on_tool_start() — langchain Function Reference

Architecture documentation for the on_tool_start() function in streaming_stdout.py from the langchain codebase.

Function python Observability TelemetryUtilities

Entity Profile

Observability→ TelemetryUtilities→ on_tool_start() — langchain Function Reference

Dependency Diagram

graph TD
  15dec698_fe33_871b_57a9_98f607e8da20["on_tool_start()"]
  6b65bf57_0fa9_b411_5886_294d6dbe5842["StreamingStdOutCallbackHandler"]
  15dec698_fe33_871b_57a9_98f607e8da20 -->|defined in| 6b65bf57_0fa9_b411_5886_294d6dbe5842
  style 15dec698_fe33_871b_57a9_98f607e8da20 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/callbacks/streaming_stdout.py lines 103–112

    def on_tool_start(
        self, serialized: dict[str, Any], input_str: str, **kwargs: Any
    ) -> None:
        """Run when the tool starts running.

        Args:
            serialized: The serialized tool.
            input_str: The input string.
            **kwargs: Additional keyword arguments.
        """