commit-msg

name	commit-msg
description	Generate a single-line commit message from conversation context and git diff, then optionally commit

Commit Message

Generate a single-line commit message based on the conversation context, using the git diff to confirm scope.

Instructions

Phase 1: Gather Context

1. Review the full conversation history — this is the primary source of intent
2. Run git diff --staged
   • If there is staged output, use it. Do NOT run git diff (unstaged). Skip to Phase 2.
   • If there is no staged output, run git diff to check for unstaged changes
   • If neither staged nor unstaged changes exist, inform the user and stop

Only one diff should be in scope — staged takes priority. Ignore any unstaged diff output from earlier in the conversation if staged changes exist.

Phase 2: Analyse

Priority order:

1. Conversation intent — what was the user trying to achieve? What problem were they solving? What did they ask for?
2. Conversation arc — did the approach evolve? Was there a key decision or pivot?
3. Diff confirmation — use the staged diff to verify scope and catch anything the conversation might not fully reflect

The conversation tells you why. The diff tells you what. Prefer why.

Phase 3: Generate Message

Create a single-line commit message following these rules:

• Start with verb: add, fix, update, remove, refactor, rename, move
• Lowercase, no period at end
• Max 72 characters
• Focus on what and why, not how
• Be specific: "fix login redirect loop" not "fix bug"
• Reflect the user's intent from the conversation, not just a mechanical description of changed lines

Phase 4: Output & Commit

1. Display only the commit message, nothing else. No explanation, no alternatives.
2. Ask the user if they want to commit with this message.
   • If yes — run git commit -m "<message>" (stage all tracked changes first with git add -u if nothing is currently staged)
   • If no — stop. Do not commit.