Breaking Change Recovery

Breaking-Change Recovery Skill

Reference: instructions/breaking-change-recovery.instructions.md

When to invoke

• Any role detects a P0/P1 runtime or schema breakage after a merge.
• Consultant Tier-3 escalation hands off to this skill.

Quick-start

1. Identify the breaking commit SHA and causal issue number.
2. Post INCIDENT_OPEN on the causal issue with severity + blocked teams.
3. Revert with git revert <sha> --no-edit — merge immediately.
4. File triage ticket: fix: [regression description] with type:bug.
5. Fix on branch fix/<triage-ticket#>-<slug>; add regression test.
6. Post SMOKE_EVIDENCE before re-merge.
7. Re-author casualties: close original (resolution:superseded), refile.

Smoke evidence block template

## SMOKE_EVIDENCE
fix_pr: #N
breaking_sha: <sha>
- [x] runtime starts without error
- [x] regression test passes
- [ ] governance hook fires correctly (schema/hook fixes)
- [ ] affected team confirms unblocked (P0 only)

Signed-by: <alias>
Team&Model: <team>:<model>@<substrate>
Role: admin

Worked example

Chain: #1917 (cause) → #1951 (triage) → #1952 / c857ce8 (fix) → #1953 (casualty closed) → #1954 (casualty refiled).

See full narrative in instructions/breaking-change-recovery.instructions.md Phase 6 "Worked Example" section.

Escalation path

If the fix cannot be completed within one session, the Manager must post a BLOCKER_NOTE on the triage ticket and elevate severity to P0.