Add vendor_id and finish_reason to Gemini/Google model responses (#1800)

Author: davide-andreoli

pydantic_ai_slim/pydantic_ai/messages.py

@@ -589,7 +589,7 @@ class ModelResponse:
     kind: Literal['response'] = 'response'
     """Message type identifier, this is available on all parts as a discriminator."""
 
-    vendor_details: dict[str, Any] | None = field(default=None, repr=False)
+    vendor_details: dict[str, Any] | None = field(default=None)
     """Additional vendor-specific details in a serializable format.
 
     This allows storing selected vendor-specific data that isn't mapped to standard ModelResponse fields.

pydantic_ai_slim/pydantic_ai/models/gemini.py

@@ -259,6 +259,8 @@ async def _make_request(
             yield r
 
     def _process_response(self, response: _GeminiResponse) -> ModelResponse:
+        vendor_details: dict[str, Any] | None = None
+
         if len(response['candidates']) != 1:
             raise UnexpectedModelBehavior('Expected exactly one candidate in Gemini response')  # pragma: no cover
         if 'content' not in response['candidates'][0]:
@@ -269,9 +271,19 @@ def _process_response(self, response: _GeminiResponse) -> ModelResponse:
                     'Content field missing from Gemini response', str(response)
                 )
         parts = response['candidates'][0]['content']['parts']
+        vendor_id = response.get('vendor_id', None)
+        finish_reason = response['candidates'][0].get('finish_reason')
+        if finish_reason:
+            vendor_details = {'finish_reason': finish_reason}
         usage = _metadata_as_usage(response)
         usage.requests = 1
-        return _process_response_from_parts(parts, response.get('model_version', self._model_name), usage)
+        return _process_response_from_parts(
+            parts,
+            response.get('model_version', self._model_name),
+            usage,
+            vendor_id=vendor_id,
+            vendor_details=vendor_details,
+        )
 
     async def _process_streamed_response(self, http_response: HTTPResponse) -> StreamedResponse:
         """Process a streamed response, and prepare a streaming response to return."""
@@ -611,7 +623,11 @@ def _function_call_part_from_call(tool: ToolCallPart) -> _GeminiFunctionCallPart
 
 
 def _process_response_from_parts(
-    parts: Sequence[_GeminiPartUnion], model_name: GeminiModelName, usage: usage.Usage
+    parts: Sequence[_GeminiPartUnion],
+    model_name: GeminiModelName,
+    usage: usage.Usage,
+    vendor_id: str | None,
+    vendor_details: dict[str, Any] | None = None,
 ) -> ModelResponse:
     items: list[ModelResponsePart] = []
     for part in parts:
@@ -623,7 +639,9 @@ def _process_response_from_parts(
             raise UnexpectedModelBehavior(
                 f'Unsupported response from Gemini, expected all parts to be function calls or text, got: {part!r}'
             )
-    return ModelResponse(parts=items, usage=usage, model_name=model_name)
+    return ModelResponse(
+        parts=items, usage=usage, model_name=model_name, vendor_id=vendor_id, vendor_details=vendor_details
+    )
 
 
 class _GeminiFunctionCall(TypedDict):
@@ -735,6 +753,7 @@ class _GeminiResponse(TypedDict):
     usage_metadata: NotRequired[Annotated[_GeminiUsageMetaData, pydantic.Field(alias='usageMetadata')]]
     prompt_feedback: NotRequired[Annotated[_GeminiPromptFeedback, pydantic.Field(alias='promptFeedback')]]
     model_version: NotRequired[Annotated[str, pydantic.Field(alias='modelVersion')]]
+    vendor_id: NotRequired[Annotated[str, pydantic.Field(alias='responseId')]]
 
 
 class _GeminiCandidates(TypedDict):

pydantic_ai_slim/pydantic_ai/models/google.py

@@ -6,7 +6,7 @@
 from contextlib import asynccontextmanager
 from dataclasses import dataclass, field, replace
 from datetime import datetime
-from typing import Literal, Union, cast, overload
+from typing import Any, Literal, Union, cast, overload
 from uuid import uuid4
 
 from typing_extensions import assert_never
@@ -291,9 +291,16 @@ def _process_response(self, response: GenerateContentResponse) -> ModelResponse:
                     'Content field missing from Gemini response', str(response)
                 )  # pragma: no cover
         parts = response.candidates[0].content.parts or []
+        vendor_id = response.response_id or None
+        vendor_details: dict[str, Any] | None = None
+        finish_reason = response.candidates[0].finish_reason
+        if finish_reason:  # pragma: no branch
+            vendor_details = {'finish_reason': finish_reason.value}
         usage = _metadata_as_usage(response)
         usage.requests = 1
-        return _process_response_from_parts(parts, response.model_version or self._model_name, usage)
+        return _process_response_from_parts(
+            parts, response.model_version or self._model_name, usage, vendor_id=vendor_id, vendor_details=vendor_details
+        )
 
     async def _process_streamed_response(self, response: AsyncIterator[GenerateContentResponse]) -> StreamedResponse:
         """Process a streamed response, and prepare a streaming response to return."""
@@ -439,7 +446,13 @@ def _content_model_response(m: ModelResponse) -> ContentDict:
     return ContentDict(role='model', parts=parts)
 
 
-def _process_response_from_parts(parts: list[Part], model_name: GoogleModelName, usage: usage.Usage) -> ModelResponse:
+def _process_response_from_parts(
+    parts: list[Part],
+    model_name: GoogleModelName,
+    usage: usage.Usage,
+    vendor_id: str | None,
+    vendor_details: dict[str, Any] | None = None,
+) -> ModelResponse:
     items: list[ModelResponsePart] = []
     for part in parts:
         if part.text:
@@ -454,7 +467,9 @@ def _process_response_from_parts(parts: list[Part], model_name: GoogleModelName,
             raise UnexpectedModelBehavior(
                 f'Unsupported response from Gemini, expected all parts to be function calls or text, got: {part!r}'
             )
-    return ModelResponse(parts=items, model_name=model_name, usage=usage)
+    return ModelResponse(
+        parts=items, model_name=model_name, usage=usage, vendor_id=vendor_id, vendor_details=vendor_details
+    )
 
 
 def _function_declaration_from_tool(tool: ToolDefinition) -> FunctionDeclarationDict:

tests/models/test_gemini.py

@@ -540,6 +540,7 @@ async def test_text_success(get_gemini_client: GetGeminiClient):
                 usage=Usage(requests=1, request_tokens=1, response_tokens=2, total_tokens=3, details={}),
                 model_name='gemini-1.5-flash-123',
                 timestamp=IsNow(tz=timezone.utc),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )
@@ -555,13 +556,15 @@ async def test_text_success(get_gemini_client: GetGeminiClient):
                 usage=Usage(requests=1, request_tokens=1, response_tokens=2, total_tokens=3, details={}),
                 model_name='gemini-1.5-flash-123',
                 timestamp=IsNow(tz=timezone.utc),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(parts=[UserPromptPart(content='Hello', timestamp=IsNow(tz=timezone.utc))]),
             ModelResponse(
                 parts=[TextPart(content='Hello world')],
                 usage=Usage(requests=1, request_tokens=1, response_tokens=2, total_tokens=3, details={}),
                 model_name='gemini-1.5-flash-123',
                 timestamp=IsNow(tz=timezone.utc),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )
@@ -585,6 +588,7 @@ async def test_request_structured_response(get_gemini_client: GetGeminiClient):
                 usage=Usage(requests=1, request_tokens=1, response_tokens=2, total_tokens=3, details={}),
                 model_name='gemini-1.5-flash-123',
                 timestamp=IsNow(tz=timezone.utc),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(
                 parts=[
@@ -647,6 +651,7 @@ async def get_location(loc_name: str) -> str:
                 usage=Usage(requests=1, request_tokens=1, response_tokens=2, total_tokens=3, details={}),
                 model_name='gemini-1.5-flash-123',
                 timestamp=IsNow(tz=timezone.utc),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(
                 parts=[
@@ -666,6 +671,7 @@ async def get_location(loc_name: str) -> str:
                 usage=Usage(requests=1, request_tokens=1, response_tokens=2, total_tokens=3, details={}),
                 model_name='gemini-1.5-flash-123',
                 timestamp=IsNow(tz=timezone.utc),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(
                 parts=[
@@ -688,6 +694,7 @@ async def get_location(loc_name: str) -> str:
                 usage=Usage(requests=1, request_tokens=1, response_tokens=2, total_tokens=3, details={}),
                 model_name='gemini-1.5-flash-123',
                 timestamp=IsNow(tz=timezone.utc),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )
@@ -1099,6 +1106,7 @@ async def get_image() -> BinaryContent:
                 usage=Usage(requests=1, request_tokens=38, response_tokens=28, total_tokens=427, details={}),
                 model_name='gemini-2.5-pro-preview-03-25',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(
                 parts=[
@@ -1122,6 +1130,7 @@ async def get_image() -> BinaryContent:
                 usage=Usage(requests=1, request_tokens=360, response_tokens=11, total_tokens=572, details={}),
                 model_name='gemini-2.5-pro-preview-03-25',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )
@@ -1244,6 +1253,7 @@ async def test_gemini_model_instructions(allow_model_requests: None, gemini_api_
                 usage=Usage(requests=1, request_tokens=13, response_tokens=8, total_tokens=21, details={}),
                 model_name='gemini-1.5-flash',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )
@@ -1284,3 +1294,18 @@ async def get_temperature(location: dict[str, CurrentLocation]) -> float:  # pra
         assert result.output == snapshot(
             'I need a location dictionary to use the `get_temperature` function.  I cannot provide the temperature in Tokyo without more information.\n'
         )
+
+
+async def test_gemini_no_finish_reason(get_gemini_client: GetGeminiClient):
+    response = gemini_response(
+        _content_model_response(ModelResponse(parts=[TextPart('Hello world')])), finish_reason=None
+    )
+    gemini_client = get_gemini_client(response)
+    m = GeminiModel('gemini-1.5-flash', provider=GoogleGLAProvider(http_client=gemini_client))
+    agent = Agent(m)
+
+    result = await agent.run('Hello World')
+
+    for message in result.all_messages():
+        if isinstance(message, ModelResponse):
+            assert message.vendor_details is None

tests/models/test_google.py

@@ -85,6 +85,7 @@ async def test_google_model(allow_model_requests: None, google_provider: GoogleP
                 usage=Usage(requests=1, request_tokens=7, response_tokens=11, total_tokens=18, details={}),
                 model_name='gemini-1.5-flash',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )
@@ -138,6 +139,7 @@ async def temperature(city: str, date: datetime.date) -> str:
                 usage=Usage(requests=1, request_tokens=101, response_tokens=14, total_tokens=115, details={}),
                 model_name='gemini-1.5-flash',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(
                 parts=[
@@ -157,6 +159,7 @@ async def temperature(city: str, date: datetime.date) -> str:
                 usage=Usage(requests=1, request_tokens=123, response_tokens=21, total_tokens=144, details={}),
                 model_name='gemini-1.5-flash',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(
                 parts=[
@@ -215,6 +218,7 @@ async def get_capital(country: str) -> str:
                 ),
                 model_name='models/gemini-2.5-pro-preview-05-06',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
             ModelRequest(
                 parts=[
@@ -235,6 +239,7 @@ async def get_capital(country: str) -> str:
                 usage=Usage(requests=1, request_tokens=104, response_tokens=18, total_tokens=122, details={}),
                 model_name='models/gemini-2.5-pro-preview-05-06',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )
@@ -491,6 +496,7 @@ def instructions() -> str:
                 usage=Usage(requests=1, request_tokens=13, response_tokens=8, total_tokens=21, details={}),
                 model_name='gemini-2.0-flash',
                 timestamp=IsDatetime(),
+                vendor_details={'finish_reason': 'STOP'},
             ),
         ]
     )