flywheel-merge-arbiter

name	flywheel-merge-arbiter
description	Arbitrate multiple candidate PRs for the same issue and merge exactly one winner. Use when running merge-pr workflow or comparing AUTOFIX candidate PRs.
allowed-tools	Read,Grep,Glob,LS,Bash(gh *),Bash(git *)

Flywheel Merge Arbiter

Goal

Choose and merge exactly one best candidate PR per issue after hard gates pass.

Workflow

1. Collect candidate PRs for one issue from title prefix.
2. Hard filters first:
   • non-draft
   • checks green
   • merge state not dirty
3. Compare eligible candidates on:
   • correctness and issue coverage (weight 0.45)
   • regression risk (weight 0.30)
   • complexity and maintainability (weight 0.15)
   • test quality and verification evidence (weight 0.10)
4. Compute weighted total score and rank candidates.
5. Post machine-readable scorecard before merge:
   • Marker line: <!-- arbiter-scorecard -->
   • Next line must be one-line JSON: {"issue":<id>,"winner_pr":<id>,"scores":[...]}
6. Include per-candidate scores for correctness, risk, maintainability, tests, total, verdict, reason.
7. Merge exactly one winner (prefer squash).
8. Comment and close non-winners.
9. If no safe winner, do not merge and comment issue with blockers.

Safety Rules

• Never merge more than one candidate per issue.
• Never bypass failing required checks.
• Never force-merge.

Output Checklist

• Eligible PR list
• Winner PR number + why
• Non-winner closure summary
• Any blockers