Add reasoning parameter to ModelSettings

src/agents/model_settings.py

@@ -40,6 +40,12 @@ class ModelSettings:
     max_tokens: int | None = None
     """The maximum number of output tokens to generate."""
 
+    reasoning: dict[str, str] | None = None
+    """Controls reasoning behavior for reasoning-capable models.
+    For o-series models: Use 'effort' key with values 'low', 'medium', or 'high' to control
+    reasoning effort. For computer_use_preview: Use 'generate_summary' key with values
+    'concise' or 'detailed' to get reasoning summaries."""
+
     store: bool | None = None
     """Whether to store the generated model response for later retrieval.
     Defaults to True if not provided."""

src/agents/models/openai_chatcompletions.py

@@ -536,6 +536,7 @@ async def _fetch_response(
             stream=stream,
             stream_options={"include_usage": True} if stream else NOT_GIVEN,
             store=store,
+            reasoning=self._non_null_or_not_given(model_settings.reasoning),
             extra_headers=_HEADERS,
         )
 
@@ -555,6 +556,7 @@ async def _fetch_response(
             temperature=model_settings.temperature,
             tools=[],
             parallel_tool_calls=parallel_tool_calls or False,
+            reasoning=model_settings.reasoning,
         )
         return response, ret
 

src/agents/models/openai_responses.py

@@ -247,6 +247,7 @@ async def _fetch_response(
             extra_headers=_HEADERS,
             text=response_format,
             store=self._non_null_or_not_given(model_settings.store),
+            reasoning=self._non_null_or_not_given(model_settings.reasoning),
         )
 
     def _get_client(self) -> AsyncOpenAI: