diff --git a/src/ZB.MOM.WW.OtOpcUa.Client.Shared/Models/AlarmEventArgs.cs b/src/ZB.MOM.WW.OtOpcUa.Client.Shared/Models/AlarmEventArgs.cs
index c068c07..069fa89 100644
--- a/src/ZB.MOM.WW.OtOpcUa.Client.Shared/Models/AlarmEventArgs.cs
+++ b/src/ZB.MOM.WW.OtOpcUa.Client.Shared/Models/AlarmEventArgs.cs
@@ -15,7 +15,10 @@ public sealed class AlarmEventArgs : EventArgs
         bool ackedState,
         DateTime time,
         byte[]? eventId = null,
-        string? conditionNodeId = null)
+        string? conditionNodeId = null,
+        string? operatorComment = null,
+        DateTime? originalRaiseTimestampUtc = null,
+        string? alarmCategory = null)
     {
         SourceName = sourceName;
         ConditionName = conditionName;
@@ -27,6 +30,9 @@ public sealed class AlarmEventArgs : EventArgs
         Time = time;
         EventId = eventId;
         ConditionNodeId = conditionNodeId;
+        OperatorComment = operatorComment;
+        OriginalRaiseTimestampUtc = originalRaiseTimestampUtc;
+        AlarmCategory = alarmCategory;
     }
 
     /// <summary>The name of the source object that raised the alarm.</summary>
@@ -58,4 +64,25 @@ public sealed class AlarmEventArgs : EventArgs
 
     /// <summary>The NodeId of the condition instance (SourceNode), used for acknowledgment.</summary>
     public string? ConditionNodeId { get; }
+
+    /// <summary>
+    ///     PR E.7 — Operator-supplied comment recorded by the upstream alarm system on
+    ///     Acknowledge transitions. Null on raise / clear, or when the upstream path
+    ///     can't surface the comment (sub-attribute fallback path collapses comments
+    ///     into a single string write).
+    /// </summary>
+    public string? OperatorComment { get; }
+
+    /// <summary>
+    ///     PR E.7 — When the alarm originally entered the active state. Preserved
+    ///     across Acknowledge transitions so OPC UA Part 9 conditions keep the
+    ///     original raise time. Null when the upstream path doesn't surface it.
+    /// </summary>
+    public DateTime? OriginalRaiseTimestampUtc { get; }
+
+    /// <summary>
+    ///     PR E.7 — Upstream alarm taxonomy bucket (e.g. <c>Process</c> /
+    ///     <c>Safety</c> / <c>Diagnostics</c>). Null when not surfaced.
+    /// </summary>
+    public string? AlarmCategory { get; }
 }
\ No newline at end of file
diff --git a/src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs b/src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs
index 2282d0f..4f261c5 100644
--- a/src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs
+++ b/src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IAlarmSource.cs
@@ -41,6 +41,30 @@ public sealed record AlarmAcknowledgeRequest(
     string? Comment);
 
 /// <summary>Event payload for <see cref="IAlarmSource.OnAlarmEvent"/>.</summary>
+/// <param name="SubscriptionHandle">Subscription this event belongs to.</param>
+/// <param name="SourceNodeId">Driver-side identifier for the alarm source.</param>
+/// <param name="ConditionId">Stable id correlating raise / ack / clear of the same condition.</param>
+/// <param name="AlarmType">Driver-defined alarm type name (e.g. AnalogLimitAlarm.HiHi).</param>
+/// <param name="Message">Human-readable alarm description.</param>
+/// <param name="Severity">Four-bucket severity ladder.</param>
+/// <param name="SourceTimestampUtc">When this transition occurred.</param>
+/// <param name="OperatorComment">
+///     Operator-supplied comment recorded by the upstream alarm system on Acknowledge
+///     transitions. Null on raise / clear, or when the upstream path can't surface
+///     the comment (the Galaxy sub-attribute fallback path collapses comments into a
+///     single string write — null on that path; the driver-native gateway path
+///     populates this).
+/// </param>
+/// <param name="OriginalRaiseTimestampUtc">
+///     When the alarm originally entered the active state. Preserved across
+///     Acknowledge transitions so OPC UA Part 9 conditions keep the original raise
+///     time in <c>Time</c>. Null when the upstream path doesn't surface it.
+/// </param>
+/// <param name="AlarmCategory">
+///     Upstream alarm taxonomy bucket (e.g. <c>Process</c> / <c>Safety</c> /
+///     <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>
 public sealed record AlarmEventArgs(
     IAlarmSubscriptionHandle SubscriptionHandle,
     string SourceNodeId,
@@ -48,7 +72,10 @@ public sealed record AlarmEventArgs(
     string AlarmType,
     string Message,
     AlarmSeverity Severity,
-    DateTime SourceTimestampUtc);
+    DateTime SourceTimestampUtc,
+    string? OperatorComment = null,
+    DateTime? OriginalRaiseTimestampUtc = null,
+    string? AlarmCategory = null);
 
 /// <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 }
diff --git a/src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs b/src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs
index 672fedc..e06d976 100644
--- a/src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs
+++ b/src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs
@@ -837,7 +837,10 @@ public sealed class GalaxyDriver
             AlarmType: transition.AlarmTypeName,
             Message: transition.Description,
             Severity: transition.SeverityBucket,
-            SourceTimestampUtc: transition.TransitionTimestampUtc);
+            SourceTimestampUtc: transition.TransitionTimestampUtc,
+            OperatorComment: string.IsNullOrEmpty(transition.OperatorComment) ? null : transition.OperatorComment,
+            OriginalRaiseTimestampUtc: transition.OriginalRaiseTimestampUtc,
+            AlarmCategory: string.IsNullOrEmpty(transition.Category) ? null : transition.Category);
         try
         {
             OnAlarmEvent?.Invoke(this, args);
diff --git a/tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmEventArgsExtensionTests.cs b/tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmEventArgsExtensionTests.cs
new file mode 100644
index 0000000..ce451c3
--- /dev/null
+++ b/tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverAlarmEventArgsExtensionTests.cs
@@ -0,0 +1,138 @@
+using System.Threading.Channels;
+using Google.Protobuf.WellKnownTypes;
+using MxGateway.Contracts.Proto;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
+using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests;
+
+/// <summary>
+///     PR E.7 — pins that the GalaxyDriver populates the extended AlarmEventArgs
+///     fields (OperatorComment, OriginalRaiseTimestampUtc, AlarmCategory) when the
+///     gateway emits a transition with the rich payload, and leaves them null on
+///     events that don't carry them.
+/// </summary>
+public sealed class GalaxyDriverAlarmEventArgsExtensionTests
+{
+    [Fact]
+    public async Task Acknowledge_transition_with_full_payload_populates_extended_fields()
+    {
+        var subscriber = new ManualSubscriber();
+        using var driver = NewDriver(subscriber);
+
+        await driver.SubscribeAlarmsAsync(["Tank01"], CancellationToken.None);
+        var observed = new List<AlarmEventArgs>();
+        driver.OnAlarmEvent += (_, args) => observed.Add(args);
+        await driver.SubscribeAsync(["Tank01.Level"], TimeSpan.Zero, CancellationToken.None);
+
+        var raise = new DateTime(2026, 5, 1, 12, 0, 0, DateTimeKind.Utc);
+        var ack = raise.AddSeconds(45);
+        await subscriber.EmitAlarmAsync(new MxEvent
+        {
+            Family = MxEventFamily.OnAlarmTransition,
+            OnAlarmTransition = new OnAlarmTransitionEvent
+            {
+                AlarmFullReference = "Tank01.Level.HiHi",
+                SourceObjectReference = "Tank01",
+                AlarmTypeName = "AnalogLimitAlarm.HiHi",
+                TransitionKind = AlarmTransitionKind.Acknowledge,
+                Severity = 750,
+                OriginalRaiseTimestamp = Timestamp.FromDateTime(raise),
+                TransitionTimestamp = Timestamp.FromDateTime(ack),
+                OperatorUser = "alice",
+                OperatorComment = "investigating",
+                Category = "Process",
+                Description = "Tank 01 high-high level",
+            },
+        });
+
+        for (var i = 0; i < 20 && observed.Count == 0; i++)
+        {
+            await Task.Delay(50);
+        }
+        observed.ShouldHaveSingleItem();
+        observed[0].OperatorComment.ShouldBe("investigating");
+        observed[0].OriginalRaiseTimestampUtc.ShouldBe(raise);
+        observed[0].AlarmCategory.ShouldBe("Process");
+    }
+
+    [Fact]
+    public async Task Raise_transition_without_optional_fields_leaves_them_null()
+    {
+        var subscriber = new ManualSubscriber();
+        using var driver = NewDriver(subscriber);
+
+        await driver.SubscribeAlarmsAsync(["Tank01"], CancellationToken.None);
+        var observed = new List<AlarmEventArgs>();
+        driver.OnAlarmEvent += (_, args) => observed.Add(args);
+        await driver.SubscribeAsync(["Tank01.Level"], TimeSpan.Zero, CancellationToken.None);
+
+        await subscriber.EmitAlarmAsync(new MxEvent
+        {
+            Family = MxEventFamily.OnAlarmTransition,
+            OnAlarmTransition = new OnAlarmTransitionEvent
+            {
+                AlarmFullReference = "Tank01.Level.HiHi",
+                AlarmTypeName = "AnalogLimitAlarm.HiHi",
+                TransitionKind = AlarmTransitionKind.Raise,
+                Severity = 750,
+                TransitionTimestamp = Timestamp.FromDateTime(DateTime.UtcNow),
+            },
+        });
+
+        for (var i = 0; i < 20 && observed.Count == 0; i++)
+        {
+            await Task.Delay(50);
+        }
+        observed.ShouldHaveSingleItem();
+        observed[0].OperatorComment.ShouldBeNull();
+        observed[0].OriginalRaiseTimestampUtc.ShouldBeNull();
+        observed[0].AlarmCategory.ShouldBeNull();
+    }
+
+    private static GalaxyDriver NewDriver(ManualSubscriber subscriber)
+    {
+        var options = new GalaxyDriverOptions(
+            new GalaxyGatewayOptions("http://localhost:5000", "literal-api-key"),
+            new GalaxyMxAccessOptions("AlarmExtensionTest"),
+            new GalaxyRepositoryOptions(),
+            new GalaxyReconnectOptions());
+        return new GalaxyDriver(
+            driverInstanceId: "drv-1",
+            options: options,
+            hierarchySource: null,
+            dataReader: null,
+            dataWriter: null,
+            subscriber: subscriber,
+            alarmAcknowledger: null);
+    }
+
+    private sealed class ManualSubscriber : IGalaxySubscriber
+    {
+        private readonly Channel<MxEvent> _stream =
+            Channel.CreateUnbounded<MxEvent>(new UnboundedChannelOptions { SingleReader = true });
+
+        public Task<IReadOnlyList<SubscribeResult>> SubscribeBulkAsync(
+            IReadOnlyList<string> fullReferences, int bufferedUpdateIntervalMs, CancellationToken cancellationToken)
+        {
+            var results = new List<SubscribeResult>();
+            var nextHandle = 100;
+            foreach (var r in fullReferences)
+            {
+                results.Add(new SubscribeResult { TagAddress = r, ItemHandle = nextHandle++, WasSuccessful = true });
+            }
+            return Task.FromResult<IReadOnlyList<SubscribeResult>>(results);
+        }
+
+        public Task UnsubscribeBulkAsync(IReadOnlyList<int> itemHandles, CancellationToken cancellationToken)
+            => Task.CompletedTask;
+
+        public IAsyncEnumerable<MxEvent> StreamEventsAsync(CancellationToken cancellationToken)
+            => _stream.Reader.ReadAllAsync(cancellationToken);
+
+        public ValueTask EmitAlarmAsync(MxEvent ev) => _stream.Writer.WriteAsync(ev);
+    }
+}