diff --git a/docs/drivers/OpcUaClient-Test-Fixture.md b/docs/drivers/OpcUaClient-Test-Fixture.md
index a05b276d..c9aac37f 100644
--- a/docs/drivers/OpcUaClient-Test-Fixture.md
+++ b/docs/drivers/OpcUaClient-Test-Fixture.md
@@ -20,7 +20,8 @@ image (follow-up).
 **Integration layer** (task #215):
 `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/` stands up
 `mcr.microsoft.com/iotedge/opc-plc:2.14.10` via `Docker/docker-compose.yml`
-on `opc.tcp://localhost:50000`. `OpcPlcFixture` probes the port at
+on `opc.tcp://10.100.0.35:50000` (the shared Docker host; override via
+`OPCUA_SIM_ENDPOINT`). `OpcPlcFixture` probes the port at
 collection init + skips tests with a clear message when the container's
 not running (matches the Modbus/pymodbus + S7/python-snap7 skip pattern).
 Docker is the launcher — no PowerShell wrapper needed because opc-plc
@@ -81,12 +82,15 @@ Capability surfaces whose contract is verified: `IDriver`, `ITagDiscovery`,
 
 ## What it does NOT cover
 
-### 1. Real stack exchange
+### 1. Full real-stack exchange (unit tests only)
 
-No UA Secure Channel is ever opened. Every test mocks `Session.ReadAsync`,
-`Session.CreateSubscription`, `Session.AddItem`, etc. — the SDK itself is
-trusted. Certificate validation, signing, nonce handling, chunk assembly,
-keep-alive cadence — all SDK-internal and untested here.
+The **unit** suite mocks `Session.ReadAsync`, `Session.CreateSubscription`,
+`Session.AddItem`, etc. — no UA Secure Channel is opened. The **integration**
+suite (`OpcUaClientSmokeTests`, task #215) does open a real Secure Channel
+against opc-plc and exercises Read + Subscribe end-to-end. What remains
+untested even in the integration suite: certificate validation under
+non-anonymous security policies, signing/encryption, nonce handling, chunk
+assembly, keep-alive cadence — all SDK-internal.
 
 ### 2. Subscription transfer across reconnect
 
@@ -124,14 +128,16 @@ ConditionType events (non-base `BaseEventType`) is not verified.
 
 ## When to trust OpcUaClient tests, when to reach for a server
 
-| Question | Unit tests | Real upstream server |
-| --- | --- | --- |
-| "Does severity 750 bucket as High?" | yes | yes |
-| "Does the driver call `TransferSubscriptions` after reconnect?" | yes | yes |
-| "Does a real OPC UA read/write round-trip work?" | no | yes (required) |
-| "Does event-filter-based alarm subscription return ConditionType events?" | no | yes (required) |
-| "Does history read from AVEVA Historian return correct aggregates?" | no | yes (required) |
-| "Does the SDK's publish queue lose notifications under load?" | no | yes (stress) |
+| Question | Unit tests | Integration (opc-plc) | Real upstream server |
+| --- | --- | --- | --- |
+| "Does severity 750 bucket as High?" | yes | - | yes |
+| "Does the driver call `TransferSubscriptions` after reconnect?" | yes | - | yes |
+| "Does a real OPC UA read round-trip work?" | no | yes | yes |
+| "Does a real OPC UA subscribe deliver changes?" | no | yes | yes |
+| "Does write round-trip work against a live server?" | no | no (not yet exercised) | yes (required) |
+| "Does event-filter-based alarm subscription return ConditionType events?" | no | no | yes (required) |
+| "Does history read from AVEVA Historian return correct aggregates?" | no | no | yes (required) |
+| "Does the SDK's publish queue lose notifications under load?" | no | no | yes (stress) |
 
 ## Follow-up candidates
 
@@ -164,8 +170,17 @@ Beyond that:
 
 - `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests/` — unit tests with
   mocked `Session`
+- `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/OpcPlcFixture.cs`
+  — collection fixture; parses `OPCUA_SIM_ENDPOINT` (default
+  `opc.tcp://10.100.0.35:50000`), TCP-probes at collection init, records
+  `SkipReason` when unreachable
+- `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/OpcUaClientSmokeTests.cs`
+  — wire-level test suite (3 `[Fact]` methods: read, batch read, subscribe)
+- `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/Docker/docker-compose.yml`
+  — `mcr.microsoft.com/iotedge/opc-plc:2.14.10` with `--ut --aa --alm --pn=50000`
 - `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientDriver.cs` — ctor +
-  session-factory seam tests mock through
+  session-factory seam tests mock through; implements `IAlarmSource` +
+  `IHistoryProvider` (unique among drivers); does NOT implement `IRediscoverable`
 - `tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests/DualEndpointTests.cs` —
   the v2 dual-endpoint integration harness a future loopback client test could
   piggyback on (v1 `OpcUaServerIntegrationTests.cs` retired with the v1 server project)