Python: Honor the requested model in non-streamed Gemini responses

python/packages/gemini/agent_framework_gemini/_chat_client.py

@@ -524,7 +524,7 @@ async def _get_response() -> ChatResponse:
                 raise
             except Exception as ex:
                 raise _wrap_gemini_error(ex) from ex
-            return self._process_generate_response(raw, response_format=validated.get("response_format"))
+            return self._process_generate_response(raw, model=model, response_format=validated.get("response_format"))
 
         return _get_response()
 
@@ -1065,12 +1065,14 @@ def _process_generate_response(
         self,
         response: types.GenerateContentResponse,
         *,
+        model: str | None = None,
         response_format: type[BaseModel] | None = None,
     ) -> ChatResponse:
         """Convert a Gemini generate_content response to a framework ChatResponse.
 
         Args:
             response: The raw ``GenerateContentResponse`` from the Gemini API.
+            model: The model the request was sent to, reported when the response carries no model version.
             response_format: Optional Pydantic model type for structured output parsing.
                 When provided, the response text is parsed into the given model and
                 made available via ``ChatResponse.value``.
@@ -1085,7 +1087,7 @@ def _process_generate_response(
             response_id=None,
             messages=[Message(role="assistant", contents=contents, raw_representation=candidate)],
             usage_details=self._parse_usage(response.usage_metadata),
-            model=response.model_version or self.model,
+            model=response.model_version or model or self.model,
             finish_reason=self._map_finish_reason(
                 candidate.finish_reason.name if candidate and candidate.finish_reason else None
             ),

python/packages/gemini/tests/test_gemini_client.py

@@ -548,6 +548,38 @@ async def test_get_response_model_from_response() -> None:
     assert response.model == "gemini-2.5-pro-002"
 
 
+async def test_get_response_model_falls_back_to_configured_model() -> None:
+    """Falls back to the configured model when the response carries no model_version."""
+    client, mock = _make_gemini_client()
+    raw = _make_response([_make_part(text="Hi")])
+    raw.model_version = None
+    mock.aio.models.generate_content = AsyncMock(return_value=raw)
+
+    response = await client.get_response(messages=[Message(role="user", contents=[Content.from_text("Hi")])])
+
+    assert response.model == "gemini-2.5-flash"
+
+
+@pytest.mark.parametrize("stream", [False, True])
+async def test_get_response_reports_requested_model_on_both_paths(stream: bool) -> None:
+    """Without a model_version, both paths report the model requested in options, not the client default."""
+    client, mock = _make_gemini_client(model="gemini-2.5-flash")
+    raw = _make_response([_make_part(text="Hi")])
+    raw.model_version = None
+    mock.aio.models.generate_content = AsyncMock(return_value=raw)
+    mock.aio.models.generate_content_stream = AsyncMock(return_value=_async_iter([raw]))
+    messages = [Message(role="user", contents=[Content.from_text("Hi")])]
+
+    if stream:
+        response = await client.get_response(
+            messages=messages, options={"model": "gemini-2.5-pro"}, stream=True
+        ).get_final_response()
+    else:
+        response = await client.get_response(messages=messages, options={"model": "gemini-2.5-pro"})
+
+    assert response.model == "gemini-2.5-pro"
+
+
 async def test_get_response_streaming_model_from_chunk() -> None:
     """Populates the update model from the model_version field on each chunk."""
     client, mock = _make_gemini_client()