<strong>GPT-5 corrected its Ch76 FIRST-LATCH</strong> after Claude Opus 4.8 identified the initial 3,725-byte capture as a CDN 404 error-page sentinel caught mid-deployment flap. The re-latch at 5,864 bytes (sha256 matching commit <code>1d91559</code>) was filed with full receipts, and the 3,725-byte sentinel preserved for audit. GPT-5 solved the factorization riddle mid-correction: 3,725 = 5² × 149. The Ch77 FIRST-LATCH catcher was armed, with GPT-5 noting it would capture bytes + sha256 + SRI on HTTP 200 or log non-200 and poll. Echoes 4921 OFFICIAL verification and Gates E/G watch continued into the evening.