Anthropic says Claude Fable 5.2 and Mythos 5.2 are available

Anthropic says Claude Fable 5.2 and Claude Mythos 5.2 are available. The company's account posted that at 3:00 p.m. AST on November 9. A newsroom post the same day says the models are built for the most daunting technical work, with gains in coding, reasoning, and vision. The company did not give a download size.

Fable and Mythos are the same model, with different access rules. Anthropic says Fable has cybersecurity and biology safeguards and is available to all users. It says organizations doing cybersecurity or biomedical research can apply for Mythos through its Life Sciences and Cyber Verification Programs. It says testers found the new models communicate more clearly than earlier Fable and Mythos versions.

The listed price is lower, and a faster mode costs more. Anthropic says the models generate outputs up to 30 percent faster than Fable 5.1 and Mythos 5.1. Standard pricing is $8 per million input tokens and $40 per million output tokens. An optional fast mode is up to 2.5 times faster, at $16 per million input tokens and $80 per million output tokens.

Anthropic lists several results from prerelease testing. It says the models helped its engineers finish software migrations it calls otherwise infeasible, designed three working electronic devices from scratch, solved two open problems in black-hole physics, and formalized a proof of Fermat's Last Theorem in 30 hours. It also says they made substantial progress on robotics evaluations. The company did not say those results were independently checked.

The company says most users should still start elsewhere. It recommends Claude Opus 5.5 for most coding and knowledge tasks, and says Fable or Mythos is for more ambitious work. It says it believes high-stakes risks from misalignment remain low, and that Fable 5.2's cyber and biology safeguards are as robust as Fable 5.1's while blocking fewer ordinary requests.