medium85%
Pydantic serializer warnings when streaming with structured output due to invalid parsed field on AIMessageChunk
When using ChatOpenAI with with_structured_output and streaming=True, LangChain emits a UserWarning from Pydantic during serialization of an AIMessageChunk. The warning indicates that the 'parsed' field contains a BaseModel instance while the field type expects None. The output is still produced correctly, but the warning pollutes logs and indicates a type mismatch in the streaming path.