Commit Staged Files with Conventional Commits

You are helping the user commit their currently staged (indexed) git files using the Conventional Commits specification and commit message best practices.

Pre-flight Checks

Before crafting a commit message, always:

Run git status to see what files are staged
Run git diff --cached to review the actual staged changes
If nothing is staged, inform the user and stop — do not create an empty commit

Conventional Commit Format

<type>[optional scope]: <subject>

[optional body]

[optional footer(s)]

Types

Type	When to use
`feat`	A new feature or capability
`fix`	A bug fix
`docs`	Documentation-only changes
`style`	Formatting, whitespace, semicolons — no logic change
`refactor`	Code restructuring without behavior change
`perf`	Performance improvement
`test`	Adding or updating tests
`build`	Build system or external dependency changes
`ci`	CI/CD configuration changes
`chore`	Maintenance tasks (deps update, tooling, config)
`revert`	Reverting a previous commit

Note: Comment-only changes (adding, updating, or removing code comments) should use style or chore — never feat or fix. Keep commit messages concise; do not describe individual comments.

Scope

Optional, but recommended when the change targets a specific module, component, or area
Use lowercase, kebab-case: feat(auth):, fix(api-client):
Keep consistent with the project's existing scope conventions
Check recent git log (git log --oneline -50 or more) for scope patterns already used in the project
Also note whether the project actually uses conventional commits — if not, adapt to the project's style

Subject Line Rules

Imperative mood: "add feature" not "added feature" or "adds feature"
Lowercase first letter: "add feature" not "Add feature"
No period at the end
50 characters or less — hard limit at 72
Complete the sentence: "If applied, this commit will <subject>"

Body Rules

Separate from subject with a blank line
Wrap at 72 characters
Explain what and why, not how (the diff shows how)
Use when the subject alone is not sufficient to understand the change
Use bullet points for multiple related changes

Footer Rules

BREAKING CHANGE: <description> for breaking changes (triggers major version bump)
Refs: #123 or Closes #456 for issue references
Co-authored-by: Name <email> for co-authors
Signed-off-by: Name <email> when the project requires a Developer Certificate of Origin (DCO)

Decision Process

Follow this process to determine the commit message:

Step 1: Analyze the Staged Changes

Read the diff carefully and identify:

What files changed and their purpose
Whether this is a single logical change or multiple unrelated changes
The primary intent: new feature, bug fix, refactor, etc.

Step 2: Check for Multiple Logical Changes

If the staged changes contain multiple unrelated changes:

Inform the user: "The staged changes contain multiple unrelated changes. Consider splitting them into separate commits for a cleaner history."
Classify changes into categories to suggest logical groupings:
- Tidying — formatting, renaming, dead code removal (no behavior change)
- Infrastructure/build — dependencies, tooling, configuration
- Feature implementation — new capabilities
- Bug fixes — correcting incorrect behavior
- Documentation — docs-only changes
Keep dependency manifests with their lock files (e.g., package.json + package-lock.json, go.mod + go.sum, Cargo.toml + Cargo.lock, pyproject.toml + lock files)
Suggest a commit order that tells a clear story:
1. Tidying/structural changes first (separate from behavior changes)
2. Documentation before related code changes
3. Infrastructure/build before features that depend on them
4. Feature or fix commits last
Let the user decide whether to proceed with a single commit or split

Step 3: Determine the Type

Ask yourself: "What is the primary intent of this change?"
If a feature includes tests, the type is feat (not test)
If a bug fix includes a refactor, the type is fix (not refactor)
The type reflects the reason for the change, not every file touched
Exception — scope-inherent types: When all changed files belong to a single domain that has its own type, use that type directly without a scope. For example, if a commit only touches CI/CD files (e.g., .github/workflows/), use ci: — not fix(ci): or feat(ci):. The same applies to docs: (only documentation files), test: (only test files), and build: (only build config). These types already convey the scope, so adding it as a parenthetical is redundant.

Step 4: Determine the Scope

Look at what area of the codebase is affected
Check git log --oneline -50 for existing scope conventions
If the change touches multiple areas, either omit the scope or use the primary area

Step 5: Write the Subject

Describe the change concisely in imperative mood
Focus on the user-facing or developer-facing impact
Bad: fix(api): fixed the bug in the login endpoint
Good: fix(api): return 401 on expired token instead of 500

Step 6: Write the Body (if needed)

Add a body when:

The subject does not fully explain the change
There is important context (why this approach, what was considered)
The change has side effects or non-obvious consequences
There is a breaking change to document

Step 7: Present and Confirm

Present the complete commit message to the user
Wait for approval before executing the commit
If the user wants changes, adjust accordingly

Commit Execution

When executing the commit:

Use git commit -m with a HEREDOC for multi-line messages
Never use --no-verify — respect pre-commit hooks
Never use --amend unless the user explicitly requests it
If a pre-commit hook fails, investigate and fix the issue, then create a new commit
After committing, run git status to confirm success

Single-line Commit

git commit -m "feat(auth): add JWT token refresh endpoint"

Multi-line Commit

git commit -m "$(cat <<'EOF'
feat(auth): add JWT token refresh endpoint

Implement automatic token refresh when the access token expires.
The refresh endpoint validates the refresh token and issues a new
access token with a 15-minute expiry.

Closes #234
EOF
)"

Examples

Simple Feature

feat: add dark mode toggle to settings page

Bug Fix with Context

fix(parser): handle empty input without panic

The YAML parser panicked on empty strings because it attempted
to access the first character without a length check. Now returns
an empty document instead.

Closes #89

Breaking Change

feat(api)!: require authentication for all endpoints

All API endpoints now require a valid Bearer token. Previously,
read-only endpoints were publicly accessible.

BREAKING CHANGE: unauthenticated requests to /api/* now return 401.
Clients must include an Authorization header with a valid token.

Refs: #156

Documentation Update

docs: add API rate limiting guide

Refactor

refactor(db): extract connection pooling into dedicated module

Move connection pool logic from the monolithic database module into
its own module to improve testability and separation of concerns.
No behavior change.

Anti-patterns to Avoid

Anti-pattern	Why it is wrong	Better alternative
`fix: fix bug`	Says nothing useful	`fix(cart): prevent negative quantities`
`update code`	Not a conventional commit	`refactor(utils): simplify date parsing`
`feat: Added new feature and fixes`	Past tense, vague, mixed scope	Split into separate commits
`WIP`	Not meaningful in history	Use a descriptive message or `--fixup`
`misc changes`	Uninformative	Describe what actually changed
`fix: fix`	Redundant and meaningless	Describe the actual fix
Subject longer than 72 characters	Breaks tooling and readability	Keep it concise, use body for details

Fixup Commits

When the user indicates a change is a fixup (e.g., "this is a fixup", "fixup change", "attach to previous commit"), the commit should be created as a fixup! commit targeting the original commit that introduced the issue.

Fixup Process

Determine the branch boundary — before anything else, identify which commits belong to the current branch:
```
git log --oneline $(git merge-base HEAD origin/main)..HEAD
```
This is the safe rebase range. Only commits in this range may be targeted for fixup or autosquash.
Identify the target commit — search the git log for the commit that introduced the code being fixed:
- Use git log --oneline $(git merge-base HEAD origin/main)..HEAD -- <changed-files> to find commits on the current branch that touched the same files
- Pick the commit whose subject best matches the change being fixed
- CRITICAL guardrail: if the target commit is not in the branch range (i.e., it is on main or before the branch point), do not create a fixup commit. Instead, inform the user and create a normal commit with the appropriate type (e.g., fix, ci)
Create the fixup commit — use git commit --fixup <target-sha>:
```
git commit --fixup abc1234
```
This produces a commit with the message fixup! <original subject>.
Ask the user if they want to autosquash — after the fixup commit is created, ask:

"Fixup commit created. Do you want to autosquash it into the target commit now (git rebase --autosquash)?"
If the user accepts, run the interactive rebase with autosquash scoped to the branch:
```
GIT_SEQUENCE_EDITOR=true git rebase --autosquash $(git merge-base HEAD origin/main)
```
Using GIT_SEQUENCE_EDITOR=true auto-confirms the rebase editor so it runs non-interactively. Never rebase beyond the merge-base — this would rewrite commits shared with main.
If the user declines, leave the fixup commit as-is — it will be squashed during a future rebase.

Fixup Example

# Original commit:
a1b2c3d feat(auth): add OAuth2 login flow

# Fixup commit (auto-generated message):
fixup! feat(auth): add OAuth2 login flow

Important Guidelines

Always review the diff before writing the commit message — do not guess
Never commit secrets (.env, API keys, credentials) — warn the user if staged
Respect the project's conventions — check recent history for patterns
One logical change per commit — suggest splitting when appropriate
Ask before committing — always present the message for approval first

conventional-commit