Anthropic: The US government has requested a suspension of access to Fable5 and Mythos5 for foreign nationals, and to ensure compliance, related models will be disabled for all users.

According to Mars Finance, on June 13th, Anthropic issued a statement saying that the US government, citing national security concerns, has issued an export control order requiring all foreign nationals to suspend access to Fable 5 and Mythos 5, regardless of their location within or outside the US, including Anthropic's foreign employees. The practical impact of this order is that the company must immediately disable Fable 5 and Mythos 5 for all customers to ensure compliance. Access to other Anthropic models is unaffected. Anthropic received the government order at 5:21 PM ET today. The letter did not provide details of specific national security concerns. Anthropic understands that the government believes it has learned of a method to bypass or "jailbreak" Fable 5. Demonstrations of this specific technique used to identify a small number of previously known, minor vulnerabilities have been reviewed; these vulnerabilities appear relatively simple, and other publicly available models could also be found without bypassing them. Anthropic stated that prior to the release of Fable, the company conducted thousands of hours of red-team testing on Fable's security measures with the US government, AISI UK, several private third-party organizations, and its internal team. Tests show that Fable's security measures are significantly stronger than any previously deployed model, and testers have not yet found a universal jailbreak method that can broadly bypass the model's security measures. Currently, the government has only provided verbal evidence of a potentially narrow, non-universal jailbreak, essentially requiring the model to access a specific codebase and fix software vulnerabilities. Anthropic has reviewed the relevant reports and confirmed that the capabilities demonstrated are already widely available from other models, including OpenAI's GPT-5.5, and are used daily by defenders to secure systems. Anthropic stated that it will comply with government legal directives and remove all user access to Fable 5 and Mythos 5. However, Anthropic disagrees with using a narrow potential jailbreak discovery as a reason to recall a commercial model deployed to hundreds of millions of people. Anthropic claims that if this standard were applied to the entire industry, it would essentially prevent all leading model providers from deploying new models. Governments should have the ability to prevent insecure deployments, but the process should be transparent, fair, clear, and based on technical facts. Anthropic believes this action did not follow these principles and calls it a misunderstanding; the company is working to restore access as quickly as possible.