feat(agent-v2): report RealmJoin release channel alongside version

RealmJoin.exe inverts the usual .NET SDK version-resource layout: the
FileVersion STRING carries the full SemVer including the channel tag
("4.21.6-canary+476277.d320cac0") while ProductVersion is the bare
"4.21.6". The previous ProductVersion-first read therefore never saw
the channel.

- RealmJoinInfo: read FileVersion first, parse SemVer into bare version
  + release channel (prerelease tag = channel; untagged = "release",
  confirmed by the RJ developer; build metadata dropped)
- realmjoin_detected signal + timeline event carry releaseChannel
- RealmJoinFacts.ReleaseChannel set-once fact + audit-trail field
  realmjoinReleaseChannel

Suites: DecisionCore 360, V2.Core 1307 green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/SystemSignals/RealmJoinInfoParseTests.cs

@@ -0,0 +1,67 @@
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.SystemSignals
+{
+    /// <summary>
+    /// Parser tests for <see cref="RealmJoinInfo.ParseVersionAndChannel"/>. The RJ binary's
+    /// FileVersion string resource carries a full SemVer where the prerelease tag IS the
+    /// release channel: "4.21.6-canary+476277.d320cac0" (canary/beta) vs "4.21.6" (stable
+    /// release — confirmed by the RJ developer that release builds carry no tag).
+    /// </summary>
+    public sealed class RealmJoinInfoParseTests
+    {
+        [Theory]
+        [InlineData("4.21.6-canary+476277.d320cac0", "4.21.6", "canary")]
+        [InlineData("4.21.6-beta+123456.abcdef00", "4.21.6", "beta")]
+        [InlineData("4.21.6-canary", "4.21.6", "canary")]
+        public void Tagged_version_yields_channel_from_prerelease_tag(string raw, string expectedVersion, string expectedChannel)
+        {
+            var info = RealmJoinInfo.ParseVersionAndChannel(raw);
+
+            Assert.Equal(expectedVersion, info.ProductVersion);
+            Assert.Equal(expectedChannel, info.ReleaseChannel);
+        }
+
+        [Theory]
+        [InlineData("4.21.6")]
+        [InlineData("4.21.6+476277.d320cac0")]
+        [InlineData(" 4.21.6 ")]
+        public void Untagged_version_yields_stable_release_channel(string raw)
+        {
+            var info = RealmJoinInfo.ParseVersionAndChannel(raw);
+
+            Assert.Equal("4.21.6", info.ProductVersion);
+            Assert.Equal(RealmJoinInfo.ReleaseChannelStable, info.ReleaseChannel);
+        }
+
+        [Fact]
+        public void Build_metadata_is_dropped_from_both_fields()
+        {
+            var info = RealmJoinInfo.ParseVersionAndChannel("4.21.6-canary+476277.d320cac0");
+
+            Assert.DoesNotContain("+", info.ProductVersion);
+            Assert.DoesNotContain("476277", info.ReleaseChannel);
+        }
+
+        [Fact]
+        public void Trailing_dash_without_tag_falls_back_to_stable_channel()
+        {
+            // Defensive: a malformed "4.21.6-" must not produce an empty channel string.
+            var info = RealmJoinInfo.ParseVersionAndChannel("4.21.6-");
+
+            Assert.Equal("4.21.6", info.ProductVersion);
+            Assert.Equal(RealmJoinInfo.ReleaseChannelStable, info.ReleaseChannel);
+        }
+
+        [Fact]
+        public void Empty_after_metadata_strip_yields_null_fields()
+        {
+            // Defensive: a string that is ONLY build metadata carries no version information.
+            var info = RealmJoinInfo.ParseVersionAndChannel("+476277.d320cac0");
+
+            Assert.Null(info.ProductVersion);
+            Assert.Null(info.ReleaseChannel);
+        }
+    }
+}

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/SignalAdapters/RealmJoinWatcherAdapterTests.cs

@@ -85,6 +85,28 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
             Assert.Contains("version=3.5.21.0", info.Payload[SignalPayloadKeys.Message]);
         }
 
+        [Fact]
+        public void TriggerDetectedFromTest_includes_ReleaseChannel_when_provided()
+        {
+            using var f = new Fixture();
+            using var adapter = new RealmJoinWatcherAdapter(f.Watcher, f.Ingress, f.Clock);
+
+            adapter.TriggerDetectedFromTest(phase: 100, productVersion: "4.21.6", releaseChannel: "canary");
+
+            var decision = f.Ingress.Posted.Single(p => p.Kind == DecisionSignalKind.RealmJoinDetected);
+            Assert.Equal("4.21.6", decision.Payload![DecisionEngine.RealmJoinPayloadKeys.ProductVersion]);
+            Assert.Equal("canary", decision.Payload[DecisionEngine.RealmJoinPayloadKeys.ReleaseChannel]);
+
+            var info = f.Ingress.Posted.Single(p =>
+                p.Kind == DecisionSignalKind.InformationalEvent
+                && p.Payload != null
+                && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
+                && et == SharedEventTypes.RealmJoinDetected);
+            Assert.Equal("canary", info.Payload!["releaseChannel"]);
+            Assert.Contains("version=4.21.6", info.Payload[SignalPayloadKeys.Message]);
+            Assert.Contains("channel=canary", info.Payload[SignalPayloadKeys.Message]);
+        }
+
         [Fact]
         public void TriggerDetectedFromTest_omits_ProductVersion_when_null_or_empty()
         {
@@ -95,6 +117,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
 
             var decision = f.Ingress.Posted.Single(p => p.Kind == DecisionSignalKind.RealmJoinDetected);
             Assert.False(decision.Payload!.ContainsKey(DecisionEngine.RealmJoinPayloadKeys.ProductVersion));
+            Assert.False(decision.Payload.ContainsKey(DecisionEngine.RealmJoinPayloadKeys.ReleaseChannel));
 
             var info = f.Ingress.Posted.Single(p =>
                 p.Kind == DecisionSignalKind.InformationalEvent
@@ -102,7 +125,9 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.SignalAdapters
                 && p.Payload.TryGetValue(SignalPayloadKeys.EventType, out var et)
                 && et == SharedEventTypes.RealmJoinDetected);
             Assert.False(info.Payload!.ContainsKey("productVersion"));
+            Assert.False(info.Payload.ContainsKey("releaseChannel"));
             Assert.DoesNotContain("version=", info.Payload[SignalPayloadKeys.Message]);
+            Assert.DoesNotContain("channel=", info.Payload[SignalPayloadKeys.Message]);
         }
 
         [Fact]

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/RealmJoinInfo.cs

@@ -103,25 +103,36 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         public const string RealmJoinExePathX86 = @"C:\Program Files (x86)\RealmJoin\RealmJoin.exe";
 
         /// <summary>
-        /// Best-effort read of <c>RealmJoin.exe</c>'s ProductVersion via
+        /// Release-channel name reported when the version string carries no SemVer prerelease
+        /// tag. Per the RJ developer, only beta/canary builds are tagged — untagged == stable.
+        /// </summary>
+        public const string ReleaseChannelStable = "release";
+
+        /// <summary>
+        /// Best-effort read of <c>RealmJoin.exe</c>'s version + release channel via
         /// <see cref="FileVersionInfo.GetVersionInfo"/>. Wrapped in a defensive try/catch so a
-        /// missing/locked/inaccessible binary returns <c>null</c> instead of throwing —
+        /// missing/locked/inaccessible binary returns an empty result instead of throwing —
         /// version is observability-only and must never block the detection signal. Probes the
         /// canonical 64-bit path first, then the (x86) fallback.
         /// </summary>
-        public static string? TryReadRealmJoinProductVersion()
+        public static RealmJoinVersionInfo TryReadRealmJoinVersionInfo()
         {
-            return TryReadVersion(RealmJoinExePath) ?? TryReadVersion(RealmJoinExePathX86);
+            return TryReadVersionInfo(RealmJoinExePath) ?? TryReadVersionInfo(RealmJoinExePathX86) ?? RealmJoinVersionInfo.Empty;
         }
 
-        private static string? TryReadVersion(string path)
+        private static RealmJoinVersionInfo? TryReadVersionInfo(string path)
         {
             try
             {
                 if (!File.Exists(path)) return null;
                 var info = FileVersionInfo.GetVersionInfo(path);
-                var version = info.ProductVersion;
-                return string.IsNullOrWhiteSpace(version) ? info.FileVersion : version;
+                // RJ inverts the usual .NET SDK resource layout: the FileVersion STRING entry
+                // carries the full SemVer including the channel tag and build metadata
+                // ("4.21.6-canary+476277.d320cac0") while the ProductVersion string is the
+                // channel-less "4.21.6". Prefer FileVersion, fall back to ProductVersion.
+                var raw = !string.IsNullOrWhiteSpace(info.FileVersion) ? info.FileVersion : info.ProductVersion;
+                if (string.IsNullOrWhiteSpace(raw)) return null;
+                return ParseVersionAndChannel(raw!);
             }
             catch
             {
@@ -129,6 +140,33 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             }
         }
 
+        /// <summary>
+        /// Split a SemVer-shaped version string (<c>version[-prerelease][+buildmetadata]</c>)
+        /// into the bare version and the RJ release channel. The prerelease tag IS the channel
+        /// ("beta", "canary"); absence of a tag means <see cref="ReleaseChannelStable"/>.
+        /// Build metadata is dropped.
+        /// </summary>
+        internal static RealmJoinVersionInfo ParseVersionAndChannel(string raw)
+        {
+            var value = raw.Trim();
+            var plus = value.IndexOf('+');
+            if (plus >= 0) value = value.Substring(0, plus);
+
+            var dash = value.IndexOf('-');
+            if (dash < 0)
+            {
+                return new RealmJoinVersionInfo(
+                    productVersion: value.Length == 0 ? null : value,
+                    releaseChannel: value.Length == 0 ? null : ReleaseChannelStable);
+            }
+
+            var version = value.Substring(0, dash).Trim();
+            var channel = value.Substring(dash + 1).Trim();
+            return new RealmJoinVersionInfo(
+                productVersion: version.Length == 0 ? null : version,
+                releaseChannel: channel.Length == 0 ? ReleaseChannelStable : channel);
+        }
+
         /// <summary>
         /// Read the <c>DeploymentPhase</c> DWORD from the Parameters key. Returns null when the
         /// key/value does not exist or is unreadable.
@@ -225,6 +263,31 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
         }
     }
 
+    /// <summary>
+    /// Version + release channel of the installed <c>RealmJoin.exe</c>, parsed from its
+    /// file-version resource by <see cref="RealmJoinInfo.TryReadRealmJoinVersionInfo"/>.
+    /// Both fields are <c>null</c> when the binary is missing or unreadable.
+    /// </summary>
+    internal readonly struct RealmJoinVersionInfo
+    {
+        public static readonly RealmJoinVersionInfo Empty = new RealmJoinVersionInfo(null, null);
+
+        public RealmJoinVersionInfo(string? productVersion, string? releaseChannel)
+        {
+            ProductVersion = productVersion;
+            ReleaseChannel = releaseChannel;
+        }
+
+        /// <summary>Bare version without prerelease tag or build metadata, e.g. <c>4.21.6</c>.</summary>
+        public string? ProductVersion { get; }
+
+        /// <summary>
+        /// SemVer prerelease tag ("beta", "canary") or <see cref="RealmJoinInfo.ReleaseChannelStable"/>
+        /// when the version string carries no tag.
+        /// </summary>
+        public string? ReleaseChannel { get; }
+    }
+
     /// <summary>
     /// Read-only snapshot of a single RealmJoin package sub-key. Built by
     /// <see cref="RealmJoinInfo.TryReadPackage"/>; consumed by <c>RealmJoinWatcher</c> to

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Enrollment/SystemSignals/RealmJoinWatcher.cs

@@ -13,16 +13,25 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
     {
         public int DeploymentPhase { get; }
         /// <summary>
-        /// ProductVersion read from <c>C:\Program Files\RealmJoin\RealmJoin.exe</c>
-        /// (or the x86 fallback). <c>null</c> when the binary is missing, locked, or read
-        /// fails — version is observability-only and never blocks detection.
+        /// Bare version parsed from <c>C:\Program Files\RealmJoin\RealmJoin.exe</c>'s
+        /// file-version resource (or the x86 fallback), e.g. <c>4.21.6</c>. <c>null</c> when
+        /// the binary is missing, locked, or read fails — version is observability-only and
+        /// never blocks detection.
         /// </summary>
         public string? ProductVersion { get; }
 
-        public RealmJoinDetectedEventArgs(int deploymentPhase, string? productVersion = null)
+        /// <summary>
+        /// RJ release channel parsed from the version string's SemVer prerelease tag
+        /// ("beta", "canary"); <see cref="RealmJoinInfo.ReleaseChannelStable"/> when untagged;
+        /// <c>null</c> when the version was unreadable.
+        /// </summary>
+        public string? ReleaseChannel { get; }
+
+        public RealmJoinDetectedEventArgs(int deploymentPhase, string? productVersion = null, string? releaseChannel = null)
         {
             DeploymentPhase = deploymentPhase;
             ProductVersion = productVersion;
+            ReleaseChannel = releaseChannel;
         }
     }
 
@@ -546,12 +555,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Enrollment.SystemSignals
             if (fireDetected)
             {
                 var initial = phase ?? 0;
-                // Read RJ ProductVersion best-effort (fail-soft to null) ONLY when the Detected
-                // event actually fires — single read per session lifetime keeps any potential
-                // file-system cost to a single hit.
-                var productVersion = RealmJoinInfo.TryReadRealmJoinProductVersion();
-                _logger.Info($"RealmJoinWatcher: RJ detected (phase={initial}, productVersion={productVersion ?? "<unknown>"})");
-                try { RealmJoinDetected?.Invoke(this, new RealmJoinDetectedEventArgs(initial, productVersion)); }
+                // Read RJ version + release channel best-effort (fail-soft to null) ONLY when
+                // the Detected event actually fires — single read per session lifetime keeps
+                // any potential file-system cost to a single hit.
+                var versionInfo = RealmJoinInfo.TryReadRealmJoinVersionInfo();
+                _logger.Info($"RealmJoinWatcher: RJ detected (phase={initial}, productVersion={versionInfo.ProductVersion ?? "<unknown>"}, releaseChannel={versionInfo.ReleaseChannel ?? "<unknown>"})");
+                try { RealmJoinDetected?.Invoke(this, new RealmJoinDetectedEventArgs(initial, versionInfo.ProductVersion, versionInfo.ReleaseChannel)); }
                 catch (Exception ex) { _logger.Error("RealmJoinWatcher: RealmJoinDetected handler threw", ex); }
             }
 

src/Agent/AutopilotMonitor.Agent.V2.Core/SignalAdapters/RealmJoinWatcherAdapter.cs

@@ -51,8 +51,8 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
         }
 
         // Test seams
-        internal void TriggerDetectedFromTest(int phase, string? productVersion = null) =>
-            OnDetected(this, new RealmJoinDetectedEventArgs(phase, productVersion));
+        internal void TriggerDetectedFromTest(int phase, string? productVersion = null, string? releaseChannel = null) =>
+            OnDetected(this, new RealmJoinDetectedEventArgs(phase, productVersion, releaseChannel));
         internal void TriggerResolvedFromTest(int phase) => OnResolved(this, new RealmJoinResolvedEventArgs(phase));
         internal void TriggerPhaseChangedFromTest(int prev, int curr) => OnPhaseChanged(this, new RealmJoinPhaseChangedEventArgs(prev, curr));
         internal void TriggerPackageStartedFromTest(string scope, RealmJoinPackageSnapshot snap) => OnPackageStarted(this, new RealmJoinPackageEventArgs(scope, snap));
@@ -68,6 +68,10 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             {
                 payload[DecisionEngine.RealmJoinPayloadKeys.ProductVersion] = e.ProductVersion!;
             }
+            if (!string.IsNullOrEmpty(e.ReleaseChannel))
+            {
+                payload[DecisionEngine.RealmJoinPayloadKeys.ReleaseChannel] = e.ReleaseChannel!;
+            }
 
             _ingress.Post(
                 kind: DecisionSignalKind.RealmJoinDetected,
@@ -75,7 +79,7 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
                 sourceOrigin: SourceLabel,
                 evidence: BuildEvidence(
                     "realmjoin-detected-v1",
-                    $"RealmJoin Parameters key observed (phase={e.DeploymentPhase}, productVersion={e.ProductVersion ?? "<unknown>"})"),
+                    $"RealmJoin Parameters key observed (phase={e.DeploymentPhase}, productVersion={e.ProductVersion ?? "<unknown>"}, releaseChannel={e.ReleaseChannel ?? "<unknown>"})"),
                 payload: payload);
 
             var data = new Dictionary<string, string>(StringComparer.Ordinal)
@@ -87,11 +91,16 @@ namespace AutopilotMonitor.Agent.V2.Core.SignalAdapters
             {
                 data["productVersion"] = e.ProductVersion!;
             }
+            if (!string.IsNullOrEmpty(e.ReleaseChannel))
+            {
+                data["releaseChannel"] = e.ReleaseChannel!;
+            }
             var versionTail = string.IsNullOrEmpty(e.ProductVersion) ? string.Empty : $", version={e.ProductVersion}";
+            var channelTail = string.IsNullOrEmpty(e.ReleaseChannel) ? string.Empty : $", channel={e.ReleaseChannel}";
             _post.Emit(
                 eventType: SharedConstants.EventTypes.RealmJoinDetected,
                 source: SourceLabel,
-                message: $"RealmJoin deployment detected (phase={e.DeploymentPhase}{versionTail})",
+                message: $"RealmJoin deployment detected (phase={e.DeploymentPhase}{versionTail}{channelTail})",
                 severity: EventSeverity.Info,
                 immediateUpload: true,
                 data: data,

src/Agent/AutopilotMonitor.DecisionCore.Tests/RealmJoinGateTests.cs

@@ -92,6 +92,35 @@ namespace AutopilotMonitor.DecisionCore.Tests
                 e.Deadline.Name == DeadlineNames.RealmJoinTimeout);
         }
 
+        [Fact]
+        public void RealmJoinDetected_records_ProductVersion_and_ReleaseChannel_facts()
+        {
+            var engine = new DecisionEngine();
+            var state = PrimeClassicAwaitingDesktop(engine);
+
+            var step = engine.Reduce(state, MakeSignal(5, DecisionSignalKind.RealmJoinDetected, T0.AddMinutes(5),
+                new Dictionary<string, string>
+                {
+                    [DecisionEngine.RealmJoinPayloadKeys.DeploymentPhase] = "100",
+                    [DecisionEngine.RealmJoinPayloadKeys.ProductVersion] = "4.21.6",
+                    [DecisionEngine.RealmJoinPayloadKeys.ReleaseChannel] = "canary",
+                }));
+
+            Assert.Equal("4.21.6", step.NewState.RealmJoinFacts.ProductVersion!.Value);
+            Assert.Equal("canary", step.NewState.RealmJoinFacts.ReleaseChannel!.Value);
+
+            // Set-once: a replayed Detected signal with different values must not overwrite.
+            var replay = engine.Reduce(step.NewState, MakeSignal(6, DecisionSignalKind.RealmJoinDetected, T0.AddMinutes(6),
+                new Dictionary<string, string>
+                {
+                    [DecisionEngine.RealmJoinPayloadKeys.DeploymentPhase] = "100",
+                    [DecisionEngine.RealmJoinPayloadKeys.ProductVersion] = "9.9.9",
+                    [DecisionEngine.RealmJoinPayloadKeys.ReleaseChannel] = "beta",
+                }));
+            Assert.Equal("4.21.6", replay.NewState.RealmJoinFacts.ProductVersion!.Value);
+            Assert.Equal("canary", replay.NewState.RealmJoinFacts.ReleaseChannel!.Value);
+        }
+
         [Fact]
         public void RealmJoinGate_closed_defers_finalizing_when_DesktopArrived_arrives_with_hello_already_resolved()
         {

src/Shared/AutopilotMonitor.DecisionCore/Engine/DecisionAuditTrailBuilder.cs

@@ -147,6 +147,10 @@ namespace AutopilotMonitor.DecisionCore.Engine
                 {
                     data["realmjoinProductVersion"] = postState.RealmJoinFacts.ProductVersion.Value;
                 }
+                if (postState.RealmJoinFacts.ReleaseChannel != null)
+                {
+                    data["realmjoinReleaseChannel"] = postState.RealmJoinFacts.ReleaseChannel.Value;
+                }
                 data["realmjoinPackages"] = BuildRealmJoinPackageSummary(postState.RealmJoinFacts.Packages);
             }
 

src/Shared/AutopilotMonitor.DecisionCore/Engine/DecisionEngine.RealmJoin.cs

@@ -31,8 +31,11 @@ namespace AutopilotMonitor.DecisionCore.Engine
             public const string Scope = "scope";          // "machine" | "user"
             public const string Success = "success";       // "true" | "false"
             public const string LastExitCode = "lastExitCode";
-            // Set on RealmJoinDetected by the agent adapter from RealmJoin.exe ProductVersion.
+            // Set on RealmJoinDetected by the agent adapter from RealmJoin.exe's
+            // file-version resource: bare version + release channel ("release"/"beta"/"canary"
+            // — the SemVer prerelease tag, absent tag == stable release).
             public const string ProductVersion = "productVersion";
+            public const string ReleaseChannel = "releaseChannel";
         }
 
         /// <summary>
@@ -80,6 +83,7 @@ namespace AutopilotMonitor.DecisionCore.Engine
 
             var phase = TryReadPhase(signal);
             var productVersion = TryReadString(signal, RealmJoinPayloadKeys.ProductVersion);
+            var releaseChannel = TryReadString(signal, RealmJoinPayloadKeys.ReleaseChannel);
             var updatedFacts = state.RealmJoinFacts.WithDetected(signal.OccurredAtUtc, signal.SessionSignalOrdinal);
             if (phase.HasValue)
             {
@@ -89,6 +93,10 @@ namespace AutopilotMonitor.DecisionCore.Engine
             {
                 updatedFacts = updatedFacts.WithProductVersion(productVersion!, signal.SessionSignalOrdinal);
             }
+            if (!string.IsNullOrEmpty(releaseChannel))
+            {
+                updatedFacts = updatedFacts.WithReleaseChannel(releaseChannel!, signal.SessionSignalOrdinal);
+            }
             builder.RealmJoinFacts = updatedFacts;
 
             var effects = Array.Empty<DecisionEffect>();

src/Shared/AutopilotMonitor.DecisionCore/State/RealmJoinFacts.cs

@@ -33,6 +33,7 @@ namespace AutopilotMonitor.DecisionCore.State
             outcome: null,
             selfDeployingDeferredCompletion: null,
             productVersion: null,
+            releaseChannel: null,
             packages: Array.Empty<RealmJoinPackageFact>());
 
         public RealmJoinFacts(
@@ -42,6 +43,7 @@ namespace AutopilotMonitor.DecisionCore.State
             SignalFact<string>? outcome,
             SignalFact<bool>? selfDeployingDeferredCompletion,
             SignalFact<string>? productVersion,
+            SignalFact<string>? releaseChannel,
             IReadOnlyList<RealmJoinPackageFact> packages)
         {
             DetectedUtc = detectedUtc;
@@ -50,6 +52,7 @@ namespace AutopilotMonitor.DecisionCore.State
             Outcome = outcome;
             SelfDeployingDeferredCompletion = selfDeployingDeferredCompletion;
             ProductVersion = productVersion;
+            ReleaseChannel = releaseChannel;
             Packages = packages ?? Array.Empty<RealmJoinPackageFact>();
         }
 
@@ -74,12 +77,19 @@ namespace AutopilotMonitor.DecisionCore.State
         public SignalFact<bool>? SelfDeployingDeferredCompletion { get; }
 
         /// <summary>
-        /// <c>ProductVersion</c> read from <c>C:\Program Files\RealmJoin\RealmJoin.exe</c> at
-        /// detection time. Observability-only — never gates a decision. Null when the binary
-        /// was missing or unreadable.
+        /// Bare version parsed from <c>C:\Program Files\RealmJoin\RealmJoin.exe</c>'s
+        /// file-version resource at detection time. Observability-only — never gates a
+        /// decision. Null when the binary was missing or unreadable.
         /// </summary>
         public SignalFact<string>? ProductVersion { get; }
 
+        /// <summary>
+        /// RJ release channel parsed from the version string's SemVer prerelease tag at
+        /// detection time: <c>"release"</c> (untagged stable), <c>"beta"</c> or <c>"canary"</c>.
+        /// Observability-only — never gates a decision. Null when the version was unreadable.
+        /// </summary>
+        public SignalFact<string>? ReleaseChannel { get; }
+
         /// <summary>Tracked per-package install rows (machine + user scope combined).</summary>
         public IReadOnlyList<RealmJoinPackageFact> Packages { get; }
 
@@ -93,6 +103,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: Outcome,
                 selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: Packages);
         }
 
@@ -112,6 +123,27 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: Outcome,
                 selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
                 productVersion: new SignalFact<string>(productVersion, sourceSignalOrdinal),
+                releaseChannel: ReleaseChannel,
+                packages: Packages);
+        }
+
+        /// <summary>
+        /// Set-once observability fact carrying the RJ release channel parsed from the
+        /// <c>RealmJoin.exe</c> version string. No-op when <paramref name="releaseChannel"/>
+        /// is empty or already set. Pure metadata — never participates in a gate decision.
+        /// </summary>
+        public RealmJoinFacts WithReleaseChannel(string releaseChannel, long sourceSignalOrdinal)
+        {
+            if (ReleaseChannel != null) return this;
+            if (string.IsNullOrEmpty(releaseChannel)) return this;
+            return new RealmJoinFacts(
+                detectedUtc: DetectedUtc,
+                resolvedUtc: ResolvedUtc,
+                lastDeploymentPhase: LastDeploymentPhase,
+                outcome: Outcome,
+                selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
+                productVersion: ProductVersion,
+                releaseChannel: new SignalFact<string>(releaseChannel, sourceSignalOrdinal),
                 packages: Packages);
         }
 
@@ -125,6 +157,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: new SignalFact<string>(OutcomeResolved, sourceSignalOrdinal),
                 selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: Packages);
         }
 
@@ -138,6 +171,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: Outcome,
                 selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: Packages);
         }
 
@@ -151,6 +185,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: new SignalFact<string>(OutcomeTimeout, sourceSignalOrdinal),
                 selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: Packages);
         }
 
@@ -164,6 +199,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: Outcome,
                 selfDeployingDeferredCompletion: new SignalFact<bool>(true, sourceSignalOrdinal),
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: Packages);
         }
 
@@ -183,6 +219,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: Outcome,
                 selfDeployingDeferredCompletion: null,
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: Packages);
         }
 
@@ -237,6 +274,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: Outcome,
                 selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: copy);
         }
 
@@ -305,6 +343,7 @@ namespace AutopilotMonitor.DecisionCore.State
                 outcome: Outcome,
                 selfDeployingDeferredCompletion: SelfDeployingDeferredCompletion,
                 productVersion: ProductVersion,
+                releaseChannel: ReleaseChannel,
                 packages: copy);
         }
     }