Anthropic received a US government export control directive to block access by foreign nationals to its AI models Fable 5 and Mythos 5 due to national security concerns related to a reported narrow jailbreak. The directive requires disabling these models for all users globally, including foreign-national employees. Fable 5 includes safeguards blocking sensitive queries, while Mythos 5 is unrestricted but limited to vetted partners. Anthropic disputes the justification, noting the jailbreak is minor and similar capabilities exist in other AI models such as OpenAI's GPT-5.5. The company is complying with the directive but is working to restore access and has communicated fallback options to customers.

Access to Anthropic's two most capable AI models, Fable 5 and Mythos 5, has been suspended worldwide, affecting all users regardless of nationality. This disrupts services relying on these models, including Pro, Max, and Enterprise customers who had access to Fable 5. Other Anthropic models remain available. The suspension impacts foreign nationals globally, including Anthropic's own employees. The directive limits availability of advanced AI capabilities and may affect organizations relying on these models for cybersecurity, biology, chemistry, and other sensitive queries.

Anthropic has suspended access to Fable 5 and Mythos 5 to comply with the US government directive. Users should migrate to other available Anthropic models such as Claude Opus 4.8, which remain unaffected. No patch or fix applies as this is a legal compliance action rather than a software vulnerability. Organizations should monitor official communications from Anthropic for updates on restoration of access or changes to the directive.