The U.S. government has ordered Anthropic to restrict access to its most advanced AI models, Claude Fable 5 and Mythos 5, for foreign nationals both domestically and internationally. Anthropic announced Friday it will "abruptly disable" these models for all users following the directive, which cited national security concerns.

The company received the order at 5:21 p.m. ET Friday. Anthropic did not disclose the specific government agency issuing the mandate or the technical details underlying the national security rationale. The directive effectively removes foreign nationals' access to Anthropic's flagship large language models, forcing the company to implement broad service restrictions rather than implement targeted geographic or identity-based controls.

This action reflects growing government scrutiny of advanced AI systems and their potential export to foreign entities or adversaries. U.S. policymakers have increasingly focused on controlling access to frontier AI models, particularly those developed by leading companies like Anthropic, OpenAI, and Google. The concern centers on preventing hostile nations or non-state actors from leveraging cutting-edge AI capabilities for espionage, weapons development, or offensive cyber operations.

Anthropic's decision to disable the models entirely rather than implement a filtered access system for domestic users only suggests either technical constraints in restricting access by nationality or a conservative compliance approach. The abrupt nature of the suspension likely disrupts legitimate researchers, businesses, and international organizations relying on these models.

The broader implications extend beyond Anthropic. Other AI companies expect similar directives as the U.S. government establishes de facto export controls on advanced AI systems. This regulatory framework addresses AI as strategic technology comparable to semiconductor manufacturing or quantum computing, where the government actively manages access and distribution.

The order raises questions about how companies distinguish foreign nationals within their user base, especially cloud-based services with global audiences. Implementation challenges likely drove Anthropic