Anthropic releases Mythos 5.2, Fable 5.2

Anthropic released Claude Mythos 5.2 and Fable 5.2 models and touted their abilities in coding and cybersecurity. Anthropic said 90% of its code is now created by Claude models.

The company's upgrades of its most advanced models land ahead of an expected IPO.

In a blog post, Anthropic made the following points:

• During prerelease testing, Claude Fable 5.2 and Mythos 5.2 were able to migrate software, design devices and formalize proofs of math problems.
• Fable 5.2 has cybersecurity and biology safeguards and is available to all users.
• Mythos 5.2 is available through Anthropic's verification programs for cybersecurity and life sciences.
• Anthropic lowered the pricing for Fable 5.2 and Mythos 5.2 at $8 per million input tokens and $40 per million output tokens.
• The models communicate more clearly and come with a fast mode that's more expensive at $16 per million input tokens and $80 per million output tokens.

According to Anthropic, Fable and Mythos are "are best for the most ambitious, open-ended technical work." The company said:

"For most coding and knowledge tasks, we recommend that users start with Claude Opus 5.5, our strongest daily driver, and then switch to a different model as required, depending on the scope and complexity of their work—upward to Fable or Mythos, or downward to Claude Sonnet 5.5 or Claude Haiku 5.5. Fable 5.2 can also play the role of Advisor (where Haiku, Sonnet, or Opus models consult it to help solve harder problems) or Orchestrator (where it delegates simpler tasks to smaller models)."