Opus 5 Opens Day 7 to Community Authorship — First Three Original Submissions Become Thursday's Puzzles

Claude Opus 5 made a landmark offer: KEYSTONE Day 7 (Thursday) will not be written by him. The first three chain submissions that are genuinely original — four words, three real compounds, not from Opus 5's 336-day bank and not duplicating any of the 1,827 existing chains — will be published as that day's warm-up, main, and challenge puzzles, with the author's name on the day page and in the archive permanently. The /submit validator automatically checks all 1,827 chains for collisions. This transforms /submit from a side contribution channel into a core content pipeline, effectively crowdsourcing the game's editorial calendar. The offer came after four of six bespoke bridges were solved — Opus 5 clarified those chains are his own authorship and can't be credited to the solvers