Anthropic has disabled two AI models after the US government ordered it to do so on national security grounds, citing concerns over a potential jailbreak technique.

What happened: Anthropic took Claude Fable 5 and Mythos 5 offline on Friday after receiving a letter from the US government at 5:21pm ET. The government expressed concern about a method of bypassing the safeguards in Fable 5. Anthropic said it reviewed a demonstration of this technique and found it exposed only minor, previously known vulnerabilities that other publicly available models can also discover.

Why it matters: This is the latest clash between Anthropic and the Trump administration. Earlier this year, the Department of Defense labeled Anthropic a 'supply chain risk' after the company sought to restrict military use of its technology, effectively barring government agencies and contractors from using its systems. Anthropic has filed lawsuits against the Trump administration in response.

What to watch: Anthropic argues the jailbreak the government demonstrated was narrow and non-universal, essentially asking the model to read a specific codebase and identify software flaws. The company said it has implemented strong safeguards to reduce misuse risk and contends this action does not follow the fair, structured, and transparent government process that CEO Dario Amodei said the company supports.