Method from_config

src/google/adk/tools/base_tool.py:162–238

Creates a tool instance from a config. This default implementation uses inspect to automatically map config values to constructor arguments based on their type hints. Subclasses should override this method for custom initialization logic. Args: config: The config for the tool

(
      cls: Type[SelfTool], config: ToolArgsConfig, config_abs_path: str
  )

  @classmethod
  def from_config(
      cls: Type[SelfTool], config: ToolArgsConfig, config_abs_path: str
  ) -> SelfTool:
    """Creates a tool instance from a config.

    This default implementation uses inspect to automatically map config values
    to constructor arguments based on their type hints. Subclasses should
    override this method for custom initialization logic.

    Args:
      config: The config for the tool.
      config_abs_path: The absolute path to the config file that contains the
        tool config.

    Returns:
      The tool instance.
    """
    from ..agents import config_agent_utils

    # Get the constructor signature and resolve type hints
    sig = inspect.signature(cls.__init__)
    type_hints = get_type_hints(cls.__init__)
    config_dict = config.model_dump()
    kwargs = {}

    # Iterate through constructor parameters (skip "self")
    for param_name, _ in sig.parameters.items():
      if param_name == "self":
        continue
      param_type = type_hints.get(param_name)

      if param_name in config_dict:
        value = config_dict[param_name]

        # Get the actual type T of the parameter if it's Optional[T]
        if get_origin(param_type) is Union:
          # This is Optional[T] which is Union[T, None]
          args = get_args(param_type)
          if len(args) == 2 and type(None) in args:
            # Get the non-None type
            actual_type = args[0] if args[1] is type(None) else args[1]
            param_type = actual_type

        if param_type in (int, str, bool, float):
          kwargs[param_name] = value
        elif (
            inspect.isclass(param_type)
            and issubclass(param_type, BaseModel)
            and value is not None
        ):
          kwargs[param_name] = param_type.model_validate(value)
        elif param_type is Callable or get_origin(param_type) is Callable:
          kwargs[param_name] = config_agent_utils.resolve_fully_qualified_name(
              value
          )
        elif param_type in (list, set, dict):
          kwargs[param_name] = param_type(value)
        elif get_origin(param_type) is list: