_on_chain_start() — langchain Function Reference

Architecture documentation for the _on_chain_start() function in core.py from the langchain codebase.

Function python Observability Tracers

Entity Profile

Observability→ Tracers→ _on_chain_start() — langchain Function Reference

Dependency Diagram

graph TD
  d43e391a_2386_190e_ffbf_9461ecc7774f["_on_chain_start()"]
  70348e44_de0f_ccb4_c06a_8453289ed93e["_TracerCore"]
  d43e391a_2386_190e_ffbf_9461ecc7774f -->|defined in| 70348e44_de0f_ccb4_c06a_8453289ed93e
  style d43e391a_2386_190e_ffbf_9461ecc7774f fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/tracers/core.py lines 617–624

    def _on_chain_start(self, run: Run) -> Coroutine[Any, Any, None] | None:
        """Process the Chain Run upon start.

        Args:
            run: The chain run.
        """
        _ = run
        return None