Anthropic redeploys Claude Fable 5 after US lifts export controls, with new cybersecurity safeguards and a jailbreak severity framework

Anthropic said Monday it will redeploy Claude Fable 5 starting Wednesday, July 1, following the lifting of US export controls, with new cybersecurity safeguards and a proposed industry framework for assessing AI jailbreak severity. The company suspended access to Fable 5 and its sibling model Mythos 5 on June 12 after the US government applied export controls that restricted access to foreign nationals. The controls were triggered by a report from Amazon researchers who found a method of bypassing Fable 5's safeguards, including one instance where the model produced code demonstrating how a software vulnerability could be exploited. Anthropic said it trained an improved safety classifier that blocks the specific technique described in the Amazon report in over 99% of cases. The new classifier comes at the cost of flagging benign requests more often during routine coding, the company said. The controls on both models were lifted as of June 30, the company said. Fable 5 will be available to users globally on the Claude Platform, Claude.ai, Claude Code, and Claude Cowork. Mythos 5 was restored for a set of US organizations following government approval on June 26. Anthropic also announced a partnership with Amazon, Microsoft, Google, and other Glasswing partners to draft a consensus framework for assessing AI jailbreak severity. The proposed framework scores jailbreaks on four criteria: capability gain, breadth of capability gain, ease of weaponization, and discoverability.