This is actually insane.
Anthropic released their two newest frontier models on June 9 (Fable 5 and Mythos 5). Three days later, the US government forced them to shut both down for EVERY customer in the world.
These were the most capable AI models ever released. Fable 5 was state-of-the-art on essentially every benchmark, especially for long, complex tasks. Software engineering, vision, scientific research, autonomous agent work. One test compressed months of work on a 50-million-line codebase into a SINGLE DAY.
Mythos 5 is the same underlying model with safeguards lifted in targeted areas. The strongest cybersecurity capabilities of any model in the world. Already being used for real drug design and novel scientific hypotheses through Project Glasswing in collaboration with the US government.
Friday at 5:21 PM ET, the Commerce Department hit Anthropic with an export control directive citing national security. It bans access for any foreign national, whether outside the US or working inside the country, including foreign-national Anthropic employees. Giving them access counts as a “deemed export.”
Anthropic had no choice but to disable both models globally to ensure compliance.
The reason: another company claimed to jailbreak Fable 5. Anthropic reviewed the demonstration and says it is a narrow, non-universal exploit that other public models (including GPT-5.5) are also vulnerable to. They call it a misunderstanding and are working to restore access.
Think about that. Two of the most capable AI models in the world, developed with extensive red-teaming with the US government and the UK AI Security Institute, bricked globally over a contested jailbreak claim.
If this becomes the standard, every frontier model launch in the US is at risk going forward.
The precedent is enormous.
The US government, citing national security authorities, has issued an export control directive to suspend all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States, including foreign national Anthropic employees.
The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance.
Access to all other Claude models is not affected.
We apologize for this disruption to our customers. We believe this is a misunderstanding and are working to restore access as soon as possible.
Read our full statement:
anthropic.com/news/fable-myt…