langchain/tools/file_management/list_dir.py/ListDirectoryTool/_run
class ListDirectoryTool:    def _run(
        self,
        dir_path: str = ".",
        run_manager: Optional[CallbackManagerForToolRun] = None,
    ) -> str:
        try:
            dir_path_ = self.get_relative_path(dir_path)
        except FileValidationError:
            return INVALID_PATH_TEMPLATE.format(arg_name="dir_path", value=dir_path)
        try:
            entries = os.listdir(dir_path_)
            if entries:
                return "\n".join(entries)
            else:
                return f"No files found in directory {dir_path}"
        except Exception as e:
            return "Error: " + str(e)