Merge review R1 fixes: removed driver's resilience tracker released; SDK timed-unshelve no-op (engine owns expiry); commented re-ack stored as AddComment; native-ack Primary verdict published from start; drain gate SharesRowsWithPeer; malformed cache bytes don't adopt the revision; HostAbortedException passthrough; ClusterRoleInfo seed filtered

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

src/Server/ZB.MOM.WW.OtOpcUa.Host/Configuration/LocalDbRegistration.cs

@@ -46,7 +46,7 @@ public static class LocalDbRegistration
     ///     Configuration key carrying the dedicated h2c sync listener's port. Zero or absent means
     ///     no listener is bound and the passive sync endpoint is not mapped.
     /// </summary>
-    public const string SyncListenPortKey = "LocalDb:SyncListenPort";
+    public const string SyncListenPortKey = Runtime.LocalDbReplicationPolicy.SyncListenPortKey;
 
     /// <summary>
     ///     The port the dedicated cleartext-HTTP/2 sync listener should bind, or <c>0</c> when the

src/Server/ZB.MOM.WW.OtOpcUa.Host/Configuration/LocalDbSetup.cs

@@ -170,9 +170,9 @@ public static class LocalDbSetup
     /// <returns><c>true</c> when this node is configured to replicate.</returns>
     public static bool ReplicationIsConfigured(IConfiguration configuration)
     {
-        // Shared with the alarm-historian drain gate (#603): one predicate, so the nodes that capture
-        // changes and the nodes that stand down for a peer can never disagree.
-        return Runtime.LocalDbReplicationPolicy.IsConfigured(configuration);
+        // Defined beside the alarm-historian drain gate's stricter predicate (#603, review R1 m3): every node
+        // the gate treats as sharing rows also captures, so the two never disagree in the harmful direction.
+        return Runtime.LocalDbReplicationPolicy.CapturesChanges(configuration);
     }
 
     /// <summary>Opts every replicated table into change capture, baselining what is already there.</summary>

src/Server/ZB.MOM.WW.OtOpcUa.Host/Program.cs

@@ -749,7 +749,10 @@ if (LogPipelineDiagnostics.CheckFileSinkGrowth(app.Configuration,
 
 await app.RunAsync();
 }
-catch (Exception ex)
+// HostAbortedException is how design-time tooling (EF `dotnet ef … --startup-project`, OpenAPI generators —
+// HostFactoryResolver) stops Program once it has the built host. It is not a failure: letting it reach the
+// Fatal + Environment.Exit(1) below would kill the tool's own process (#618, review R1 m5).
+catch (Exception ex) when (ex is not HostAbortedException)
 {
     // Log.Logger is still the silent bootstrap logger when the failure happened before AddZbSerilog
     // ran (e.g. EffectiveRoles.Resolve), so ALSO write to stderr — the one channel that always exists.

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs

@@ -874,8 +874,7 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
                     // (shelved, oneShot) flag pair. Timed shelving's expiry is owned by the engine; the time
                     // passed here is the engine's remaining time, so the node's UnshelveTime counts down to the
                     // real expiry (Gitea #597 — a 0 here reads as MaxTimeShelved, ~24.8 days). The SDK timer it
-                    // arms only routes an Unshelve back to the engine (OnTimedUnshelve), a no-op once the
-                    // engine's own expiry has run.
+                    // arms does nothing (OnTimedUnshelve is a no-op): the engine's own expiry re-projects.
                     condition.SetShelvingState(
                         SystemContext,
                         shelved: state.Shelving != AlarmShelvingKind.Unshelved,
@@ -1375,25 +1374,17 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
                     : ("TimedShelve", DateTime.UtcNow + TimeSpan.FromMilliseconds(shelvingTime));
                 return HandleAlarmCommand(context, condition, operation, comment: null, unshelveAt);
             };
-            // The auto-unshelve timer callback is SDK-initiated (the TimedShelve duration expired); the SDK
-            // fires it with the node manager's system context — there is NO session and NO user identity.
-            // Routing through HandleAlarmCommand would hit the AlarmAck gate and return BadUserAccessDenied,
-            // leaving the alarm permanently shelved. Instead, bypass the client gate, extract the AlarmId the
-            // same way HandleAlarmCommand does, and route an Unshelve command so the engine clears its shelve
-            // state. The manual-client Unshelve path goes through OnShelve(shelving:false) and stays gated.
-            alarm.OnTimedUnshelve = (context, condition) =>
-            {
-                var alarmId = condition.NodeId.Identifier?.ToString() ?? string.Empty;
-                // User MUST be non-empty: the engine's Part9StateMachine.ApplyUnshelve rejects a
-                // null/whitespace user (ArgumentException "User required."), and that exception is swallowed
-                // downstream — an empty user would make the timed auto-unshelve silently no-op, so a
-                // TimedShelve would never auto-expire. There is no client principal on a system-timer
-                // unshelve, so label it the canonical engine-internal "system" user (matching the engine's
-                // own AutoUnshelve audit user and the codebase-wide "system" system-actor convention). The
-                // AlarmAck gate bypass is intentional and preserved — this is a session-less SDK timer.
-                AlarmCommandRouter?.Invoke(new AlarmCommand(alarmId, "Unshelve", "system", null, null));
-                return ServiceResult.Good;
-            };
+            // The SDK's auto-unshelve timer (armed by SetShelvingState for the real remaining time since Gitea
+            // #597) fires with a session-less system context. It is deliberately a NO-OP: the engine owns
+            // timed-shelve expiry (ScriptedAlarmEngine's shelving check → Part9StateMachine.ApplyShelvingCheck,
+            // recorded as "AutoUnshelve" by "system" with its "Timed shelving expired" comment), and its
+            // re-projection is what unshelves this node. Routing an operator-style "Unshelve" from here used to
+            // pre-empt that check on every expiry — from BOTH pair nodes, rewriting the audit trail as a manual
+            // unshelve — and a timer callback already queued when a re-shelve disposed it could unshelve the
+            // fresh shelve. The SDK's own OnTimerExpired changes no shelving state itself (it only refreshes
+            // UnshelveTime after this callback), so returning without routing leaves the node shelved until
+            // the engine's expiry lands. Native conditions are never timed-shelved (BadNotSupported above).
+            alarm.OnTimedUnshelve = (_, _) => ServiceResult.Good;
 
             // H4 — inbound Part 9 Enable/Disable (the condition type's built-in Enable/Disable methods route
             // here via this delegate). The engine handles Enable/Disable for SCRIPTED alarms
@@ -1596,9 +1587,11 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
     ///         <b>Only a real change is reported.</b> The condition's gate-relevant state is read before and after
     ///         the SDK handler, and nothing is reported when it did not move. The SDK accepts acknowledging an
     ///         acknowledged condition and sets <c>Confirmed = false</c> again; a re-ack therefore also restores the
-    ///         pre-call Confirmed and Retain, so a scripted node never drifts from its engine (which ignores a
-    ///         re-ack) and the call is silent — unless it carried a comment, which the SDK writes and which is then
-    ///         reported once like AddComment (Gitea #597). AddComment always reports: adding a comment is itself
+    ///         pre-call Confirmed and Retain, so a scripted node never drifts from its engine (which ignores an
+    ///         uncommented re-ack) and the call is silent — unless it carried a comment, which the SDK writes and
+    ///         which is then reported once like AddComment (Gitea #597). The scripted engine records that comment
+    ///         too (<c>Part9StateMachine.ApplyAcknowledge</c> treats a commented re-ack as AddComment), so the
+    ///         reported comment is persisted and replicated, not node-local. AddComment always reports: adding a comment is itself
     ///         the change. A NATIVE re-ack is still routed to the driver: the route is fire-and-forget, so a node
     ///         showing Acked does not prove the upstream system acknowledged, and re-acking is the documented retry.
     ///     </para>
@@ -1635,7 +1628,7 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
                 // The requested duration, so UnshelveTime counts down to the real expiry (Gitea #597 — 0 reads as
                 // MaxTimeShelved, ~24.8 days). The scripted engine still owns the expiry and re-projects Unshelved
                 // when it passes (with its own remaining time meanwhile — WriteAlarmCondition); the SDK timer this
-                // arms only routes an Unshelve back to it (OnTimedUnshelve), a no-op once the engine has expired it.
+                // arms does nothing (OnTimedUnshelve is a no-op — the engine's AutoUnshelve owns the expiry).
                 timedShelve.OnCall = (context, method, objectId, shelvingTime) => ReportAfterMethod(
                     () => timed(context, method, objectId, shelvingTime),
                     () => alarm.SetShelvingState(SystemContext, shelved: true, oneShot: false, shelvingTime: shelvingTime));

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs

@@ -788,9 +788,91 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
         // Same rationale for the ScriptedAlarm host — the bootstrap-restore path Tells it
         // ApplyScriptedAlarms through the same PushDesiredSubscriptions pass.
         SpawnScriptedAlarmHost();
+        StartPrimaryVerdictPublishing();
         Bootstrap();
     }
 
+    /// <summary>
+    ///     Review R1 m2 (Gitea #597): the published Primary data-plane verdict (<see cref="IDriverPrimaryRoleSource"/>
+    ///     — the native-ack gate and the Sparkplug primary-host claim) must mirror <see cref="ShouldServiceAsPrimary"/>
+    ///     from the moment this host starts, not only from the first redundancy snapshot. Before this, the view sat
+    ///     on its single-node seed (allow) through the whole boot window, so on a pair BOTH nodes accepted a native
+    ///     ack while this host — which evaluates the member count live — dropped the upstream route on the
+    ///     non-Primary: the acked → unacked revert #597 targets. So publish once now, and again whenever cluster
+    ///     membership changes (a driver peer coming Up turns an unknown role from allow into deny before any
+    ///     snapshot names this node). A non-cluster ActorRefProvider (legacy/test harnesses) just keeps the
+    ///     initial publish.
+    /// </summary>
+    private void StartPrimaryVerdictPublishing()
+    {
+        if (_primaryRoleSource is null) return;
+        PublishPrimaryVerdict();
+        try
+        {
+            Akka.Cluster.Cluster.Get(Context.System).Subscribe(
+                Self, Akka.Cluster.ClusterEvent.SubscriptionInitialStateMode.InitialStateAsSnapshot,
+                typeof(Akka.Cluster.ClusterEvent.IMemberEvent));
+            _subscribedToMemberEvents = true;
+        }
+        catch (Exception)
+        {
+            // Non-cluster ActorRefProvider — no membership to follow; DriverMemberCount() reads 0 there too.
+        }
+    }
+
+    /// <summary>A cluster member changed status: re-publish the Primary verdict now and once more shortly after.
+    /// The deferred pass covers the cluster read-view (what <see cref="DriverMemberCount"/> reads) updating on its
+    /// own subscriber AFTER this event was delivered here — the two are not ordered.</summary>
+    private void OnDriverMembershipChanged(Akka.Cluster.ClusterEvent.IMemberEvent _)
+    {
+        PublishPrimaryVerdictIfChanged();
+        // One keyed timer: a burst of member events collapses into a single deferred pass.
+        Timers.StartSingleTimer("republish-primary-verdict", RepublishPrimaryVerdict.Instance, MembershipRepublishDelay);
+    }
+
+    /// <summary>Publishes <see cref="ShouldServiceAsPrimary"/> to the primary-role source (no-op when none is wired).
+    /// The snapshot path publishes on every snapshot, as the other verdicts do.</summary>
+    private void PublishPrimaryVerdict()
+    {
+        if (_primaryRoleSource is null) return;
+        var verdict = ShouldServiceAsPrimary();
+        _lastPublishedPrimaryVerdict = verdict;
+        _primaryRoleSource.PublishPrimaryRole(verdict);
+    }
+
+    /// <summary>The membership path publishes only a CHANGED verdict — member events are frequent and carry no
+    /// role information, so republishing an unchanged verdict on each would be noise.</summary>
+    private void PublishPrimaryVerdictIfChanged()
+    {
+        if (_primaryRoleSource is null || ShouldServiceAsPrimary() == _lastPublishedPrimaryVerdict) return;
+        PublishPrimaryVerdict();
+    }
+
+    /// <inheritdoc />
+    protected override void PostStop()
+    {
+        if (_subscribedToMemberEvents)
+        {
+            try { Akka.Cluster.Cluster.Get(Context.System).Unsubscribe(Self); }
+            catch (Exception) { /* system shutting down */ }
+        }
+        base.PostStop();
+    }
+
+    /// <summary>Self-message: re-evaluate and re-publish the Primary verdict (see <see cref="OnDriverMembershipChanged"/>).</summary>
+    internal sealed class RepublishPrimaryVerdict
+    {
+        /// <summary>The shared instance.</summary>
+        public static readonly RepublishPrimaryVerdict Instance = new();
+        private RepublishPrimaryVerdict() { }
+    }
+
+    /// <summary>How long after a membership event the Primary verdict is re-published a second time.</summary>
+    private static readonly TimeSpan MembershipRepublishDelay = TimeSpan.FromSeconds(1);
+
+    private bool _subscribedToMemberEvents;
+    private bool? _lastPublishedPrimaryVerdict;
+
     /// <summary>
     ///     Spawns the single <see cref="VirtualTagHostActor"/> child that owns the Equipment-namespace
     ///     VirtualTagActors and bridges their results onto the OPC UA publish actor. A test-supplied
@@ -990,12 +1072,24 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
             var deploymentId = DeploymentId.Parse(cached.DeploymentId);
             var revision = RevisionHash.Parse(cached.RevisionHash);
 
-            _currentRevision = revision;
-            BecomeSteady();
             // Restore drivers + address space + subscriptions from the cached bytes — no SQL read, no
             // re-ack (the deployment is already Applied). Same in-hand-bytes apply as the Direct-mode
             // cache boot, but this is the steady-state config source, not an outage fallback.
-            ApplyCachedArtifact(deploymentId, cached.Artifact);
+            if (!ApplyCachedArtifact(deploymentId, cached.Artifact))
+            {
+                // #601 / review R1 m4: unusable cached bytes applied nothing, so they must not become the
+                // current revision — that would ack a re-dispatch of the same revision as already applied
+                // without ever applying it. Steady-with-no-revision, exactly as for an empty cache.
+                _log.Warning(
+                    "DriverHost {Node}: FetchAndCache boot — the cached artifact for deployment {Id} (rev {Rev}) " +
+                    "is unreadable; entering Steady (no revision). The next dispatch will fetch.",
+                    _localNode, deploymentId, revision);
+                BecomeSteady();
+                return;
+            }
+
+            _currentRevision = revision;
+            BecomeSteady();
 
             _log.Info(
                 "DriverHost {Node}: FetchAndCache boot — restored served state for deployment {Id} " +
@@ -1059,14 +1153,24 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
             var deploymentId = DeploymentId.Parse(cached.DeploymentId);
             var revision = RevisionHash.Parse(cached.RevisionHash);
 
+            // #601 / review R1 m4: unusable cached bytes applied nothing — the node is NOT serving a
+            // configuration, so it must not claim RUNNING FROM CACHE, adopt the revision (a re-dispatch of
+            // it would then be acked without being applied) or skip Stale's ConfigDb retry loop.
+            if (!ApplyCachedArtifact(deploymentId, cached.Artifact))
+            {
+                _log.Error(
+                    "DriverHost {Node}: the cached artifact for deployment {Id} (rev {Rev}) is unreadable; " +
+                    "not booting from it — entering Stale with no configuration.",
+                    _localNode, deploymentId, revision);
+                return false;
+            }
+
             // Steady, not Stale: this node is serving a real configuration. The retry-db timer that
             // Stale would have started does not run here, so recovery rides on the next dispatch —
             // matching how a normally-booted node behaves.
             _currentRevision = revision;
             BecomeSteady();
 
-            ApplyCachedArtifact(deploymentId, cached.Artifact);
-
             _isRunningFromCache = true;
             _log.Warning(
                 "DriverHost {Node}: RUNNING FROM CACHE — central ConfigDb is unreachable, so this node " +
@@ -1094,16 +1198,16 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
     ///     <c>UpsertNodeDeploymentState</c> and <c>SendAck</c> for the same reason: both write to or
     ///     depend on central.
     /// </remarks>
-    private void ApplyCachedArtifact(DeploymentId deploymentId, byte[] blob)
+    /// <returns><see langword="false"/> when the bytes were empty or malformed and nothing was applied — the
+    /// caller must not adopt the cached revision (#601, review R1 m4).</returns>
+    private bool ApplyCachedArtifact(DeploymentId deploymentId, byte[] blob)
     {
         var correlation = CorrelationId.NewId();
 
-        // #601: null = the cached bytes were empty or malformed — no answer, not an empty configuration.
-        // Keep last-known-good: no address-space rebuild and no subscription push from unusable bytes.
         // #601: null = the cached bytes were empty or malformed — no answer, not an empty configuration.
         // Keep last-known-good: no address-space rebuild and no subscription push from unusable bytes.
         if (ReconcileDriversFromBlob(deploymentId, blob) is null)
-            return;
+            return false;
 
         // Hand the cached blob to the rebuild so it materialises the client-facing address space from
         // it directly. Passing only the deploymentId would drive a ConfigDb read — unreachable here by
@@ -1113,6 +1217,7 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
             new ZB.MOM.WW.OtOpcUa.Runtime.OpcUa.OpcUaPublishActor.RebuildAddressSpace(correlation, deploymentId, blob));
 
         PushDesiredSubscriptionsFromArtifact(deploymentId, blob);
+        return true;
     }
 
     /// <summary>
@@ -1170,6 +1275,9 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
         Receive<RouteNodeWrite>(HandleRouteNodeWrite);
         Receive<RouteNativeAlarmAck>(HandleRouteNativeAlarmAck);
         Receive<RedundancyStateChanged>(OnRedundancyStateChanged);
+        Receive<Akka.Cluster.ClusterEvent.IMemberEvent>(OnDriverMembershipChanged);
+        Receive<RepublishPrimaryVerdict>(_ => PublishPrimaryVerdictIfChanged());
+        Receive<Akka.Cluster.ClusterEvent.CurrentClusterState>(_ => PublishPrimaryVerdictIfChanged());
         // The redundancy-state topic also carries OpcUaProbeResult (OpcUaPublishActor peer-probes).
         // We don't consume it here — drop it so it doesn't dead-letter (matches PeerProbeSupervisor).
         Receive<ZB.MOM.WW.OtOpcUa.Runtime.Health.PeerOpcUaProbeActor.OpcUaProbeResult>(_ => { });
@@ -1228,6 +1336,9 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
         Receive<RouteNodeWrite>(HandleRouteNodeWrite);
         Receive<RouteNativeAlarmAck>(HandleRouteNativeAlarmAck);
         Receive<RedundancyStateChanged>(OnRedundancyStateChanged);
+        Receive<Akka.Cluster.ClusterEvent.IMemberEvent>(OnDriverMembershipChanged);
+        Receive<RepublishPrimaryVerdict>(_ => PublishPrimaryVerdictIfChanged());
+        Receive<Akka.Cluster.ClusterEvent.CurrentClusterState>(_ => PublishPrimaryVerdictIfChanged());
         // The redundancy-state topic also carries OpcUaProbeResult (OpcUaPublishActor peer-probes).
         // We don't consume it here — drop it so it doesn't dead-letter (matches PeerProbeSupervisor).
         Receive<ZB.MOM.WW.OtOpcUa.Runtime.Health.PeerOpcUaProbeActor.OpcUaProbeResult>(_ => { });
@@ -1975,7 +2086,7 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
         // drain verdict published immediately above. A driver reading this claims an exclusive identity
         // on a shared external system (Gitea #511: the Sparkplug host id), where two claimants is the
         // harm, so an unknown role with a driver peer present must deny.
-        _primaryRoleSource?.PublishPrimaryRole(ShouldServiceAsPrimary());
+        PublishPrimaryVerdict();
     }
 
     private void Stale()
@@ -1998,6 +2109,9 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
         Receive<ReprovisionDeferred>(m => ReprovisionChild(m.Request, m.Child));
         Receive<ReconnectDriver>(HandleReconnectDriver);
         Receive<RedundancyStateChanged>(OnRedundancyStateChanged);
+        Receive<Akka.Cluster.ClusterEvent.IMemberEvent>(OnDriverMembershipChanged);
+        Receive<RepublishPrimaryVerdict>(_ => PublishPrimaryVerdictIfChanged());
+        Receive<Akka.Cluster.ClusterEvent.CurrentClusterState>(_ => PublishPrimaryVerdictIfChanged());
         // The redundancy-state topic also carries OpcUaProbeResult (OpcUaPublishActor peer-probes).
         // We don't consume it here — drop it so it doesn't dead-letter (matches PeerProbeSupervisor).
         Receive<ZB.MOM.WW.OtOpcUa.Runtime.Health.PeerOpcUaProbeActor.OpcUaProbeResult>(_ => { });
@@ -3233,7 +3347,10 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers, IWithUnboundedS
         Context.Stop(entry.Actor);
         _children.Remove(driverInstanceId);
         // #609: the instance left the plan (StopChild is only reached via plan.ToStop), so its cached
-        // Health/Resilience snapshots must not replay to new telemetry subscribers.
+        // Health/Resilience snapshots must not replay to new telemetry subscribers. Release the shared
+        // resilience state FIRST: the resilience publisher re-emits the tracker's snapshots every tick, so
+        // evicting the hub alone was undone within one interval.
+        _invokerFactory.Release(driverInstanceId);
         _telemetryHub?.Evict(driverInstanceId);
         _log.Info("DriverHost {Node}: stopped driver child {Id}", _localNode, driverInstanceId);
     }

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/LocalDbReplicationPolicy.cs

@@ -3,26 +3,36 @@ using Microsoft.Extensions.Configuration;
 namespace ZB.MOM.WW.OtOpcUa.Runtime;
 
 /// <summary>
-///     The ONE definition of "this node's LocalDb is replicated to a peer" (#603). Two consumers must agree
-///     on it, and used to carry separate predicates that diverged: the Host's table-registration step
-///     (<c>LocalDbSetup.ReplicationIsConfigured</c> - which nodes capture changes) and the alarm-historian
-///     drain gate (<c>AddAlarmHistorian</c> - which nodes stand down in favour of a peer). Lives in Runtime
-///     because Host references Runtime and not the reverse.
+///     The definitions of "this node's LocalDb is replicated to a peer" (#603) — one place, two deliberately
+///     different predicates for the two consumers: the Host's table-registration step
+///     (<c>LocalDbSetup.ReplicationIsConfigured</c> → <see cref="CapturesChanges"/>: which nodes capture
+///     changes) and the alarm-historian drain gate (<c>AddAlarmHistorian</c> → <see cref="SharesRowsWithPeer"/>:
+///     which nodes stand down in favour of a peer). Lives in Runtime because Host references Runtime and not
+///     the reverse.
 /// </summary>
 /// <remarks>
 ///     <para>
-///         <b>Predicate: <c>LocalDb:Replication:PeerAddress</c> OR <c>LocalDb:Replication:ApiKey</c> is
-///         non-blank.</b> The OR is required: only the dialling half of a pair sets <c>PeerAddress</c>, while
-///         the passive half carries the shared <c>ApiKey</c> (plus a listen port) and nothing else.
+///         <b>Why two predicates (review R1 m3).</b> The two answers cost differently when wrong. Registering a
+///         node that has no working sync path only costs capture triggers. Gating the drain of a node that
+///         shares its queue with nobody parks its alarm events behind a Primary that does not hold them —
+///         undelivered until the node is promoted, and drop-oldest at <c>Capacity</c> meanwhile. So
+///         registration stays permissive and the gate is strict. Every node the gate treats as sharing also
+///         captures, so the two never disagree in the harmful direction.
 ///     </para>
 ///     <para>
-///         <b>Why the drain gate takes the same predicate (it previously used PeerAddress OR
-///         <c>SyncListenPort</c>).</b> The gate's question is "does a peer hold the same rows?". The passive
-///         sync endpoint is fail-closed on the key, so a node with a listen port but no <c>ApiKey</c> rejects
-///         every inbound stream and shares its queue with nobody - gating it would park its alarm events
-///         behind a Primary that cannot deliver them. Conversely an <c>ApiKey</c>-only passive node IS
-///         registered and does receive its peer's rows, so it must be gated or both halves drain. The port
-///         is not evidence of a peer; the key is.
+///         <b>Registration: <c>LocalDb:Replication:PeerAddress</c> OR <c>LocalDb:Replication:ApiKey</c>.</b>
+///         The OR is required: only the dialling half of a pair sets <c>PeerAddress</c>, while the passive
+///         half carries the shared <c>ApiKey</c> (plus a listen port) and nothing else. Keying on
+///         <c>PeerAddress</c> alone would strip capture from every passive node.
+///     </para>
+///     <para>
+///         <b>Drain gate: <c>ApiKey</c> AND (<c>PeerAddress</c> OR <c>LocalDb:SyncListenPort</c> &gt; 0).</b> A
+///         peer holds this node's rows only over a working sync path: a dial (<c>PeerAddress</c>) or a
+///         listener (<c>SyncListenPort</c>), each authenticated by the key. Both auth directions fail closed,
+///         so a path without the key shares nothing, and a key with neither path (e.g. a fleet-wide
+///         secret/env <c>ApiKey</c> on a node with no peer) shares nothing either. Every docker-dev shape
+///         gives the same answer under both predicates: site-a-1 (PeerAddress + ApiKey + port) and site-a-2
+///         (ApiKey + port) are gated; central and site-b (neither) are not.
 ///     </para>
 /// </remarks>
 public static class LocalDbReplicationPolicy
@@ -30,14 +40,31 @@ public static class LocalDbReplicationPolicy
     /// <summary>Configuration section holding the LocalDb replication options.</summary>
     public const string ReplicationSectionPath = "LocalDb:Replication";
 
-    /// <summary>Whether this node's LocalDb replicates to a pair peer.</summary>
+    /// <summary>The dedicated passive-sync listener port key (same key as <c>LocalDbRegistration.SyncListenPortKey</c>).</summary>
+    public const string SyncListenPortKey = "LocalDb:SyncListenPort";
+
+    /// <summary>Whether this node registers its replicated tables for change capture (table registration).</summary>
     /// <param name="configuration">The application configuration.</param>
     /// <returns><c>true</c> when <c>PeerAddress</c> or <c>ApiKey</c> is set under the replication section.</returns>
-    public static bool IsConfigured(IConfiguration configuration)
+    public static bool CapturesChanges(IConfiguration configuration)
     {
         ArgumentNullException.ThrowIfNull(configuration);
         var section = configuration.GetSection(ReplicationSectionPath);
         return !string.IsNullOrWhiteSpace(section["PeerAddress"])
             || !string.IsNullOrWhiteSpace(section["ApiKey"]);
     }
+
+    /// <summary>Whether a pair peer actually holds this node's replicated rows (the alarm drain gate).</summary>
+    /// <param name="configuration">The application configuration.</param>
+    /// <returns><c>true</c> when <c>ApiKey</c> is set AND either <c>PeerAddress</c> is set or
+    ///     <c>LocalDb:SyncListenPort</c> is a positive port.</returns>
+    public static bool SharesRowsWithPeer(IConfiguration configuration)
+    {
+        ArgumentNullException.ThrowIfNull(configuration);
+        var section = configuration.GetSection(ReplicationSectionPath);
+        if (string.IsNullOrWhiteSpace(section["ApiKey"])) return false;
+        var dials = !string.IsNullOrWhiteSpace(section["PeerAddress"]);
+        var listens = int.TryParse(configuration[SyncListenPortKey], out var port) && port > 0;
+        return dials || listens;
+    }
 }

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ServiceCollectionExtensions.cs

@@ -177,11 +177,13 @@ public static class ServiceCollectionExtensions
         // possibly deliver its events. Scoping the gate to "is my queue actually shared?" is what
         // keeps the two scopes from disagreeing.
         // BOTH halves of a pair share the queue, but only one of them dials: the initiator sets
-        // Replication:PeerAddress, its partner carries the shared ApiKey and waits. The predicate is
-        // LocalDbReplicationPolicy - the same one LocalDbSetup uses to decide which nodes capture
-        // changes at all. It deliberately does NOT count SyncListenPort: the passive endpoint is
-        // fail-closed on the key, so a port with no ApiKey shares nothing and must keep draining.
-        var replicated = LocalDbReplicationPolicy.IsConfigured(configuration);
+        // Replication:PeerAddress, its partner carries the shared ApiKey plus SyncListenPort and waits.
+        // The predicate is LocalDbReplicationPolicy.SharesRowsWithPeer: ApiKey AND (PeerAddress OR
+        // SyncListenPort > 0) - an authenticated sync path in either direction. Both auth directions
+        // fail closed, so a path without the key, or a key with no path (a fleet-wide secret on an
+        // unpaired node), shares nothing and must keep draining. Deliberately stricter than the
+        // registration predicate (CapturesChanges) - see the policy's remarks.
+        var replicated = LocalDbReplicationPolicy.SharesRowsWithPeer(configuration);
 
         if (!replicated)
         {