U.S. Directive Leads Anthropic to Suspend Fable 5 and Mythos 5 Worldwide
Summary
Anthropic says it disabled Fable 5 and Mythos 5 worldwide after a U.S. directive barred foreign nationals from accessing them. The order reportedly followed a narrow jailbreak; Anthropic disputes the assessment and is seeking to restore access.
Key points
- Anthropic disabled Fable 5 and Mythos 5 worldwide to comply with a directive barring foreign nationals from accessing them, including Anthropic employees.
- Anthropic says the directive cites national security authorities and that disabling both models was necessary to comply.
- The company says the government cited a potential narrow jailbreak involving asking a model to inspect a codebase and fix software flaws.
- Anthropic says it reviewed a demonstration and found only minor, previously known bugs; it disputes the government’s assessment and is working to restore access.
- Fable 5 blocks or diverts sensitive cybersecurity, biology, and chemistry queries; Anthropic says unrestricted Mythos 5 is available only to vetted government cyberdefenders and life sciences partners.
- Other Anthropic models, including Claude Opus 4.8, remain available.
Article Details
- Event Type
- US government export-control directive requiring Anthropic to block foreign-national access to Fable 5 and Mythos 5, resulting in their worldwide suspension.
- Impact
- Anthropic disabled Fable 5 and Mythos 5 for all users to comply with the directive, which bars foreign nationals inside and outside the United States from accessing them, including Anthropic employees. New sessions fall back to a default model or Claude Opus 4.8, existing Fable 5 sessions may end with an error, and Platform requests to Fable 5 fail. Other Anthropic models remain available. Anthropic says it disagrees with the government’s assessment of a reported, narrow potential jailbreak and is working to restore access.
People
Vendors
AnthropicAnthropic has suspended global access to Fable 5 and Mythos 5 after a US government export control directive barred foreign nationals, forcing the company to disable the models for all users.OpenAIThe company says the capability is widely available elsewhere, pointing to OpenAI’s GPT-5.5, and is used by defenders every day.
Products
Claude Opus 4.8All other Anthropic models, including Claude Opus 4.8, remain available.Fable 5Anthropic has suspended global access to Fable 5 and Mythos 5 after a US government export control directive barred foreign nationals, forcing the company to disable the models for all users.GPT-5.5The company says the capability is widely available elsewhere, pointing to OpenAI’s GPT-5.5, and is used by defenders every day.Mythos 5Anthropic has suspended global access to Fable 5 and Mythos 5 after a US government export control directive barred foreign nationals, forcing the company to disable the models for all users.
Countries
United KingdomUK’s Minister for AI and Online Safety, Kanishka Narayan MP, said the pause affected customers in both the US and UK, framing it as a case for technological sovereignty and pointing to the government’s £1.1bn AI chipUnited StatesAnthropic has suspended global access to Fable 5 and Mythos 5 after a US government export control directive barred foreign nationals, forcing the company to disable the models for all users.