@@ -19,6 +19,7 @@
 import sys
 import typing
 from typing import Optional, assert_never
+import warnings
 import PIL.Image
 import pydantic
 import pytest
@@ -1095,7 +1096,6 @@ def func_under_test(
   assert actual_schema_mldev == expected_schema
 
 
-
 @pytest.mark.skip(
     reason=(
         'AFC is in progress of refactoring, this test is failing python 3.14'
@@ -2768,6 +2768,28 @@ def test_unknown_enum_value_in_nested_dict():
   assert schema.category.value == 'NEW_CATEGORY'
 
 
+def test_finish_reason_malformed_response():
+  """MALFORMED_RESPONSE from the API parses into a real member, unwarned."""
+  with warnings.catch_warnings(record=True) as caught:
+    warnings.simplefilter('always')
+    response = types.GenerateContentResponse._from_response(
+        response={'candidates': [{'finish_reason': 'MALFORMED_RESPONSE'}]},
+        kwargs={},
+    )
+  assert not [w for w in caught if 'is not a valid' in str(w.message)]
+  assert 'MALFORMED_RESPONSE' in types.FinishReason.__members__
+  assert response.candidates[0].finish_reason in list(types.FinishReason)
+
+
+def test_finish_reason_malformed_response_case_insensitive():
+  """A lowercase value resolves to the same member without a warning."""
+  with warnings.catch_warnings(record=True) as caught:
+    warnings.simplefilter('always')
+    reason = types.FinishReason('malformed_response')
+  assert not [w for w in caught if 'is not a valid' in str(w.message)]
+  assert reason is types.FinishReason.MALFORMED_RESPONSE
+
+
 # Tests that TypedDict types from types.py are compatible with pydantic
 # pydantic requires TypedDict from typing_extensions for Python <3.12
 def test_typed_dict_pydantic_field():
@@ -2969,4 +2991,3 @@ def test_computer_use_types():
   assert c.enable_prompt_injection_detection is True
   assert len(c.disabled_safety_policies) == 2
   assert types.SafetyPolicy.FINANCIAL_TRANSACTIONS in c.disabled_safety_policies
-
 
@@ -558,6 +558,8 @@ class FinishReason(_common.CaseInSensitiveEnum):
   """Image generation stopped for a reason not otherwise specified."""
   CONTINUATION = 'CONTINUATION'
   """Token generation stopped because the response reached the per-request token limit, but generation is not yet complete. The response can be continued by passing the returned `continuation_token` in a subsequent request."""
+  MALFORMED_RESPONSE = 'MALFORMED_RESPONSE'
+  """Token generation stopped because the response was malformed."""
 
 
 class HarmProbability(_common.CaseInSensitiveEnum):