Keep a Changelog Format

This skill provides guidelines for writing and formatting changelogs following the Keep a Changelog specification.

Core Principles

1. Changelogs are for humans - Write for users, not machines
2. Every version gets a section - Including

   [Unreleased]

   for upcoming changes
3. Changes are grouped by type - Consistent categorization
4. Versions are linkable - Each version header links to comparison
5. Latest version comes first - Reverse chronological order
6. Release dates are shown - ISO format: YYYY-MM-DD

Change Categories

Use these categories in this order:

Category Guidelines

Added

• New user-facing features
• New API endpoints
• New configuration options
• New integrations

Changed

• Performance improvements
• UX/UI changes
• Default value changes
• Behavior modifications

Deprecated

• Features planned for removal
• APIs being replaced
• Include migration path when possible

Removed

• Breaking changes (removed functionality)
• Deleted APIs or features
• Always note what replaced it (if applicable)

Fixed

• Bug corrections
• Error handling improvements
• Edge case fixes

Security

• Vulnerability patches
• Security-related fixes
• Always include CVE if available

Entry Writing Guidelines

Use Imperative Mood

Start entries with imperative verbs:

Focus on User Impact

Write from the user's perspective:

Be Specific and Concise

Include Context When Helpful

Use parenthetical context for clarity:

- Add OAuth2 support (Google, GitHub)
- Fix timezone handling (UTC offset calculation)
- Change rate limit (100 -> 500 requests/minute)

Changelog Structure

# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/),
and this project adheres to [Semantic Versioning](https://semver.org/).

## [Unreleased]

### Added
- New entries go here

## [1.0.0] - 2024-01-15

### Added
- Initial public release
- Feature A with description
- Feature B with description

### Changed
- Improvement to existing feature

### Fixed
- Bug fix description

## [0.9.0] - 2024-01-01

### Added
- Beta release features

[Unreleased]: https://github.com/owner/repo/compare/v1.0.0...HEAD
[1.0.0]: https://github.com/owner/repo/compare/v0.9.0...v1.0.0
[0.9.0]: https://github.com/owner/repo/releases/tag/v0.9.0

Semantic Versioning Connection

Changelog categories map to version bumps:

What NOT to Include

• Internal refactoring (unless it affects users)
• Dependency updates (unless they affect functionality)
• Test changes
• CI/CD changes
• Documentation-only changes (unless user-facing docs)
• Code style/formatting changes

Changelog Entry Examples

This section provides examples of well-written and poorly-written changelog entries to guide entry creation.

Added Category

Good Examples

- Add user authentication with email/password and OAuth (Google, GitHub)
- Add bulk export of transactions to CSV and Excel formats
- Add keyboard shortcuts for common actions (Ctrl+S to save, Ctrl+Z to undo)
- Add dark mode with automatic system preference detection
- Add webhook support for order status changes
- Add rate limiting (100 requests/minute per API key)

Poor Examples (with corrections)

Added new feature

Add invoice PDF generation

Implemented AuthService class

Add user authentication

Added support for thing

Add support for WebP image uploads

New button

Add "Export All" button to dashboard

Changed Category

Good Examples

- Improve search performance (3x faster for large datasets)
- Change default session timeout from 30 minutes to 2 hours
- Update password requirements: minimum 12 characters, 1 number required
- Redesign settings page with tabbed navigation
- Move API documentation to /docs endpoint
- Increase file upload limit from 5MB to 25MB

Poor Examples (with corrections)

Refactored code

Improve page load speed by 40%

Updated dependencies

Changed stuff

Change notification preferences to opt-in

Made improvements

Improve error messages with specific guidance

Fixed Category

Good Examples

- Fix crash when uploading files larger than 10MB
- Fix incorrect tax calculation for international orders
- Fix login button not responding on mobile Safari
- Fix timezone display showing UTC instead of local time
- Fix memory leak causing slowdown after extended use
- Fix email notifications not sending for new comments

Poor Examples (with corrections)

Fixed bug

Fix duplicate orders created on retry

Bug fix

Fix search returning stale results

Fixed issue #123

Fix CSV export missing header row (#123)

Fixed null pointer exception in UserService.java:42

Fix crash when viewing deleted user profile

Removed Category

Good Examples

- Remove deprecated /api/v1 endpoints (use /api/v2 instead)
- Remove support for Internet Explorer 11
- Remove "Classic" theme (migrate to "Modern" theme in settings)
- Remove automatic social media sharing (use manual share buttons)
- Remove legacy import format (use CSV import instead)

Poor Examples (with corrections)

Removed old code

Remove legacy report generator

Deleted files

Removed feature

Remove email digest option

Deprecated Category

Good Examples

- Deprecate /api/v1/users endpoint (use /api/v2/users, removal in v3.0)
- Deprecate XML export format (use JSON export, removal in 6 months)
- Deprecate "Classic" theme (will be removed in next major version)
- Deprecate basicAuth parameter (use apiKey authentication instead)

Poor Examples (with corrections)

Deprecated old API

Deprecate /legacy endpoint (use /api/v2, removal in v2.0)

Will remove soon

Deprecate CSV import (use Excel import, removal March 2024)

Security Category

Good Examples

- Fix XSS vulnerability in comment rendering (CVE-2024-1234)
- Fix SQL injection in search query parameter
- Add Content-Security-Policy headers
- Update authentication to prevent session fixation attacks
- Fix CSRF vulnerability in account settings form
- Upgrade TLS minimum version to 1.2

Poor Examples (with corrections)

Security fix

Fix authentication bypass vulnerability

Fixed vulnerability

Fix stored XSS in user profile bio field

Updated security

Add rate limiting to prevent brute force attacks

Grouping Related Changes

When multiple related changes are made, group them thoughtfully:

Good Grouping

### Added
- Add user profile customization
  - Profile picture upload
  - Bio and social links
  - Custom theme colors
- Add team collaboration features
  - Shared workspaces
  - Real-time presence indicators
  - Comment threads on items

Alternative: Separate Entries

### Added
- Add profile picture upload with crop and resize
- Add customizable bio and social media links
- Add shared team workspaces
- Add real-time presence indicators for team members

Entries with Technical Context

When technical details help users, include them appropriately:

Good Examples

- Add GraphQL API alongside existing REST API
- Add WebSocket support for real-time updates (replaces polling)
- Fix N+1 query issue causing slow dashboard load
- Change database connection pooling (improves concurrent user handling)

Avoid Over-Technical Entries

Migrate from Redux to Zustand

Improve app responsiveness

Refactor to use React hooks

Upgrade PostgreSQL 14 -> 16

Add index on users.email column

Improve login speed

Breaking Changes

Clearly indicate breaking changes:

### Removed
- **BREAKING**: Remove support for Node.js 14 (minimum now Node.js 18)
- **BREAKING**: Remove /api/v1 endpoints (migrate to /api/v2)

### Changed
- **BREAKING**: Change config file format from YAML to TOML
- **BREAKING**: Rename `user.name` field to `user.displayName` in API responses