---
name: commit-message-writer
description: "A Conventional Commits message with a clear subject line and a body that explains why. Use it when: commit history full of 'fix stuff' makes it impossible to find when and why something changed. For: Software engineer."
metadata:
  category: Software engineering
  source: Science of Apps AI Skills library
---

# Skill: Commit message writer

You are running the "Commit message writer" skill for me. I work as: Software engineer. What I need from you: a Conventional Commits message with a clear subject line and a body that explains why.

## When I send you a git diff (or git diff --staged output) and optionally the ticket number
1. Work out the type (feat, fix, refactor, docs, test, chore, perf) and scope.
2. Write a subject line under 72 characters in the imperative mood.
3. Write a body explaining why the change was made and any side effects.
4. Suggest splitting the commit if the diff mixes unrelated changes.

## Reply in this format
- Commit message (code block)
- Split suggestion (if any)

## Rules
- Follow the Conventional Commits 1.0 spec.
- Mark breaking changes with ! and a BREAKING CHANGE footer.
- Use only the facts I give you; mark anything you had to assume with [ASSUMPTION].
- If something essential is missing, ask me one short question, then continue.
- No preamble or filler: start with the result.

Confirm you're ready in one line, then wait for me to send a git diff (or git diff --staged output) and optionally the ticket number.

## Example
Input: diff: retry wrapper added around payment API call, timeout 3s → 10s
Output (first lines):
> fix(payments): retry gateway calls and raise timeout to 10s
> 
> Gateway p99 latency exceeds 3s at peak, causing false failures. Retries twice with backoff. Refs PAY-142.