keep-a-changelog

name	keep-a-changelog
description	Maintain CHANGELOG.md in Keep a Changelog format by updating Unreleased and version sections with user-relevant changes.

Keep a Changelog Assistant

This skill helps keep CHANGELOG.md accurate, current, and user-focused following Keep a Changelog format.

It is intended for maintaining changelog entries as the product evolves.
The agent helps update ## [Unreleased] and, when explicitly asked, prepare version sections in the changelog.
The human remains responsible for deciding when and how to cut a release.

Use this skill when

• The user explicitly asks to update or maintain CHANGELOG.md
• The user provides changes and wants them added to ## [Unreleased]
• The repository changes imply that CHANGELOG.md should be updated
• The user wants help categorizing changes into Added, Changed, Deprecated, Removed, Fixed, Security
• The user wants to turn accumulated Unreleased notes into a versioned changelog section

Do not use this skill when

• There is no CHANGELOG.md
• CHANGELOG.md does not follow Keep a Changelog structure
• The requested changes are purely internal and not relevant to users
• The user is asking the agent to publish, tag, or perform the release itself

Repository Conventions (MUST FOLLOW)

Scope of Changelog Entries

The changelog must include only user-relevant product changes.

For this repository, that generally means:

• Changes to code inside src/
• Changes affecting public APIs
• New domain primitives, contracts, or behaviors
• Behavioral changes in existing modules
• Packaging changes that affect installation or runtime behavior

The changelog must NOT include:

• Test changes (tests/)
• CI/CD workflow updates
• GitHub Actions changes
• Agent skills or internal tooling
• Documentation-only changes
• Formatting or lint-only changes
• Refactors with no observable behavior impact
• Internal development tooling adjustments

If a change does not affect how users import, use, or install the library, it should generally be excluded from the changelog.

Notability Rule

Only include changes that are meaningful to library consumers.

Do not include:

• trivial renames
• internal restructuring
• minor refactors without API impact
• small code cleanups

Changelog format

CHANGELOG.md must remain in this structure:

• ## [Unreleased]
  • ### Added
  • ### Changed
  • ### Deprecated
  • ### Removed
  • ### Fixed
  • ### Security
• Version sections:
  • ## [X.Y.Z] - YYYY-MM-DD
  • same categories inside as needed
• Reference links at the bottom exist (for example [unreleased]: ..., [0.1.1]: ...)

The six categories above are the baseline. Additional semantic sections MAY be introduced when a change does not fit the basics (for example a dedicated ### Security callout, or another clearly-named category). Add them only when they improve clarity; do not invent categories for changes that already fit.

Important:
Do not add or modify bottom reference links unless explicitly asked.

Entry formatting (MUST FOLLOW)

• Blank line between entries. Every list item is separated from the next by one blank line. Never stack bullets directly on adjacent lines.

# wrong
- Something
- Something 2

# right
- Something

- Something 2

• Self-contained. Each entry must stand on its own without referencing other entries, commits, or external context.
• Compact. Up to 3 sentences and at most 320 characters per entry.
• Minimal inline code. Use inline code (`like_this`) as sparingly as possible — only for an essential identifier such as a symbol or flag. Prefer plain prose.
• No structural extras. Entries must NOT contain tables, migration instructions, upgrade steps, code blocks, or similar. The changelog records what changed, not how to adapt to it.

Categorization rules

Use these types as defined by Keep a Changelog:

• Added: new features
• Changed: changes in existing functionality
• Deprecated: soon-to-be removed features
• Removed: now removed features
• Fixed: any bug fixes
• Security: in case of vulnerabilities

Additional rules:

• Avoid duplicates between categories
• Keep entries short, neutral, and user-focused
• Prefer outcome-oriented wording over implementation detail
• Exclude internal-only changes even if they are technically substantial

Workflow A — Update Unreleased

When the user says "update changelog", "add to changelog", or provides a list of changes:

1. Extract notable user-facing changes from the user summary, commits, PR descriptions, or diffs.
2. Exclude non-user-facing and non-notable changes.
3. Place each remaining change under the best category in ## [Unreleased].
4. Preserve existing formatting and spacing, and apply the entry formatting rules (blank line between entries, self-contained, ≤ 3 sentences / 320 characters, minimal inline code, no tables or migration steps).
5. Output:
   • a patch/diff, or
   • the updated ## [Unreleased] block

Workflow B — Create a version section in CHANGELOG.md

When the user explicitly asks to convert current changelog notes into a versioned section:

1. Use the target version X.Y.Z.

2. Use today's date in YYYY-MM-DD using the user's timezone.

3. Create a new section directly under Unreleased:

   ## [X.Y.Z] - YYYY-MM-DD

4. Move content from ## [Unreleased] into that new version section:

   • Keep the same category headings
   • Omit empty categories

5. Reset ## [Unreleased] categories back to placeholder state (- ...)

6. Do not edit reference links at the bottom unless explicitly asked

7. Output the proposed changelog edits as a diff or updated blocks

Output format (always)

When updating the changelog, always produce:

1. Proposed CHANGELOG.md changes (diff or updated sections)
2. Any assumptions or TBDs (if applicable)
3. A short note that release decisions and tagging are handled by the human, while the agent only helps keep CHANGELOG.md current