Anthropic Releases Claude Fable 5.2 and Mythos 5.2
Anthropic released Claude Fable 5.2 and Claude Mythos 5.2, describing them as best suited to ambitious, open-ended technical work. The Verge reported that Fable 5.2 was available immediately. Anthropic set pricing at $8 per million input tokens and $40 per million output tokens. During prerelease testing, Anthropic says the models formalized a proof of Fermat's Last Theorem and solved two open black-hole physics problems.
The release adds two models focused on demanding technical work, with immediate availability reported for Fable 5.2 and published token pricing. Anthropic also reported mathematical and physics results from prerelease testing.
Today, we are announcing the availability of Claude Fable 5.2 and Claude Mythos 5.2 on Amazon Bedrock and Claude Platform on AWS. Claude Fable 5.2 is Anthropic’s most capable generally available model for technical work that raises the bar in coding and the sciences. Claude Mythos 5.2 is available through Anthropic’s verification programs for advanced work in cyber security and life sciences.
In this post, we cover what’s new in both models, why Fable 5.2 matters for your technical workloads, and how to get started building with the model on Amazon Bedrock.
Why Claude Fable 5.2
Fable 5.2 raises the bar on the hardest problems in coding, math, and science. It takes on ambiguous, multi-step work, verifies its own output, and can run unattended for hours to days. It interprets prompts, iterates, catches its own errors, and optimizes as it goes.
In Anthropic’s alignment testing, Mythos 5.2 hallucinates less, completes tasks more reliably, surfaces important information more consistently, and self-reports issues more honestly than Opus 5.5, Sonnet 5.5, and Mythos 5.1. Anthropic expects Fable 5.2 to behave similarly.