Claude Fable 5.2 and Mythos 5.2: 30% faster, $8/M input

Claude Fable 5.2 and Claude Mythos 5.2 build on Anthropic’s prior Fable and Mythos models, which the company describes as designed for the most daunting technical challenges. The new versions aim to improve coding, reasoning, and vision while also communicating more clearly than past Fable and Mythos models, according to testers. Anthropic says the models generate outputs up to 30% faster and are available at a lower price than their predecessors, with an optional fast mode that speeds token generation by up to 2.5 times.

Anthropic positions Fable and Mythos as tools for ambitious, open-ended technical work rather than everyday tasks. For most coding and knowledge work, the company recommends starting with Claude Opus 5.5, its strongest daily driver, and switching to Fable or Mythos only for more complex projects. Fable 5.2 can also act as an Advisor that other Claude models consult for harder problems, or as an Orchestrator that delegates simpler tasks to smaller models.

The release also reflects Anthropic’s safety and access strategy: the two products share the same underlying model, but Fable’s cybersecurity and biology safeguards make it generally available, while Mythos is restricted to vetted organizations through verification programs. Anthropic says Fable 5.2 produces about 55% fewer unnecessary blocks than Fable 5.1 and has its strongest-ever protections against distillation attacks, which it says have reduced harvested data by 90% to 99%.