Late last night the US government took the dramatic step of ordering Anthropic to block all non-American nationals from using its new AI model, Fable 5 — including those who helped build it. The company responded by pulling the system for everyone, saying it was the only way to comply.
Fable 5, a version of Anthropic’s Claude Mythos, had been publicly released only days earlier and was widely regarded as the most powerful AI tool available to the public. But the order, issued on national security grounds, forced Anthropic to abruptly disable both Fable 5 and Mythos 5 for all customers.
“US government orders Anthropic to block non-Americans from its new AI model, prompting the company to suspend it entirely.”
“The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance,” the company wrote in a statement.
Anthropic said US national security authorities had not identified specific concerns. “Our understanding is that the government believes it has become aware of a method of bypassing, or ‘jailbreaking’ Fable 5,” the company said. Jailbreaking is a process of getting past software restrictions designed to protect a cyber network, allowing hackers to access sensitive information or unblock features.
Anthropic said it reviewed a demonstration of the technique, which was used to identify “a small number of previously known, minor vulnerabilities”. The company added: “These vulnerabilities all appear relatively simple, and we have found that other publicly-available models are able to discover them as well without requiring a bypass.”
The company had touted various “safeguards” ahead of Fable 5’s release, and had given private access in April for previewing and testing. Finance, technology and government leaders had expressed concerns about its public rollout. Anthropic enabled pre-release access for a handful of organisations because the tool was so intelligent that it could be dangerous due to its ability to exploit or hack computer systems. The company self-described the model as “too powerful to release” — a claim some critics questioned as inflated hype.
“Fable’s capabilities exceed those of any model we’ve ever made generally available,” Anthropic said.
The European Union, which gained access to Mythos earlier in June after weeks of talks, said the development underlined “Europe’s need for technological sovereignty”. “We take note of Anthropic’s statement and are assessing,” said Thomas Regnier, a spokesman for the European Commission.
The order adds to existing tensions between Anthropic and the Trump administration, which are involved in a separate ongoing lawsuit over an order to stop government agencies using the company’s AI tools.