| name | commit-message-storyteller |
| description | Analyses git diffs or staged changes and generates narrative commit messages that explain WHY a change was made, not just what changed — following Conventional Commits format. Use when asked to "write a commit message", "generate a commit", "describe my changes", "what should I commit this as", "commit this", "summarise my diff", or "help me commit". Works with git diff output, staged files, or plain descriptions of changes. |
| metadata | {"skill-author":"Marie-Lynne Block"} |
Commit Message Storyteller
Transforms raw git diffs and change descriptions into clear, story-driven commit messages that follow the Conventional Commits specification. Instead of "update file.js", you get messages that communicate intent, context, and impact.
When to Use This Skill
- User says "write a commit message", "help me commit", or "generate a commit"
- User pastes a git diff or describes code changes
- User says "what should I commit this as?" or "summarise my diff"
- User wants better commit history for their team or open-source project
- User is preparing a pull request and wants meaningful commit messages
Prerequisites
Have at least one of the following ready:
- Output from
git diff or git diff --staged
- A description of what you changed and why
- A list of modified files
How It Works
Step 1: Gather the Change Context
Ask the user (or infer from the diff) for:
- What changed — files, functions, logic affected
- Why it changed — bug fix, new feature, refactor, performance, etc.
- Who/what triggered it — issue number, user request, tech debt, etc.
If the user provides a raw git diff, extract this context automatically from the diff.
Step 2: Identify the Commit Type
Map the change to a Conventional Commits type using this guide:
| Type | Use When |
|---|
feat | A new feature or capability is added |
fix | A bug or incorrect behaviour is corrected |
refactor | Code restructured without changing behaviour |
perf | A change that improves performance |
docs | Documentation only changes |
style | Formatting, whitespace, missing semicolons (no logic change) |
test | Adding or updating tests |
chore | Build process, dependency updates, config changes |
ci | CI/CD pipeline changes |
revert | Reverting a previous commit |
See references/conventional-commits-guide.md for detailed examples.
Step 3: Write the Commit Message
Follow this structure:
<type>(<optional scope>): <short imperative summary>
<body — the story: why this change was made, what problem it solves>
<footer — issue refs, breaking change notices>
Rules for Each Part
Subject line (first line):
- Use imperative mood: "add", "fix", "remove" — not "added" or "fixes"
- Max 72 characters
- No period at the end
- Lowercase after the colon
Body (the story):
- Explain the why, not the what (the diff already shows the what)
- Describe the problem that existed before this change
- Mention any alternatives considered if relevant
- Keep lines under 100 characters
- Separate from subject with a blank line
Footer:
- Reference issues:
Closes #123, Fixes #456, Refs #789
- Mark breaking changes:
BREAKING CHANGE: <description>
Step 4: Generate Output
Produce the commit message in a copyable code block, followed by a one-line plain-English explanation of the story you told.
Example output:
fix(auth): prevent token refresh loop on expired sessions
When a user's session expired mid-request, the auth middleware was
triggering a token refresh, which itself failed validation and triggered
another refresh — causing an infinite retry loop that crashed the app.
This adds a recursion guard flag that aborts the refresh cycle if a
refresh is already in progress, returning a clean 401 instead.
Closes #312
Story told: A silent infinite loop on session expiry was crashing the app; this stops the cycle early and returns a clean error.
Multiple Commits from One Diff
If the diff contains logically separate changes, split them into multiple commit messages and tell the user. Use this heuristic:
- Different files with unrelated purposes → likely separate commits
- Same file but distinct concerns (e.g., bug fix + refactor) → suggest splitting
- Everything tightly coupled → one commit is fine
Edge Cases
| Situation | How to Handle |
|---|
| User provides no context beyond a diff | Infer type and scope from file names and changed symbols |
| Changes span many files with no clear theme | Ask: "Is this one logical change, or multiple?" |
| Breaking change detected | Add BREAKING CHANGE: footer automatically |
| User says "keep it short" | Omit body, just write a strong subject line |
| No issue number available | Omit the footer entirely |
Quick Reference
git diff --staged
git diff
See references/conventional-commits-guide.md for type examples and scope guidelines.
