git-intelligence Skill

Zero-install git analysis skill. The agent runs read-only git commands directly and uses its own reasoning to produce structured reports — no CLI tools, no API keys, no compilation.

When to Use

Activate when the user asks to:

• "Summarize commits from the last N days / this week"
• "Generate release notes between two tags"
• "Analyze this PR / branch"
• "Is this branch / PR risky?"
• "What does this branch affect?"
• "Who should review this PR?"

Step 1 — Verify Git Repository

Before any analysis, run:

git rev-parse --git-dir

• If it returns a path → proceed
• If it fails → stop and tell the user: "This directory is not a git repository. Please navigate to your project root first."

Step 2 — Intent Mapping

Step 3A — Summarize Commits

Collect data:

# Convert duration: 7d=7 days ago, 2w=14 days, 1mo=1 month
git log --since="<ISO date>" --oneline --no-merges

Analyze: Classify each commit message by keyword:

• feat / add / new / implement / support → Features
• fix / bug / patch / resolve / hotfix → Fixes
• refactor / clean / move / rename → Refactor
• perf / optim / speed / cache → Performance
• BREAKING CHANGE or !: notation → Breaking Changes
• Unmatched → Features (default)

Use your own understanding to improve on keyword matching when the meaning is clear.

Output format:

## Commit Summary (since <duration>)

### Features
- <commit message>

### Fixes
- <commit message>

### Performance
- <commit message>

Omit empty sections. If no commits found: "No commits found since <date>."

Step 3B — Release Notes

Collect data:

# Verify tags exist first
git rev-parse --verify refs/tags/<from>
git rev-parse --verify refs/tags/<to>

# Get commits between tags
git log <from>..<to> --oneline --no-merges

If a tag doesn't exist, stop and report: "Tag <tag> not found. Run git tag -l to list available tags."

Analyze: Same classification as Step 3A, but rewrite commit messages into user-facing language where appropriate.

Output format:

## Release Notes: <from> → <to>

### Breaking Changes
- <change>

### Features
- <feature description>

### Fixes
- <fix description>

### Performance
- <improvement>

Omit empty sections (especially Breaking Changes).

Step 3C — Analyze PR

Combines risk detection + impact analysis + reviewer suggestion.

Collect data:

# Auto-detect base branch
git symbolic-ref refs/remotes/origin/HEAD   # e.g. refs/remotes/origin/main → "main"
# If fails → use "master"

# Get diff statistics
git diff <base>...<branch> --numstat

# For reviewer suggestion: blame top changed files (up to 5)
git blame --porcelain -- <file>

Analyze:

1. Compute risk score (same rules as Step 3D)
2. Map changed files → logical modules (group by top 2 path segments)
3. Parse blame output → count lines per author email → take top 3 authors by blame-line count
4. If fewer than 2 blame authors found, add role fallbacks: auth/ → "security team", payment/ → "payments team", infra/ → "infra team"
5. Suggest test cases based on affected modules and sensitive areas

Output format:

## PR Analysis: <branch>

### Summary
<1–2 sentence description of what the branch changes>

### Impacted Modules
- <module>

### Risk Score
<🔴/🟡/🟢> <score>/10

### Suggested Reviewers
- <name or role>

### Suggested Tests
- <test scenario>

Step 3D — Detect Risk

Collect data:

git symbolic-ref refs/remotes/origin/HEAD   # base branch, fallback to master
git diff <base>...<branch> --numstat

Risk scoring (heuristic):

Start at 1. Clamp final score to [1, 10]. Add your own reasoning on top of the heuristic if the code context warrants it.

Risk label: 🔴 score ≥ 8 · 🟡 score 5–7 · 🟢 score ≤ 4

Output format:

## Risk Assessment: <branch>

**Risk Score**: 🔴 8/10

**Reasons**:
- Large diff (1200 lines)
- Middleware module modified
- Low test coverage for changed files

Step 3E — Change Impact

Collect data:

git symbolic-ref refs/remotes/origin/HEAD   # base branch, fallback to master
git diff <base>...<branch> --numstat

Analyze:

• Group files by top 2 path segments → logical module names
• Identify sensitive modules (auth, payment, infra, middleware, cache) and flag them
• Use your understanding of the codebase to infer downstream effects

Output format:

## Change Impact: <branch>

### Modules Affected
- <module path> — <brief impact note>

### Potential Risks
- <risk description>

Handling Edge Cases

Read-Only Guarantee

This skill ONLY runs read-only git commands: git log, git diff, git blame, git rev-parse, git symbolic-ref, git tag, git show.

It NEVER runs: git commit, git checkout, git merge, git push, git stash, git reset, git add.

No files are created or modified in the repository.