> We've been including product tips in PRs created by Copilot coding agent

If the PR is wholly authored by Copilot I get the spirit of this, although maybe not the best implementation. And "tips" like this that look like an ad for a product _definitely_ feel like an enshittification betrayal of the user, even if it was a genuine recommendation and not a paid advertisement.

In the OP's situation, where where Copilot was summoned to fix some thing within a human-authored PR, irrelevant modification of the PR description to insert unrelated content is specifically egregious. Copilot can easily include the tip in its own comment, so I'm curious why it was decided to edit the description of a PR instead.