Anthropic was forced to abruptly shut down its two most advanced AI models on Friday after the United States government issued an export control directive ordering the company to suspend all access to Fable 5 and Mythos 5.
The directive, issued under national security authorities, bars any foreign national from accessing the models, whether inside or outside the United States, including foreign national Anthropic employees.
Because enforcing that restriction selectively proved impractical, Anthropic was compelled to disable the models for all its customers to ensure compliance, though access to all other Anthropic models remains unaffected.
The San Francisco-based AI company says it received the directive with little warning and even less explanation, at 5:21 p.m. Eastern time on Thursday, and the letter did not provide specific details of the national security concern behind it.
The US government, citing national security authorities, has issued an export control directive to suspend all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States, including foreign national Anthropic employees.
The net effect of…
— Anthropic (@AnthropicAI) June 13, 2026
At the center of the dispute is an alleged jailbreak; a technique for coaxing an AI model into bypassing its safety guardrails.
The government’s understanding is that it had become aware of a method of bypassing Fable 5, and Anthropic reviewed a demonstration of the specific technique, finding it surfaced only a small number of previously known, minor vulnerabilities.
Crucially, Anthropic found that other publicly available models were able to produce the same results without requiring any bypass at all.
Read More: Mythos AI Has Raised Serious Cyber Security Concerns
The company argues that the government has so far provided only verbal evidence of a potential narrow, non-universal jailbreak, and that the capability demonstrated is widely available from other models, including OpenAI’s GPT-5.5, and is routinely used by cybersecurity defenders.
The company warned of broader implications for the AI industry. If this standard were applied consistently across the industry, Anthropic believes it would essentially halt all new model deployments for every frontier AI provider.
Anthropic called the action a misunderstanding and said it is working to restore access as soon as possible, while apologizing for the disruption to its customers. The company said it would share more technical details within 24 hours of the directive.
