# Recent Optimizer effect wording

<!-- auto-oncall-optimization-record
{
  "schemaVersion": "auto-oncall-optimization-record-v1",
  "optimizationId": "recent-optimizer-effect-wording-2026-07-21",
  "problems": [
    {
      "problemId": "recent-optimizer-regression-term-is-ambiguous",
      "summary": "The user-facing Recent Optimizer result uses the term 回归 for a candidate effect decrease, which can be confused with regression testing instead of an observed outcome rollback.",
      "status": "optimized_verified",
      "issueKeys": [],
      "sourceRefs": [],
      "signalTextIncludesAny": ["有回归", "改善、回归并存"],
      "observedThrough": "2026-07-21",
      "effectiveAt": "2026-07-21T06:36:57Z",
      "verifiedAt": "2026-07-21T06:37:31Z",
      "attemptedAction": "Replace the user-facing term 回归 with 回退 while preserving the internal regressions field and checkpoint schema.",
      "evidenceUrl": "https://github.com/tidbcloud/aisupport/pull/405"
    }
  ]
}
-->

- Optimization ID: `recent-optimizer-effect-wording-2026-07-21`
- Owner: auto-oncall-services
- Source type: user terminology correction
- Source reference: Focus #375 attempt 1 result discussion

## Bounded problem

The notification term `回归` is technically correct but ambiguous in Chinese:
it can mean regression testing rather than an observed decrease from baseline.

## Implementation and effective status

- Render `回退` in user-facing Recent Optimizer effect summaries.
- Keep internal `regressions` fields unchanged for checkpoint and API
  compatibility.
- Keep `回归` only for actions such as regression evaluation; use `回退` for
  states, effects, and signals.
- Status: deployed and verified in staging.

## Post-change evidence

- Aisupport PR #414 merged as `b9ae399f232c672c14770c7b41492d38ea1303a3`.
- App-delivery PR #75075 updated the staging Deployment and Recent Optimizer
  CronJob to that image.
- At `2026-07-21T06:37:31Z`, the live staging formatter rendered `无回退` and
  `改善、回退并存`; the result contained neither `回归` nor `效果回退`.

## Validation plan

- Cover partitioned and legacy aggregate notification formats.
- Verify the deployed formatter renders `回退` and no longer renders the
  ambiguous user-facing phrases.

## Unresolved gaps and next action

- Confirm the terminology in the next newly generated Feishu result; no
  duplicate notification was sent during live formatter validation.