Changes over time Recommended
Keep a changelog
Publish a dated changelog for the API, with every addition, deprecation and removal.
How to do it
Write one entry per release, linking to the endpoints that changed. Offer it as a feed, such as Atom or RSS, so clients and agents can follow it. See also keep a changelog written for users.
How to check
The last three contract changes each have a dated changelog entry.
For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers api design playbook: https://agentwranglers.se/playbook/api-design/changes-over-time/api-changelog.