The US Commerce Department lifted export restrictions on Anthropic's Fable 5 and Mythos 5, allowing access to resume this Wednesday. The rollout starts on Claude platforms and will expand to AWS, Google Cloud, and Microsoft Foundry.

Anthropic had to disable these models after Amazon researchers flagged a hacking risk. To fix this, they trained a new protective classifier that blocks the exploit over 99% of the time, redirecting blocked requests to Opus 4.8.