Merge Check
Predicts whether a GitHub PR will get merged by analyzing it against a comprehensive rejection vector taxonomy. Not a generic code quality tool — this answers: "Will this PR get merged by the maintainer?"
Quick Start
- Run the data gathering script:
```bash
bash skills/merge-check/scripts/merge-check.sh owner/repo#123
# or
bash skills/merge-check/scripts/merge-check.sh https://github.com/owner/repo/pull/123
```
- Parse the JSON output
- Analyze against the dimensions below
- Produce the mergeability report
Analysis Dimensions
After gathering data, analyze across ALL of these dimensions. Load skills/merge-check/references/rejection-taxonomy.md for the detailed rejection vector framework.
1. Technical Signals (Automated Gates)
- CI status: Are all checks passing? Any failed or pending?
- Build status: Does it compile/build?
- Coverage: Any coverage regression indicated?
2. PR Hygiene
- Size (most predictive single factor):
- 🟢 <400 LOC changed — ideal, easy to review
- 🟡 400–1000 LOC — risky, reviewer fatigue
- 🔴 >1000 LOC — danger zone, likely to stall or get rejected
- File spread: Concentrated in one area or scattered across directories?
- Single concern: Does it do one thing, or is it a kitchen-sink PR?
- Title & description: Clear, descriptive? Or vague/empty?
- Linked issue: Does it reference an issue? (Signals intentionality)
- Commit hygiene: Clean messages? Reasonable count? Squash-ready?
3. Architectural Fit
- Pattern consistency: Does it follow repo conventions? (language, directory structure, naming)
- Dependencies: New dependencies introduced? (High friction signal)
- Scope creep: Does it touch things outside its stated purpose?
- File types: Consistent with repo's tech stack?
4. Review Status
- Approvals: Any already? How many required?
- Changes requested: Outstanding and unaddressed? (Strong rejection signal)
- Reviewer assignment: Are required reviewers assigned?
- Review comment sentiment: Positive, neutral, or adversarial?
- CODEOWNERS: Does the PR touch files with code owners? Are they reviewing?
5. Process Compliance
- Draft status: Draft PRs won't merge
- Blocking labels: WIP, do-not-merge, needs-work, etc.
- PR template: Was it followed? (Empty template = red flag)
- CLA/DCO: If repo requires it, is it signed?
6. Social/Meta Signals
- Author merge history: What % of this author's recent PRs were merged in this repo?
- Staleness: How long has it been open? (>2 weeks = concern, >30 days = likely abandoned)
- Activity level: Recent comments/updates, or radio silence?
- First-time contributor: Higher rejection rate for newcomers
Output Format
Produce a structured report:
Mergeability Score
- 🟢 High (>80% likely to merge) — No blockers, reviews positive, CI green
- 🟡 Medium (40–80%) — Some concerns but addressable
- 🔴 Low (<40%) — Significant blockers present
Report Sections
- Mergeability Score: 🟢/🟡/🔴 with percentage estimate
- Risk Factors: Bullet list of specific concerns, ordered by severity
- Strengths: What's working in the PR's favor
- Recommendations: Actionable steps to improve mergeability (if not already 🟢)
- Verdict: One-sentence summary
Example Output
## PR Mergeability Report: owner/repo#123
**Score: 🟡 Medium (~55%)**
### Risk Factors
- ⚠️ 847 lines changed — approaching reviewer fatigue threshold
- ⚠️ Changes requested by @maintainer not yet addressed
- ⚠️ Touches 12 files across 6 directories — scattered scope
- ℹ️ No linked issue
### Strengths
- ✅ All 14 CI checks passing
- ✅ Clear title and detailed description
- ✅ Author has 73% merge rate in this repo (8/11 recent PRs)
- ✅ Active discussion — last update 2 hours ago
### Recommendations
1. Address @maintainer's review comments before requesting re-review
2. Consider splitting into smaller PRs (config changes vs logic changes)
3. Link the relevant issue for traceability
### Verdict
Solid PR with passing CI and an active author, but stalled on unaddressed review feedback — resolving those comments is the critical path to merge.
Script Reference
The script (scripts/merge-check.sh) gathers all data via gh CLI and outputs a single JSON object with these keys:
| Key | Contents |
|---|
| ----- | ---------- |
pr | Full PR metadata (title, body, author, state, draft, labels, reviewers) |
files | List of changed files with patch stats |
diff_stats | Total additions, deletions, changed files count |
checks | CI/check run results for the head commit |
reviews | All reviews (approved, changes_requested, commented) |
review_comments | Inline review comments |
issue_comments | PR conversation comments |
commits | Commit list with messages |
repo | Repository metadata (language, size, defaults) |
author_history | Author's recent closed PRs and merge rate |
has_codeowners | Boolean |
has_contributing | Boolean |
Error Handling
The script outputs "error" fields when individual API calls fail (e.g., rate limits, 404s). Analyze what's available and note any missing data in the report.