fix(runtime): Primary verdict published from host start, cache boot never adopts malformed bytes, strict drain-gate predicate, HostAbortedException passthrough, seed only Up members

Review R1:
- M1 (#609): DriverHostActor.StopChild releases the instance's resilience state before evicting the hub.
- m2 (#597): DriverHostActor publishes ShouldServiceAsPrimary() to IDriverPrimaryRoleSource at start and on
  cluster membership changes (deduped), so the native-ack gate denies in a pair's boot window.
- m4 (#601): ApplyCachedArtifact returns false on empty/malformed bytes; the cached revision is not adopted,
  Direct mode goes Stale (no RUNNING FROM CACHE), FetchAndCache lands Steady-with-no-revision and a
  re-dispatch of the same revision really applies.
- m3 (#603): LocalDbReplicationPolicy splits into CapturesChanges (PeerAddress||ApiKey, registration) and
  SharesRowsWithPeer (ApiKey && (PeerAddress||SyncListenPort>0), alarm drain gate).
- m5 (#618): Program.cs catch-all filters HostAbortedException (design-time tooling).
- m6 (Cluster-002): ClusterRoleInfo seeds only Up/WeaklyUp members.

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

docs/AlarmHistorian.md

@@ -93,6 +93,16 @@ Two postures are deliberate:
 - **Unset (the default) means drain.** So does an unpublished view. A deployment
   that runs no redundancy never publishes a role, and defaulting closed would
   silently stop its alarm history forever.
+- **Only a shared queue is gated.** Standing down is safe only because a peer
+  holds the same rows, so the gate applies only when
+  `LocalDbReplicationPolicy.SharesRowsWithPeer` holds:
+  `LocalDb:Replication:ApiKey` **AND** (`LocalDb:Replication:PeerAddress` **OR**
+  `LocalDb:SyncListenPort > 0`) — an authenticated sync path in either
+  direction. Any other node always drains its own queue. This is deliberately
+  stricter than the table-registration predicate (`PeerAddress` OR `ApiKey`):
+  a key with no dial and no listener (e.g. a fleet-wide secret on an unpaired
+  node) captures changes but shares them with nobody, and gating it would park
+  its events behind a Primary that does not hold them (review R1 m3).
 - **A gate that throws means "not now", never permission.** Draining on a gate
   fault would put a pair into dual delivery exactly when its redundancy signal is
   sick.

docs/Configuration.md

@@ -218,7 +218,7 @@ See the [ClusterClient→gRPC migration design](plans/2026-08-06-clusterclient-t
 | `GrpcListenPort` | int | `0` | Dedicated **h2c-only** Kestrel port for the artifact gRPC service. `0` = disabled (nothing bound). Must differ from the main HTTP port and from `LocalDb:SyncListenPort` (h2c cannot share a cleartext HTTP/1 port). Mapped only on admin-role nodes. |
 | `ApiKey` | string | `""` | Shared bearer key the serve-side interceptor checks (constant-time, **fail-closed**: an unset key rejects every call). **Supply via env `ConfigServe__ApiKey` — never commit.** |
 
-**It is a dark switch; the serve side is always wired.** Central maps the `DeploymentArtifactService` behind the `ConfigServeAuthInterceptor` (path-scoped, `FixedTimeEquals`, fail-closed) whenever `ConfigServe:GrpcListenPort > 0`, in both modes — so flipping a node to `FetchAndCache` is a config change, not a redeploy. A `FetchAndCache` node that cannot fetch (all endpoints down, `NotFound`, SHA mismatch) **fails the apply and keeps last-known-good** — a null fetch is "no answer," never an empty configuration (the [#485](plans/2026-07-15-v3-batch4-address-space-plan.md) contract). At boot it restores served state from the LocalDb pointer with no SQL read; an empty or unreadable cache lands Steady-with-no-revision (the first dispatch fetches), never Stale.
+**It is a dark switch; the serve side is always wired.** Central maps the `DeploymentArtifactService` behind the `ConfigServeAuthInterceptor` (path-scoped, `FixedTimeEquals`, fail-closed) whenever `ConfigServe:GrpcListenPort > 0`, in both modes — so flipping a node to `FetchAndCache` is a config change, not a redeploy. A `FetchAndCache` node that cannot fetch (all endpoints down, `NotFound`, SHA mismatch) **fails the apply and keeps last-known-good** — a null fetch is "no answer," never an empty configuration (the [#485](plans/2026-07-15-v3-batch4-address-space-plan.md) contract). At boot it restores served state from the LocalDb pointer with no SQL read; an empty or unreadable cache — including a cached row whose bytes are malformed (review R1 m4) — lands Steady-with-no-revision (the first dispatch fetches, even of the same revision), never Stale.
 
 **The listener is dedicated h2c and coexists with the LocalDb-sync listener.** A fused admin+driver node with **both** `ConfigServe:GrpcListenPort` and `LocalDb:SyncListenPort` set re-binds its existing HTTP surface exactly once and adds both dedicated HTTP/2-only ports on top — see the same Kestrel-takeover caveat under [`LocalDb`](#localdb-pair-local-config-cache--driver-role-only).
 
@@ -431,7 +431,10 @@ replication stays inert until the sync port + peer are set.
 `PeerAddress` **OR** `ApiKey` non-blank — the OR because only the *dialling* half sets `PeerAddress`, so
 keying on it alone would strip change capture from every passive node and leave the pair converging in one
 direction only. `SyncListenPort` is deliberately **not** part of it (a port with no `ApiKey` is fail-closed
-and syncs with nobody). A configured node registers all four tables with `baselineExistingRows: true`, so
+and syncs with nobody). (The alarm-historian **drain gate** uses a stricter predicate on purpose —
+`ApiKey` AND (`PeerAddress` OR `SyncListenPort > 0`), `LocalDbReplicationPolicy.SharesRowsWithPeer` — because
+gating a node that shares its queue with nobody strands its alarm history; see `docs/AlarmHistorian.md`
+§"The drain gate".) A configured node registers all four tables with `baselineExistingRows: true`, so
 turning replication on converges the rows **already in the file** and not merely subsequent writes; an
 unconfigured node **deregisters** them at boot, dropping capture triggers an earlier build installed. ⚠️ The
 sync handshake compares registered-table digests **fail-closed**, so flipping either key is a

docs/Redundancy.md

@@ -526,13 +526,13 @@ Three data-plane surfaces are **Primary-gated** so a warm standby never touches
 
 Before archreview 03/S4 the unknown-role case defaulted to *allow* unconditionally, opening a dual-primary window: a freshly-booted secondary on a multi-node cluster serviced shared-device writes and emitted duplicate fleet-wide alerts for up to the ~10 s `RedundancyStateActor` heartbeat (and indefinitely if the snapshot's NodeId never matched this node). Membership is authoritative much earlier than DPS delivery, so an unknown role on a **multi-driver** cluster now default-**denies**. The driver member count is read live from `Cluster.State.Members` (Up members with the `driver` role); a non-cluster ActorRefProvider yields 0 ⇒ single-node posture. If a snapshot arrives that never mentions this node while a driver peer exists (the 03/S5 identity-mismatch shape), `DriverHostActor` logs a one-time Warning so the silent mismatch is diagnosable.
 
-**What a client sees during the boot window (multi-node, role unknown):** an inbound write is **rejected** (not queued — OT actuation seconds late is a surprise). The reject rides the sanctioned optimistic-write self-correction surface: the node reverts to its prior value with a transient Bad-quality blip and a Part 8 `AuditWriteUpdateEvent`; the client's synchronous write call still returned Good (exactly as any failed device write behaves since the #5 write-outcome self-correction). The rejection reason distinguishes the boot window (`"not primary (role unknown)"`) from a steady-state Secondary (`"not primary"`). Acks are dropped (Warning-logged when role-unknown). The alerts emit is skipped (the Primary peer publishes the single fleet copy). The window closes on the first delivered snapshot.
+**What a client sees during the boot window (multi-node, role unknown):** an inbound write is **rejected** (not queued — OT actuation seconds late is a surprise). The reject rides the sanctioned optimistic-write self-correction surface: the node reverts to its prior value with a transient Bad-quality blip and a Part 8 `AuditWriteUpdateEvent`; the client's synchronous write call still returned Good (exactly as any failed device write behaves since the #5 write-outcome self-correction). The rejection reason distinguishes the boot window (`"not primary (role unknown)"`) from a steady-state Secondary (`"not primary"`). Acks are dropped (Warning-logged when role-unknown) — and since review R1 m2 a native OPC UA Acknowledge is refused up front (`BadInvalidState`) in the same window: `DriverHostActor` publishes its Primary verdict to `IDriverPrimaryRoleSource` (the native-ack gate, and the MQTT Sparkplug primary-host claim) once at start and again on every cluster membership change, not only on redundancy snapshots, so the published verdict denies as soon as a driver peer is Up rather than sitting on the single-node "allow" seed until the first snapshot. The alerts emit is skipped (the Primary peer publishes the single fleet copy). The window closes on the first delivered snapshot.
 
 Under warm/hot redundancy both cluster nodes run `ScriptedAlarmHostActor` and evaluate scripted alarms, keeping each node's address space and engine state warm for instant failover. To avoid duplicate rows on `/alerts` and duplicate historian writes, only the Primary node publishes externally:
 
 - **`alerts` topic emission** — `ScriptedAlarmHostActor` and `DriverHostActor.ForwardNativeAlarm` subscribe to the `redundancy-state` DPS topic and cache the local node's `RedundancyRole`, then gate the cluster `alerts` publish through `PrimaryGatePolicy` (table above). The OPC UA condition-node write and inbound ack/shelve command processing remain **ungated** on both nodes so the secondary is always ready to serve clients after a failover.
 - **`HistorianAdapterActor` historization** — likewise Primary-gated so alarm historization is exactly-once across all alarm sources. The actor subscribes to the `alerts` DPS topic and translates each `AlarmTransitionEvent` → `AlarmHistorianEvent` before enqueuing it on the sink; scripted alarms therefore historize exactly once regardless of cluster size.
-- **The alarm sink's DRAIN** — a second, independent gate on the same decision. The enqueue gate above is not sufficient any more: since Phase 2 the store-and-forward buffer lives in the replicated LocalDb, so the Secondary holds a full copy of the Primary's queued rows and an ungated drain there would re-deliver every event continuously. `LocalDbStoreAndForwardSink` takes a `drainGate` fed from `IRedundancyRoleView` — a singleton `DriverHostActor` publishes its `PrimaryGatePolicy` verdict to, because the drain runs on a timer and cannot receive `RedundancyStateChanged` itself. A gated-off node reports `HistorianDrainState.NotPrimary`. Delivery is **at-least-once across a failover** by design: rows the old Primary delivered just before dying may not have replicated their deletes yet. See [AlarmHistorian.md](AlarmHistorian.md).
+- **The alarm sink's DRAIN** — a second, independent gate on the same decision. The enqueue gate above is not sufficient any more: since Phase 2 the store-and-forward buffer lives in the replicated LocalDb, so the Secondary holds a full copy of the Primary's queued rows and an ungated drain there would re-deliver every event continuously. `LocalDbStoreAndForwardSink` takes a `drainGate` fed from `IRedundancyRoleView` — a singleton `DriverHostActor` publishes its `PrimaryGatePolicy` verdict to, because the drain runs on a timer and cannot receive `RedundancyStateChanged` itself. A gated-off node reports `HistorianDrainState.NotPrimary`. The gate applies only to a node whose queue a peer actually holds — `LocalDbReplicationPolicy.SharesRowsWithPeer`: `LocalDb:Replication:ApiKey` AND (`PeerAddress` OR `LocalDb:SyncListenPort` > 0); any other node always drains (review R1 m3). Delivery is **at-least-once across a failover** by design: rows the old Primary delivered just before dying may not have replicated their deletes yet. See [AlarmHistorian.md](AlarmHistorian.md).
 
 - **Continuous-historization value CAPTURE** (Gitea #537) — a third gate on the same role rule, and the
   one that gates the *opposite* half of its pipeline. Both pair nodes serve the same address space and see
@@ -622,7 +622,10 @@ and [AlarmHistorian.md](AlarmHistorian.md). Phase 1 caches the **deployed-config
 artifact** (chunked). Its job is a single failure mode redundancy does not otherwise cover: a driver
 node restarting into a **central-SQL-Server outage** would come up with no configuration at all. With
 the cache, it **boots from the last artifact it applied** instead, and logs a running-from-cache
-signal.
+signal. A cached artifact whose bytes are empty or malformed is **no answer** (#601): nothing is applied,
+the node does **not** adopt that revision or claim running-from-cache, and it goes **Stale** (retrying the
+ConfigDb) — so a later dispatch of that same revision really applies instead of being acked as already
+current (review R1 m4). A `FetchAndCache` node lands Steady-with-no-revision instead, as for an empty cache.
 
 - **What replicates.** The cache can *optionally* replicate to the node's redundant pair peer over
   the LocalDb library's gRPC sync (HLC-stamped, last-writer-wins). Two tables replicate:

docs/operations/2026-07-20-localdb-pair-replication.md

@@ -92,7 +92,9 @@ Replication has two knobs, both under `LocalDb`:
 > 2026-08-18 `LocalDbSetup.OnReady` installs the change-capture triggers only when the node is
 > configured to replicate — the predicate is **`PeerAddress` OR `ApiKey` non-blank** (the OR because
 > the passive node has no `PeerAddress`; `SyncListenPort` is deliberately not part of it, since a
-> port with no key is fail-closed and syncs with nobody). Consequences at enablement time:
+> port with no key is fail-closed and syncs with nobody). The alarm-historian drain gate uses the
+> stricter `ApiKey` AND (`PeerAddress` OR `SyncListenPort > 0`) — so set the key **and** the port/peer
+> together, or the node keeps draining its own queue. Consequences at enablement time:
 >
 > - A configured node registers with **`baselineExistingRows: true`**, so the rows **already in the
 >   file** are seeded into the row-version ledger at the LWW floor (HLC `0`) and actually travel.

src/Core/ZB.MOM.WW.OtOpcUa.Cluster/ClusterRoleInfo.cs

@@ -76,7 +76,7 @@ public sealed class ClusterRoleInfo : IClusterRoleInfo, IDisposable
             }
         }
 
-        SeedFromCurrentState();
+        SeedFrom(_cluster.State);
         _subscriber = system.ActorOf(Props.Create(() => new SubscriberActor(this)), "clusterroleinfo-subscriber");
     }
 
@@ -121,12 +121,19 @@ public sealed class ClusterRoleInfo : IClusterRoleInfo, IDisposable
     /// <summary>Occurs when the leader for a role changes.</summary>
     public event EventHandler<RoleLeaderChangedEventArgs>? RoleLeaderChanged;
 
-    private void SeedFromCurrentState()
+    /// <summary>Seeds the member/leader maps from a cluster-state snapshot (the constructor passes the live
+    /// <c>Cluster.State</c>; exposed for tests).</summary>
+    /// <param name="snapshot">The cluster-state snapshot.</param>
+    internal void SeedFrom(ClusterEvent.CurrentClusterState snapshot)
     {
-        var snapshot = _cluster.State;
         lock (_lock)
         {
-            foreach (var member in snapshot.Members)
+            // Cluster-002 (review R1 m6): seed only USABLE members. A member already Leaving / Exiting / Down
+            // (or still Joining) at seed time is not one, and a departing member never fires a later
+            // MemberLeft / MemberExited / MemberDowned that HandleMemberEvent would drop it on — it would
+            // linger until MemberRemoved, the very delay the member-event handling exists to avoid. A
+            // Joining member is added by its MemberUp.
+            foreach (var member in snapshot.Members.Where(m => m.Status is MemberStatus.Up or MemberStatus.WeaklyUp))
                 foreach (var role in member.Roles)
                 {
                     if (!_membersByRole.TryGetValue(role, out var set))

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
+        // Defined beside the alarm-historian drain gate's stricter predicate (#603, review R1 m3): every node
-        // changes and the nodes that stand down for a peer can never disagree.
+        // the gate treats as sharing rows also captures, so the two never disagree in the harmful direction.
-        return Runtime.LocalDbReplicationPolicy.IsConfigured(configuration);
+        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.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
+///     The definitions of "this node's LocalDb is replicated to a peer" (#603) — one place, two deliberately
-///     on it, and used to carry separate predicates that diverged: the Host's table-registration step
+///     different predicates for the two consumers: the Host's table-registration step
-///     (<c>LocalDbSetup.ReplicationIsConfigured</c> - which nodes capture changes) and the alarm-historian
+///     (<c>LocalDbSetup.ReplicationIsConfigured</c> → <see cref="CapturesChanges"/>: which nodes capture
-///     drain gate (<c>AddAlarmHistorian</c> - which nodes stand down in favour of a peer). Lives in Runtime
+///     changes) and the alarm-historian drain gate (<c>AddAlarmHistorian</c> → <see cref="SharesRowsWithPeer"/>:
-///     because Host references Runtime and not the reverse.
+///     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
+///         <b>Why two predicates (review R1 m3).</b> The two answers cost differently when wrong. Registering a
-///         non-blank.</b> The OR is required: only the dialling half of a pair sets <c>PeerAddress</c>, while
+///         node that has no working sync path only costs capture triggers. Gating the drain of a node that
-///         the passive half carries the shared <c>ApiKey</c> (plus a listen port) and nothing else.
+///         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
+///         <b>Registration: <c>LocalDb:Replication:PeerAddress</c> OR <c>LocalDb:Replication:ApiKey</c>.</b>
-///         <c>SyncListenPort</c>).</b> The gate's question is "does a peer hold the same rows?". The passive
+///         The OR is required: only the dialling half of a pair sets <c>PeerAddress</c>, while the passive
-///         sync endpoint is fail-closed on the key, so a node with a listen port but no <c>ApiKey</c> rejects
+///         half carries the shared <c>ApiKey</c> (plus a listen port) and nothing else. Keying on
-///         every inbound stream and shares its queue with nobody - gating it would park its alarm events
+///         <c>PeerAddress</c> alone would strip capture from every passive node.
-///         behind a Primary that cannot deliver them. Conversely an <c>ApiKey</c>-only passive node IS
+///     </para>
-///         registered and does receive its peer's rows, so it must be gated or both halves drain. The port
+///     <para>
-///         is not evidence of a peer; the key is.
+///         <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
+        // Replication:PeerAddress, its partner carries the shared ApiKey plus SyncListenPort and waits.
-        // LocalDbReplicationPolicy - the same one LocalDbSetup uses to decide which nodes capture
+        // The predicate is LocalDbReplicationPolicy.SharesRowsWithPeer: ApiKey AND (PeerAddress OR
-        // changes at all. It deliberately does NOT count SyncListenPort: the passive endpoint is
+        // SyncListenPort > 0) - an authenticated sync path in either direction. Both auth directions
-        // fail-closed on the key, so a port with no ApiKey shares nothing and must keep draining.
+        // fail closed, so a path without the key, or a key with no path (a fleet-wide secret on an
-        var replicated = LocalDbReplicationPolicy.IsConfigured(configuration);
+        // 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)
         {

tests/Core/ZB.MOM.WW.OtOpcUa.Cluster.Tests/ClusterRoleInfoMemberEventTests.cs

@@ -97,4 +97,30 @@ public sealed class ClusterRoleInfoMemberEventTests
             return Task.CompletedTask;
         });
     }
+
+    /// <summary>
+    ///     Review R1 m6: the initial seed lists only Up / WeaklyUp members. A member already departing at seed
+    ///     time never fires a later Left/Exited/Downed event, so seeding it would list it until MemberRemoved.
+    ///     The Up and WeaklyUp members are the positive control (the seed does list members).
+    /// </summary>
+    [Fact]
+    public async Task Initial_seed_lists_only_up_and_weakly_up_members()
+    {
+        await WithInfoAsync(info =>
+        {
+            var members = ImmutableSortedSet.Create<Member>(
+                NewMember(21001, MemberStatus.Up),
+                NewMember(21002, MemberStatus.WeaklyUp),
+                NewMember(21003, MemberStatus.Leaving),
+                NewMember(21004, MemberStatus.Exiting),
+                NewMember(21005, MemberStatus.Down),
+                NewMember(21006, MemberStatus.Joining));
+
+            info.SeedFrom(new ClusterEvent.CurrentClusterState().Copy(members: members));
+
+            info.MembersWithRole("driver").Select(n => n.Value).OrderBy(v => v).ShouldBe(
+                ["127.0.0.1:21001", "127.0.0.1:21002"]);
+            return Task.CompletedTask;
+        });
+    }
 }

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

@@ -102,8 +102,14 @@ public sealed class DriverHostActorBootFromCacheTests : RuntimeActorTestBase
 
         // Barrier: diagnostics are served only after PreStart's boot work ran, so the absence below is
         // asserted after the boot path had its chance to Tell (positive control is the valid-bytes test).
-        AskDiagnostics(actor);
+        var snapshot = AskDiagnostics(actor);
         publishProbe.ExpectNoMsg(TimeSpan.FromMilliseconds(500));
+
+        // Review R1 m4: nothing was applied, so the node is NOT running from cache and has NOT adopted the
+        // cached revision (Stale with no configuration, retrying the ConfigDb) — the valid-bytes test above
+        // is the control that both flip when the bytes are usable.
+        snapshot.RunningFromCache.ShouldBeFalse();
+        snapshot.CurrentRevision.ShouldBeNull();
     }
 
     [Fact]

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

@@ -111,6 +111,39 @@ public sealed class DriverHostActorFetchAndCacheBootstrapTests : RuntimeActorTes
         fetcher.Calls.ShouldBe(1);
     }
 
+    /// <summary>
+    ///     #601 / review R1 m4 — a cache row whose bytes are malformed applied nothing, so its revision must not
+    ///     become current: the boot lands Steady-with-no-revision (as for an empty cache), and a re-dispatch of
+    ///     the SAME revision really applies (fetches) instead of being acked by the "already at this rev"
+    ///     short-circuit. <see cref="WithCachedArtifact_RestoresServedState_WithoutReadingCentralSql"/> is the
+    ///     control: valid bytes do adopt the revision.
+    /// </summary>
+    [Fact]
+    public void WithMalformedCachedBytes_TheRevisionIsNotAdopted_AndARedispatchOfItActuallyApplies()
+    {
+        var cached = new CachedDeploymentArtifact(
+            DeploymentId.NewId().ToString(), CachedRev.Value,
+            System.Text.Encoding.UTF8.GetBytes("{\"DriverInstances\": ["), DateTimeOffset.UtcNow.AddHours(-1));
+        var fetcher = new RecordingFetcher(Artifact());
+        var coordinator = CreateTestProbe();
+
+        var actor = Sys.ActorOf(DriverHostActor.Props(
+            new ThrowingDbFactory(), TestNode, coordinator.Ref,
+            localRoles: new HashSet<string> { "driver" },
+            deploymentArtifactCache: new StubArtifactCache(cached),
+            fetchAndCacheMode: true,
+            artifactFetcher: fetcher));
+
+        var snapshot = AskDiagnostics(actor);
+        snapshot.CurrentRevision.ShouldBeNull();
+        snapshot.RunningFromCache.ShouldBeFalse();
+
+        actor.Tell(new DispatchDeployment(DeploymentId.Parse(cached.DeploymentId), CachedRev, CorrelationId.NewId()));
+        coordinator.ExpectMsg<ApplyAck>(TimeSpan.FromSeconds(5)).Outcome.ShouldBe(ApplyAckOutcome.Applied);
+        fetcher.Calls.ShouldBe(1);
+        AskDiagnostics(actor).CurrentRevision.ShouldBe(CachedRev);
+    }
+
     private NodeDiagnosticsSnapshot AskDiagnostics(IActorRef actor)
     {
         var probe = CreateTestProbe();

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

@@ -0,0 +1,109 @@
+using Akka.Actor;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.Messages.Redundancy;
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
+using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Drivers;
+
+/// <summary>
+///     Review R1 m2 (Gitea #597) — the Primary data-plane verdict published to <see cref="IDriverPrimaryRoleSource"/>
+///     (read by the native-ack gate and the Sparkplug primary-host claim) mirrors the host's own live gate from the
+///     moment the host starts, not only from the first redundancy snapshot.
+/// </summary>
+/// <remarks>
+///     <c>RedundancyRoleView</c> is seeded with the single-node verdict (allow). Before this fix nothing published to
+///     it until a snapshot arrived, so on a pair both nodes accepted a native ack through the whole boot window while
+///     <c>DriverHostActor</c> — which evaluates the driver member count live — denied the upstream route on the
+///     non-Primary. Assertions are on what was PUBLISHED: the seed already reads <c>true</c>, so a current-value
+///     assertion of the single-node case would pass with no publish at all.
+/// </remarks>
+public sealed class DriverHostActorPrimaryRoleSourceTests : RuntimeActorTestBase
+{
+    private static readonly NodeId TestNode = NodeId.Parse("driver-primary-source-test");
+    private static readonly TimeSpan Timeout = TimeSpan.FromSeconds(5);
+
+    /// <summary>On a pair, an unknown role publishes DENY at start — before any snapshot. The later Primary snapshot
+    /// is the positive control: the source is wired, and the deny was the verdict, not a missing publish.</summary>
+    [Fact]
+    public void A_paired_host_publishes_deny_before_the_first_snapshot()
+    {
+        var source = new RecordingPrimaryRoleSource();
+        var host = SpawnHost(source, () => 2);
+
+        AwaitAssert(() => source.Published.ShouldBe([false]), duration: Timeout);
+
+        host.Tell(Snapshot(RedundancyRole.Primary));
+        AwaitAssert(() => source.Published.ShouldBe([false, true]), duration: Timeout);
+    }
+
+    /// <summary>A single-driver node keeps the allow posture — it is published, not merely seeded.</summary>
+    [Fact]
+    public void A_single_node_host_publishes_allow_at_start()
+    {
+        var source = new RecordingPrimaryRoleSource();
+        SpawnHost(source, () => 1);
+
+        AwaitAssert(() => source.Published.ShouldBe([true]), duration: Timeout);
+    }
+
+    /// <summary>A driver peer coming Up while the role is still unknown flips the published verdict to deny, with no
+    /// snapshot involved — the membership re-publish path.</summary>
+    [Fact]
+    public void A_peer_joining_before_any_snapshot_flips_the_published_verdict_to_deny()
+    {
+        var source = new RecordingPrimaryRoleSource();
+        var members = 1;
+        var host = SpawnHost(source, () => Volatile.Read(ref members));
+        AwaitAssert(() => source.Published.ShouldBe([true]), duration: Timeout);
+
+        Volatile.Write(ref members, 2);
+        host.Tell(DriverHostActor.RepublishPrimaryVerdict.Instance);
+
+        AwaitAssert(() => source.Published.ShouldBe([true, false]), duration: Timeout);
+    }
+
+    private IActorRef SpawnHost(IDriverPrimaryRoleSource source, Func<int> driverMemberCount) =>
+        Sys.ActorOf(DriverHostActor.Props(
+            NewInMemoryDbFactory(),
+            TestNode,
+            ackRouter: null,
+            driverMemberCountProvider: driverMemberCount,
+            primaryRoleSource: source));
+
+    private static RedundancyStateChanged Snapshot(RedundancyRole role) =>
+        new(
+            [
+                new NodeRedundancyState(TestNode, role,
+                    IsClusterLeader: role == RedundancyRole.Primary,
+                    IsDriverPrimary: role == RedundancyRole.Primary,
+                    AsOfUtc: DateTime.UtcNow),
+            ],
+            CorrelationId.NewId());
+
+    /// <summary>Remembers every published verdict, so tests assert on the actor's action, not on the seed.</summary>
+    private sealed class RecordingPrimaryRoleSource : IDriverPrimaryRoleSource
+    {
+        private readonly List<bool> _published = [];
+        private readonly Lock _gate = new();
+
+        /// <summary>Every value published so far, in order.</summary>
+        public IReadOnlyList<bool> Published
+        {
+            get { lock (_gate) return _published.ToArray(); }
+        }
+
+        public bool ShouldActAsPrimary
+        {
+            get { lock (_gate) return _published.Count == 0 || _published[^1]; }
+        }
+
+        public void PublishPrimaryRole(bool shouldActAsPrimary)
+        {
+            lock (_gate) _published.Add(shouldActAsPrimary);
+        }
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Historian/AlarmHistorianRegistrationTests.cs

@@ -109,7 +109,8 @@ public sealed class AlarmHistorianRegistrationTests
     /// <remarks>
     ///     <para>
     ///         Standing down is only safe because a peer holds the same rows and will send them
-    ///         instead. Without <c>LocalDb:Replication:PeerAddress</c> there is no such peer: the rows
+    ///         instead. Without an authenticated sync path (<c>ApiKey</c> plus a dial or a listener —
+    ///         <c>LocalDbReplicationPolicy.SharesRowsWithPeer</c>) there is no such peer: the rows
     ///         are here and nowhere else, so any deferral means nobody ever delivers them.
     ///     </para>
     ///     <para>
@@ -124,14 +125,18 @@ public sealed class AlarmHistorianRegistrationTests
     // Neither key: an unpaired node. Its rows exist nowhere else.
     [InlineData(null, null, null, true)]
     // The dialing half of a pair — gated, because its partner holds the same rows.
-    [InlineData("http://peer:9001", null, null, false)]
+    [InlineData("http://peer:9001", null, "k", false)]
     // The LISTENING half. Same shared queue, but it never dials, so a PeerAddress-only test would
-    // wrongly class it as unpaired and leave it permanently ungated. It is identified by the shared
+    // wrongly class it as unpaired and leave it permanently ungated. Key + listen port = a peer.
-    // ApiKey (the same predicate LocalDbSetup registers tables on), not by its listen port.
     [InlineData(null, "9001", "k", false)]
     // A listen port with NO key: the fail-closed passive endpoint rejects every inbound stream, so the
     // queue is shared with nobody and the node must keep draining (#603: this used to be gated).
     [InlineData(null, "9001", null, true)]
+    // A dial with NO key: the peer's fail-closed endpoint rejects it — shares nothing, keeps draining.
+    [InlineData("http://peer:9001", null, null, true)]
+    // A key with NEITHER path (review R1 m3: e.g. a fleet-wide secret on an unpaired node) — no listener,
+    // no dial, so no peer holds these rows. Registered for capture, but must keep draining.
+    [InlineData(null, null, "k", true)]
     public async Task Only_an_unreplicated_node_ignores_the_role_view(
         string? peerAddress, string? syncListenPort, string? apiKey, bool expectDrain)
     {

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Historian/LocalDbReplicationPolicyTests.cs

@@ -4,29 +4,64 @@ using Xunit;
 
 namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Historian;
 
-/// <summary>#603: the single "is this node's LocalDb replicated" predicate shared by table registration and the alarm drain gate.</summary>
+/// <summary>
+///     #603 + review R1 m3: the two "is this node's LocalDb replicated" predicates — permissive for table
+///     registration (<see cref="LocalDbReplicationPolicy.CapturesChanges"/>), strict for the alarm drain gate
+///     (<see cref="LocalDbReplicationPolicy.SharesRowsWithPeer"/>).
+/// </summary>
 public sealed class LocalDbReplicationPolicyTests
 {
+    private const string Peer = "LocalDb:Replication:PeerAddress";
+    private const string Key = "LocalDb:Replication:ApiKey";
+    private const string Port = "LocalDb:SyncListenPort";
+
     private static IConfiguration Config(params (string Key, string? Value)[] pairs) =>
         new ConfigurationBuilder()
             .AddInMemoryCollection(pairs.Select(p => new KeyValuePair<string, string?>(p.Key, p.Value)))
             .Build();
 
-    /// <summary>PeerAddress OR ApiKey counts; the listen port alone and blank values do not.</summary>
+    /// <summary>Registration: PeerAddress OR ApiKey counts; the listen port alone and blank values do not.</summary>
     [Theory]
-    [InlineData("LocalDb:Replication:PeerAddress", "http://peer:9001", true)]
+    [InlineData(Peer, "http://peer:9001", true)]
-    [InlineData("LocalDb:Replication:ApiKey", "k", true)]
+    [InlineData(Key, "k", true)]
-    [InlineData("LocalDb:SyncListenPort", "9001", false)]
+    [InlineData(Port, "9001", false)]
-    [InlineData("LocalDb:Replication:ApiKey", "  ", false)]
+    [InlineData(Key, "  ", false)]
-    public void IsConfigured_follows_the_PeerAddress_or_ApiKey_rule(string key, string value, bool expected)
+    public void CapturesChanges_follows_the_PeerAddress_or_ApiKey_rule(string key, string value, bool expected)
     {
-        LocalDbReplicationPolicy.IsConfigured(Config((key, value))).ShouldBe(expected);
+        LocalDbReplicationPolicy.CapturesChanges(Config((key, value))).ShouldBe(expected);
     }
 
-    /// <summary>No replication keys at all is an unpaired node.</summary>
+    /// <summary>Drain gate: ApiKey AND (PeerAddress OR SyncListenPort &gt; 0).</summary>
-    [Fact]
+    [Theory]
-    public void IsConfigured_is_false_for_an_empty_configuration()
+    [InlineData("http://peer:9001", "k", null, true)]   // dialling half of a pair
+    [InlineData(null, "k", "9001", true)]               // listening half of a pair
+    [InlineData("http://peer:9001", "k", "9001", true)] // both
+    [InlineData(null, "k", null, false)]                // key, no path: shares nothing (review R1 m3)
+    [InlineData(null, "k", "0", false)]                 // port 0 = no listener
+    [InlineData(null, "k", "nope", false)]              // unparseable port = no listener
+    [InlineData("http://peer:9001", null, "9001", false)] // paths, no key: both auth directions fail closed
+    [InlineData(null, "  ", "9001", false)]             // blank key
+    public void SharesRowsWithPeer_needs_a_key_and_a_sync_path(string? peer, string? key, string? port, bool expected)
     {
-        LocalDbReplicationPolicy.IsConfigured(Config()).ShouldBeFalse();
+        LocalDbReplicationPolicy.SharesRowsWithPeer(Config((Peer, peer), (Key, key), (Port, port))).ShouldBe(expected);
+    }
+
+    /// <summary>Every node the gate treats as sharing rows also captures — never a gated node with no capture.</summary>
+    [Theory]
+    [InlineData("http://peer:9001", "k", null)]
+    [InlineData(null, "k", "9001")]
+    public void A_node_sharing_rows_always_captures(string? peer, string? key, string? port)
+    {
+        var config = Config((Peer, peer), (Key, key), (Port, port));
+        LocalDbReplicationPolicy.SharesRowsWithPeer(config).ShouldBeTrue();
+        LocalDbReplicationPolicy.CapturesChanges(config).ShouldBeTrue();
+    }
+
+    /// <summary>No replication keys at all is an unpaired node under both predicates.</summary>
+    [Fact]
+    public void Both_predicates_are_false_for_an_empty_configuration()
+    {
+        LocalDbReplicationPolicy.CapturesChanges(Config()).ShouldBeFalse();
+        LocalDbReplicationPolicy.SharesRowsWithPeer(Config()).ShouldBeFalse();
     }
 }