{
    "error": "请提供参数",
    "usage": {
        "单个域名": "?domain=example.com",
        "所有域名": "?action=all",
        "分页列表": "?action=list&page=1&per_page=20",
        "删除域名": "?action=delete (POST: id=123 或 domain=example.com)"
    }
}