METR system card reportedly confirms Fable/Mythos 5.2 is Model 3, internal Model 4 exists
toptickcrypto · x · 2026-11-10
toptickcrypto highlights that METR's Fable/Mythos 5.2 system card directly identifies the deployed model as Model 3, with the "internal model" referenced there being Model 4. A screenshot shows METR's September 23 observations on [Claude Mythos 5.2]'s AI R&D-relevant capabilities, based on API access and pre-deployment evaluation info provided by Anthropic, feeding into an Independent Assessment of AI R&D Acceleration at Anthropic published in October 2026, where the snapshot is called "Model 3 Early". Third-party reading, not officially confirmed.
More from Models
- Anthropic says it deliberately capped Model 3's AI-accelerating research capabilities — ziv_ravid · 2026-11-10
- MiniMax H3 Image early access: 16 reference images, 4K output, striking realism — flowersslop · 2026-11-10
- Blogger benchmarks three top models: Opus for code, Fable for architecture — aigclink · 2026-11-10
- Plus Subscriber Complains: No Free Resets, Out of Usage for Three Days — TameYour · 2026-11-10
- Anthropic's paternalism and Claude's paternalism are the same phenomenon — amplifiedamp · 2026-11-10
- SemiAnalysis Launches GDPx Leaderboard: Claude Fable 5.2 Debuts on Top at 16.4% — scaling01 · 2026-11-10