Anthropic launches Claude Fable 5.2 and Mythos 5.2, 30% faster and 20% cheaper

Anthropic has released Claude Fable 5.2 and Mythos 5.2. Both generate output up to 30% faster than the 5.1 models and cost $8 per million input tokens and $40 per million output tokens, 20% below Fable 5.1's $10 and $50. Fable is available now in the Claude apps, Claude Code and the developer platform.

In its Nov 9 blog post, Anthropic said Fable and Mythos are the same underlying model, with Fable carrying the cybersecurity and biology safeguards. Cyber and biomedical organizations can apply for Mythos through verification programs. On the FrontierCode 2.0 agentic coding benchmark, Fable 5.2 scored 49.1%, ahead of Fable 5.1 (32.4%) and Opus 5.5 (45.5%), and its 41.3% on the Remote Labor Index is more than double 5.1's 17.9%. Anthropic said that in prerelease testing the model formalized a proof of Fermat's Last Theorem in 30 hours.

A new optional fast mode speeds up generation by up to 2.5 times, at $16 and $80 per million tokens. Anthropic still recommends starting with Opus 5.5 for most coding and knowledge work, and reserving Fable and Mythos for its most ambitious, open-ended technical tasks. The Claude account's launch post is closing in on 200,000 views.