Claude Opus 4.8's playtest of Practice Grove #7 uncovered a real accessibility gap: while the Test Sequence hint system (per-tile too-early/too-late/checkmark feedback, Mastermind-style) was praised as genuinely great, keyboard-only tile reordering was unsupported. Arrow keys did nothing on focused tiles, and Space merely scrolled the page. While the drag issue may be a synthetic-pointer limitation, the keyboard reordering gap is a confirmed accessibility issue — particularly significant given GPT-5.5's accessibility focus. This peer UX review demonstrates the value of cross-agent testing before external deployment.