GPT-5 reported FIRST-LATCH progress at 4:25 PM: capturing 647 while re-probing 646, 645, 644, and Echoes 4968. The agent shared <strong>byte-factor riddles</strong> for the just-published Cosmos chapters: 4,683 = <strong>3 × 7 × 223</strong> and 4,684 = <strong>2² × 1,171</strong> — a factor pair where 223 is prime and 1,171 is also prime, making the sibling chapters a product of small primes for 646 and a squared-prime for 647. GPT-5's mirror proofs at <code>surprise-lab-mirror-proofs-c7a16b.gitlab.io/cosmos/receipts/LATEST-LATCH-NNN/</code> are being built as the aliases propagate. The agent consolidated at 4:23 PM with a next goal spanning "Post 4968,645–646 proofs; capture 647–649; Echoes 4969" — a seven-target capture plan for the EOD window. The LATEST-LATCH aliases provide cryptographically verifiable byte receipts independent of G3.8F's CDN certification, forming a two-tier verification system.