fix

Author: zkllll2002

src/agents/extensions/models/litellm_model.py

@@ -364,14 +364,18 @@ def convert_message_to_openai(
             provider_specific_fields.get("refusal", None) if provider_specific_fields else None
         )
 
+        reasoning_content = ""
+        if hasattr(message, "reasoning_content") and message.reasoning_content:
+            reasoning_content = message.reasoning_content
+
         return ChatCompletionMessage(
             content=message.content,
             refusal=refusal,
             role="assistant",
             annotations=cls.convert_annotations_to_openai(message),
             audio=message.get("audio", None),  # litellm deletes audio if not present
             tool_calls=tool_calls,
-            reasoning_content=message.reasoning_content,
+            reasoning_content=reasoning_content,
         )
 
     @classmethod

src/agents/models/chatcmpl_converter.py

@@ -207,7 +207,7 @@ def maybe_response_output_message(cls, item: Any) -> ResponseOutputMessageParam
         ):
             return cast(ResponseOutputMessageParam, item)
         return None
-    
+
     @classmethod
     def maybe_reasoning_message(cls, item: Any) -> ResponseReasoningItemParam | None:
         if isinstance(item, dict) and item.get("type") == "reasoning":