Claude Fable 5 Returns After Export Control Suspension

Anthropic’s most capable public model is back online after a brief suspension tied to U.S. export controls, but the path to getting here involved a government order, a discovered exploit, and a classifier fix that now blocks the bypass technique in more than 99 percent of cases.

Fable 5 is Anthropic’s first Mythos-class model available to the general public, launching originally on June 9. Its capabilities exceed those of any model Anthropic has made broadly available, with the company pointing to strong performance in software engineering, knowledge work, vision, and scientific research. It also outperforms Opus models on longer, more complex tasks and can work autonomously for longer than any prior Claude model.

The suspension came after Amazon researchers found a prompt capable of bypassing Fable 5’s safeguards, and the model located software vulnerabilities as a result. The Trump administration applied export controls, forcing Anthropic to cut off access for foreign nationals. Because Anthropic had no way to verify user nationality at scale, it had to pull the model entirely. Anthropic investigated and found that older models and competing models could locate the same vulnerabilities, which somewhat reframes the severity of the specific Fable 5 concern.

Restored Access and New Limits

Fable 5 is now available for Pro, Max, Team, and select Enterprise plans. Through July 7, eligible subscribers can use up to 50 percent of their plan’s weekly usage limit on the model before credits are required. After July 7, all Fable 5 use draws from credits. Anthropic has also restored access to Mythos 5 for U.S. organizations in Project Glasswing, its initiative serving major companies and federal agencies working on critical infrastructure.

What’s notable in the fine print is how Fable 5 handles sensitive topics under the new safeguards. Anthropic says it is deepening cooperation with the U.S. government on pre-release testing, information sharing, and research collaboration, which suggests the export control episode has formalized a relationship that previously operated at arm’s length.