changelog— agent skill

Generate or update a changelog file that accumulates history across all releases.

Rules:

• Tagged release sections are permanent — never modify them.
• Only the ## Unreleased section at the top is updated on each run.
• If CHANGELOG.md does not exist, create it from scratch using all tags.

Steps:

1. Run git tag --sort=-version:refname to list all tags.
2. Check if CHANGELOG.md exists.

If `CHANGELOG.md` does not exist, generate the full changelog from scratch. For each tag (newest first), run git log <previous-tag>..<tag> --oneline to get commits for that release (for the oldest tag, use the first commit as the base). Group and format commits under a ## <tag> heading. After all tagged sections, add an ## Unreleased section for commits since the most recent tag; omit it if there are none. Write the full result to CHANGELOG.md.

If `CHANGELOG.md` exists, only update the ## Unreleased section. Run git tag --sort=-version:refname | head -1 to find the most recent tag, then git log <last-tag>..HEAD --oneline to get commits since it. Replace the existing ## Unreleased section with a freshly generated one, or prepend a new one if absent. Leave all other sections untouched.

Formatting rules for each section:

• Group commits by type: Features (feat), Bug Fixes (fix), Performance (perf), Documentation (docs), Chores & Maintenance (chore, refactor, style, test, ci). Omit empty groups.
• Write each entry as a plain-English bullet point — not the raw commit message. Include the short commit hash at the end in parentheses.
• For the ## Unreleased heading, append the suggested next semver bump in parentheses if the last tag is semver: bump patch for fixes only, minor for any feat, major for any BREAKING CHANGE.

$ARGUMENTS