async def file_reader(file_path: str) -> str:
    """读取本地文件的内容。

    Args:
        file_path: 文件的绝对路径或相对路径

    Returns:
        文件内容文本，若文件不存在则返回错误信息
    """
    from kilostar.utils.sandbox import validate_path, PathViolation

    try:
        file_path = validate_path(file_path, write=False)
    except PathViolation as e:
        return f"[Sandbox] {e}"

    try:
        with open(file_path, "r", encoding="utf-8") as f:
            return f.read()
    except FileNotFoundError:
        return f"[Error] File not found: {file_path}"
    except Exception as e:
        return f"[Error] Failed to read file: {str(e)}"