commit-message-writer#

Description#

Write Conventional Commit messages from a git diff, code snippet, or plain description. Also generates PR titles and 3-bullet PR summaries. Works with any language and any project — no setup, no config.

Use when#

• "write a commit message"
• "what should I commit this as"
• "conventional commit for this diff"
• "write a PR title and description"
• Any git diff or code change needing a message

Supported conventions#

• Conventional Commits 1.0 (default)
• Angular commit format
• GitHub squash-merge style
• Plain descriptive (no convention)

Request a specific one or it defaults to Conventional Commits.

Input#

Paste one of:

• A git diff ( git diff --staged)
• A description of what changed ("I added rate limiting to the API")
• Code before/after

Optionally specify:

• Convention (defaults to Conventional Commits)
• Scope (component, module, or area affected)
• Whether this is a breaking change

Output format#

text

## Commit Message

[type]([scope]): [subject]

[body — explains WHY, not just WHAT. Omitted if obvious from subject]

[BREAKING CHANGE: description — only if applicable]
[Closes #123 — only if issue number is known]

---

## PR Title
[short, imperative, under 70 chars]

## PR Summary
- [What changed]
- [Why it changed / what problem it solves]
- [Any notable side effects, caveats, or follow-up needed]

Conventional Commits type guide#

TypeWhen to usefeatNew feature (triggers minor version bump)fixBug fix (triggers patch version bump)docsDocumentation onlystyleFormatting, whitespace — no logic changerefactorRestructure without changing behaviorperfPerformance improvementtestAdding or fixing testschoreBuild system, CI, dependency updatesrevertReverts a prior commitciCI pipeline changes

Writing rules#

• Subject: imperative mood ("add", "fix", "remove" — not "added", "fixed", "removes")
• Subject: no period at end
• Subject: under 72 characters
• Body: explain WHY the change was made, not just what the diff shows
• Breaking change: always include BREAKING CHANGE: footer with migration notes
• Scope: use the module, file, or feature name (e.g., auth, api, db, ui)
• If the diff touches multiple concerns: suggest splitting into multiple commits

Examples#

Simple fix#

text

fix(auth): reject expired JWT tokens before checking claims

Previously, token expiry was checked after claim validation,
which allowed attackers to replay expired tokens with valid claims.

New feature with breaking change#

text

feat(api)!: require API key on all public endpoints

BREAKING CHANGE: All requests now require `X-API-Key` header.
Clients using anonymous access will receive 401. See migration guide.

Dependency update#

text

chore(deps): bump openssl from 1.1.1 to 3.0.8

Addresses CVE-2023-0286 (X.400 address type confusion).
No API changes.

Self-improvement instructions#

After each commit message written, note whether the input was a diff, description, or code snippet. After 20 uses, surface the most common missing context that leads to weaker messages.