Changelog Generator

Convert a git log, commit list, or release notes into a polished, user-facing changelog. Use when writing release notes, generating a CHANGELOG.md entry, or documenting what changed in a version. Produces a structured changelog section with version header, categorised changes, and migration notes. For an already-curated change list use changelog-writer instead.

Changelog Generator Skill

Converts raw git commits, a diff summary, or developer release notes into a polished changelog entry — categorised, user-facing, and following Keep a Changelog conventions.

Required Inputs

Ask for these if not provided:

• Commits or release notes (paste git log --oneline, raw commit messages, or a description of what changed)
• Version number (e.g. 2.4.0, v1.0.0-beta.2)
• Release date (or "today")
• Audience (developers using an API / end users of a product / internal team — affects language)
• Any breaking changes (flag these explicitly if known)
• Previous version behaviour (optional — paste the previous changelog entry or describe what is changing; needed for accurate "Changed" entries)
• Scope (whole product / specific package or module — e.g. "payments SDK only", "iOS app", "all services")

Output Format

Follow Keep a Changelog format:

---

[X.Y.Z] — YYYY-MM-DD

Breaking Changes ⚠️

[Only include if there are breaking changes]

• [Breaking change]: [What changed and what it breaks]
• Migration required: [Specific action the user must take]

Added

• [New feature or capability, written from the user's perspective]
• [Another addition]

Changed

• [Changed behaviour — what it did before vs. what it does now]
• [Performance improvement with measurable impact if known]

Fixed

• [Bug fixed — describe what was broken, not the fix implementation]
• [Another fix]

Deprecated

• [Deprecated thing] — use [replacement] instead. Will be removed in [version].

Removed

• [Removed thing] — was deprecated in [version]

Security

• [Security fix — describe the vulnerability class, not exploit details]

---

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Skill guidance — do not include the following section in the delivered changelog:

Formatting Rules Applied

Language: Write for the reader, not the committer. "Add dark mode support" not "implement ThemeProvider with dark palette variant".

Breaking changes: Always call these out first with ⚠️. Include a migration path.

Bug fixes: Describe what was broken, not what was changed. "Fix crash when user has no profile picture" not "null-check avatar URL before rendering".

Granularity: Group related commits into one line. Don't list every micro-commit separately.

Tone: Active voice, imperative mood. "Add", "Fix", "Remove" — not "Added", "Fixed", "Removed".

Empty sections: Omit any section with no entries. Don't include empty ### Fixed blocks.

Scoring Rubric (0–40)

Score any output of this skill before handing it over; 32+ is ship-quality.

Dimension	0	5	10
Reader-facing translation	Entries restate commit messages, with internal identifiers and implementation details	Mostly user-facing, but a few entries leak internals or describe the patch rather than what was broken	Every entry describes the change from the reader's perspective — what changed for them, never how the code was refactored
Breaking-change handling	Breaking changes buried mid-list or missing a migration path	Flagged at the top, but migration guidance is vague ("update your code")	At the top with ⚠️, each with a specific migration action the user can execute
Curation & grouping	Every micro-commit listed; internal-only commits included	Some grouping, but related commits still appear as separate entries or noise slips through	Related commits grouped into single entries; internal-only commits excluded; nothing a user can't observe
Format discipline	Wrong or missing version/date header; past-tense verbs; empty sections left in	Header correct but tense or empty-section slips remain	Keep a Changelog conventions throughout — correct header, imperative mood, only populated sections

Quality Checks

• Breaking changes are at the top with migration instructions
• All entries are user-facing language (no internal variable names or implementation details)
• Related commits are grouped into single entries (not listed individually)
• Version and date header is correct
• Empty sections are omitted
• No entries start with past-tense verbs (no "Added", "Fixed", "Removed" — use "Add", "Fix", "Remove")
• Every breaking change entry includes a specific migration action (not just "update your code")

Anti-Patterns

• Do not include implementation details in changelog entries — users need to know what changed for them, not how the code was refactored internally
• Do not list every micro-commit as a separate entry — related commits should be grouped into one user-facing change
• Do not omit the migration path for breaking changes — a breaking change entry without a specific migration action forces users to read the source code
• Do not include empty sections — a "### Fixed" section with no entries signals the template was filled in carelessly
• Do not write breaking changes in the same casual tone as minor additions — breaking changes must be visually prominent and call out migration requirements explicitly

Usage Examples

• "Write a changelog for version [X]" + [paste commits]
• "Generate release notes from these commits"
• "Turn this git log into a CHANGELOG entry"
• "Write the CHANGELOG.md update for this release"
• "What changed in this release?" + [paste commit list]