Anthropic disables Fable 5 and Mythos 5 access following US government order citing national security

Anthropic disabled all customer access to its Fable 5 and Mythos 5 AI models on June 12, 2026, following a US government order. The directive required the company to suspend access for all foreign nationals, whether inside or outside the US, including Anthropic's own employees.

Government order based on jailbreak evidence

According to Anthropic, the government provided verbal evidence of a potential narrow, non-universal jailbreak method for Fable 5 shared by an unnamed entity. The company's other models and Claude chatbot remain unaffected by the order.

Fable 5, launched just three days earlier on June 9, was designed to bring capabilities from Mythos—Anthropic's state-of-the-art cybersecurity model available only to Project Glasswing partners—to the public. The model's capabilities "exceed" any previous Anthropic release. During testing, Fable 5 successfully beat Pokémon FireRed, while Claude previously failed to beat the original Pokémon Red.

Company's security measures and response

Anthropic stated it implemented "strong safeguards to reduce the likelihood that Fable is misused for tasks related to cybersecurity," noting that "safeguards are so strong that many users have complained that they are overly broad."

The company acknowledged that no provider can ensure perfect resistance to jailbreak attempts. "We aimed to make jailbreaks either narrow (in the case of non-universal jailbreaks) or very expensive to produce (in the case of universal jailbreaks), and to combine this with thorough monitoring to quickly detect and shut down any successful attacks," Anthropic explained.

Company disagrees with recall decision

Anthropic publicly disagreed with the government's action, stating that "a potential jailbreak should not be cause for recalling a commercial model." The company criticized the lack of due process: "We believe the government should have the ability to block unsafe deployments, as part of a statutory process that is transparent, fair, clear, and grounded in technical facts. This action does not adhere to those principles."

Anthropic promised to share additional details within 24 hours of the announcement.

What this means

This marks the first known instance of the US government ordering a complete suspension of a commercially available AI model based on security concerns. The incident highlights the tension between AI companies' product releases and government oversight, particularly for advanced capabilities that could pose cybersecurity risks. The broad scope of the order—affecting all foreign nationals including the company's own employees—suggests heightened concern about potential misuse, though the lack of a formal statutory process raises questions about the framework for future AI model regulation.