'Claude Fable & Mythos 5.2' leak shows benchmark sweep past Opus 5.5 — but the model names don't exist
thesaraharminta · x · 2026-11-10
X user @synthwavedd claims "Claude Fable & Mythos 5.2" is now rolling out, calling it likely the new best model in the world, with OpenAI's "6.2 Astra" allegedly close behind. The attached benchmark table shows:
- Agentic coding: 49.1% on FrontierCode 2.0 vs Opus 5.5's 45.5%; 69.9% on FrontierSWE v2
- Agentic scientific research: 74.6% (Mythos 5.2: 75.3%); CVE Rediscovery 89.6%; protein design 85.1%
- Computer use (OSWorld 2.1) 89.3%; Robotics (RoboDoJo Sim) 64.9% vs Fable 5.1's 27.6%
- Humanity's Last Exam (with tools) 74.2%; Elo 1785, still below Opus 5.5's 1800
⚠️ Caveat: "Fable," "Mythos," "GPT-6 Astra," and "Gemini 4 Carbon" are not known real models — the claim and scores are highly suspect, likely fictional/parody, and unverified.
Related event: Anthropic Launches Claude Fable 5.2 and Mythos 5.2(45 posts)→
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