How do you hear about API changes that needs documentation update?

Question for folks documenting APIs, especially with docs in a separate repo from the code: how do you find out about changes before a customer does?

The big features usually reach us. What slips is side effects: a PR about a new filter that also lowers the max page size from 100 to 50, a default that flips, a new error code, a renamed webhook field. One line in a diff that's mostly about something else.

Things I've seen teams try:

• a "docs needed" label applied in code review

• writers watching merged PRs in the API repo

• a spec diff in CI (oasdiff, openapi-diff), which catches reference changes but not guides

• a weekly sync with an engineer from each team

What's worked for you long term? And does anyone get the linked ticket along with the diff? It's usually the only place that says why something changed.