diff --git a/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs b/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs
index fa66e5a4..09521fc6 100644
--- a/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs
+++ b/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs
@@ -71,6 +71,12 @@ public sealed record AlarmAcknowledgeRequest(
 ///     <c>Diagnostics</c>). Maps to OPC UA <c>ConditionClassName</c> downstream when
 ///     a class mapping is configured. Null when the upstream path doesn't carry it.
 /// </param>
+/// <param name="Kind">
+///     The alarm transition kind (raise / acknowledge / clear / retrigger). Lets a
+///     consumer derive OPC UA Part 9 active/ack state without inferring it from
+///     other fields. <see cref="AlarmTransitionKind.Unspecified"/> when the upstream
+///     path doesn't surface a distinct kind.
+/// </param>
 public sealed record AlarmEventArgs(
     IAlarmSubscriptionHandle SubscriptionHandle,
     string SourceNodeId,
@@ -81,7 +87,15 @@ public sealed record AlarmEventArgs(
     DateTime SourceTimestampUtc,
     string? OperatorComment = null,
     DateTime? OriginalRaiseTimestampUtc = null,
-    string? AlarmCategory = null);
+    string? AlarmCategory = null,
+    AlarmTransitionKind Kind = AlarmTransitionKind.Unspecified);
 
 /// <summary>Mirrors the <c>NodePermissions</c> alarm-severity enum in <c>docs/v2/acl-design.md</c>.</summary>
 public enum AlarmSeverity { Low, Medium, High, Critical }
+
+/// <summary>
+///     Kind of alarm state change carried by <see cref="AlarmEventArgs.Kind"/>, letting a
+///     consumer derive OPC UA Part 9 active/ack state. Mirrors the driver-side
+///     transition-kind enums (e.g. Galaxy's <c>GalaxyAlarmTransitionKind</c>).
+/// </summary>
+public enum AlarmTransitionKind { Unspecified = 0, Raise, Acknowledge, Clear, Retrigger }
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs
index 1bc2cedd..2cc822b6 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs
@@ -1153,7 +1153,17 @@ public sealed class GalaxyDriver
             SourceTimestampUtc: transition.TransitionTimestampUtc,
             OperatorComment: string.IsNullOrEmpty(transition.OperatorComment) ? null : transition.OperatorComment,
             OriginalRaiseTimestampUtc: transition.OriginalRaiseTimestampUtc,
-            AlarmCategory: string.IsNullOrEmpty(transition.Category) ? null : transition.Category);
+            AlarmCategory: string.IsNullOrEmpty(transition.Category) ? null : transition.Category,
+            // Fully-qualify the Core.Abstractions enum: this file also imports
+            // MxGateway.Contracts.Proto, which defines a same-named AlarmTransitionKind.
+            Kind: transition.TransitionKind switch
+            {
+                GalaxyAlarmTransitionKind.Raise => Core.Abstractions.AlarmTransitionKind.Raise,
+                GalaxyAlarmTransitionKind.Acknowledge => Core.Abstractions.AlarmTransitionKind.Acknowledge,
+                GalaxyAlarmTransitionKind.Clear => Core.Abstractions.AlarmTransitionKind.Clear,
+                GalaxyAlarmTransitionKind.Retrigger => Core.Abstractions.AlarmTransitionKind.Retrigger,
+                _ => Core.Abstractions.AlarmTransitionKind.Unspecified,
+            });
         try
         {
             OnAlarmEvent?.Invoke(this, args);
diff --git a/tests/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions.Tests/AlarmEventArgsTests.cs b/tests/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions.Tests/AlarmEventArgsTests.cs
new file mode 100644
index 00000000..3815c210
--- /dev/null
+++ b/tests/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions.Tests/AlarmEventArgsTests.cs
@@ -0,0 +1,23 @@
+using Shouldly;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions.Tests;
+
+public class AlarmEventArgsTests
+{
+    private static AlarmEventArgs Make(AlarmTransitionKind? kind = null) =>
+        kind is null
+            ? new AlarmEventArgs(new FakeHandle(), "Tank1.Hi", "c1", "LimitAlarm.Hi", "msg", AlarmSeverity.High, DateTime.UnixEpoch)
+            : new AlarmEventArgs(new FakeHandle(), "Tank1.Hi", "c1", "LimitAlarm.Hi", "msg", AlarmSeverity.High, DateTime.UnixEpoch, Kind: kind.Value);
+
+    [Fact]
+    public void Kind_defaults_to_Unspecified_so_existing_callers_compile()
+        => Make().Kind.ShouldBe(AlarmTransitionKind.Unspecified);
+
+    [Fact]
+    public void Kind_round_trips_when_supplied()
+        => Make(AlarmTransitionKind.Raise).Kind.ShouldBe(AlarmTransitionKind.Raise);
+
+    private sealed class FakeHandle : IAlarmSubscriptionHandle { public string DiagnosticId => "t"; }
+}
diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmSourceTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmSourceTests.cs
index af5a0560..ebc90a7a 100644
--- a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmSourceTests.cs
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmSourceTests.cs
@@ -42,6 +42,39 @@ public sealed class GalaxyDriverAlarmSourceTests
         observed[0].SubscriptionHandle.ShouldBe(handle);
     }
 
+    /// <summary>
+    ///     Verifies that the driver maps each Galaxy transition kind onto the matching
+    ///     <see cref="AlarmTransitionKind"/> on the surfaced <see cref="AlarmEventArgs"/>,
+    ///     so a Part 9 consumer can derive active/ack state. The Galaxy kind is passed by
+    ///     name because <c>GalaxyAlarmTransitionKind</c> is internal to the driver and so
+    ///     cannot appear in a public test method signature.
+    /// </summary>
+    /// <param name="galaxyKindName">The <c>GalaxyAlarmTransitionKind</c> member name fed into the alarm feed.</param>
+    /// <param name="expectedKind">The expected <see cref="AlarmTransitionKind"/> on the surfaced event.</param>
+    [Theory]
+    [InlineData(nameof(GalaxyAlarmTransitionKind.Raise), AlarmTransitionKind.Raise)]
+    [InlineData(nameof(GalaxyAlarmTransitionKind.Acknowledge), AlarmTransitionKind.Acknowledge)]
+    [InlineData(nameof(GalaxyAlarmTransitionKind.Clear), AlarmTransitionKind.Clear)]
+    [InlineData(nameof(GalaxyAlarmTransitionKind.Retrigger), AlarmTransitionKind.Retrigger)]
+    [InlineData(nameof(GalaxyAlarmTransitionKind.Unspecified), AlarmTransitionKind.Unspecified)]
+    public async Task Transition_kind_maps_onto_AlarmEventArgs_Kind(
+        string galaxyKindName, AlarmTransitionKind expectedKind)
+    {
+        var galaxyKind = Enum.Parse<GalaxyAlarmTransitionKind>(galaxyKindName);
+        var feed = new FakeAlarmFeed();
+        var ack = new RecordingAcknowledger();
+        using var driver = NewDriver(feed, ack);
+
+        var handle = await driver.SubscribeAlarmsAsync(["Tank01"], CancellationToken.None);
+        var observed = new List<AlarmEventArgs>();
+        driver.OnAlarmEvent += (_, args) => observed.Add(args);
+
+        feed.Emit(NewTransition("Tank01.Level.HiHi", "Tank01", galaxyKind, AlarmSeverity.High));
+
+        observed.ShouldHaveSingleItem();
+        observed[0].Kind.ShouldBe(expectedKind);
+    }
+
     /// <summary>Verifies that OnAlarmEvent does not fire before any alarm subscription.</summary>
     [Fact]
     public void OnAlarmEvent_does_not_fire_before_any_alarm_subscription()
diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/GatewayGalaxyAlarmFeedTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/GatewayGalaxyAlarmFeedTests.cs
index 077a9efd..e0482d60 100644
--- a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/GatewayGalaxyAlarmFeedTests.cs
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/GatewayGalaxyAlarmFeedTests.cs
@@ -6,6 +6,11 @@ using Xunit;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;
 
+// Core.Abstractions now also defines an AlarmTransitionKind (the AlarmEventArgs surface
+// kind). This file drives the gateway proto, so pin the bare token to the proto enum to
+// preserve the existing references unchanged.
+using AlarmTransitionKind = ZB.MOM.WW.MxGateway.Contracts.Proto.AlarmTransitionKind;
+
 namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests.Runtime;
 
 /// <summary>