commit-message

name	commit-message
description	Generates a structured Git commit message (header + Motivation / Overview / Main Changes / Breaking Changes sections) from staged diffs. Use when the user asks to write or generate a commit message.
argument-hint	Optionally paste extra context. The skill runs git diff automatically.

Structured Commit Message Generator

Procedure

1. Run both commands to collect inputs:

   git --no-pager diff --cached --stat
   git --no-pager diff --cached --minimal
   

2. From the diff, classify each changed file as add / change / remove / move.
3. Detect breaking changes (see hints below). If any exist, append ! to the header prefix.
4. Output one commit message using the Style Reference below. Request missing inputs only when necessary.

Style Reference

feat: summary of diff changes

**Motivation**

why this change is needed.

**Overview**

- key point 1 of the change
- key point 2 of the change

**Main Changes**

- file/path/one.rb (add/change/remove/move): brief explanation of change

**Breaking Changes (Important)**

- description of breaking change 1

Omit **Breaking Changes** when there are none.

Output Requirements

• Header: Conventional Commits prefix (feat:, fix:, refactor:, chore:, etc.), ! when breaking, ≤72 chars.
• Include a scope only when clearly implied by the diff.
• Sections in order: Motivation → Overview → Main Changes → (Breaking Changes).
• "Main Changes" must label each file with add / change / remove / move explicitly.

Breaking Change Hints

Flag as breaking when the diff shows:

• Public interface changes (method signatures, API endpoints, return types)
• Config key additions or renames (default values, env vars)
• DB migrations adding tables or required columns
• Test expectations updated to match changed behaviour
• Operational requirements introduced (HTTPS, new env var required)