diff --git a/google/genai/tests/shared/tunings/test_list.py b/google/genai/tests/shared/tunings/test_list.py
index 3ab10a273..8e040f810 100644
--- a/google/genai/tests/shared/tunings/test_list.py
+++ b/google/genai/tests/shared/tunings/test_list.py
@@ -26,6 +26,7 @@
         parameters=genai_types._ListTuningJobsParameters(
             config=genai_types.ListTuningJobsConfig(page_size=1)
         ),
+        exception_if_mldev='only supported in'
     ),
 ]
 
diff --git a/google/genai/tests/tunings/test_list.py b/google/genai/tests/tunings/test_list.py
index cabc273a6..ea6502b08 100644
--- a/google/genai/tests/tunings/test_list.py
+++ b/google/genai/tests/tunings/test_list.py
@@ -26,12 +26,14 @@
     pytest_helper.TestTableItem(
         name='test_default',
         parameters=genai_types._ListTuningJobsParameters(),
+        exception_if_mldev='only supported in',
     ),
     pytest_helper.TestTableItem(
         name='test_with_config',
         parameters=genai_types._ListTuningJobsParameters(
             config=genai_types.ListTuningJobsConfig(page_size=2)
         ),
+        exception_if_mldev='only supported in',
     ),
 ]
 
@@ -46,6 +48,9 @@
 
 
 def test_pager(client):
+  if not client._api_client.vertexai:
+    return
+
   tuning_jobs = client.tunings.list(config={'page_size': 2})
   assert 'content-type' in tuning_jobs.sdk_http_response.headers
   assert tuning_jobs.name == 'tuning_jobs'
@@ -61,6 +66,9 @@ def test_pager(client):
 
 @pytest.mark.asyncio
 async def test_async_pager(client):
+  if not client._api_client.vertexai:
+    return
+
   tuning_jobs = await client.aio.tunings.list(config={'page_size': 2})
 
   assert 'Content-Type' in tuning_jobs.sdk_http_response.headers
diff --git a/google/genai/tunings.py b/google/genai/tunings.py
index 9b53b49b8..7883f00f0 100644
--- a/google/genai/tunings.py
+++ b/google/genai/tunings.py
@@ -907,31 +907,6 @@ def _GetTuningJobParameters_to_vertex(
   return to_object
 
 
-def _ListTuningJobsConfig_to_mldev(
-    from_object: Union[dict[str, Any], object],
-    parent_object: Optional[dict[str, Any]] = None,
-    root_object: Optional[Union[dict[str, Any], object]] = None,
-) -> dict[str, Any]:
-  to_object: dict[str, Any] = {}
-
-  if getv(from_object, ['page_size']) is not None:
-    setv(
-        parent_object, ['_query', 'pageSize'], getv(from_object, ['page_size'])
-    )
-
-  if getv(from_object, ['page_token']) is not None:
-    setv(
-        parent_object,
-        ['_query', 'pageToken'],
-        getv(from_object, ['page_token']),
-    )
-
-  if getv(from_object, ['filter']) is not None:
-    setv(parent_object, ['_query', 'filter'], getv(from_object, ['filter']))
-
-  return to_object
-
-
 def _ListTuningJobsConfig_to_vertex(
     from_object: Union[dict[str, Any], object],
     parent_object: Optional[dict[str, Any]] = None,
@@ -957,20 +932,6 @@ def _ListTuningJobsConfig_to_vertex(
   return to_object
 
 
-def _ListTuningJobsParameters_to_mldev(
-    from_object: Union[dict[str, Any], object],
-    parent_object: Optional[dict[str, Any]] = None,
-    root_object: Optional[Union[dict[str, Any], object]] = None,
-) -> dict[str, Any]:
-  to_object: dict[str, Any] = {}
-  if getv(from_object, ['config']) is not None:
-    _ListTuningJobsConfig_to_mldev(
-        getv(from_object, ['config']), to_object, root_object
-    )
-
-  return to_object
-
-
 def _ListTuningJobsParameters_to_vertex(
     from_object: Union[dict[str, Any], object],
     parent_object: Optional[dict[str, Any]] = None,
@@ -985,33 +946,6 @@ def _ListTuningJobsParameters_to_vertex(
   return to_object
 
 
-def _ListTuningJobsResponse_from_mldev(
-    from_object: Union[dict[str, Any], object],
-    parent_object: Optional[dict[str, Any]] = None,
-    root_object: Optional[Union[dict[str, Any], object]] = None,
-) -> dict[str, Any]:
-  to_object: dict[str, Any] = {}
-  if getv(from_object, ['sdkHttpResponse']) is not None:
-    setv(
-        to_object, ['sdk_http_response'], getv(from_object, ['sdkHttpResponse'])
-    )
-
-  if getv(from_object, ['nextPageToken']) is not None:
-    setv(to_object, ['next_page_token'], getv(from_object, ['nextPageToken']))
-
-  if getv(from_object, ['tunedModels']) is not None:
-    setv(
-        to_object,
-        ['tuning_jobs'],
-        [
-            _TuningJob_from_mldev(item, to_object, root_object)
-            for item in getv(from_object, ['tunedModels'])
-        ],
-    )
-
-  return to_object
-
-
 def _ListTuningJobsResponse_from_vertex(
     from_object: Union[dict[str, Any], object],
     parent_object: Optional[dict[str, Any]] = None,
@@ -1632,8 +1566,9 @@ def _list(
     )
 
     request_url_dict: Optional[dict[str, str]]
-
-    if self._api_client.vertexai:
+    if not self._api_client.vertexai:
+      raise ValueError('This method is only supported in the Vertex AI client.')
+    else:
       request_dict = _ListTuningJobsParameters_to_vertex(
           parameter_model, None, parameter_model
       )
@@ -1642,15 +1577,7 @@ def _list(
         path = 'tuningJobs'.format_map(request_url_dict)
       else:
         path = 'tuningJobs'
-    else:
-      request_dict = _ListTuningJobsParameters_to_mldev(
-          parameter_model, None, parameter_model
-      )
-      request_url_dict = request_dict.get('_url')
-      if request_url_dict:
-        path = 'tunedModels'.format_map(request_url_dict)
-      else:
-        path = 'tunedModels'
+
     query_params = request_dict.get('_query')
     if query_params:
       path = f'{path}?{urlencode(query_params)}'
@@ -1676,11 +1603,6 @@ def _list(
           response_dict, None, parameter_model
       )
 
-    if not self._api_client.vertexai:
-      response_dict = _ListTuningJobsResponse_from_mldev(
-          response_dict, None, parameter_model
-      )
-
     return_value = types.ListTuningJobsResponse._from_response(
         response=response_dict,
         kwargs={
@@ -2215,8 +2137,9 @@ async def _list(
     )
 
     request_url_dict: Optional[dict[str, str]]
-
-    if self._api_client.vertexai:
+    if not self._api_client.vertexai:
+      raise ValueError('This method is only supported in the Vertex AI client.')
+    else:
       request_dict = _ListTuningJobsParameters_to_vertex(
           parameter_model, None, parameter_model
       )
@@ -2225,15 +2148,7 @@ async def _list(
         path = 'tuningJobs'.format_map(request_url_dict)
       else:
         path = 'tuningJobs'
-    else:
-      request_dict = _ListTuningJobsParameters_to_mldev(
-          parameter_model, None, parameter_model
-      )
-      request_url_dict = request_dict.get('_url')
-      if request_url_dict:
-        path = 'tunedModels'.format_map(request_url_dict)
-      else:
-        path = 'tunedModels'
+
     query_params = request_dict.get('_query')
     if query_params:
       path = f'{path}?{urlencode(query_params)}'
@@ -2261,11 +2176,6 @@ async def _list(
           response_dict, None, parameter_model
       )
 
-    if not self._api_client.vertexai:
-      response_dict = _ListTuningJobsResponse_from_mldev(
-          response_dict, None, parameter_model
-      )
-
     return_value = types.ListTuningJobsResponse._from_response(
         response=response_dict,
         kwargs={