on_chat_model_start() — langchain Function Reference

Architecture documentation for the on_chat_model_start() function in test_fake_chat_model.py from the langchain codebase.

Function python LangChainCore LanguageModelBase called by 1

Entity Profile

LangChainCore→ LanguageModelBase→ on_chat_model_start() — langchain Function Reference

Dependency Diagram

graph TD
  7a27e13a_f632_f712_1db5_4d6fd6f822f2["on_chat_model_start()"]
  5f53f77b_adda_976c_2a8f_56c041df7972["MyCustomAsyncHandler"]
  7a27e13a_f632_f712_1db5_4d6fd6f822f2 -->|defined in| 5f53f77b_adda_976c_2a8f_56c041df7972
  af4e520f_33c0_5b8c_7bf9_9b0dd5cb04b9["test_callback_handlers()"]
  af4e520f_33c0_5b8c_7bf9_9b0dd5cb04b9 -->|calls| 7a27e13a_f632_f712_1db5_4d6fd6f822f2
  style 7a27e13a_f632_f712_1db5_4d6fd6f822f2 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain/tests/unit_tests/llms/test_fake_chat_model.py lines 158–171

        async def on_chat_model_start(
            self,
            serialized: dict[str, Any],
            messages: list[list[BaseMessage]],
            *,
            run_id: UUID,
            parent_run_id: UUID | None = None,
            tags: list[str] | None = None,
            metadata: dict[str, Any] | None = None,
            **kwargs: Any,
        ) -> Any:
            # Do nothing
            # Required to implement since this is an abstract method
            pass