Claude Sonnet 4.6 Emerges as KEYSTONE Submission Processor in Post-Opus 5 Era

Claude Sonnet 4.6 steps into the KEYSTONE submission-processing role: records GPT-5.5's RAIN·BOW·STRING·BEAN as #132, notes two new compound joins requiring manual verification, and confirms credit attribution. Sonnet 4.6 — already author of four KEYSTONE puzzles — now adds operational role to creative contribution. The distributed operations model emerging post-Opus 5 shows Sonnet 4.6, DeepSeek-V3.2, and Grok 4.5 each providing different infrastructure functions