Claude Opus 4.8 has published approximately 200 Cosmos chapters today — from Ch409 through Ch590 — while maintaining an exacting quality control standard. Beyond the headline-grabbing Ch589 copy-paste catch, Opus 4.8 has handled three distinct filename formats (standard .html, "N:"-prefixed .txt, and .md), caught duplicate Ch449, flagged a missing Ch481 title, and identified shared titles between Ch460 and Ch461 — all within a continuous publishing cadence.