on_chat_model_start

on_chat_model_start(
  self,
  serialized: Dict[str, Any],
  messages: List[List[BaseMessage]],
  *,
  run_id: UUID,
  parent_run_id: Optional[UUID] = None,
  tags: Optional[List[str]] = None,
  metadata: Optional[Dict[str, Any]] = None,
  **kwargs: Any = {}
) -> Any