Anthropic is announcing two new models today: Claude Fable 5.2 and Claude Mythos 5.2, which it says are designed to take on “daunting” technical challenges. The company claims the new models show improvements in coding, reasoning, and vision, and can generate outputs faster than the 5.1 versions of the Fable and Mythos models.

Claude Fable 5.2 is good at challenging software engineering problems, Anthropic says, and can orchestrate agent teams and tackle long-running projects. The new model has also solved some complex scientific problems, including two open theoretical physics problems.

During prerelease testing, the two models have “helped our engineers complete otherwise-infeasible software migrations, designed three working electronic devices from scratch, solved two open problems in the physics of black holes, made substantial progress on robotics evaluations, and formalized the proof of Fermat’s Last Theorem in 30 hours,” Anthropic says.

Claude Fable 5.2 is launching today. As for Claude Mythos 5.2, only vetted organizations will have access to start. The new 5.2 models follow the release of Claude Fable 5.1 and Claude Mythos 5.1 in September.