Rollback and remediation examples

Example 1: First-proof threshold breach on main

Signal - build/first-proof/weekly-threshold-check.json reports breach: true - owner escalation payload routes to release-ops

Immediate response 1. Freeze further merges to main until triage owner acknowledges. 2. Run make first-proof-verify on latest passing baseline commit and failing head commit. 3. Compare first-proof-summary.json and weekly-trend.json to isolate failing steps.

Rollback 1. Revert the highest-risk change set linked to first failing step. 2. Re-run make first-proof-verify. 3. Confirm threshold returns to non-breach state before reopening merges.

Example 2: Dependency radar threshold breach (critical > 0)

Signal - docs/artifacts/phase3-dependency-radar-*.json shows threshold_check.breach: true

Immediate response 1. Open weekly drift issue from template. 2. Assign package owners from priority queue. 3. Stage targeted upgrades in a remediation branch.

Rollback 1. If upgrades regress CI, revert only the failing package bump. 2. Pin to last compatible version in constraints/requirements. 3. Keep remaining safe upgrades and rerun radar + first-proof lanes.