Anthropic Halts Fable 5, Mythos 5 Access Over US Directive

Anthropic has halted access to its Fable 5 and Mythos 5 models. This decision comes after a directive from the US government, citing national security concerns under export control regulations. The directive prohibits access by any foreign national, including foreign Anthropic employees, leading to a complete service shutdown for these models. Anthropic received the directive on June 12th, stating it lacked specifics on national security risks. The company believes the decision is linked to techniques bypassing Fable 5's safeguards, but claims its review found only minor, known vulnerabilities. Anthropic also states that other publicly available models can identify these issues. Before launch, Fable 5's security was tested extensively by various entities, including the US government. Anthropic highlighted that the government provided only verbal information about a possible narrow bypass, not a universal jailbreak. The company reviewed the report believed to be the basis for the directive and noted that the demonstrated capabilities are also present in other models, including OpenAI's GPT-5.5. Anthropic will comply with the legal requirement but disagrees with the withdrawal of a commercial product over a narrow potential bypass. The company believes such a standard would effectively halt the launch of new models across the industry. Access to other Anthropic products remains unchanged, and the company is working to resolve what it calls a "misunderstanding." This situation shows the growing tension between AI development and government regulation.