megacode-best-of-n

name	megacode-best-of-n
description	Plan N independent worktree attempts for exploration or implementation, plus judge criteria to select a winner. Use for best-of-n-explore workflows.
disable-model-invocation	true

MegaCode Best-of-N

Set up N independent attempts in isolated worktrees and define how a judge picks the best outcome.

Inputs

• Task or exploration goal.
• N (typically 2–4; respect max_concurrency and worktree policy).
• Constraints: time budget, models allowed, read-only vs write attempts.
• Evaluation criteria (correctness, simplicity, test pass, performance).

Output format

1. Attempt matrix

Attempt	Branch	Worktree path	Profile	Model	Strategy summary
A	megacode/bon-<run>-A	.megacode/worktrees/bon-<run>-A	implementer	...	...

2. Isolation rules

• One worktree per attempt; unique branch names tied to run ID.
• No shared uncommitted state between attempts.
• Record metadata: base SHA, owner profile, created time.
• Stop all attempts before any foldback.

3. Execution phases (workflow sketch)

phases:
  - id: spawn-attempts
    type: codex_batch
    profile: implementer
    concurrency: <N>
    worktree: per_attempt
  - id: local-verify-each
    type: shell
    depends_on: [spawn-attempts]
    verification:
      - pnpm verify
  - id: judge
    type: codex_run
    profile: reviewer
    depends_on: [local-verify-each]
    context_policy: artifact_only

4. Judge prompt template

The judge receives artifacts only (diffs, test output, summaries) and returns:

{
  "winner": "A",
  "ranking": ["A", "C", "B"],
  "criteria_scores": {},
  "rationale": "...",
  "losers_cleanup": "safe | keep_for_review"
}

5. Foldback

• Only the winner worktree proceeds to foldback (megacode-foldback checklist).
• Losers: stop agents, archive or delete per policy — never delete dirty worktrees without explicit discard.

Rules

• Parallel implementation requires worktree safety rules from AGENTS.md.
• Local verify on every attempt before judging.
• No GitHub Actions comparison — judge uses local test results and diffs only.