Anthropic disables Fable 5, Mythos 5 after US security directive
Anthropic announced on Friday that it is disabling its Fable 5 and Mythos 5 artificial intelligence models for all users after receiving a US government export control directive citing national security concerns, arguing that the alleged safety vulnerabilities were minor and already addressed in testing.
Artificial intelligence company Anthropic on Friday suspended access to its Fable 5 and Mythos 5 models for all users after the US government issued an export control directive citing national security concerns, a move that bars foreign nationals — including the company's own employees — from using the systems while leaving its other AI models unaffected.
US Export Control Directive
Anthropic said it received the order at 5:21 pm ET (2121GMT) on Friday, noting that the directive did not explain the specific security concern in detail. The company stated that Washington believes someone has found a way to “jailbreak,” or bypass, the safety controls of Fable 5. The government has provided only verbal details of one limited bypass method, which Anthropic described as asking the model “to read a specific codebase and fix any software flaws.”
Safety Testing and Industry Standards
Before releasing Fable 5, Anthropic spent thousands of hours testing the model's safety systems alongside the US government, the UK's AI safety body and other organizations, according to the company. Anthropic said the issues demonstrated were already known, were “minor,” and could be reproduced using other publicly available AI models. The company reviewed a report it believes prompted the government's order and found that the same capability is “widely available from other models (including OpenAI's GPT-5.5), and is used every day by the defenders who keep systems safe.”
Compliance and Dispute
“We suspect that perfect jailbreak resistance is not currently possible for any model provider,” Anthropic said, adding that all AI safety systems in the industry have some weaknesses. While stating it will comply with the government's order, the company said it disagrees that such limited issues should lead to withdrawing a commercial AI model used by hundreds of millions of people. The company warned that applying this standard across the industry “would essentially halt all new model deployments for all frontier model providers,” and assured users it is working to restore access to the models as soon as possible.
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