commit-message.md

Generate a well-structured conventional commit message from the currently staged git changes.

Step 1 — Get the Staged Diff

Run git diff --cached to see what is staged. Also run git diff --cached --stat for a file summary.

If nothing is staged, inform the user: "No changes are staged. Run git add first, then invoke this command again." Then stop.

Step 2 — Determine the Commit Type

Analyze the diff to select the most appropriate type:

Type	When to Use
feat	A new feature or user-facing capability
fix	A bug fix
refactor	Code restructuring with no behavior change
perf	A performance improvement
test	Adding or updating tests only
docs	Documentation-only changes
style	Formatting, whitespace, semicolons — no logic change
chore	Build scripts, CI config, dependency bumps, tooling
ci	CI/CD pipeline changes
build	Build system or external dependency changes
revert	Reverting a previous commit

If the diff spans multiple types, choose the dominant one. If it is truly mixed, prefer feat > fix > refactor > chore.

Step 3 — Determine the Scope

Identify a short scope in parentheses that indicates the area of the codebase:

• Module or package name: feat(auth):, fix(payments):
• Component name: refactor(Button):
• Layer: test(api):, docs(readme):

Omit the scope only if the change is truly project-wide.

Step 4 — Write the Subject Line

Format: type(scope): imperative description

Rules:

• Use imperative mood ("add", not "added" or "adds")
• Do not capitalize the first word after the colon
• Do not end with a period
• Keep it under 72 characters
• Be specific — "fix null check" is too vague; "fix null dereference in user lookup when email is missing" is good

Step 5 — Write the Body (if needed)

Add a body separated by a blank line if the change is non-trivial. The body should explain:

• Why the change was made (not just what changed — the diff shows that)
• Any non-obvious decisions or trade-offs
• Breaking changes prefixed with BREAKING CHANGE:

Step 6 — Check for Issue References

If the diff or branch name contains issue numbers, append a footer:

Closes #123

Step 7 — Present the Result

Output the commit message inside a single code block so the user can copy it. Also provide the ready-to-run command:

git commit -m "type(scope): subject line" -m "Optional body paragraph"

If the user provided $ARGUMENTS containing "apply" or "run", execute the git commit command directly instead of just displaying it.