Anthropic Disables Claude Fable 5 and Mythos 5 After US Government Order

After US Government Order">

Anthropic has disabled its two most capable models for every customer. The shutdown followed a US government export control directive. The order arrived on June 12, 2026. It named Claude Fable 5 and Claude Mythos 5 specifically. Both models had launched only three days earlier, on June 9.

The directive cited national security authorities, according to Anthropic. It suspended access by any foreign national, inside or outside the United States. That scope included Anthropic’s own foreign national employees. Anthropic cannot filter foreign nationals from US users in real time. So it shut both models down for everyone to ensure compliance.

Access to all other Anthropic models was unaffected. Claude Opus 4.8 and the rest stayed online.

Anthropic published a public statement within hours of the order. Commerce Secretary Howard Lutnick sent the letter to CEO Dario Amodei. The letter did not spell out the specific national security concern.

Anthropic’s own reading is narrower. It believes the government learned of a method to “jailbreak” Fable 5. A jailbreak bypasses a model’s safeguards to elicit blocked behavior. Anthropic reviewed a demonstration tied to a few minor vulnerabilities. It says other public models find the same flaws without any bypass. Anthropic also said the demonstrated capability is widely available elsewhere. It named OpenAI’s GPT-5.5 as a comparable example.

The Commerce Department moved after another company claimed it jailbroke Mythos. That claim alarmed officials about possible national security risk. The administration had earlier tried to delay the launch. Anthropic declined, and the export control letter followed.

Anthropic is complying while disputing the rationale openly. It calls the situation a likely misunderstanding. The company says the cited jailbreak is narrow and non-universal. The technique essentially asks the model to read a codebase and fix flaws. Anthropic argues a narrow jailbreak should not justify a full recall. It warns that this standard would halt new deployments industry-wide.

The table below summarizes the current status of each model.

Fable 5 is a Mythos-class model, a tier above Opus. Anthropic made it safe for general use with new classifiers. Classifiers are separate AI systems that detect potential misuse. They flag queries on cybersecurity, biology and chemistry, and distillation. Flagged queries fall back to Claude Opus 4.8 instead. Users are told whenever a fallback happens.