langchain/callbacks/aim_callback.py/AimCallbackHandler/on_tool_start
class AimCallbackHandler:    def on_tool_start(
        self, serialized: Dict[str, Any], input_str: str, **kwargs: Any
    ) -> None:
        """Run when tool starts running."""
        aim = import_aim()
        self.step += 1
        self.tool_starts += 1
        self.starts += 1

        resp = {"action": "on_tool_start"}
        resp.update(self.get_custom_callback_meta())

        self._run.track(aim.Text(input_str), name="on_tool_start", context=resp)