U.S. order forces Anthropic to disable Fable 5 and Mythos 5

The U.S. government issued a national security order to Anthropic on June 12 at 5:21 p.m. Eastern requiring suspension of access to the company’s two most advanced models, Fable 5 and Mythos 5, for any foreign national. Anthropic said it could not reliably separate foreign users from others in real time and disabled both models for all customers worldwide.

Anthropic wrote in a statement: “The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance. Access to all other Anthropic models will not be affected.”

The directive invoked national security authorities and required suspension of access for “any foreign national, whether inside or outside the United States, including foreign national Anthropic employees.” The Commerce Department issued the order after receiving a report that another firm had demonstrated a way to jailbreak Mythos, according to government officials.

Anthropic said the evidence it reviewed was verbal and narrowly focused on a prompting technique that asked the model to read a specific codebase to fix software flaws. The company argued a limited demonstration did not justify recalling a commercial model used at scale and called for action to follow a transparent statutory process. The company added: “The finding of a narrow potential jailbreak should not be cause for recalling a commercial model deployed to hundreds of millions of people.”

The shutdown removed access for hundreds of millions of users and affected developers and organizations that relied on the models. Some developers were cut off mid-project and some businesses lost access to customer-facing or internal tools. Anthropic said it will comply with the directive while contesting the basis for the order and working to restore access where possible.

Regulators have tightened export controls in recent years on advanced chips and high-performance computing. The language of the order applies a nationality-based restriction directly to commercial AI models and includes foreign national employees in its scope.

Onchain markets track pre-IPO perpetual futures tied to private companies, including contracts referencing Anthropic. Those contracts let traders take leveraged positions on a firm’s implied valuation; a regulatory order that disables core products can affect sentiment and the prices of such contracts.

For now, Fable 5 and Mythos 5 remain offline worldwide while other Anthropic models continue to operate. The company and the government may pursue further steps through formal procedures or lift the directive.