Leak: Anthropic's unreleased Claude Mythos 5.1 surfaces; Fable 5.5 launch expected this week
haider1 · x · 2026-11-02
A leak claims Anthropic's mythos is essentially an unlocked version of fable, and Anthropic's own page references Claude Mythos 5.1 — a model previously limited to a small set of vetted partner organizations, with gains in cybersecurity and biology. The poster predicts Fable 5.5 will likely be released publicly this week, regardless of whether OpenAI ships astra 6.2. Unverified third-party rumor.
Related event: Leak Claims Anthropic's Mythos Model Exists, Fable 5.5 Launch Imminent(2 posts)→
More from Models
- Meituan's LongCat-2.5 lands as 1.6T MoE agent model, with DeepSeek copycat speculation — teortaxesTex · 2026-11-02
- Asked what AI firms want you to stop owning, Claude said: your own compute — alex_verem · 2026-11-02
- Compacting earlier cuts agent costs 16-23%; GLM 5.3 costs 30x less than Grok 4.7 — yb2698 · 2026-11-02
- Codex capacity errors spike whenever OpenAI hands out banked resets — CtrlAltDwayne · 2026-11-02
- Predictions: Opus 5.5-tier models at V4.1F inference cost within a year — teortaxesTex · 2026-11-02
- Google AI Pro user says Gemini keeps darkening his skin tone in generated portraits — Revolutionary-Pin664 · 2026-11-02