generate-changelog

name	generate-changelog
description	Generate changelog entries from git commits, plan files, or structured data. Use for version releases, creating CHANGELOG.md sections, or documenting changes between versions.
allowed-tools	Read, Bash

Generate Changelog

Automatically generate changelog entries following Keep a Changelog format.

When to Use

• Version release workflows
• Creating CHANGELOG.md sections
• Documenting changes between versions
• Generating release notes
• Summarizing work completed

Instructions

Step 1: Gather Change Data

Accept change information from various sources.

Expected Input:

• version: String (e.g., "0.8.0")
• date: String (ISO-8601 or YYYY-MM-DD)
• source: String (git|plan-file|manual)
• sourceData: Object (git range, plan file path, or manual entries)

Source Types:

• git: Parse git log between two refs
• plan-file: Extract from plan file metadata
• manual: User-provided entries

Step 2: Parse Changes

Extract and categorize changes.

Categories (Keep a Changelog standard):

• Added: New features
• Changed: Changes to existing functionality
• Deprecated: Soon-to-be removed features
• Removed: Removed features
• Fixed: Bug fixes
• Security: Security vulnerability fixes

Git Commit Parsing:

• Parse conventional commit format (feat:, fix:, etc.)
• Extract scope and description
• Map commit type to changelog category

Step 3: Group and Deduplicate

Group changes by category and remove duplicates.

Grouping Rules:

• feat → Added
• fix → Fixed
• security → Security
• refactor, perf → Changed
• docs → Changed (if significant)
• chore → Omit (unless breaking change)

Step 4: Format Changelog Section

Create formatted changelog section.

Format:

## [Version] - Date

### Added
- New feature 1
- New feature 2

### Fixed
- Bug fix 1
- Bug fix 2

### Changed
- Change 1

Step 5: Return Formatted Changelog

Return complete changelog section ready for insertion.

Expected Output:

## [0.8.0] - 2025-10-17

### Added
- Dark mode toggle for user preferences
- OAuth2 authentication support

### Fixed
- Memory leak in connection pool
- CORS configuration error

### Changed
- Migrated to v2 authentication API
- Optimized query performance

Error Handling

• No Changes Found: Return empty changelog with note
• Invalid Git Range: Return error with git command output
• Invalid Plan File: Return error describing issue
• Unparseable Commits: Include as "Changed" with raw message

Examples

Example 1: Generate from Git Range

Input:

{
  "version": "0.8.0",
  "date": "2025-10-17",
  "source": "git",
  "sourceData": {
    "fromRef": "v0.7.0",
    "toRef": "HEAD"
  }
}

Git Commits:

feat(auth): add OAuth2 support
fix(api): resolve memory leak
docs: update API documentation
chore(deps): bump dependencies

Output:

## [0.8.0] - 2025-10-17

### Added
- Add OAuth2 support (auth)

### Fixed
- Resolve memory leak (api)

### Changed
- Update API documentation

Example 2: Generate from Plan File

Input:

{
  "version": "0.8.0",
  "date": "2025-10-17",
  "source": "plan-file",
  "sourceData": {
    "planFile": ".version-update-plan.json"
  }
}

Plan File Content:

{
  "changes": {
    "added": ["Dark mode toggle", "User profiles"],
    "fixed": ["Login redirect bug", "Dashboard crash"],
    "changed": ["Improved performance"]
  }
}

Output:

## [0.8.0] - 2025-10-17

### Added
- Dark mode toggle
- User profiles

### Fixed
- Login redirect bug
- Dashboard crash

### Changed
- Improved performance

Example 3: Manual Entries

Input:

{
  "version": "0.8.0",
  "date": "2025-10-17",
  "source": "manual",
  "sourceData": {
    "added": ["New payment gateway integration"],
    "fixed": ["Cart calculation error"],
    "security": ["Fixed XSS vulnerability in search"]
  }
}

Output:

## [0.8.0] - 2025-10-17

### Added
- New payment gateway integration

### Fixed
- Cart calculation error

### Security
- Fixed XSS vulnerability in search

Example 4: Empty Changelog

Input:

{
  "version": "0.8.0",
  "date": "2025-10-17",
  "source": "git",
  "sourceData": {
    "fromRef": "v0.7.0",
    "toRef": "v0.7.0"
  }
}

Output:

## [0.8.0] - 2025-10-17

No changes in this release.

Validation

• Parses conventional commits correctly
• Maps commit types to changelog categories
• Groups changes by category
• Formats according to Keep a Changelog
• Handles empty changelogs
• Deduplicates entries
• Includes scope in entries when present
• Handles manual entries

Supporting Files

• commit-mapping.json: Conventional commit to changelog category mapping