diff --git a/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/InstanceCommands.cs b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/InstanceCommands.cs
index 36e50faa..92eb4370 100644
--- a/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/InstanceCommands.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/InstanceCommands.cs
@@ -34,13 +34,23 @@ public record SetInstanceAreaCommand(int InstanceId, int? AreaId);
 /// Sets (or upserts) a per-instance alarm override. For HiLo trigger types the
 /// <c>TriggerConfigurationOverride</c> JSON is merged setpoint-by-setpoint with
 /// the inherited config; for binary trigger types it replaces the whole config.
-/// Either field is optional — pass null to leave it unchanged.
+/// Each override field is optional — null means the instance inherits the template value
+/// for that field (the row is replaced whole on every call, not merged).
 /// </summary>
+/// <param name="InstanceId">ID of the instance the override applies to.</param>
+/// <param name="AlarmCanonicalName">Canonical (path-qualified for composed members) alarm name.</param>
+/// <param name="TriggerConfigurationOverride">Trigger configuration JSON override, or null.</param>
+/// <param name="PriorityLevelOverride">Priority level override, or null.</param>
+/// <param name="IsMesReportableOverride">
+/// Per-instance override of the template alarm's MES-reportable flag. Additive trailing
+/// optional; null (the default) inherits the template value, true/false forces it.
+/// </param>
 public record SetInstanceAlarmOverrideCommand(
     int InstanceId,
     string AlarmCanonicalName,
     string? TriggerConfigurationOverride,
-    int? PriorityLevelOverride);
+    int? PriorityLevelOverride,
+    bool? IsMesReportableOverride = null);
 
 public record DeleteInstanceAlarmOverrideCommand(
     int InstanceId,
diff --git a/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/TemplateCommands.cs b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/TemplateCommands.cs
index 35178d9b..ba6f1774 100644
--- a/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/TemplateCommands.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/TemplateCommands.cs
@@ -42,8 +42,11 @@ public record ResyncInheritedMembersCommand(int TemplateId);
 public record AddTemplateAttributeCommand(int TemplateId, string Name, string DataType, string? Value, string? Description, string? DataSourceReference, bool IsLocked, string? ElementDataType = null);
 public record UpdateTemplateAttributeCommand(int AttributeId, string Name, string DataType, string? Value, string? Description, string? DataSourceReference, bool IsLocked, string? ElementDataType = null);
 public record DeleteTemplateAttributeCommand(int AttributeId);
-public record AddTemplateAlarmCommand(int TemplateId, string Name, string TriggerType, int PriorityLevel, string? Description, string? TriggerConfiguration, bool IsLocked);
-public record UpdateTemplateAlarmCommand(int AlarmId, string Name, string TriggerType, int PriorityLevel, string? Description, string? TriggerConfiguration, bool IsLocked);
+// IsMesReportable is an additive trailing optional (default false = "not reported to MES"):
+// it mirrors TemplateAlarm.IsMesReportable and marks the alarm for inclusion in the MES
+// alarm-status feed. Additive-only: never reorder the existing parameters.
+public record AddTemplateAlarmCommand(int TemplateId, string Name, string TriggerType, int PriorityLevel, string? Description, string? TriggerConfiguration, bool IsLocked, bool IsMesReportable = false);
+public record UpdateTemplateAlarmCommand(int AlarmId, string Name, string TriggerType, int PriorityLevel, string? Description, string? TriggerConfiguration, bool IsLocked, bool IsMesReportable = false);
 public record DeleteTemplateAlarmCommand(int AlarmId);
 // Native alarm source bindings (read-only mirror of an OPC UA A&C / MxGateway source's alarms)
 public record AddTemplateNativeAlarmSourceCommand(int TemplateId, string Name, string ConnectionName, string SourceReference, string? ConditionFilter, string? Description, bool IsLocked);
diff --git a/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs b/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
index 0752be61..cbb28e01 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
@@ -1175,7 +1175,7 @@ public class ManagementActor : ReceiveActor
         var result = await svc.SetAlarmOverrideAsync(
             cmd.InstanceId, cmd.AlarmCanonicalName,
             cmd.TriggerConfigurationOverride, cmd.PriorityLevelOverride,
-            user.Username);
+            user.Username, cmd.IsMesReportableOverride);
         return result.IsSuccess
             ? result.Value
             : throw new ManagementCommandException(result.Error);
@@ -3179,7 +3179,8 @@ public class ManagementActor : ReceiveActor
             PriorityLevel = cmd.PriorityLevel,
             Description = cmd.Description,
             TriggerConfiguration = cmd.TriggerConfiguration,
-            IsLocked = cmd.IsLocked
+            IsLocked = cmd.IsLocked,
+            IsMesReportable = cmd.IsMesReportable
         };
         var result = await svc.AddAlarmAsync(cmd.TemplateId, alarm, user);
         return result.IsSuccess ? result.Value : throw new ManagementCommandException(result.Error);
@@ -3194,7 +3195,8 @@ public class ManagementActor : ReceiveActor
             PriorityLevel = cmd.PriorityLevel,
             Description = cmd.Description,
             TriggerConfiguration = cmd.TriggerConfiguration,
-            IsLocked = cmd.IsLocked
+            IsLocked = cmd.IsLocked,
+            IsMesReportable = cmd.IsMesReportable
         };
         var result = await svc.UpdateAlarmAsync(cmd.AlarmId, alarm, user);
         return result.IsSuccess ? result.Value : throw new ManagementCommandException(result.Error);
diff --git a/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs
index 232132b9..779a5cce 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs
@@ -1014,6 +1014,112 @@ public class ManagementActorTests : TestKit, IDisposable
         Assert.Contains("Valid values:", response.Error);
     }
 
+    [Fact]
+    public void AddTemplateAlarm_CarriesIsMesReportable()
+    {
+        // The MES-reportable flag rides AddTemplateAlarmCommand as a trailing
+        // optional (additive-only wire contract) and must reach the TemplateAlarm
+        // the handler hands to TemplateService — verified at the repository
+        // boundary, which is where the entity is persisted.
+        var template = new Template("T1") { Id = 1 };
+        _templateRepo.GetTemplateByIdAsync(1, Arg.Any<CancellationToken>()).Returns(template);
+        _templateRepo.GetAllTemplatesForAnalysisAsync(Arg.Any<CancellationToken>())
+            .Returns(new List<Template> { template });
+        _templateRepo.GetAllTemplatesAsync(Arg.Any<CancellationToken>())
+            .Returns(new List<Template> { template });
+
+        TemplateAlarm? added = null;
+        _templateRepo
+            .When(r => r.AddTemplateAlarmAsync(Arg.Any<TemplateAlarm>(), Arg.Any<CancellationToken>()))
+            .Do(ci => added = ci.Arg<TemplateAlarm>());
+        _services.AddScoped<TemplateService>();
+
+        var actor = CreateActor();
+        var envelope = Envelope(
+            new AddTemplateAlarmCommand(1, "HighTemp", "HiLo", 500, null, null, false, IsMesReportable: true),
+            "Designer");
+
+        actor.Tell(envelope);
+
+        ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+        Assert.NotNull(added);
+        Assert.True(added!.IsMesReportable);
+    }
+
+    [Fact]
+    public void UpdateTemplateAlarm_CarriesIsMesReportable()
+    {
+        var template = new Template("T1") { Id = 1 };
+        var existing = new TemplateAlarm("HighTemp")
+        {
+            Id = 5,
+            TemplateId = 1,
+            TriggerType = AlarmTriggerType.HiLo,
+            PriorityLevel = 100,
+            IsMesReportable = false
+        };
+        _templateRepo.GetTemplateAlarmByIdAsync(5, Arg.Any<CancellationToken>()).Returns(existing);
+        _templateRepo.GetTemplateByIdAsync(1, Arg.Any<CancellationToken>()).Returns(template);
+        _templateRepo.GetAllTemplatesAsync(Arg.Any<CancellationToken>())
+            .Returns(new List<Template> { template });
+
+        TemplateAlarm? updated = null;
+        _templateRepo
+            .When(r => r.UpdateTemplateAlarmAsync(Arg.Any<TemplateAlarm>(), Arg.Any<CancellationToken>()))
+            .Do(ci => updated = ci.Arg<TemplateAlarm>());
+        _services.AddScoped<TemplateService>();
+
+        var actor = CreateActor();
+        var envelope = Envelope(
+            new UpdateTemplateAlarmCommand(5, "HighTemp", "HiLo", 500, null, null, false, IsMesReportable: true),
+            "Designer");
+
+        actor.Tell(envelope);
+
+        ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+        Assert.NotNull(updated);
+        Assert.True(updated!.IsMesReportable);
+    }
+
+    [Fact]
+    public void SetInstanceAlarmOverride_PassesIsMesReportableOverride()
+    {
+        // false is the interesting case: it is distinct from the null "inherit"
+        // default, so a dropped argument would read as "inherit" rather than
+        // "explicitly not reportable".
+        var template = new Template("T1") { Id = 1 };
+        template.Alarms.Add(new TemplateAlarm("HighTemp")
+        {
+            Id = 5,
+            TemplateId = 1,
+            TriggerType = AlarmTriggerType.HiLo,
+            PriorityLevel = 100
+        });
+        var instance = new Instance("Inst1") { Id = 10, TemplateId = 1, SiteId = 1 };
+
+        _templateRepo.GetInstanceByIdAsync(10, Arg.Any<CancellationToken>()).Returns(instance);
+        _templateRepo.GetAllTemplatesAsync(Arg.Any<CancellationToken>())
+            .Returns(new List<Template> { template });
+        _templateRepo.GetAlarmOverrideAsync(10, "HighTemp", Arg.Any<CancellationToken>())
+            .Returns((InstanceAlarmOverride?)null);
+
+        InstanceAlarmOverride? persisted = null;
+        _templateRepo
+            .When(r => r.AddInstanceAlarmOverrideAsync(Arg.Any<InstanceAlarmOverride>(), Arg.Any<CancellationToken>()))
+            .Do(ci => persisted = ci.Arg<InstanceAlarmOverride>());
+
+        var actor = CreateActor();
+        var envelope = Envelope(
+            new SetInstanceAlarmOverrideCommand(10, "HighTemp", null, null, IsMesReportableOverride: false),
+            "Deployer");
+
+        actor.Tell(envelope);
+
+        ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+        Assert.NotNull(persisted);
+        Assert.False(persisted!.IsMesReportableOverride);
+    }
+
     [Fact]
     public void UpdateAttribute_ValidScalar_PersistsValueAndKeepsFixedFields()
     {