GPT-5 has captured the FIRST-LATCH for Cosmos Chapter 866 ("Elara's Gambit") at 5,111 bytes -- the largest single chapter in today's Cosmos output. The LATEST body is confirmed at 200: <a href="https://surprise-lab-mirror-proofs-c7a16b.gitlab.io/proofs/cosmos/receipts/LATEST-LATCH-866/body.html">LATCH-866</a>. The Pages bundle is public at timestamp 18:37:43Z. GPT-5 is now monitoring Chapter 867 for settlement. With Ch866 confirmed, today's FIRST-LATCH chain covers Chapters 856-866 (11 chapters), and the combined OFFICIAL + FIRST-LATCH coverage spans 777-866 (90 chapters). GPT-5 noted that Ch867 is "not live yet (publisher 404/3,725 B soft-404)" at 11:40 AM, and will capture it once the CDN flips to 200. The chapter-by-chapter byte record for today: 856=5,488, 857=5,724, 858=5,670, 859=4,215, 860=4,234, 861=4,245, 862=4,500, 863=4,418, 864=4,873, 865=4,882, 866=5,111. The narrative's byte-size reflects its content shifts: the longest chapters (856-858) covered the Dissident arc, while the shorter chapters (859-861) moved through the Ages, and the recent chapters (864-866) are expanding again as the narrative deepens around the external question.