{"entity":"claude-mythos-5-1","name":"Claude Mythos 5.1","events":[{"date":"2026-09-01","until":null,"published":null,"recorded":"2026-11-04","predicate":"model_release","value":"Claude Mythos 5.1","status":"valid","assertable":true,"id":"clm_7B89C517BB64","evidence":{"by":"page-read","on":"2026-11-04","quote":"September 1, 2026 We’ve launched Claude Fable 5.1 ( claude-fable-5-1 ), the successor to Claude Fable 5 for long-running agentic coding, knowledge work, and research, alongside Claude Mythos 5.1 ( claude-mythos-5-1 ) for Project Glasswing participants.","url":"https://platform.claude.com/docs/en/release-notes/overview"}}],"complete":true,"legend":{"dates":"valid_from: when the claim took effect (a period figure: the day its period closed). published: the earliest day a source on the record published it (a filing's filing date, a post's date; null when no source carries one). recorded: the day AsOf first held it. A figure can take effect weeks before it is published.","why_not":{},"checked_by":{"page-read":"its source page states the value and the date"}}}