Anthropic has released Claude Fable 5.2 and Claude Mythos 5.2, aimed at the hardest technical work, with gains in coding, reasoning, and vision. btw... still didn't get GPT 6.2 ...
Claude Fable 5.2 and Claude Mythos 5.2 are the same underlying model. Fable comes with stronger cybersecurity and biosecurity safeguards and is available on paid plans and major cloud platforms; Mythos requires applying through a life sciences or cybersecurity verification program and is aimed at beneficial biomedical or cybersecurity research. For most everyday coding and knowledge work, the official recommendation is still to start with Opus 5.5, and switch to this tier for complex, open-ended long-horizon tasks.
https://www.anthropic.com/claude-fable-and-mythos-5-2
On alignment, most metrics are no lower than recent models, and external pre-release evaluations were conducted by the UK AI Security Institute, Frontier Design, METR, and others. On capability, nearly every evaluation dimension is above Opus 5.5. On FrontierCode 2.0, Fable 5.2 at High effort scores about 45.3%, roughly even with Opus 5.5's top score of 45.5%, at about half the per-task cost; at Xhigh effort it scores 49.1%, the highest among tested and released models. The app default is Medium effort.
Demonstration results: about 1,000 Fable 5.2 agents formalized Fermat's Last Theorem in 30 hours; under the same setup, Opus 5.5 reached 26% in about 18 hours and barely advanced after 30 hours. Mythos accurately modeled 28 of 34 attempted gene therapy capsids. On the simulated dual-arm benchmark RoboDojo, the internal highest tier scored 64.9%, above Opus 5.5's 39.4% and Fable 5.1's 27.6%.