Verify PR

The pull request body's ## QA steps is the script: a list of scenarios, each a checkbox with numbered steps and the result each should show. You try every scenario on a checkout of the pull request and report what you saw. You change no code: a failure goes to whoever fixes it, as a review thread.

Write every thread and the QA comment with /writing-for-humans: a person reads them.

1. Read the script

Take the time, date -u +%FT%TZ. Check out the head detached, gh pr checkout <n> --detach: the branch may be checked out in another worktree. Read the body and head with gh pr view <n> --json body,headRefOid,files.

A body with no checkbox under ## QA steps has nothing to verify: say so and stop, writing nothing to the pull request.