Anthropic suspends Claude Fable 5 and Mythos 5 models at US government request
Anthropic suspended its Claude Fable 5 and Mythos 5 AI models following a US government directive due to security concerns about jailbreaking methods. The company disabled the models for all customers, including a ban on foreign national access, after authorities identified vulnerabilities in the systems days after their public release.
What happened
Anthropic suspended Claude Fable 5 and Mythos 5 following US government security concerns raised days after the models' public release.
The company stated it was ordered to suspend foreign nationals from using Claude Fable 5 and must disable both models for all customers to ensure compliance.
US national security authorities identified a method of jailbreaking Fable 5, and Anthropic reviewed a demonstration showing a small number of previously known, minor vulnerabilities.
Reported impact
The suspension resulted in the abrupt disabling of Fable 5 and Mythos 5 for all Anthropic customers.
Index analysis
Anthropic stated the vulnerabilities identified appeared relatively simple and that other publicly available models could discover them without requiring a bypass.
Governance controls
Anthropic has an ongoing lawsuit with the Trump administration over an order to stop government agencies using the company's AI tools.
Classification
Sources and evidence
This record was researched and written by the Index, based on the following original reporting.