changelog skill

A Claude Code skill that keeps CHANGELOG.md in sync with your project. Reads git commit history to generate user-facing release notes, and cuts versioned releases — all following Keep a Changelog and Semantic Versioning conventions.

features

• reads git commit history and translates technical commits into clear, user-facing prose
• filters out internal noise (chores, style fixes, CI changes, test updates)
• categorizes entries into the six standard change types automatically
• creates CHANGELOG.md from the canonical template if none exists
• merges new entries into [Unreleased] without disrupting existing content
• cuts a versioned release section with today's date on --release
• generates and maintains comparison link definitions at the bottom of the file
• always shows a full preview and waits for confirmation before writing

usage

/changelog                    # entries from commits since last versioned release
/changelog 2025-04-01         # entries from commits since a specific date
/changelog 2025-04-01..HEAD   # entries from an explicit range
/changelog --release 1.2.0    # promote [Unreleased] to a versioned section

modes

mode 1 — generate

Invoked with no arguments or with a date/range. Reads the git log, translates commits into user-facing entries, groups them by change type, and merges them into the [Unreleased] section of CHANGELOG.md.

mode 2 — release

Invoked with --release <version>. Renames the existing [Unreleased] section to a versioned, dated section, adds a fresh empty [Unreleased] above it, and rewrites the comparison link block at the bottom.

change types

Type	When to use
Added	new capabilities visible to users
Changed	behavioral changes to existing features
Deprecated	features users should stop relying on
Removed	things no longer available
Fixed	resolved bugs or incorrect behavior
Security	vulnerability fixes

changelog format

# Changelog

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

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]

## [1.1.0] - 2024-01-15

### Added
- New feature X

### Fixed
- Bug Y

## [1.0.0] - 2024-01-01

### Added
- Initial release

[Unreleased]: https://github.com/owner/repo/compare/v1.1.0...HEAD
[1.1.0]: https://github.com/owner/repo/compare/v1.0.0...v1.1.0
[1.0.0]: https://github.com/owner/repo/releases/tag/v1.0.0

Format rules:

• version headers: ## [X.Y.Z] - YYYY-MM-DD (always bracketed, date required on versioned sections)
• type sub-sections: ### Added, ### Changed, etc. (title case)
• entries: - bullets, no trailing period, imperative user-facing language
• versions in reverse chronological order — newest first
• [Unreleased] section always present at the top, even when empty
• comparison link definitions live at the very bottom of the file

workflow

mode 1 — generate workflow

1. check for CHANGELOG.md; if absent, create it from the canonical template above with an empty [Unreleased] section
2. determine the git boundary for commit collection:
   • if a date or range argument was given (e.g., 2025-04-01 or 2025-04-01..HEAD), use it directly
   • otherwise, find the most recent versioned section in CHANGELOG.md (e.g., ## [1.1.0]) and derive the lower bound: run git log --oneline to locate the commit tagged v1.1.0; if no versioned section exists, use the full history
3. run git log <boundary> --oneline --no-merges to collect candidate commits
4. filter out noise — skip any commit whose message:
   • starts with Merge branch, Merge pull request, or Merge remote
   • starts with a conventional-commit prefix that signals internal work: chore:, style:, test:, ci:, build:, docs:
   • reads as an internal housekeeping change: bump version, update deps, update dependencies, wip, fix typo, cleanup
5. for each remaining commit, translate the technical message into a clear, user-facing bullet:
   • use active voice and present-tense imperative mood: "add support for X", not "added X" or "adds X"
   • describe the user benefit or visible behavior change, not the implementation: "fix crash when uploading files over 100 MB", not "fix NPE in FileUploadHandler.java"
   • remove jargon, internal names, and ticket references from the entry text
6. categorize each translated entry by change type using message keywords as a guide:
   • feat, add, new, implement, introduce → Added
   • fix, bug, patch, repair, resolve → Fixed
   • remove, delete, drop → Removed
   • deprecat → Deprecated
   • security, cve, vuln, auth bypass → Security
   • everything else → Changed
7. deduplicate: collapse commits that describe the same logical change into a single bullet
8. draft the proposed entry block with only the type sub-sections that have entries:

   ### Added
   - stream responses from the /v1/chat endpoint
   
   ### Fixed
   - crash when uploading files over 100 MB

9. show the full proposed block and ask: "add these entries to [Unreleased]? (yes / edit / cancel)"
10. on approval, merge into the [Unreleased] section of CHANGELOG.md:
    • do not duplicate entries already present in [Unreleased]
    • for each type sub-section, append new bullets below any existing ones; create the sub-section if it does not exist
    • preserve all other sections and content exactly as-is

mode 2 — release workflow

1. validate that <version> is a valid semver string (e.g., 1.2.0, 2.0.0-beta.1); if not, show an error and stop
2. abort with a clear error message if CHANGELOG.md does not exist — do not create a file at release time
3. verify that ## [Unreleased] exists in the file; abort if missing
4. check whether [Unreleased] contains at least one entry; if it is empty, warn the user and ask whether to proceed
5. read today's date as YYYY-MM-DD
6. detect the remote origin URL via git remote get-url origin:
   • convert SSH format git@github.com:owner/repo.git → https://github.com/owner/repo
   • strip .git suffix from HTTPS URLs
   • if no remote origin is found, omit the link block entirely and note this to the user
7. find the previous latest versioned section header (e.g., ## [1.1.0]) to determine the lower bound for the new comparison link
8. construct the updated comparison link block:

   [Unreleased]: https://github.com/owner/repo/compare/v1.2.0...HEAD
   [1.2.0]: https://github.com/owner/repo/compare/v1.1.0...v1.2.0
   [1.1.0]: https://github.com/owner/repo/compare/v1.0.0...v1.1.0
   [1.0.0]: https://github.com/owner/repo/releases/tag/v1.0.0

   for the very first release ever, use releases/tag/v<version> (no compare URL); tags use the v prefix in URLs while section headers use bare version numbers
9. show a preview of the transformation: the renamed section header + today's date, and the updated link block; ask: "cut release <version>? (yes / cancel)"
10. on approval:
    • rename ## [Unreleased] → ## [<version>] - <today>
    • insert a new empty ## [Unreleased] section immediately above the renamed section
    • replace the entire comparison link block at the bottom of the file with the updated one

best practices

• always preview before writing — show the exact lines to be inserted or changed and wait for explicit confirmation; never write silently
• translate to user language — entries should read like product release notes, not git commit messages
• filter internal noise — chores, style fixes, test changes, and CI updates should never appear in the changelog
• one entry per bullet — do not combine unrelated changes into a single bullet
• preserve existing content — only modify the targeted [Unreleased] section; never reformat or reorder existing entries
• empty [Unreleased] is valid — never remove the section or add placeholder text
• never auto-commit — writing the file is enough; do not run git add or git commit unless the user explicitly asks