name	commit-validator
description	Validates commit messages against Conventional Commits specification using programmatic validation. Replaces the git-conventional-commit-messages text file with a tool that provides instant feedback.
allowed-tools	read, grep, bash

Commit Message Validator - Programmatically validates commit messages against the [Conventional Commits](https://www.conventionalcommits.org/) specification. - Before committing code - In pre-commit hooks - In CI/CD pipelines - During code review - To enforce team standards

Step 1: Validate Commit Message

Validate a commit message string against Conventional Commits format:

Format: <type>(<scope>): <subject>

Types:

feat: A new feature
fix: A bug fix
docs: Documentation only changes
style: Code style changes (formatting, etc.)
refactor: Code refactoring
perf: Performance improvements
test: Adding or updating tests
chore: Maintenance tasks
ci: CI/CD changes
build: Build system changes
revert: Reverting a previous commit

Validation Rules:

Must start with type (required)
Scope is optional (in parentheses)
Subject is required (after colon and space)
Use imperative, present tense ("add" not "added")
Don't capitalize first letter
No period at end
Can include body and footer (separated by blank line)

**Implementation**

Use this regex pattern for validation:

const CONVENTIONAL_COMMIT_REGEX = /^(feat|fix|docs|style|refactor|perf|test|chore|ci|build|revert)(\(.+\))?: .{1,72}/;

function validateCommitMessage(message) {
  const lines = message.trim().split('\n');
  const header = lines[0];
  
  // Check format
  if (!CONVENTIONAL_COMMIT_REGEX.test(header)) {
    return {
      valid: false,
      error: 'Commit message does not follow Conventional Commits format'
    };
  }
  
  // Check length
  if (header.length > 72) {
    return {
      valid: false,
      error: 'Commit header exceeds 72 characters'
    };
  }
  
  return { valid: true };
}

**Valid Examples**:

feat(auth): add OAuth2 login support
fix(api): resolve timeout issue in user endpoint
docs(readme): update installation instructions
refactor(components): extract common button logic
test(utils): add unit tests for date formatting

**Invalid Examples**:

Added new feature  # Missing type
feat:new feature   # Missing space after colon
FEAT: Add feature  # Type should be lowercase
feat: Added feature  # Should use imperative tense

**Pre-commit Hook** (`.git/hooks/pre-commit`):

#!/bin/bash
commit_msg=$(git log -1 --pretty=%B)
if ! node .claude/tools/validate-commit.js "$commit_msg"; then
  echo "Commit message validation failed"
  exit 1
fi

**CI/CD Integration**:

# .github/workflows/validate-commits.yml
- name: Validate commit messages
  run: |
    git log origin/main..HEAD --pretty=%B | while read msg; do
      node .claude/tools/validate-commit.js "$msg" || exit 1
    done

**Output Format**

Returns structured validation result:

{
  "valid": true,
  "type": "feat",
  "scope": "auth",
  "subject": "add OAuth2 login support",
  "warnings": []
}

Or for invalid messages:

{
  "valid": false,
  "error": "Commit message does not follow Conventional Commits format",
  "suggestions": [
    "Use format: <type>(<scope>): <subject>",
    "Valid types: feat, fix, docs, style, refactor, perf, test, chore, ci, build, revert"
  ]
}

Or for invalid messages:

{
  "valid": false,
  "error": "Commit message does not follow Conventional Commits format",
  "suggestions": [
    "Use format: <type>(<scope>): <subject>",
    "Valid types: feat, fix, docs, style, refactor, perf, test, chore, ci, build, revert"
  ]
}

1. **Validate Early**: Check commit messages before pushing 2. **Provide Feedback**: Show clear error messages with suggestions 3. **Enforce in CI**: Add validation to CI/CD pipelines 4. **Team Training**: Educate team on Conventional Commits format 5. **Tool Integration**: Integrate with Git hooks and IDEs

commit-validator

Install Skill

SKILL.md

Step 1: Validate Commit Message