—
| value | 必需 evidence | 禁止携带 |
|---|---|---|
recorded | event_id / source / retrieved_at | query 错误 |
not_recorded | source / answer / answered_at | query_failed / undetermined 的字段 |
query_failed | error / attempted_at | answer（会像 not_recorded） |
cross_federation_unsynchronised | local_source / local_answer / route.unsynced_path | recorded 证据 |
undetermined | attempted | event_id（recorded 证据） |
不变量：无记录 ≠ 已撤销 ≠ 查询失败；undetermined 不得回落为 recorded。