Changelog keeper skill

Description

A house entry. Written by the people who run Promptea, published here so the catalogue has something to show and so the required fields have a worked example.

Skills are instructions plus files that an agent loads only when the task calls for them. This entry is a worked example of the shape, using a small and genuinely annoying job: keeping a changelog honest.

Layout

changelog-keeper/
  SKILL.md          instructions, loaded when the skill triggers
  reference/
    format.md       the exact heading and date grammar
    examples.md     three good entries and three bad ones

The instruction body

Trigger: any change that a user of this project could notice,
and any request to "update the changelog" or "cut a release".

Rules:
1. New entries go under "## [Unreleased]". Never invent a
   version number. Versions are assigned by a human at release.
2. One entry per user-visible change. If you cannot phrase it
   without naming an internal symbol, it is not user-visible,
   so do not add it.
3. Order inside a release: Breaking, Added, Changed, Deprecated,
   Removed, Fixed, Security. Skip empty groups.
4. Dates are ISO 8601 and are only added when a version is cut.
5. Never edit an entry under an already released version. If it
   was wrong, add a correction to Unreleased saying so.

Refuse politely if asked to backdate or reword shipped history.

Why rule 5

A changelog whose past can be edited is not a record, it is a marketing page. Every other rule here is convention. That one is the reason the file is worth keeping at all.