Anthropic is restoring full access to Claude Fable 5 starting tomorrow, weeks after a US government directive forced the company to suspend the model for all users. The government order arrived on June 12 and required Anthropic to block foreign nationals from using Fable 5 and its more capable Mythos 5 model. Since the rule took effect immediately and Anthropic had no way to verify a user’s nationality in real time, the company suspended both models entirely rather than risk a violation.

What triggered the shutdown

The restrictions followed a report from Amazon researchers, who found a way to prompt Fable 5 into identifying software vulnerabilities its safeguards were designed to block. In one instance, the model generated code showing how a flaw could be exploited.

Anthropic says it later confirmed that several less capable models, including Opus 4.8 and competing models, could produce similar results, which suggests the bypass didn’t hinge on capabilities unique to Fable 5.

Return terms and new safeguards

Fable 5 will be available globally starting July 1 to users on the Claude Platform, Claude.ai, Claude Code, and Claude Cowork. For Pro, Max, Team, and select Enterprise plans, Fable 5 usage will count toward up to 50 percent of the weekly usage limit through July 7. After that date, the model will draw from usage credits.

Anthropic says it built a new safety classifier, developed in coordination with the government, that blocks the flagged technique in more than 99 percent of cases. It adds that if a request to Fable 5 is blocked, the user will be notified and the query will be automatically rerouted to Opus 4.8.

The clearance follows a similar government review that restored Mythos 5 access on June 26 for a limited set of approved US organizations. Anthropic says it’s coordinating with the government to expand that access to more domestic and international partners. The company is also working with Amazon, Microsoft, and Google on a shared industry standard for grading the severity of AI jailbreaks going forward.