on_chat_model_start() — langchain Function Reference

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

Function python LangChainCore LanguageModelBase calls 1

Entity Profile

LangChainCore→ LanguageModelBase→ on_chat_model_start() — langchain Function Reference

Dependency Diagram

graph TD
  414ea979_e52b_c5c6_9d19_a726ab06229d["on_chat_model_start()"]
  9758c14a_d917_d7d4_3cca_2845f9175ec6["FakeCallbackHandlerWithChatStart"]
  414ea979_e52b_c5c6_9d19_a726ab06229d -->|defined in| 9758c14a_d917_d7d4_3cca_2845f9175ec6
  18d8ec02_b9a0_5b8f_68d7_f00aaf1bb50f["on_chat_model_start_common()"]
  414ea979_e52b_c5c6_9d19_a726ab06229d -->|calls| 18d8ec02_b9a0_5b8f_68d7_f00aaf1bb50f
  style 414ea979_e52b_c5c6_9d19_a726ab06229d fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/tests/unit_tests/fake/callbacks.py lines 285–295

    def on_chat_model_start(
        self,
        serialized: dict[str, Any],
        messages: list[list[BaseMessage]],
        *,
        run_id: UUID,
        parent_run_id: UUID | None = None,
        **kwargs: Any,
    ) -> Any:
        assert all(isinstance(m, BaseMessage) for m in chain(*messages))
        self.on_chat_model_start_common()