_get_schema_from_runnable_and_arg_types() — langchain Function Reference

Source Code

libs/core/langchain_core/tools/convert.py lines 399–416

def _get_schema_from_runnable_and_arg_types(
    runnable: Runnable,
    name: str,
    arg_types: dict[str, type] | None = None,
) -> type[BaseModel]:
    """Infer `args_schema` for tool."""
    if arg_types is None:
        try:
            arg_types = get_type_hints(runnable.InputType)
        except TypeError as e:
            msg = (
                "Tool input must be str or dict. If dict, dict arguments must be "
                "typed. Either annotate types (e.g., with TypedDict) or pass "
                f"arg_types into `.as_tool` to specify. {e}"
            )
            raise TypeError(msg) from e
    fields = {key: (key_type, Field(...)) for key, key_type in arg_types.items()}
    return cast("type[BaseModel]", create_model(name, **fields))  # type: ignore[call-overload]