async def list_artifacts(self) -> list[str]:
    """Lists the filenames of the artifacts attached to the current session."""
    if self._invocation_context.artifact_service is None:
      raise ValueError('Artifact service is not initialized.')
    return await self._invocation_context.artifact_service.list_artifact_keys(
        app_name=self._invocation_context.app_name,
        user_id=self._invocation_context.user_id,
        session_id=self._invocation_context.session.id,
    )
Lists the filenames of the artifacts attached to the current session.
src/google/adk/tools/tool_context.py