diff --git a/src/machinelearningservices/azext_mlv2/manual/custom/deployment_template.py b/src/machinelearningservices/azext_mlv2/manual/custom/deployment_template.py
index df8befc614a..103af1030b7 100644
--- a/src/machinelearningservices/azext_mlv2/manual/custom/deployment_template.py
+++ b/src/machinelearningservices/azext_mlv2/manual/custom/deployment_template.py
@@ -144,13 +144,25 @@ def _ml_deployment_template_update(
     )
 
     try:
-        deployment_template = ml_client.deployment_templates.get(name=parameters["name"], version=parameters["version"])
-
-        # Only update optional fields if they are explicitly present in parameters
+        deployment_template = ml_client.deployment_templates.get(
+            name=parameters["name"], version=parameters["version"]
+        )
+
+        # Detect if user tried to update immutable fields
+        original = deployment_template._to_dict()  # pylint: disable=protected-access
+        mutable_fields = {"tags", "description"}
+        for key, value in parameters.items():
+            if key not in mutable_fields and key in original and original[key] != value:
+                raise ValueError(
+                    f"Field '{key}' is immutable and cannot be updated. "
+                    "Only 'tags' and 'description' can be modified."
+                )
+
+        # Apply mutable field changes
         if "description" in parameters:
-            deployment_template.description = parameters.get("description")
+            deployment_template.description = parameters["description"]
         if "tags" in parameters:
-            deployment_template.tags = parameters.get("tags")
+            deployment_template.tags = parameters["tags"]
 
         deployment_template_result = ml_client.deployment_templates.create_or_update(deployment_template)
 
diff --git a/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_04_deployment_template_update.yaml b/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_04_deployment_template_update.yaml
index 4d20566deda..9ef4089b949 100644
--- a/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_04_deployment_template_update.yaml
+++ b/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_04_deployment_template_update.yaml
@@ -325,7 +325,7 @@ interactions:
   response:
     body:
       string: '{"type": "deploymenttemplates", "name": "test-deployment-template",
-        "stage": "Archived", "version": "1", "description": "Updated_description_for_deployment_template_testing",
+        "stage": "Development", "version": "1", "description": "Updated_description_for_deployment_template_testing",
         "createdBy": {"userObjectId": "e7ae4769-61f9-4372-8392-79c1757a70b0", "userTenantId":
         "72f988bf-86f1-41af-91ab-2d7cd011db47", "userName": "Kshitij Chawla"}, "capabilities":
         [], "createdTime": "2025-11-07T07:25:14.9461737+00:00", "modifiedTime": "2025-11-07T16:40:14.7312037+00:00",
@@ -443,7 +443,7 @@ interactions:
       code: 200
       message: OK
 - request:
-    body: '{"stage": "Archived", "description": "Updated_description_for_deployment_template_testing",
+    body: '{"stage": "Development", "description": "Updated_description_for_deployment_template_testing",
       "tags": {"stage": "Open", "environment": "test", "updated": "True"}, "deploymentTemplateType":
       "Managed", "environmentId": "azureml://registries/kchawla-reg/environments/kchawla-environment/versions/1",
       "environmentVariables": {"MODEL_BASE_PATH": "/var/azureml-app/azureml-models/tfs-model1/1",
diff --git a/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_10_deployment_template_update_multiple_tags.yaml b/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_10_deployment_template_update_multiple_tags.yaml
index 671a6c8eaed..9a17c5a70bd 100644
--- a/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_10_deployment_template_update_multiple_tags.yaml
+++ b/src/machinelearningservices/azext_mlv2/tests/latest/recordings/test_10_deployment_template_update_multiple_tags.yaml
@@ -325,7 +325,7 @@ interactions:
   response:
     body:
       string: '{"type": "deploymenttemplates", "name": "test-deployment-template",
-        "stage": "Archived", "version": "1", "description": "Updated_description_for_deployment_template_testing",
+        "stage": "Development", "version": "1", "description": "Updated_description_for_deployment_template_testing",
         "createdBy": {"userObjectId": "e7ae4769-61f9-4372-8392-79c1757a70b0", "userTenantId":
         "72f988bf-86f1-41af-91ab-2d7cd011db47", "userName": "Kshitij Chawla"}, "capabilities":
         [], "createdTime": "2025-11-07T07:25:14.9461737+00:00", "modifiedTime": "2025-11-07T16:40:14.7312037+00:00",
@@ -443,7 +443,7 @@ interactions:
       code: 200
       message: OK
 - request:
-    body: '{"stage": "Archived", "description": "Updated_description_for_deployment_template_testing",
+    body: '{"stage": "Development", "description": "Updated_description_for_deployment_template_testing",
       "tags": {"stage": "Open", "environment": "test", "updated": "True", "author":
       "test-automation", "project": "cli-testing", "iteration": "second-update", "validated":
       "True"}, "deploymentTemplateType": "Managed", "environmentId": "azureml://registries/kchawla-reg/environments/kchawla-environment/versions/1",