Anthropic disabled access to its Fable 5 and Mythos 5 models on Friday, following a directive from the US Commerce Department that subjects the models to export controls. The decision was made to comply with the government order, which restricts the use of the models outside the United States. According to a message posted by the company, the only way to ensure compliance with the directive was to abruptly disable the models for all customers. Access to other Anthropic models remains unaffected.
The US administration reportedly raised concerns about a jailbreak that bypasses broad classifier-based safeguards to access Fable 5 prompts related to cybersecurity, chemistry, and biology. An Axios report cited an administration official stating that the administration requested a pause in the release of these models to allow the national security apparatus to be hardened against such threats. The hardening process could be completed within the next few weeks, according to the source.
Anthropic stated that the government provided only verbal evidence of a potential narrow jailbreak involving Fable 5 reviewing a specific codebase for software flaws. The company claims it has only seen evidence of this jailbreak being used to find minor and relatively simple vulnerabilities, and that other models like GPT-5.5 have similar capabilities. The company emphasized its compliance with the legal directive and its disagreement with the standard of recalling a commercial model deployed to hundreds of millions of users.
Source: arstechnica
