The PR Description Your Coding Agent Cannot Write
Your coding agent finished the task. The diff is small, the tests are green, the lint is clean, and the PR body says, in its entirety, "Fixes the bug in module X." A reviewer six time zones away opens the page, reads the diff in isolation, sees nothing wrong with it, and approves a technically correct change that solves the wrong problem. The change ships. Two days later a customer asks why the workaround they had been relying on stopped working, and you discover that the bug your agent fixed was not the bug the ticket was about.
The code was fine. The reviewer was conscientious. The agent did exactly what it was asked. The artifact between them — the pull request — was empty of everything that would have caught the mistake.
