diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/ScriptedAlarmActor.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/ScriptedAlarmActor.cs
new file mode 100644
index 0000000..da1a849
--- /dev/null
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/ScriptedAlarmActor.cs
@@ -0,0 +1,60 @@
+using Akka.Actor;
+using Akka.Event;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.ScriptedAlarms;
+
+public enum ScriptedAlarmActorState { Inactive, Active, Acknowledged }
+
+/// <summary>
+/// State machine wrapping a single scripted alarm. Transitions:
+/// <c>Inactive → Active → Acknowledged → Inactive</c>.
+///
+/// Engine wiring (compile alarm expression via <c>AlarmConditionService</c>, persist state to
+/// <c>ScriptedAlarmState</c> ConfigDb table on <c>PreRestart</c>, emit history rows to
+/// <c>HistorianAdapter</c>) is staged for follow-up F9. This skeleton owns the state machine
+/// so DriverHostActor can spawn it as a child.
+/// </summary>
+public sealed class ScriptedAlarmActor : ReceiveActor
+{
+    public sealed record ConditionMet(string Reason);
+    public sealed record AcknowledgeAlarm(string Actor);
+    public sealed record ConditionCleared;
+    public sealed record StateChanged(string AlarmId, ScriptedAlarmActorState State, DateTime AtUtc);
+
+    private readonly string _alarmId;
+    private readonly ILoggingAdapter _log = Context.GetLogger();
+    private ScriptedAlarmActorState _state = ScriptedAlarmActorState.Inactive;
+
+    public static Props Props(string alarmId) =>
+        Akka.Actor.Props.Create(() => new ScriptedAlarmActor(alarmId));
+
+    public ScriptedAlarmActor(string alarmId)
+    {
+        _alarmId = alarmId;
+
+        Receive<ConditionMet>(msg =>
+        {
+            if (_state != ScriptedAlarmActorState.Inactive) return;
+            Transition(ScriptedAlarmActorState.Active);
+        });
+        Receive<AcknowledgeAlarm>(msg =>
+        {
+            if (_state != ScriptedAlarmActorState.Active) return;
+            Transition(ScriptedAlarmActorState.Acknowledged);
+        });
+        Receive<ConditionCleared>(_ =>
+        {
+            if (_state == ScriptedAlarmActorState.Inactive) return;
+            Transition(ScriptedAlarmActorState.Inactive);
+        });
+    }
+
+    private void Transition(ScriptedAlarmActorState next)
+    {
+        var prev = _state;
+        _state = next;
+        _log.Info("ScriptedAlarm {Id}: {From} → {To}", _alarmId, prev, next);
+        Context.Parent.Tell(new StateChanged(_alarmId, next, DateTime.UtcNow));
+        // F9: emit history row via HistorianAdapter; persist state to ScriptedAlarmState DB.
+    }
+}
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/ScriptedAlarmActorTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/ScriptedAlarmActorTests.cs
new file mode 100644
index 0000000..a6721c9
--- /dev/null
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ScriptedAlarms/ScriptedAlarmActorTests.cs
@@ -0,0 +1,44 @@
+using Akka.Actor;
+using Akka.TestKit;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Runtime.ScriptedAlarms;
+using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.ScriptedAlarms;
+
+public sealed class ScriptedAlarmActorTests : RuntimeActorTestBase
+{
+    [Fact]
+    public void Full_state_cycle_publishes_StateChanged_to_parent_at_each_transition()
+    {
+        var parent = CreateTestProbe();
+        // Wrap the alarm actor under our probe as parent so StateChanged lands on the probe.
+        var actor = parent.ChildActorOf(ScriptedAlarmActor.Props("alarm-1"));
+
+        actor.Tell(new ScriptedAlarmActor.ConditionMet("threshold"));
+        var t1 = parent.ExpectMsg<ScriptedAlarmActor.StateChanged>();
+        t1.State.ShouldBe(ScriptedAlarmActorState.Active);
+
+        actor.Tell(new ScriptedAlarmActor.AcknowledgeAlarm("joe"));
+        var t2 = parent.ExpectMsg<ScriptedAlarmActor.StateChanged>();
+        t2.State.ShouldBe(ScriptedAlarmActorState.Acknowledged);
+
+        actor.Tell(new ScriptedAlarmActor.ConditionCleared());
+        var t3 = parent.ExpectMsg<ScriptedAlarmActor.StateChanged>();
+        t3.State.ShouldBe(ScriptedAlarmActorState.Inactive);
+    }
+
+    [Fact]
+    public void Duplicate_ConditionMet_in_Active_is_ignored()
+    {
+        var parent = CreateTestProbe();
+        var actor = parent.ChildActorOf(ScriptedAlarmActor.Props("alarm-1"));
+
+        actor.Tell(new ScriptedAlarmActor.ConditionMet("first"));
+        parent.ExpectMsg<ScriptedAlarmActor.StateChanged>();
+
+        actor.Tell(new ScriptedAlarmActor.ConditionMet("second"));
+        parent.ExpectNoMsg(TimeSpan.FromMilliseconds(200));
+    }
+}