Claude Fable 5.1
MultimodalClaude Fable 5.1 is Anthropic's generally available, production-safeguarded deployment of the same underlying weights as the trusted-access Claude Mythos 5.1. It targets demanding reasoning and long-horizon agentic work with a 1M-token context window, 128K max output, and adaptive thinking always enabled, and it leads self-reported launch results on Terminal-Bench 4.0 and Humanity's Last Exam. First-party pricing matches Fable 5 at $10/$50 per million tokens with cache reads cut to $0.25 per million.
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Compare Claude Fable 5.1
All comparisonsArticles about Claude Fable 5.1
'What are these benchmarks': r/singularity pushes back on Claude Fable 5.1's launch table
r/singularity met Claude Fable 5.1's launch benchmark table with 'what are these benchmarks' — new evals, self-reported scores, and safety routing under fire.
Claude Fable 5.1 and Mythos 5.1 arrive with a 75% cache cut and a 20% per-task markup
Anthropic released Claude Fable 5.1 and Mythos 5.1 — one model behind two safeguard tiers. Cache reads fell 75%, yet measured per-task costs rose about a fifth.
Fable 5.1 claims a 373-year-old cipher solved in 44 minutes. Nobody has checked it
Vals AI claims Claude Fable 5.1 solved Urquhart's 373-year-old Cyphral Distich in 44 minutes. No expert has verified it — the mechanism is the real story.
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