conventional-commit

name	conventional-commit
description	Guides committing staged (indexed) git files using the Conventional Commits specification and commit message best practices. Use when user mentions commit, git commit, conventional commit, commit message, staged files, indexed files, fixup, or fixup commit. Helps craft well-structured, meaningful commit messages including fixup commits with optional autosquash.

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:

1. Run git status to see what files are staged
2. Run git diff --cached to review the actual staged changes
3. 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

1. 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.

2. 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)

3. Create the fixup commit — use git commit --fixup <target-sha>:

   git commit --fixup abc1234
   

   This produces a commit with the message fixup! <original subject>.

4. 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)?"

5. 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.

6. 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