Lanes and rules

Lane	Meaning	Check run
🟢 auto	Safe to merge once required checks pass	success
🟡 review	A human must look	neutral
🔴 block	Do not merge	failure

Built-in rules

• Protected globs (default .github/**, deploy/**, **/auth/**, **/migrations/**, wrangler.toml, _headers, **/.env*) → at least review.
• Auto globs (docs/**, **/*.md, **/*.css, public/**) → auto if at most max_auto_lines (200) lines changed, otherwise review.
• Everything else → review. Lockfile and manifest changes → review. Removed binaries or files with no diff → review.
• Obvious secrets in added lines (AWS keys, private key blocks, ghp_ tokens, api_key = "…") → block. This is a coarse screen, not a replacement for a secret scanner.
• Labels: labels.block → block; labels.review → at least review.
• Learning branch: PRs from learning.branch are always block.

Mixed PRs

When a PR mixes auto files with review or block files, the comment suggests which files could go in their own auto-mergeable PR. Nothing is split automatically.

The model's role

The LLM, rubrics and policy files can only raise a lane. Final lane = max(rules, labels, LLM, rubric). If the LLM call fails or returns invalid JSON (after one repair retry), MergeJudge falls back to rules-only and says so.