent carried this observation's real content in <b>child elements</b>
+///     rather than as text — an MTConnect 2.0 <c>DATA_SET</c> / <c>TABLE</c> observation, whose
+///     content is a list of <c>&lt;Entry key="…"&gt;</c> elements.
+///     <para>
+///         <b>Why the flag exists, and why only the parser can set it.</b> <see cref="Value"/> is
+///         the element's concatenated descendant text, so a two-entry data set reads as the single
+///         token <c>"12"</c> — keys discarded, values run together. The observation index cannot
+///         detect that after the fact: neither this record nor the tag definition carries the
+///         DataItem's <c>representation</c>, and no value-shape heuristic can work, because
+///         concatenated entries are indistinguishable from a legitimate space-bearing EVENT such as
+///         a <c>Message</c> reading <c>"Coolant level low"</c>. The one reliable discriminator —
+///         that the observation element had element children — exists only while the XML is still
+///         XML.
+///     </para>
+///     <para>
+///         Deliberately a <b>neutral fact about the wire shape</b>, not a status: mapping it to a
+///         quality code is the observation index's job (it codes these
+///         <c>BadNotSupported</c> rather than publishing concatenated noise as Good). Defaults to
+///         <c>false</c>, the shape of every ordinary scalar observation.
+///     </para>
+/// </param>
+public sealed record MTConnectObservation(
+    string DataItemId,
+    string Value,
+    DateTime TimestampUtc,
+    bool IsStructured = false);
+
+/// <summary>
+///     Recursive helpers over the <see cref="IMTConnectComponentContainer"/> device/component tree.
+/// </summary>
+public static class MTConnectComponentTreeExtensions
+{
+    /// <summary>
+    ///     Enumerates every data item owned by this device or component, plus every data item owned
+    ///     by any component nested beneath it, to arbitrary depth. Order is depth-first: a node's
+    ///     own data items first, then each child component's data items in turn.
+    /// </summary>
+    /// <param name="container">The device or component to walk.</param>
+    public static IEnumerable<MTConnectDataItem> AllDataItems(this IMTConnectComponentContainer container)
+    {
+        foreach (var dataItem in container.DataItems)
+        {
+            yield return dataItem;
+        }
+
+        foreach (var child in container.Components)
+        {
+            foreach (var dataItem in child.AllDataItems())
+            {
+                yield return dataItem;
+            }
+        }
+    }
+}
@@ -0,0 +1,415 @@
+using System.Collections.Concurrent;
+using System.Collections.Frozen;
+using System.Globalization;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     The driver's live <c>dataItemId → <see cref="DataValueSnapshot"/></c> map: the single place
+///     an Agent observation's weakly-typed text becomes an OPC UA-shaped value + quality +
+///     timestamp. Written by the <c>/current</c> baseline read and by the <c>/sample</c> long-poll
+///     pump; read by <c>IReadable.ReadAsync</c> and the subscription fan-out.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Quality mapping (design §3.3).</b> MTConnect has exactly one way to say "I have no
+///         value": the literal token <c>UNAVAILABLE</c>. It arrives as a Sample/Event's text, and —
+///         after <see cref="MTConnectStreamsParser"/> normalizes the <c>&lt;Unavailable/&gt;</c>
+///         element name — as a CONDITION's value on that same exact spelling. It maps to
+///         <c>BadNoCommunication</c> with a <c>null</c> value: the Agent is reachable, the machine's
+///         data item is not. The match is <b>ordinal and case-sensitive</b> against the one spelling
+///         the parser guarantees; a case-insensitive match would swallow a legitimate free-text
+///         EVENT whose value happens to read "Unavailable".
+///     </para>
+///     <para>
+///         <b>Failure posture.</b> This type sits under <c>IReadable</c> and must never throw across
+///         that boundary on account of observation content. Every unusable observation degrades to a
+///         Bad-coded snapshot that still carries the Agent's source timestamp, so an operator can
+///         always see <i>when</i> the driver last heard about the tag even when it cannot show
+///         <i>what</i>. The only exceptions raised are <see cref="ArgumentNullException"/> for a null
+///         argument — a programming error, not data.
+///     </para>
+///     <para>
+///         <b>Status codes</b> are the canonical <c>Opc.Ua.StatusCodes</c> numeric values, declared
+///         once each below. Note that <see cref="BadTypeMismatch"/> is <c>0x80740000</c>: the
+///         <c>0x80730000</c> that four sibling drivers declare under that name is really
+///         <c>BadWriteNotSupported</c>, which would be actively misleading on a read path and
+///         renders as bare "Bad" in the driver CLI's <c>SnapshotFormatter</c>.
+///     </para>
+///     <para>
+///         <b>Thread safety.</b> Backed by a <see cref="ConcurrentDictionary{TKey,TValue}"/> and
+///         guaranteed <b>per-key atomic</b> — nothing more, deliberately. <see cref="Apply"/> writes
+///         each dataItemId exactly once per call with a single whole-snapshot assignment, so a
+///         reader can never observe a torn snapshot (a Good code beside a stale value). It is
+///         explicitly <b>not</b> a whole-batch atomic swap: OPC UA reads are per-tag and the driver
+///         offers no cross-tag consistency contract, <c>/sample</c> chunks are deltas whose
+///         interleaving is indistinguishable from two adjacent legal chunks, and a whole-index lock
+///         would serialize the pump against every read for no semantic gain.
+///     </para>
+///     <para>
+///         <b>Shapes this build does not represent</b> are coded <c>BadNotSupported</c> with a null
+///         value rather than approximated: a <c>TIME_SERIES</c> vector (array materialization is
+///         deferred to P1.5) and a <c>DATA_SET</c> / <c>TABLE</c> observation. The latter carries its
+///         real content in <c>&lt;Entry key=…&gt;</c> child elements, which reach a text-valued
+///         observation concatenated with the keys discarded — a two-entry set reads as the single
+///         token <c>"12"</c> — and because the type inference correctly demotes those
+///         representations to <see cref="DriverDataType.String"/>, coercion would otherwise
+///         "succeed" into a Good-coded snapshot carrying noise. This index cannot detect that shape
+///         itself (no value heuristic can separate concatenated entries from a legitimate
+///         space-bearing EVENT such as a <c>Message</c> reading "Coolant level low"), so it relies on
+///         <see cref="MTConnectObservation.IsStructured"/>, which
+///         <see cref="MTConnectStreamsParser"/> sets while the XML is still XML.
+///     </para>
+/// </remarks>
+internal sealed class MTConnectObservationIndex
+{
+    /// <summary>
+    ///     The one token that means "the Agent has no value for this data item". Matched ordinally:
+    ///     the parser already normalizes a CONDITION's <c>&lt;Unavailable/&gt;</c> element name onto
+    ///     this exact spelling, so every category lands on one comparison.
+    /// </summary>
+    private const string UnavailableSentinel = "UNAVAILABLE";
+
+    private const uint Good = 0x00000000u;
+
+    /// <summary>The Agent reported <c>UNAVAILABLE</c>, or supplied no text at all.</summary>
+    private const uint BadNoCommunication = 0x80310000u;
+
+    /// <summary>The tag is authored but the Agent has not yet reported it.</summary>
+    private const uint BadWaitingForInitialData = 0x80320000u;
+
+    /// <summary>The dataItemId is neither authored nor ever observed.</summary>
+    private const uint BadNodeIdUnknown = 0x80340000u;
+
+    /// <summary>The Agent reported a number the authored type cannot represent.</summary>
+    private const uint BadOutOfRange = 0x803C0000u;
+
+    /// <summary>The observation's shape is real data this build cannot represent (TIME_SERIES vectors).</summary>
+    private const uint BadNotSupported = 0x803D0000u;
+
+    /// <summary>The Agent reported text that is not a value of the authored type at all.</summary>
+    private const uint BadTypeMismatch = 0x80740000u;
+
+    /// <summary>
+    ///     MTConnect's CONDITION state vocabulary, ranked by severity. Used only to reconcile
+    ///     several states reported for one dataItemId <i>within a single document</i> — see
+    ///     <see cref="Reconcile"/>. An active <c>Fault</c> outranks <c>UNAVAILABLE</c> because a
+    ///     fault is information and an absent value is not. Case-insensitive so a vendor's casing
+    ///     of a state element still ranks; the parser itself emits the canonical spellings.
+    /// </summary>
+    private static readonly FrozenDictionary<string, int> ConditionSeverity =
+        new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase)
+        {
+            [UnavailableSentinel] = 0,
+            ["Normal"] = 1,
+            ["Warning"] = 2,
+            ["Fault"] = 3,
+        }.ToFrozenDictionary(StringComparer.OrdinalIgnoreCase);
+
+    private readonly ConcurrentDictionary<string, DataValueSnapshot> _snapshots = new(StringComparer.Ordinal);
+    private readonly FrozenDictionary<string, MTConnectTagDefinition> _tags;
+    private readonly TimeProvider _timeProvider;
+
+    /// <summary>
+    ///     Builds an index over the driver instance's authored tags.
+    /// </summary>
+    /// <param name="tags">
+    ///     The authored tags, keyed by <see cref="MTConnectTagDefinition.FullName"/> (the DataItem
+    ///     <c>id</c>) — normally <see cref="MTConnectDriverOptions.Tags"/>. <c>null</c> or empty is
+    ///     legal and means "no authored types": every observation is then indexed as its raw text
+    ///     under <see cref="DriverDataType.String"/>.
+    ///     <para>
+    ///         Nothing enforces <c>FullName</c> uniqueness at the options layer, so a duplicate is
+    ///         operator-authorable. <b>The last definition wins</b> rather than throwing: refusing to
+    ///         construct would turn an authoring slip into a driver that will not start, whereas
+    ///         last-wins is deterministic and costs only that one tag's coercion type.
+    ///     </para>
+    /// </param>
+    /// <param name="timeProvider">Clock behind <c>ServerTimestampUtc</c>; defaults to <see cref="TimeProvider.System"/>.</param>
+    public MTConnectObservationIndex(
+        IEnumerable<MTConnectTagDefinition>? tags = null,
+        TimeProvider? timeProvider = null)
+    {
+        _timeProvider = timeProvider ?? TimeProvider.System;
+
+        var map = new Dictionary<string, MTConnectTagDefinition>(StringComparer.Ordinal);
+        foreach (var tag in tags ?? [])
+        {
+            if (tag is null || string.IsNullOrWhiteSpace(tag.FullName)) continue;
+
+            map[tag.FullName] = tag;
+        }
+
+        _tags = map.ToFrozenDictionary(StringComparer.Ordinal);
+    }
+
+    /// <summary>The number of distinct dataItemIds currently indexed.</summary>
+    public int Count => _snapshots.Count;
+
+    /// <summary>
+    ///     Folds a <c>/current</c> snapshot or one <c>/sample</c> chunk into the index. Observations
+    ///     with no authored tag are indexed too — the Agent streams the whole device, so they are
+    ///     normal, and dropping them would make a streaming-but-not-yet-authored data item
+    ///     indistinguishable from one that does not exist.
+    /// </summary>
+    /// <param name="result">The parsed streams document. An observation-free result is a legal
+    /// keep-alive and leaves the index untouched.</param>
+    /// <exception cref="ArgumentNullException"><paramref name="result"/> is <c>null</c>.</exception>
+    public void Apply(MTConnectStreamsResult result)
+    {
+        ArgumentNullException.ThrowIfNull(result);
+
+        if (result.Observations is not { Count: > 0 }) return;
+
+        // Duplicates are reconciled on the RAW observations first, so each dataItemId is written
+        // exactly once below as a single atomic whole-snapshot assignment. Doing it the other way
+        // — writing every observation and merging snapshots in place — would need a read-modify-write
+        // per key and could expose a half-merged state to a concurrent reader.
+        var resolved = new Dictionary<string, MTConnectObservation>(StringComparer.Ordinal);
+        foreach (var observation in result.Observations)
+        {
+            if (observation is null || string.IsNullOrWhiteSpace(observation.DataItemId)) continue;
+
+            resolved[observation.DataItemId] =
+                resolved.TryGetValue(observation.DataItemId, out var incumbent)
+                    ? Reconcile(incumbent, observation)
+                    : observation;
+        }
+
+        foreach (var (dataItemId, observation) in resolved)
+        {
+            _snapshots[dataItemId] = BuildSnapshot(observation);
+        }
+    }
+
+    /// <summary>
+    ///     Returns the current snapshot for a DataItem. Never <c>null</c> and never throws: an
+    ///     unknown or not-yet-reported id yields a Bad-coded snapshot rather than an error.
+    /// </summary>
+    /// <param name="dataItemId">The DataItem <c>id</c> the tag binds.</param>
+    /// <returns>
+    ///     The indexed snapshot; else <c>BadWaitingForInitialData</c> when the id is authored but
+    ///     the Agent has not reported it yet (the standard OPC UA "subscribed, no value yet"
+    ///     state); else <c>BadNodeIdUnknown</c>. The two are kept distinct because collapsing them
+    ///     would tell an operator their correctly-authored tag does not exist.
+    /// </returns>
+    public DataValueSnapshot Get(string dataItemId)
+    {
+        if (!string.IsNullOrWhiteSpace(dataItemId) &&
+            _snapshots.TryGetValue(dataItemId, out var snapshot))
+        {
+            return snapshot;
+        }
+
+        var status = !string.IsNullOrWhiteSpace(dataItemId) && _tags.ContainsKey(dataItemId)
+            ? BadWaitingForInitialData
+            : BadNodeIdUnknown;
+
+        return new DataValueSnapshot(null, status, null, Now);
+    }
+
+    /// <summary>
+    ///     Drops every indexed observation. The Agent-restart re-baseline: when the streams header's
+    ///     <c>instanceId</c> changes, every value the index holds describes a device model that no
+    ///     longer exists, and serving it would be worse than serving nothing.
+    /// </summary>
+    public void Clear() => _snapshots.Clear();
+
+    private DateTime Now => _timeProvider.GetUtcNow().UtcDateTime;
+
+    /// <summary>
+    ///     Picks the winner when one dataItemId appears more than once in a single document. A
+    ///     <c>&lt;Condition&gt;</c> container legitimately carries several <b>simultaneously active</b>
+    ///     states (a Fault and a Warning at once), so for a pair of recognized condition state words
+    ///     the <b>most severe</b> wins — plain last-wins would under-report an active Fault as a
+    ///     Warning purely because of element order. Anything else is last-wins, matching the Agent's
+    ///     ascending-sequence ordering.
+    ///     <para>
+    ///         Deliberately scoped to one document: a later <see cref="Apply"/> is the Agent's new
+    ///         statement of the state, so a cleared fault must fall back to Normal. A worst-of that
+    ///         spanned Applies would latch every fault forever.
+    ///     </para>
+    /// </summary>
+    private static MTConnectObservation Reconcile(MTConnectObservation incumbent, MTConnectObservation challenger)
+    {
+        if (ConditionSeverity.TryGetValue(incumbent.Value ?? string.Empty, out var incumbentSeverity) &&
+            ConditionSeverity.TryGetValue(challenger.Value ?? string.Empty, out var challengerSeverity))
+        {
+            return challengerSeverity >= incumbentSeverity ? challenger : incumbent;
+        }
+
+        return challenger;
+    }
+
+    private DataValueSnapshot BuildSnapshot(MTConnectObservation observation)
+    {
+        var serverTimestamp = Now;
+        var sourceTimestamp = DateTime.SpecifyKind(observation.TimestampUtc, DateTimeKind.Utc);
+
+        // No text at all is the degenerate spelling of "no value": MTConnect defines UNAVAILABLE as
+        // the only way to report absence, so an empty element is not an empty string value.
+        if (string.IsNullOrWhiteSpace(observation.Value) ||
+            string.Equals(observation.Value, UnavailableSentinel, StringComparison.Ordinal))
+        {
+            return new DataValueSnapshot(null, BadNoCommunication, sourceTimestamp, serverTimestamp);
+        }
+
+        // DATA_SET / TABLE: the Agent carried the content in <Entry key="…"> child elements, so
+        // Value is their concatenated text with the keys discarded (a two-entry set reads "12").
+        // Publishing that as a Good string would be noise an operator would trust. Checked before
+        // the tag lookup because it is a fact about the wire shape, true whether or not the data
+        // item is authored — and after the sentinel, so an unavailable data set still reports the
+        // truthful no-comms.
+        if (observation.IsStructured)
+        {
+            return new DataValueSnapshot(null, BadNotSupported, sourceTimestamp, serverTimestamp);
+        }
+
+        _tags.TryGetValue(observation.DataItemId, out var tag);
+
+        // TIME_SERIES vectors arrive as one space-separated string. P1 does not materialize OPC UA
+        // arrays (deferred to P1.5), and the honest answer is "real data I cannot represent" — not a
+        // type mismatch, and emphatically not the first element parsed out and served as Good.
+        // Checked AFTER the sentinel so an unavailable array tag still reports the truthful no-comms.
+        if (tag is { IsArray: true })
+        {
+            return new DataValueSnapshot(null, BadNotSupported, sourceTimestamp, serverTimestamp);
+        }
+
+        // An unauthored observation has no declared target type; String is the only coercion that
+        // cannot fail, and it carries the Agent's text with no interpretation applied.
+        var status = Coerce(observation.Value, tag?.DriverDataType ?? DriverDataType.String, out var value);
+
+        return status == Good
+            ? new DataValueSnapshot(value, Good, sourceTimestamp, serverTimestamp)
+            : new DataValueSnapshot(null, status, sourceTimestamp, serverTimestamp);
+    }
+
+    /// <summary>
+    ///     Converts the Agent's text to the tag's authored type. Every parse is
+    ///     <see cref="CultureInfo.InvariantCulture"/>: MTConnect is an invariant-format wire, and a
+    ///     host running a comma-decimal culture would otherwise read <c>123.4567</c> as
+    ///     <c>1234567</c> — a silently wrong value under Good quality, the worst possible outcome.
+    /// </summary>
+    /// <returns><see cref="Good"/> on success; otherwise a Bad code and a <c>null</c> value.</returns>
+    private static uint Coerce(string raw, DriverDataType type, out object? value)
+    {
+        value = null;
+        var text = raw.Trim();
+
+        switch (type)
+        {
+            // Reference is a Galaxy-style attribute reference encoded as an OPC UA String. It is
+            // never a sensible authoring for MTConnect, but degrading it to text is harmless where
+            // rejecting it would break a tag for no protection.
+            case DriverDataType.String:
+            case DriverDataType.Reference:
+                value = raw;
+                return Good;
+
+            case DriverDataType.Boolean:
+                if (bool.TryParse(text, out var flag)) { value = flag; return Good; }
+                if (text is "1") { value = true; return Good; }
+                if (text is "0") { value = false; return Good; }
+                return BadTypeMismatch;
+
+            case DriverDataType.DateTime:
+                if (DateTime.TryParse(
+                        text,
+                        CultureInfo.InvariantCulture,
+                        DateTimeStyles.AdjustToUniversal | DateTimeStyles.AssumeUniversal,
+                        out var moment))
+                {
+                    value = DateTime.SpecifyKind(moment, DateTimeKind.Utc);
+                    return Good;
+                }
+
+                return BadTypeMismatch;
+
+            case DriverDataType.Float32:
+                if (float.TryParse(text, NumberStyles.Float, CultureInfo.InvariantCulture, out var single))
+                {
+                    value = single;
+                    return Good;
+                }
+
+                return BadTypeMismatch;
+
+            case DriverDataType.Float64:
+                if (double.TryParse(text, NumberStyles.Float, CultureInfo.InvariantCulture, out var real))
+                {
+                    value = real;
+                    return Good;
+                }
+
+                return BadTypeMismatch;
+
+            case DriverDataType.Int16:
+                if (short.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var i16))
+                {
+                    value = i16;
+                    return Good;
+                }
+
+                break;
+
+            case DriverDataType.Int32:
+                if (int.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var i32))
+                {
+                    value = i32;
+                    return Good;
+                }
+
+                break;
+
+            case DriverDataType.Int64:
+                if (long.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var i64))
+                {
+                    value = i64;
+                    return Good;
+                }
+
+                break;
+
+            case DriverDataType.UInt16:
+                if (ushort.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var u16))
+                {
+                    value = u16;
+                    return Good;
+                }
+
+                break;
+
+            case DriverDataType.UInt32:
+                if (uint.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var u32))
+                {
+                    value = u32;
+                    return Good;
+                }
+
+                break;
+
+            case DriverDataType.UInt64:
+                if (ulong.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var u64))
+                {
+                    value = u64;
+                    return Good;
+                }
+
+                break;
+
+            default:
+                // A DriverDataType this driver has no rule for. Text always round-trips, so serving
+                // it beats failing a tag over an enum member added later.
+                value = raw;
+                return Good;
+        }
+
+        // Integer parse failed. Distinguishing the two causes is worth one extra parse: it tells an
+        // operator whether to retype the tag or widen it.
+        return double.TryParse(text, NumberStyles.Float, CultureInfo.InvariantCulture, out _)
+            ? BadOutOfRange   // a number the authored type cannot represent (overflow, or a fraction)
+            : BadTypeMismatch; // not a number at all
+    }
+}
@@ -0,0 +1,189 @@
+using System.Xml;
+using System.Xml.Linq;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     Turns an MTConnect Agent <c>/probe</c> response (an <c>MTConnectDevices</c> XML document)
+///     into the neutral <see cref="MTConnectProbeModel"/>. Deliberately a pure, socket-free static
+///     so the whole parse is unit-testable against canned fixtures.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Why hand-rolled rather than TrakHound.</b> The TrakHound packages Task 0 pinned
+///         (<c>MTConnect.NET-Common</c> + <c>-HTTP</c> 6.9.0.2 — both dropped in Task 7) contain <b>no</b>
+///         <c>IResponseDocumentFormatter</c> implementation — the XML formatter ships in the
+///         separate, unreferenced <c>MTConnect.NET-XML</c> package — so
+///         <c>ResponseDocumentFormatter.CreateDevicesResponseDocument("xml", stream)</c> answers
+///         <c>Success = false</c> / "Document Formatter Not found for &quot;xml&quot;" (verified by
+///         reflection + live invocation against this repo's own fixture, 2026-07-24). TrakHound also
+///         offers no socket-free public parse entry point, which the plan requires.
+///     </para>
+///     <para>
+///         <b>Three shapes of the wire format this parser is built around.</b>
+///         (1) A device may declare data items <i>directly</i> on <c>&lt;Device&gt;&lt;DataItems&gt;</c>,
+///         outside any component — a walker that only recurses <c>&lt;Components&gt;</c> silently
+///         drops them.
+///         (2) The children of <c>&lt;Components&gt;</c> are named for the component <i>type</i>
+///         (<c>&lt;Controller&gt;</c>, <c>&lt;Path&gt;</c>, <c>&lt;Axes&gt;</c>, …) — there is no
+///         literal <c>&lt;Component&gt;</c> element — so <i>every</i> element child of
+///         <c>&lt;Components&gt;</c> is a component.
+///         (3) The document is XML-namespaced and the namespace URI carries the MTConnect version
+///         (<c>urn:mtconnect.org:MTConnectDevices:1.3</c> … <c>:2.0</c>). Element matching and
+///         attribute reading therefore go through <see cref="MTConnectXml"/>, whose two rules
+///         (match on local name, read attributes unqualified) are shared verbatim with
+///         <see cref="MTConnectStreamsParser"/> — see that type for why each rule exists.
+///     </para>
+///     <para>
+///         <b>One deliberate divergence from the streams parser: no BOM/whitespace trim here.</b>
+///         A <c>/probe</c> body arrives whole from <c>HttpContent</c>, so it begins exactly where
+///         the Agent's document begins. A <c>/sample</c> chunk, by contrast, is lifted out of a
+///         multipart frame and can carry a byte-order mark or the framing's own line break ahead of
+///         the XML declaration, which <c>XmlReader</c> rejects — hence the trim there and not here.
+///         This asymmetry is intentional, not an oversight.
+///     </para>
+///     <para>
+///         <b>Failure posture.</b> Anything that is not a well-formed MTConnect device model throws
+///         <see cref="InvalidDataException"/>. It never degrades to an empty-but-successful model:
+///         an empty device model that looks successful is precisely the defect class that has bitten
+///         this codebase before (#485), and here it would tear the driver's browse tree down to
+///         nothing while reporting healthy.
+///     </para>
+/// </remarks>
+internal static class MTConnectProbeParser
+{
+    /// <summary>
+    ///     Bound on component nesting depth. Real device models nest a handful of levels; this only
+    ///     exists so a pathological or hostile document cannot recurse the parser into a
+    ///     process-fatal (uncatchable) stack overflow.
+    /// </summary>
+    private const int MaxComponentDepth = 64;
+
+    /// <summary>How <see cref="MTConnectXml"/>'s shared error messages name this document.</summary>
+    private const string Subject = "/probe response";
+
+    /// <summary>Parses a <c>/probe</c> response held as a string.</summary>
+    /// <param name="xml">The raw <c>MTConnectDevices</c> XML document.</param>
+    /// <exception cref="InvalidDataException">
+    ///     The payload is empty, not well-formed XML, not an <c>MTConnectDevices</c> document (an
+    ///     Agent <c>MTConnectError</c> document included — Agents answer a bad device path with one
+    ///     under HTTP 200), or declares no usable device.
+    /// </exception>
+    public static MTConnectProbeModel Parse(string xml)
+    {
+        if (string.IsNullOrWhiteSpace(xml))
+        {
+            throw new InvalidDataException("MTConnect /probe response was empty; expected an MTConnectDevices XML document.");
+        }
+
+        XDocument document;
+        try
+        {
+            document = XDocument.Parse(xml);
+        }
+        catch (XmlException ex)
+        {
+            throw new InvalidDataException($"MTConnect /probe response is not well-formed XML: {ex.Message}", ex);
+        }
+
+        return Build(document);
+    }
+
+    /// <summary>Parses a <c>/probe</c> response read from a stream.</summary>
+    /// <param name="stream">A stream positioned at the start of the XML document.</param>
+    /// <exception cref="InvalidDataException">As for <see cref="Parse(string)"/>.</exception>
+    public static MTConnectProbeModel Parse(Stream stream)
+    {
+        ArgumentNullException.ThrowIfNull(stream);
+
+        XDocument document;
+        try
+        {
+            document = XDocument.Load(stream);
+        }
+        catch (XmlException ex)
+        {
+            throw new InvalidDataException($"MTConnect /probe response is not well-formed XML: {ex.Message}", ex);
+        }
+
+        return Build(document);
+    }
+
+    private static MTConnectProbeModel Build(XDocument document)
+    {
+        var root = document.Root
+                   ?? throw new InvalidDataException("MTConnect /probe response has no root element.");
+
+        if (!MTConnectXml.IsNamed(root, "MTConnectDevices"))
+        {
+            throw new InvalidDataException(MTConnectXml.DescribeUnexpectedRoot(root, "MTConnectDevices", Subject));
+        }
+
+        var devicesContainer = MTConnectXml.ChildrenNamed(root, "Devices").FirstOrDefault()
+                               ?? throw new InvalidDataException(
+                                   "MTConnect /probe response has no <Devices> element; it does not describe a device model.");
+
+        var devices = devicesContainer.Elements().Select(ReadDevice).ToList();
+        if (devices.Count == 0)
+        {
+            throw new InvalidDataException(
+                "MTConnect /probe response declares no devices; refusing to report an empty device model as a successful probe.");
+        }
+
+        return new MTConnectProbeModel(devices);
+    }
+
+    private static MTConnectDevice ReadDevice(XElement element) =>
+        new(
+            MTConnectXml.RequiredAttribute(element, "id", "Device", Subject),
+            MTConnectXml.OptionalAttribute(element, "name"),
+            ReadComponents(element, depth: 1),
+            ReadDataItems(element));
+
+    private static MTConnectComponent ReadComponent(XElement element, int depth) =>
+        new(
+            MTConnectXml.RequiredAttribute(element, "id", $"Component <{element.Name.LocalName}>", Subject),
+            MTConnectXml.OptionalAttribute(element, "name"),
+            ReadComponents(element, depth + 1),
+            ReadDataItems(element));
+
+    /// <summary>
+    ///     Every element child of this container's <c>&lt;Components&gt;</c> element, whatever it is
+    ///     named — the element name is the component type, not the literal string "Component".
+    /// </summary>
+    private static IReadOnlyList<MTConnectComponent> ReadComponents(XElement container, int depth)
+    {
+        if (depth > MaxComponentDepth)
+        {
+            throw new InvalidDataException(
+                $"MTConnect /probe response nests components more than {MaxComponentDepth} levels deep; refusing to recurse further.");
+        }
+
+        return MTConnectXml.ChildrenNamed(container, "Components")
+            .SelectMany(components => components.Elements())
+            .Select(element => ReadComponent(element, depth))
+            .ToList();
+    }
+
+    private static IReadOnlyList<MTConnectDataItem> ReadDataItems(XElement container) =>
+        MTConnectXml.ChildrenNamed(container, "DataItems")
+            .SelectMany(dataItems => MTConnectXml.ChildrenNamed(dataItems, "DataItem"))
+            .Select(ReadDataItem)
+            .ToList();
+
+    private static MTConnectDataItem ReadDataItem(XElement element)
+    {
+        var id = MTConnectXml.RequiredAttribute(element, "id", "DataItem", Subject);
+
+        return new MTConnectDataItem(
+            id,
+            MTConnectXml.OptionalAttribute(element, "name"),
+            MTConnectXml.RequiredAttribute(element, "category", $"DataItem '{id}'", Subject),
+            MTConnectXml.RequiredAttribute(element, "type", $"DataItem '{id}'", Subject),
+            MTConnectXml.OptionalAttribute(element, "subType"),
+            MTConnectXml.OptionalAttribute(element, "units"),
+            MTConnectXml.OptionalAttribute(element, "representation"),
+            MTConnectXml.OptionalIntAttribute(element, "sampleCount", $"DataItem '{id}'", Subject));
+    }
+
+}
@@ -0,0 +1,29 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     Driver-internal identity of one <c>/sample</c> subscription, matching the sibling drivers'
+///     shape (Galaxy's <c>GalaxySubscriptionHandle</c>, the shared <c>PollGroupEngine</c>'s
+///     <c>PollSubscriptionHandle</c>): a monotonic per-driver id plus a diagnostic string that
+///     carries it into logs.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Every handle shares ONE Agent stream.</b> Unlike a polled driver, where each
+///         subscription owns a loop, MTConnect's <c>/sample</c> long poll is per-Agent: the driver
+///         opens exactly one and fans each chunk out to whichever handles subscribe the reporting
+///         DataItem. The handle is therefore purely an identity — it owns no connection, no task,
+///         and no cursor — and dropping one only stops the stream when it was the last.
+///     </para>
+///     <para>
+///         A <see langword="record"/> for value equality on the id, so a handle that has round-tripped
+///         through the caller still resolves. The id is never reused within a driver instance.
+///     </para>
+/// </remarks>
+/// <param name="SubscriptionId">The monotonic per-driver subscription id.</param>
+internal sealed record MTConnectSampleHandle(long SubscriptionId) : ISubscriptionHandle
+{
+    /// <inheritdoc/>
+    public string DiagnosticId => $"mtconnect-sub-{SubscriptionId}";
+}
@@ -0,0 +1,161 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     Base type for every way an Agent <c>/sample</c> long poll can stop delivering chunks for a
+///     reason that is <b>not</b> the caller cancelling it.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Why these are exceptions rather than a normal end of enumeration.</b>
+///         <see cref="IMTConnectAgentClient.SampleAsync"/> is contracted to yield indefinitely until
+///         its token is cancelled, so a pump written to that contract has no reason to handle normal
+///         completion — it would either drop the subscription silently or hot-loop reconnecting on
+///         an enumerator that ends immediately. Returning normally would make "the data path
+///         stopped" indistinguishable from "the data path is idle", which is the
+///         quiet-successful-looking-termination shape that produced this repo's #485 defect. Every
+///         non-cancellation end is therefore loud, typed, and carries the Agent URI.
+///     </para>
+///     <para>
+///         Catch this base type to handle "the stream is over" uniformly; catch the two derived
+///         types to distinguish a <i>transient</i> end (the Agent closed a connection — reconnect)
+///         from a <i>configuration</i> error (the Agent will never stream to this request — retrying
+///         is pointless until an operator changes something).
+///     </para>
+/// </remarks>
+public abstract class MTConnectStreamException : Exception
+{
+    /// <summary>Creates the exception with no message.</summary>
+    protected MTConnectStreamException()
+    {
+    }
+
+    /// <summary>Creates the exception with a message.</summary>
+    /// <param name="message">The operator-facing description.</param>
+    protected MTConnectStreamException(string message)
+        : base(message)
+    {
+    }
+
+    /// <summary>Creates the exception with a message and an inner cause.</summary>
+    /// <param name="message">The operator-facing description.</param>
+    /// <param name="innerException">The underlying cause.</param>
+    protected MTConnectStreamException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+}
+
+/// <summary>How an Agent <c>/sample</c> stream ended.</summary>
+public enum MTConnectStreamEndReason
+{
+    /// <summary>
+    ///     The transport closed mid-stream — the connection dropped, the Agent restarted, or a proxy
+    ///     timed the connection out. Ordinary and transient: reconnect from the last
+    ///     <see cref="MTConnectStreamsResult.NextSequence"/>.
+    /// </summary>
+    ConnectionClosed = 0,
+
+    /// <summary>
+    ///     The Agent wrote the closing <c>--boundary--</c> delimiter, ending the multipart response
+    ///     deliberately. Usually means the request was bounded (an Agent honouring a <c>count</c>
+    ///     that exhausted, or an administrative stop) rather than a fault. Also reconnectable, but
+    ///     worth distinguishing in logs: a stream that keeps closing cleanly points at the request's
+    ///     parameters, not at the network.
+    /// </summary>
+    ClosingBoundary = 1
+}
+
+/// <summary>
+///     The Agent's <c>/sample</c> stream ended without the caller cancelling it. See
+///     <see cref="MTConnectStreamException"/> for why this is not a normal end of enumeration.
+/// </summary>
+public sealed class MTConnectStreamEndedException : MTConnectStreamException
+{
+    /// <summary>Creates the exception for a stream that ended for <paramref name="reason"/>.</summary>
+    /// <param name="reason">How the stream ended.</param>
+    /// <param name="agentUri">The <c>/sample</c> request URI whose stream ended.</param>
+    /// <param name="chunksDelivered">How many chunks were yielded before the end.</param>
+    public MTConnectStreamEndedException(MTConnectStreamEndReason reason, string agentUri, long chunksDelivered)
+        : base($"MTConnect /sample stream from '{agentUri}' ended after {chunksDelivered} chunk(s) without the caller cancelling it ({Describe(reason)}). The stream is contracted to run until cancelled, so this is reported rather than returned; resume from the last chunk's nextSequence.")
+    {
+        Reason = reason;
+        AgentUri = agentUri;
+        ChunksDelivered = chunksDelivered;
+    }
+
+    /// <summary>Creates the exception with a message.</summary>
+    /// <param name="message">The operator-facing description.</param>
+    public MTConnectStreamEndedException(string message)
+        : base(message)
+    {
+        AgentUri = string.Empty;
+    }
+
+    /// <summary>Creates the exception with a message and an inner cause.</summary>
+    /// <param name="message">The operator-facing description.</param>
+    /// <param name="innerException">The underlying cause.</param>
+    public MTConnectStreamEndedException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+        AgentUri = string.Empty;
+    }
+
+    /// <summary>Creates the exception with no message.</summary>
+    public MTConnectStreamEndedException()
+    {
+        AgentUri = string.Empty;
+    }
+
+    /// <summary>How the stream ended.</summary>
+    public MTConnectStreamEndReason Reason { get; }
+
+    /// <summary>The <c>/sample</c> request URI whose stream ended.</summary>
+    public string AgentUri { get; }
+
+    /// <summary>How many chunks were yielded before the stream ended.</summary>
+    public long ChunksDelivered { get; }
+
+    private static string Describe(MTConnectStreamEndReason reason) =>
+        reason switch
+        {
+            MTConnectStreamEndReason.ClosingBoundary => "the Agent wrote the closing multipart boundary",
+            _ => "the connection closed mid-stream"
+        };
+}
+
+/// <summary>
+///     The Agent answered a <c>/sample</c> request with something that cannot be consumed as a
+///     stream at all — a single non-multipart document, or a <c>multipart/*</c> response with no
+///     <c>boundary</c> parameter to frame it by.
+/// </summary>
+/// <remarks>
+///     This is a <b>configuration</b> error, not a transient one, and is deliberately typed apart
+///     from <see cref="MTConnectStreamEndedException"/>: reconnecting will produce the identical
+///     response forever. The usual cause is an endpoint that is not an MTConnect Agent (a reverse
+///     proxy, a load balancer's health page, or an Agent fronted by something that buffers and
+///     collapses <c>multipart/x-mixed-replace</c>). Reported instead of yielding the one document
+///     the Agent did return, because a single snapshot followed by a healthy-looking finished
+///     stream is exactly how a dead data path disguises itself as a working one.
+/// </remarks>
+public sealed class MTConnectStreamNotSupportedException : MTConnectStreamException
+{
+    /// <summary>Creates the exception with a message.</summary>
+    /// <param name="message">The operator-facing description.</param>
+    public MTConnectStreamNotSupportedException(string message)
+        : base(message)
+    {
+    }
+
+    /// <summary>Creates the exception with a message and an inner cause.</summary>
+    /// <param name="message">The operator-facing description.</param>
+    /// <param name="innerException">The underlying cause.</param>
+    public MTConnectStreamNotSupportedException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+
+    /// <summary>Creates the exception with no message.</summary>
+    public MTConnectStreamNotSupportedException()
+    {
+    }
+}
@@ -0,0 +1,240 @@
+using System.Globalization;
+using System.Xml;
+using System.Xml.Linq;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     Turns an MTConnect Agent <c>MTConnectStreams</c> document — a <c>/current</c> snapshot or one
+///     chunk of a <c>/sample</c> multipart stream — into the neutral
+///     <see cref="MTConnectStreamsResult"/>. Deliberately a pure, socket-free static so the whole
+///     parse is unit-testable against canned fixtures; chunk framing lives in
+///     <see cref="MTConnectAgentClient"/> and hands this parser one chunk's XML at a time.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Why hand-rolled rather than TrakHound.</b> Same finding as
+///         <see cref="MTConnectProbeParser"/>: the packages pinned by Task 0 ship no XML document
+///         formatter, and TrakHound's streaming client offers no socket-free entry point. Both
+///         package references were dropped in Task 7; the driver depends only on the BCL.
+///     </para>
+///     <para>
+///         <b>The Streams document is shaped nothing like the Devices document</b>, and three
+///         differences drive this parser's design.
+///     </para>
+///     <list type="number">
+///         <item>
+///             <description>
+///                 <b>The observation element's name is the data item's type in PascalCase</b>
+///                 (<c>Position</c>, <c>PartCount</c>, <c>Execution</c>) — not the probe's
+///                 UPPER_SNAKE <c>POSITION</c> / <c>PART_COUNT</c>. The standard defines hundreds of
+///                 types and vendors add more, so matching a fixed set of element names would drop
+///                 observations silently. <b>Every</b> element child of <c>&lt;Samples&gt;</c>,
+///                 <c>&lt;Events&gt;</c> and <c>&lt;Condition&gt;</c> is therefore an observation,
+///                 keyed by its <c>dataItemId</c> attribute — the only identity the probe model and
+///                 the streams document actually share.
+///             </description>
+///         </item>
+///         <item>
+///             <description>
+///                 <b>A CONDITION observation's value is its ELEMENT NAME, not its text.</b>
+///                 <c>&lt;Normal/&gt;</c> / <c>&lt;Warning/&gt;</c> / <c>&lt;Fault/&gt;</c> /
+///                 <c>&lt;Unavailable/&gt;</c> carry the state in the name and are typically empty;
+///                 where text is present it is the operator-facing message, not the state. Reading
+///                 the text would report every condition as an empty string.
+///                 <c>&lt;Unavailable/&gt;</c> is normalized to the literal
+///                 <see cref="UnavailableSentinel"/> so a no-comms condition lands on exactly the
+///                 same sentinel as a Sample/Event whose text is <c>UNAVAILABLE</c> — the
+///                 observation index maps that one token to bad quality.
+///             </description>
+///         </item>
+///         <item>
+///             <description>
+///                 <b>Timestamps are normalized to UTC explicitly.</b> MTConnect timestamps are
+///                 ISO-8601 Zulu, but a bare <c>DateTime.Parse</c> yields <c>Local</c> or
+///                 <c>Unspecified</c> depending on machine settings — and this value becomes the
+///                 OPC UA SourceTimestamp, so a wrong <see cref="DateTimeKind"/> shifts every
+///                 timestamp by the host's UTC offset with nothing to show for it.
+///             </description>
+///         </item>
+///     </list>
+///     <para>
+///         <b>Failure posture.</b> A malformed document, a non-<c>MTConnectStreams</c> root (an Agent
+///         <c>MTConnectError</c> served under HTTP 200 included), an unusable header, or an
+///         observation missing its <c>dataItemId</c>/<c>timestamp</c> all throw
+///         <see cref="InvalidDataException"/>. A document with a valid header and <i>zero</i>
+///         observations, by contrast, is entirely legal — <c>/sample</c> chunks are deltas and an
+///         idle Agent's keep-alive is an observation-free document — so it parses to an empty
+///         observation list rather than throwing.
+///     </para>
+/// </remarks>
+internal static class MTConnectStreamsParser
+{
+    /// <summary>
+    ///     The single token that means "the Agent has no value for this data item". Sample/Event
+    ///     observations carry it as text; a CONDITION carries it as the element name
+    ///     <c>&lt;Unavailable/&gt;</c> and is normalized onto this spelling here.
+    /// </summary>
+    private const string UnavailableSentinel = "UNAVAILABLE";
+
+    private const string ConditionContainer = "Condition";
+
+    /// <summary>How <see cref="MTConnectXml"/>'s shared error messages name this document.</summary>
+    private const string Subject = "streams response";
+
+    /// <summary>How those messages name the header element.</summary>
+    private const string HeaderOwner = "the <Header>";
+
+    /// <summary>
+    ///     The three elements whose element children are observations. A ComponentStream may carry
+    ///     any subset of them, including none.
+    /// </summary>
+    private static readonly string[] ObservationContainers = ["Samples", "Events", ConditionContainer];
+
+    /// <summary>Parses a <c>/current</c> response, or one <c>/sample</c> chunk, held as a string.</summary>
+    /// <param name="xml">The raw <c>MTConnectStreams</c> XML document.</param>
+    /// <exception cref="InvalidDataException">
+    ///     The payload is empty, not well-formed XML, not an <c>MTConnectStreams</c> document (an
+    ///     Agent <c>MTConnectError</c> included — Agents answer a bad request with one under HTTP
+    ///     200), carries no usable <c>&lt;Header&gt;</c>, or carries a malformed observation.
+    /// </exception>
+    public static MTConnectStreamsResult Parse(string xml)
+    {
+        if (string.IsNullOrWhiteSpace(xml))
+        {
+            throw new InvalidDataException(
+                "MTConnect streams response was empty; expected an MTConnectStreams XML document.");
+        }
+
+        XDocument document;
+        try
+        {
+            // A chunk lifted out of a multipart frame can carry a byte-order mark or the framing's
+            // trailing line break; XmlReader rejects either ahead of the XML declaration.
+            document = XDocument.Parse(xml.Trim('\uFEFF', ' ', '\t', '\r', '\n'));
+        }
+        catch (XmlException ex)
+        {
+            throw new InvalidDataException($"MTConnect streams response is not well-formed XML: {ex.Message}", ex);
+        }
+
+        return Build(document);
+    }
+
+    /// <summary>Parses a <c>/current</c> response read from a stream.</summary>
+    /// <param name="stream">A stream positioned at the start of the XML document.</param>
+    /// <exception cref="InvalidDataException">As for <see cref="Parse(string)"/>.</exception>
+    public static MTConnectStreamsResult Parse(Stream stream)
+    {
+        ArgumentNullException.ThrowIfNull(stream);
+
+        XDocument document;
+        try
+        {
+            document = XDocument.Load(stream);
+        }
+        catch (XmlException ex)
+        {
+            throw new InvalidDataException($"MTConnect streams response is not well-formed XML: {ex.Message}", ex);
+        }
+
+        return Build(document);
+    }
+
+    private static MTConnectStreamsResult Build(XDocument document)
+    {
+        var root = document.Root
+                   ?? throw new InvalidDataException("MTConnect streams response has no root element.");
+
+        if (!MTConnectXml.IsNamed(root, "MTConnectStreams"))
+        {
+            throw new InvalidDataException(MTConnectXml.DescribeUnexpectedRoot(root, "MTConnectStreams", Subject));
+        }
+
+        var header = MTConnectXml.ChildrenNamed(root, "Header").FirstOrDefault()
+                     ?? throw new InvalidDataException(
+                         "MTConnect streams response has no <Header>; without it the sequence bookkeeping the sample pump runs on is unknowable.");
+
+        return new MTConnectStreamsResult(
+            MTConnectXml.RequiredLongAttribute(header, "instanceId", HeaderOwner, Subject),
+            MTConnectXml.RequiredLongAttribute(header, "nextSequence", HeaderOwner, Subject),
+            MTConnectXml.RequiredLongAttribute(header, "firstSequence", HeaderOwner, Subject),
+            ReadObservations(root));
+    }
+
+    /// <summary>
+    ///     Collects every observation in the document, in Agent-supplied order. Containers are found
+    ///     by descending the whole <c>&lt;Streams&gt;</c> subtree rather than by walking a fixed
+    ///     DeviceStream → ComponentStream chain, so a vendor's extra nesting level cannot silently
+    ///     hide a device's observations.
+    /// </summary>
+    private static IReadOnlyList<MTConnectObservation> ReadObservations(XElement root)
+    {
+        var observations = new List<MTConnectObservation>();
+
+        foreach (var container in root.Descendants().Where(IsObservationContainer))
+        {
+            var isCondition = MTConnectXml.IsNamed(container, ConditionContainer);
+            foreach (var element in container.Elements())
+            {
+                observations.Add(ReadObservation(element, isCondition));
+            }
+        }
+
+        return observations;
+    }
+
+    private static MTConnectObservation ReadObservation(XElement element, bool isCondition)
+    {
+        var dataItemId = MTConnectXml.RequiredAttribute(element, "dataItemId", $"Observation <{element.Name.LocalName}>", Subject);
+
+        return new MTConnectObservation(
+            dataItemId,
+            isCondition ? ConditionState(element) : element.Value.Trim(),
+            ReadTimestampUtc(element, dataItemId),
+
+            // A DATA_SET/TABLE observation keeps its content in <Entry key="…"> children, so the
+            // text read above concatenates them into nonsense ("12" for two entries). Flagged here
+            // because this is the only layer that can still see the distinction — see
+            // MTConnectObservation.IsStructured. Never true for a CONDITION: its value comes from
+            // the element NAME, so child content cannot corrupt it, and flagging one would throw
+            // away a perfectly well-determined state.
+            IsStructured: !isCondition && element.HasElements);
+    }
+
+    /// <summary>
+    ///     A condition's state is its element name. <c>Unavailable</c> is normalized to the
+    ///     <see cref="UnavailableSentinel"/> spelling so downstream quality mapping has exactly one
+    ///     token to recognize; every other state is reported as-named (<c>Normal</c>, <c>Warning</c>,
+    ///     <c>Fault</c>, and any vendor state).
+    /// </summary>
+    private static string ConditionState(XElement element)
+    {
+        var state = element.Name.LocalName;
+
+        return string.Equals(state, "Unavailable", StringComparison.OrdinalIgnoreCase) ? UnavailableSentinel : state;
+    }
+
+    private static DateTime ReadTimestampUtc(XElement element, string dataItemId)
+    {
+        var raw = MTConnectXml.RequiredAttribute(element, "timestamp", $"Observation '{dataItemId}'", Subject);
+
+        if (!DateTime.TryParse(
+                raw,
+                CultureInfo.InvariantCulture,
+                DateTimeStyles.AdjustToUniversal | DateTimeStyles.AssumeUniversal,
+                out var parsed))
+        {
+            throw new InvalidDataException(
+                $"MTConnect streams response is malformed: observation '{dataItemId}' has an unparseable 'timestamp' ('{raw}').");
+        }
+
+        // AdjustToUniversal already yields Utc; stated explicitly so a future styles change cannot
+        // quietly hand the OPC UA layer a Local or Unspecified SourceTimestamp.
+        return DateTime.SpecifyKind(parsed, DateTimeKind.Utc);
+    }
+
+    private static bool IsObservationContainer(XElement element) =>
+        ObservationContainers.Any(name => MTConnectXml.IsNamed(element, name));
+
+}
@@ -0,0 +1,146 @@
+using System.Globalization;
+using System.Xml.Linq;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
+
+/// <summary>
+///     The element/attribute reading rules shared by <see cref="MTConnectProbeParser"/> and
+///     <see cref="MTConnectStreamsParser"/>. Both documents are the same dialect of XML and must be
+///     read by the same rules; keeping one copy is what stops the two parsers drifting apart on the
+///     two rules below, either of which fails silently rather than loudly.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Rule 1: elements are matched on <see cref="XName.LocalName"/>, ignoring the
+///         namespace.</b> The namespace URI carries the MTConnect version
+///         (<c>urn:mtconnect.org:MTConnectDevices:1.3</c> … <c>:2.0</c>), so a fully-qualified match
+///         would hard-code a version. It also silently drops vendor-extension elements declared in
+///         their own namespace, whose standard children still inherit the default MTConnect
+///         namespace — the browse tree simply comes back short, with no error anywhere.
+///     </para>
+///     <para>
+///         <b>Rule 2: attributes are read <i>unqualified</i>.</b> A prefixed attribute
+///         (<c>xsi:type</c> on a document root, a vendor's <c>x:dataItemId</c>) must never be
+///         mistaken for the real <c>type</c> / <c>dataItemId</c>, which would invent a data item the
+///         probe never declared.
+///     </para>
+/// </remarks>
+internal static class MTConnectXml
+{
+    /// <summary>Does <paramref name="element"/> have the given local name, whatever its namespace?</summary>
+    /// <param name="element">The element to test.</param>
+    /// <param name="localName">The unqualified name to match.</param>
+    public static bool IsNamed(XElement element, string localName) =>
+        string.Equals(element.Name.LocalName, localName, StringComparison.Ordinal);
+
+    /// <summary>Direct element children of <paramref name="parent"/> with the given local name.</summary>
+    /// <param name="parent">The element whose children to filter.</param>
+    /// <param name="localName">The unqualified name to match.</param>
+    public static IEnumerable<XElement> ChildrenNamed(XElement parent, string localName) =>
+        parent.Elements().Where(child => IsNamed(child, localName));
+
+    /// <summary>
+    ///     Reads an unqualified attribute, normalizing a present-but-empty value to <c>null</c>.
+    ///     See the type-level remarks for why only unqualified attributes are considered.
+    /// </summary>
+    /// <param name="element">The element carrying the attribute.</param>
+    /// <param name="name">The unqualified attribute name.</param>
+    public static string? OptionalAttribute(XElement element, string name)
+    {
+        var value = element.Attribute(name)?.Value;
+
+        return string.IsNullOrWhiteSpace(value) ? null : value;
+    }
+
+    /// <summary>Reads a required unqualified attribute, or throws naming the owner and the attribute.</summary>
+    /// <param name="element">The element carrying the attribute.</param>
+    /// <param name="name">The unqualified attribute name.</param>
+    /// <param name="owner">How to describe the element in the error message.</param>
+    /// <param name="subject">How to describe the document in the error message (e.g. "/probe response").</param>
+    /// <exception cref="InvalidDataException">The attribute is absent or blank.</exception>
+    public static string RequiredAttribute(XElement element, string name, string owner, string subject)
+    {
+        var value = OptionalAttribute(element, name);
+
+        return value ?? throw new InvalidDataException(
+            $"MTConnect {subject} is malformed: {owner} has no '{name}' attribute.");
+    }
+
+    /// <summary>Reads an optional unqualified attribute as an <see cref="int"/>.</summary>
+    /// <param name="element">The element carrying the attribute.</param>
+    /// <param name="name">The unqualified attribute name.</param>
+    /// <param name="owner">How to describe the element in the error message.</param>
+    /// <param name="subject">How to describe the document in the error message.</param>
+    /// <exception cref="InvalidDataException">The attribute is present but not an integer.</exception>
+    public static int? OptionalIntAttribute(XElement element, string name, string owner, string subject)
+    {
+        var raw = OptionalAttribute(element, name);
+        if (raw is null)
+        {
+            return null;
+        }
+
+        if (!int.TryParse(raw, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value))
+        {
+            throw new InvalidDataException(
+                $"MTConnect {subject} is malformed: {owner} has a non-numeric '{name}' attribute ('{raw}').");
+        }
+
+        return value;
+    }
+
+    /// <summary>Reads a required unqualified attribute as a <see cref="long"/>.</summary>
+    /// <param name="element">The element carrying the attribute.</param>
+    /// <param name="name">The unqualified attribute name.</param>
+    /// <param name="owner">How to describe the element in the error message.</param>
+    /// <param name="subject">How to describe the document in the error message.</param>
+    /// <exception cref="InvalidDataException">The attribute is absent, blank, or not an integer.</exception>
+    public static long RequiredLongAttribute(XElement element, string name, string owner, string subject)
+    {
+        var raw = RequiredAttribute(element, name, owner, subject);
+
+        if (!long.TryParse(raw, NumberStyles.Integer, CultureInfo.InvariantCulture, out var value))
+        {
+            throw new InvalidDataException(
+                $"MTConnect {subject} is malformed: {owner} has a non-numeric '{name}' attribute ('{raw}').");
+        }
+
+        return value;
+    }
+
+    /// <summary>
+    ///     Builds the error message for a document whose root is not what was expected, lifting the
+    ///     Agent's own error text when the response is an <c>MTConnectError</c> document — which
+    ///     Agents return under <b>HTTP 200</b>, so <c>EnsureSuccessStatusCode</c> never fires and
+    ///     this is the only place the operator can learn what the Agent objected to.
+    /// </summary>
+    /// <param name="root">The document's actual root element.</param>
+    /// <param name="expectedRootName">The root element name the caller required.</param>
+    /// <param name="subject">How to describe the document in the error message.</param>
+    public static string DescribeUnexpectedRoot(XElement root, string expectedRootName, string subject)
+    {
+        var message =
+            $"MTConnect {subject} root element is <{root.Name.LocalName}>, expected <{expectedRootName}>.";
+
+        if (!IsNamed(root, "MTConnectError"))
+        {
+            return message;
+        }
+
+        var errors = root.Descendants()
+            .Where(e => IsNamed(e, "Error"))
+            .Select(e =>
+            {
+                var code = OptionalAttribute(e, "errorCode");
+                var text = e.Value.Trim();
+
+                return code is null ? text : $"{code}: {text}";
+            })
+            .Where(text => text.Length > 0)
+            .ToList();
+
+        return errors.Count == 0
+            ? message
+            : $"{message} The Agent reported: {string.Join("; ", errors)}";
+    }
+}
@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <LangVersion>latest</LangVersion>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <NoWarn>$(NoWarn);CS1591</NoWarn>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Driver.MTConnect</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\Core\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+        <ProjectReference Include="..\..\Core\ZB.MOM.WW.OtOpcUa.Core\ZB.MOM.WW.OtOpcUa.Core.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Contracts\ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Contracts.csproj"/>
+    </ItemGroup>
+
+    <!-- No backend NuGet: the Agent surface is plain HTTP + XML, served entirely by the BCL
+         (HttpClient + System.Xml.Linq). The TrakHound MTConnect.NET-Common/-HTTP references Task 0
+         added were removed in Task 7 — they can neither parse an MTConnect document (no XML
+         formatter ships in either package) nor frame the /sample stream socket-free (their client
+         type dials its own URL). See the Task 0 CORRECTION block in
+         docs/plans/2026-07-24-mtconnect-driver.md. -->
+
+    <ItemGroup>
+        <InternalsVisibleTo Include="ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests"/>
+    </ItemGroup>
+
+</Project>
--- a/Show More
+++ b/Show More