Anthropic Pulls Fable 5 and Mythos 5 Offline After U.S. Government Issues National Security Order
Anthropic moved swiftly on Friday to suspend access to two of its most advanced artificial intelligence models after receiving a directive from the U.S. government citing national security concerns. The sudden shutdown of Fable 5 and Mythos 5 affected all customers globally and came just days after the models were publicly launched to considerable fanfare.
Government Order Arrives Without Warning or Explanation
According to Anthropic’s official statement, the company received the government order at 5:21 p.m. ET on Friday. The directive instructed Anthropic to immediately suspend access to the models for “any foreign national, whether inside or outside the United States, including foreign national Anthropic employees.” Faced with broad compliance requirements and no clear technical mechanism to filter users by nationality in real time, Anthropic took the decision to disable both models for all customers worldwide.
The company said the government did not provide any specific details about the nature of its national security concern. Anthropic apologised to its customers for the disruption and confirmed that all of its other models remain fully operational and unaffected by the order.
Fable 5 and Mythos 5: Anthropic’s Most Advanced Models Yet
The timing made the shutdown particularly jarring. Anthropic had announced Fable 5 and Mythos 5 just days earlier, positioning both as state-of-the-art models across a range of industry benchmarks. Fable 5 was especially significant — it represented the first time Anthropic had made such a powerful model broadly available to the public, made possible by new safety mechanisms designed to block responses in specific high-risk categories.
Both models built on the foundation established by Claude Mythos Preview, an earlier release that generated significant attention from Wall Street and government circles alike for its sophisticated cybersecurity capabilities. Anthropic had previously signalled that Mythos Preview would not be made generally available, instead limiting access to a carefully selected group of organisations through a restricted cybersecurity initiative known as Project Glasswing.
Anthropic Pushes Back, Calls Order Inconsistent With Its Own Principles
While complying with the directive, Anthropic made clear it does not consider the order to have been handled appropriately. In its public statement, the company said it supports the principle of government oversight of AI deployments, but only within a framework that is transparent, fair, technically grounded, and governed by statute.
“As we have stated publicly, 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,” the company said. “This action does not adhere to those principles.”
A Deepening Rift Between Anthropic and Washington
Friday’s shutdown is the latest flashpoint in what has become an increasingly fraught relationship between Anthropic and the U.S. government. Earlier this year, after negotiations between the company and the Department of Defense broke down publicly, the DOD took the extraordinary step of designating Anthropic a supply chain risk — a label historically reserved for foreign adversaries and one that requires defence contractors to certify they will not use Claude models in military-related work.
Anthropic responded by filing a lawsuit against the Trump administration seeking to overturn the blacklisting. That legal battle remains ongoing, and Friday’s national security order is likely to add further complexity to an already contentious dispute between one of the AI industry’s leading companies and the federal government.
The broader implications for the AI industry are significant. As frontier models grow more capable — particularly in sensitive domains like cybersecurity — the intersection of U.S. export control policy and AI access is likely to become an increasingly contested battleground for companies and regulators alike.
Disclaimer: This article is for informational purposes only. All facts, names, and quotes have been sourced from publicly available information at the time of writing.
