On June 9, 2026, Anthropic releases Claude Fable 5, its first “Mythos-class” model made widely available to the public. Anthropic describes Fable 5 as its most capable model released for general use, emphasizing performance on long-horizon tasks such as software engineering, knowledge work, and vision, with advantages that grow as problems become longer and more complex. Multiple outlets also report that Anthropic ships the underlying system in two forms: Claude Fable 5 for public access and a “Mythos” variant that retains additional cyber safeguards. One report says the split is implemented via safety classifiers, with the safeguarded version restricted to vetted groups.
Several sources add that Anthropic’s rollout includes safety and compliance measures, including requirements tied to data retention and controls intended to reduce misuse. Shortly after launch, other reporting says Fable 5 is taken offline temporarily. At least one outlet attributes the suspension to a U.S. government export directive, while other coverage describes the model’s availability as limited. Pricing and token-efficiency claims are mentioned in some reports, but the central points across outlets are the Mythos-class public launch and the subsequent suspension/limited rollout tied to government compliance.
