[
  {
    "code": "sys.cancelled",
    "http": 499,
    "severity": "info",
    "retry": "never",
    "side_effects": "possible",
    "summary": "操作已取消",
    "hint": "不要把取消当成成功或普通失败；需要时由调用方重新发起"
  },
  {
    "code": "sys.conflict",
    "http": 409,
    "severity": "warn",
    "retry": "never",
    "side_effects": "possible",
    "summary": "状态冲突",
    "hint": "刷新当前状态后再决定是否重试，不要盲目重放"
  },
  {
    "code": "sys.internal",
    "http": 500,
    "severity": "error",
    "retry": "never",
    "side_effects": "unknown",
    "summary": "内部错误",
    "hint": "保留 trace_id，按错误日志定位，不要对调用方暴露内部细节"
  },
  {
    "code": "sys.invalid_argument",
    "http": 400,
    "severity": "warn",
    "retry": "never",
    "side_effects": "none",
    "summary": "参数不合法",
    "hint": "检查请求字段与类型，修正后重新提交"
  },
  {
    "code": "sys.not_found",
    "http": 404,
    "severity": "info",
    "retry": "never",
    "side_effects": "none",
    "summary": "资源不存在",
    "hint": "确认标识是否正确，或资源是否已删除"
  },
  {
    "code": "sys.rate_limited",
    "http": 429,
    "severity": "warn",
    "retry": "transient",
    "side_effects": "none",
    "summary": "触发限流",
    "hint": "按退避重试，不要立即打满重试"
  },
  {
    "code": "sys.timeout",
    "http": 504,
    "severity": "error",
    "retry": "transient",
    "side_effects": "possible",
    "summary": "操作超时",
    "hint": "先确认是否已产生副作用，再做有界重试"
  },
  {
    "code": "sys.unauthorized",
    "http": 401,
    "severity": "warn",
    "retry": "never",
    "side_effects": "none",
    "summary": "未授权",
    "hint": "检查凭证是否缺失、过期或与资源不匹配"
  },
  {
    "code": "sys.unavailable",
    "http": 503,
    "severity": "error",
    "retry": "transient",
    "side_effects": "none",
    "summary": "依赖不可用",
    "hint": "确认依赖健康后退避重试"
  },
  {
    "code": "sys.unknown_code",
    "http": 500,
    "severity": "error",
    "retry": "never",
    "side_effects": "unknown",
    "summary": "未登记的错误码",
    "hint": "按失败处理（fail-closed），并把该码补登记后再放行"
  }
]