feat(alarms): condition Quality tracks source connectivity (#477)

Part 9 ConditionType.Quality was never assigned; default(StatusCode)==Good
so every native + scripted condition reported Good unconditionally — a
comms-lost device still showed a healthy, inactive, Good condition (a
wrong-VALUE bug, distinct from the null-value #473/#475). Clients (and HMIs
bucketing on IsGood) could not tell "genuinely inactive" from "lost contact".

Layer 1 — make Quality a real, plumbed field:
- AlarmConditionSnapshot gains OpcUaQuality Quality (default Good).
- MaterialiseAlarmCondition sets it (native BadWaitingForInitialData, scripted Good).
- WriteAlarmCondition projects snapshot.Quality; the delta-gate gains a Quality
  member so a quality-bucket change fires a Part 9 event.

Layer 2 — drive native quality from driver connectivity (a comms-lost driver
emits no alarm transitions, and an alarm-bearing raw tag has no value variable,
so quality can't come from either existing channel):
- DriverInstanceActor Tells parent ConnectivityChanged on Connected/Reconnecting.
- DriverHostActor fans it to every native condition the driver owns as
  OpcUaPublishActor.AlarmQualityUpdate (Good on connect, Bad on disconnect).
- New dedicated IOpcUaAddressSpaceSink.WriteAlarmQuality sets ONLY Quality and
  fires only on a bucket change — never touches Active/Acked/Retain (an active
  alarm that loses comms stays active). Not a full-snapshot re-projection, so it
  can't clobber severity/message and works for a never-fired condition.
  Forwarded through DeferredAddressSpaceSink (F10b trap; auto-verified by the
  reflection forwarding guard). Ungated by redundancy role; no /alerts row.

Scripted conditions stay Good; worst-of-input quality deferred to #478 (Layer 3).

Tests: node-level (materialise/project/no-clobber/unknown-node no-op),
NativeAlarmProjector, DriverInstanceActor connectivity emission, DriverHostActor
fan-out, OpcUaPublishActor routing, and the wire-level guard
(Condition_event_Quality_tracks_source_connectivity_on_the_wire) — RED-verified
against a simulated pre-fix always-Good server. Existing DriverInstanceActor
parent probes ignore the new ConnectivityChanged.

Docs: docs/AlarmTracking.md §"Condition source-data Quality (#477)";
design doc docs/plans/2026-07-17-alarm-condition-quality-477-design.md.

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DiscoveryInjectionEndToEndTests.cs

@@ -328,6 +328,7 @@ public sealed class DiscoveryInjectionEndToEndTests : RuntimeActorTestBase
             => _values.Enqueue((nodeId, value, quality, sourceTimestampUtc));
 
         /// <summary>No-op: alarm writes are not exercised by this suite.</summary>
+        public void WriteAlarmQuality(string alarmNodeId, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
         public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
 
         /// <summary>No-op: alarm materialise is not exercised by this suite.</summary>

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverHostActorNativeAlarmTests.cs

@@ -271,6 +271,46 @@ public sealed class DriverHostActorNativeAlarmTests : RuntimeActorTestBase
         evt.User.ShouldBe("device");
     }
 
+    /// <summary>#477 Layer 2 — a driver <see cref="DriverInstanceActor.ConnectivityChanged"/> annotates the
+    /// Quality of the driver's native conditions via <see cref="OpcUaPublishActor.AlarmQualityUpdate"/>: comms
+    /// lost → Bad, restored → Good, at the raw condition NodeId + realm. No alarm transition is involved — this
+    /// is the ONLY signal for a comms-lost native source.</summary>
+    [Fact]
+    public void Driver_disconnect_and_reconnect_annotate_native_condition_quality()
+    {
+        var db = NewInMemoryDbFactory();
+        var deploymentId = SeedV3AlarmDeployment(db, RevA, Driver: "drv-1", Tag: "temp_hi");
+
+        var (actor, publish) = SpawnHostAndApply(db, deploymentId);
+
+        // Comms lost → the raw condition is annotated Bad.
+        actor.Tell(new DriverInstanceActor.ConnectivityChanged("drv-1", Connected: false));
+        var bad = publish.ExpectMsg<OpcUaPublishActor.AlarmQualityUpdate>(TimeSpan.FromSeconds(5));
+        bad.AlarmNodeId.ShouldBe(AlarmRawPath);
+        bad.Realm.ShouldBe(AddressSpaceRealm.Raw);
+        bad.Quality.ShouldBe(OpcUaQuality.Bad);
+
+        // Comms restored → annotated Good.
+        actor.Tell(new DriverInstanceActor.ConnectivityChanged("drv-1", Connected: true));
+        var good = publish.ExpectMsg<OpcUaPublishActor.AlarmQualityUpdate>(TimeSpan.FromSeconds(5));
+        good.AlarmNodeId.ShouldBe(AlarmRawPath);
+        good.Quality.ShouldBe(OpcUaQuality.Good);
+    }
+
+    /// <summary>#477 Layer 2 — connectivity for a DIFFERENT driver instance annotates none of this driver's
+    /// conditions (the fan-out is scoped by DriverInstanceId).</summary>
+    [Fact]
+    public void Connectivity_for_another_driver_annotates_nothing()
+    {
+        var db = NewInMemoryDbFactory();
+        var deploymentId = SeedV3AlarmDeployment(db, RevA, Driver: "drv-1", Tag: "temp_hi");
+
+        var (actor, publish) = SpawnHostAndApply(db, deploymentId);
+
+        actor.Tell(new DriverInstanceActor.ConnectivityChanged("drv-OTHER", Connected: false));
+        publish.ExpectNoMsg(TimeSpan.FromMilliseconds(500));
+    }
+
     /// <summary>Subscribe <paramref name="probe"/> to the <c>alerts</c> DPS topic and wait for the ack.</summary>
     private void SubscribeToAlerts(TestProbe probe)
     {

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverInstanceActorDiscoveryTests.cs

@@ -30,6 +30,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new DiscoverableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         // Tiny interval so the bounded retry runs in well under a second (no real-time waits).
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20)));
@@ -68,6 +71,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new SubscribableStubDriver(); // IDriver + ISubscribable, NOT ITagDiscovery
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20)));
 
@@ -92,6 +98,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new DiscoverableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         // Tiny reconnect + rediscover intervals so the whole reconnect-then-rediscover cycle runs fast.
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver,
@@ -133,6 +142,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new YieldingDiscoverableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20)));
 
@@ -167,6 +179,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
             driverType: "Stub");
         var driver = new YieldingDiscoverableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20), invoker: invoker));
 
@@ -187,6 +202,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new GrowingDiscoverableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20), rediscoverMaxAttempts: 3));
 
@@ -215,6 +233,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new DiscoverableStubDriver(DiscoveryRediscoverPolicy.Never);
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20)));
 
@@ -239,6 +260,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new GrowingDiscoverableStubDriver(DiscoveryRediscoverPolicy.Once);
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20)));
 
@@ -269,6 +293,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new GrowingDiscoverableStubDriver(DiscoveryRediscoverPolicy.Once);
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         // Small reconnect + rediscover intervals so the cycle runs fast; cap 3 so a (wrong) full loop is
         // visibly more than the one pass Once must run per (re)connect.
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
@@ -314,6 +341,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
         // Props must accept the new optional parameter — no throw and actor starts normally.
         var driver = new DiscoverableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver,
             rediscoverInterval: TimeSpan.FromMilliseconds(20),
@@ -340,6 +370,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
         // (no second settling pass to drain, and no stale-tick double pass alongside the fresh one).
         var driver = new GrowingDiscoverableStubDriver(DiscoveryRediscoverPolicy.Once);
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20)));
 
@@ -373,6 +406,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
     {
         var driver = new DiscoverableStubDriver(DiscoveryRediscoverPolicy.Never);
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver, rediscoverInterval: TimeSpan.FromMilliseconds(20)));
 
@@ -400,6 +436,9 @@ public sealed class DriverInstanceActorDiscoveryTests : RuntimeActorTestBase
         // a long reconnect interval so the actor parks in Reconnecting deterministically within the test window.
         var driver = new GrowingDiscoverableStubDriver(DiscoveryRediscoverPolicy.Once);
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(
             driver,
             reconnectInterval: TimeSpan.FromSeconds(30),

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverInstanceActorNativeAlarmTests.cs

@@ -30,6 +30,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -77,6 +80,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -110,6 +116,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new SubscribableOnlyStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -170,6 +179,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
         // Long reconnect interval (default 10 s) so the retry doesn't fire during the assertion window.
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         // Drive to Connected; confirm the alarm handler is attached.
@@ -217,6 +229,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromMilliseconds(50)));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -245,6 +260,33 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
         parent.ExpectNoMsg(TimeSpan.FromMilliseconds(300));
     }
 
+    /// <summary>#477 Layer 2 — the actor announces connectivity to its parent (the host): Connected on
+    /// reaching the Connected state, then Connected=false on a <see cref="DriverInstanceActor.DisconnectObserved"/>,
+    /// then Connected=true again on the reconnect. This is the signal the host uses to annotate the driver's
+    /// native alarm conditions' Quality (comms lost → Bad, restored → Good).</summary>
+    [Fact]
+    public void ConnectivityChanged_is_announced_to_parent_on_connect_disconnect_and_reconnect()
+    {
+        var driver = new AlarmSourceStubDriver();
+        var parent = CreateTestProbe(); // deliberately does NOT ignore ConnectivityChanged — it's the subject.
+        var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromMilliseconds(50)));
+
+        actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
+
+        // Initial connect → Connected=true.
+        parent.FishForMessage<DriverInstanceActor.ConnectivityChanged>(m => true, TimeSpan.FromSeconds(3))
+            .Connected.ShouldBeTrue();
+
+        // Disconnect → Connected=false (this is what drives the conditions Bad).
+        actor.Tell(new DriverInstanceActor.DisconnectObserved("backend blip"));
+        parent.FishForMessage<DriverInstanceActor.ConnectivityChanged>(m => true, TimeSpan.FromSeconds(3))
+            .Connected.ShouldBeFalse();
+
+        // Reconnect → Connected=true again (drives them back Good).
+        parent.FishForMessage<DriverInstanceActor.ConnectivityChanged>(m => true, TimeSpan.FromSeconds(3))
+            .Connected.ShouldBeTrue();
+    }
+
     // --- stub drivers ----------------------------------------------------------------------------
 
     private class StubDriver : IDriver

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverInstanceActorTests.cs

@@ -109,6 +109,9 @@ public sealed class DriverInstanceActorTests : RuntimeActorTestBase
     {
         var driver = new SubscribableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -134,6 +137,9 @@ public sealed class DriverInstanceActorTests : RuntimeActorTestBase
     {
         var driver = new SubscribableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -162,6 +168,9 @@ public sealed class DriverInstanceActorTests : RuntimeActorTestBase
     {
         var driver = new SubscribableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromMilliseconds(50)));
 
         // Desired set arrives BEFORE connect — retained, not yet applied.
@@ -197,6 +206,9 @@ public sealed class DriverInstanceActorTests : RuntimeActorTestBase
         // is used — the exact condition that throws NotSupportedException on the subsequent Sender read.
         var driver = new SubscribableStubDriver { UnsubscribeYields = true };
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -242,6 +254,9 @@ public sealed class DriverInstanceActorTests : RuntimeActorTestBase
     {
         var driver = new SubscribableStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromSeconds(30)));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -271,6 +286,9 @@ public sealed class DriverInstanceActorTests : RuntimeActorTestBase
             InitBehavior = cfg => cfg == good ? Task.CompletedTask : throw new InvalidOperationException("bad-cfg"),
         };
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromMilliseconds(50)));
 
         actor.Tell(new DriverInstanceActor.SetDesiredSubscriptions(new[] { "tag-a" }, TimeSpan.FromMilliseconds(100)));
@@ -304,6 +322,9 @@ public sealed class DriverInstanceActorTests : RuntimeActorTestBase
             InitBehavior = cfg => cfg == v1 ? gate1.Task : gate2.Task,
         };
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromSeconds(30)));
         actor.Tell(new DriverInstanceActor.SetDesiredSubscriptions(new[] { "tag-a" }, TimeSpan.FromMilliseconds(100)));
 

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/NativeAlarmProjectorTests.cs

@@ -153,6 +153,19 @@ public class NativeAlarmProjectorTests
         snap.Acknowledged.ShouldBeTrue();
     }
 
+    // #477 — native transitions carry Good quality; comms-loss quality is applied out-of-band via the
+    // dedicated WriteAlarmQuality path (connectivity → DriverHostActor), NOT through the projector, so the
+    // projector stays quality-agnostic and its transition snapshots default to Good.
+    [Fact]
+    public void Transition_projection_defaults_to_good_quality()
+    {
+        var sut = new NativeAlarmProjector();
+
+        var snap = sut.Project("n1", Evt(AlarmTransitionKind.Raise));
+
+        snap.Quality.ShouldBe(OpcUaQuality.Good);
+    }
+
     private static AlarmEventArgs Evt(
         AlarmTransitionKind kind,
         AlarmSeverity sev = AlarmSeverity.High,

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Observability/OtOpcUaTelemetryHookTests.cs

@@ -199,6 +199,7 @@ public sealed class OtOpcUaTelemetryHookTests : RuntimeActorTestBase
         /// <param name="alarmNodeId">The alarm node identifier.</param>
         /// <param name="state">The full condition state snapshot.</param>
         /// <param name="occurredUtc">The time the alarm occurred in UTC.</param>
+        public void WriteAlarmQuality(string alarmNodeId, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
         public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime occurredUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) => Writes++;
         /// <summary>Materialises an alarm condition (stub implementation).</summary>
         /// <param name="alarmNodeId">The alarm node identifier.</param>

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/OpcUa/OpcUaPublishActorApplyFailureTests.cs

@@ -119,6 +119,7 @@ public sealed class OpcUaPublishActorApplyFailureTests : RuntimeActorTestBase
     private sealed class ThrowOnRebuildSink : IOpcUaAddressSpaceSink
     {
         public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WriteAlarmQuality(string alarmNodeId, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
         public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime occurredUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
         public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
@@ -133,6 +134,7 @@ public sealed class OpcUaPublishActorApplyFailureTests : RuntimeActorTestBase
     private sealed class NoopSink : IOpcUaAddressSpaceSink
     {
         public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WriteAlarmQuality(string alarmNodeId, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
         public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime occurredUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
         public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/OpcUa/OpcUaPublishActorRebuildTests.cs

@@ -443,6 +443,7 @@ public sealed class OpcUaPublishActorRebuildTests : RuntimeActorTestBase
         /// <param name="alarmNodeId">The alarm node ID.</param>
         /// <param name="state">The full condition state snapshot.</param>
         /// <param name="ts">The timestamp of the state change.</param>
+        public void WriteAlarmQuality(string alarmNodeId, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
         public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime ts, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => Calls.Enqueue($"WA:{alarmNodeId}");
         /// <summary>Records a materialise-alarm-condition call.</summary>

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/OpcUa/OpcUaPublishActorTests.cs

@@ -76,6 +76,26 @@ public sealed class OpcUaPublishActorTests : RuntimeActorTestBase
         }, duration: TimeSpan.FromMilliseconds(500));
     }
 
+    /// <summary>#477 — AlarmQualityUpdate routes to sink.WriteAlarmQuality with the quality + realm.</summary>
+    [Fact]
+    public void AlarmQualityUpdate_routes_to_sink_WriteAlarmQuality()
+    {
+        var sink = new RecordingSink();
+        var actor = Sys.ActorOf(OpcUaPublishActor.PropsForTests(sink: sink));
+
+        actor.Tell(new OpcUaPublishActor.AlarmQualityUpdate(
+            "Plant/Modbus/dev1/temp_hi", OpcUaQuality.Bad, DateTime.UtcNow, Realm: AddressSpaceRealm.Raw));
+
+        AwaitAssert(() =>
+        {
+            sink.AlarmQualityQueue.Count.ShouldBe(1);
+            sink.AlarmQualityQueue.TryPeek(out var q).ShouldBeTrue();
+            q.AlarmNodeId.ShouldBe("Plant/Modbus/dev1/temp_hi");
+            q.Quality.ShouldBe(OpcUaQuality.Bad);
+            q.Realm.ShouldBe(AddressSpaceRealm.Raw);
+        }, duration: TimeSpan.FromMilliseconds(500));
+    }
+
     /// <summary>Builds a test <see cref="AlarmConditionSnapshot"/> with sensible defaults so each test
     /// only specifies the fields it cares about.</summary>
     private static AlarmConditionSnapshot Snapshot(
@@ -577,6 +597,8 @@ public sealed class OpcUaPublishActorTests : RuntimeActorTestBase
         public ConcurrentQueue<(string NodeId, object? Value, OpcUaQuality Quality, DateTime Ts)> ValueQueue { get; } = new();
         /// <summary>Gets the queue of recorded alarm condition updates.</summary>
         public ConcurrentQueue<(string AlarmNodeId, AlarmConditionSnapshot State, DateTime Ts)> AlarmQueue { get; } = new();
+        /// <summary>Gets the queue of recorded alarm-quality annotations (#477).</summary>
+        public ConcurrentQueue<(string AlarmNodeId, OpcUaQuality Quality, DateTime Ts, AddressSpaceRealm Realm)> AlarmQualityQueue { get; } = new();
         /// <summary>Count of rebuild calls.</summary>
         public int RebuildCalls;
         /// <summary>Gets the queue of recorded EnsureFolder calls.</summary>
@@ -616,6 +638,10 @@ public sealed class OpcUaPublishActorTests : RuntimeActorTestBase
         public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime ts, AddressSpaceRealm realm = AddressSpaceRealm.Uns) =>
             AlarmQueue.Enqueue((alarmNodeId, state, ts));
 
+        /// <summary>Records an alarm-quality annotation (#477).</summary>
+        public void WriteAlarmQuality(string alarmNodeId, OpcUaQuality quality, DateTime ts, AddressSpaceRealm realm = AddressSpaceRealm.Uns) =>
+            AlarmQualityQueue.Enqueue((alarmNodeId, quality, ts, realm));
+
         /// <summary>Materialises an alarm condition (no-op in test).</summary>
         /// <param name="alarmNodeId">The alarm node ID.</param>
         /// <param name="equipmentNodeId">The equipment folder node ID.</param>