Get pydantic serializer warnings in calling Runner.run

[qianxiaoming]

Sometimes in Runner.run get this warning in console:

lib/python3.11/site-packages/pydantic/main.py:463: UserWarning: Pydantic serializer warnings:
  PydanticSerializationUnexpectedValue(Expected 9 fields but got 6: Expected `Message` - serialized value may not be as expected [input_value=Message(content='\n\n生...务执行Agent。\n'}), input_type=Message])
  PydanticSerializationUnexpectedValue(Expected `StreamingChoices` - serialized value may not be as expected [input_value=Choices(finish_reason='st...ider_specific_fields={}), input_type=Choices])
  return self.__pydantic_serializer__.to_python(

Debug information

• Agents SDK version: v0.0.17
• Python 3.11
• pydantic 2.11.7

Input for Runner.run

• str
• [{"role": "user", "content": "What state is it in?"}]

LLM Model

• deepseek/deepseek-chat
• volcengine/doubao-1-5-thinking-pro-250415

[damien-king]

+1 I'm getting this in run_streamed on version 0.0.18 with python version 3.11.7:

/.pyenv/versions/flowgentic/lib/python3.11/site-packages/pydantic/main.py:463: UserWarning: Pydantic serializer warnings: PydanticSerializationUnexpectedValue(Expected 9 fields but got 5: Expected Message- serialized value may not be as expected [input_value=Message(content="Let me a...er_specific_fields=None), input_type=Message]) PydanticSerializationUnexpectedValue(ExpectedStreamingChoices - serialized value may not be as expected [input_value=Choices(finish_reason='st...r_specific_fields=None)), input_type=Choices]) return self.__pydantic_serializer__.to_python(

Have tried o4-mini-high through openrouter and bedrock with Sonnet 4 both through the litellm adapter.

Maybe related: BerriAI/litellm#11759

[OnlyC]

getting same warning for gemini

[seratch]

may be related to #772