Anthropic’s Claude Fable 5 Is Back With New Usage Limits And Safeguards

Anthropic relaunched Claude Fable 5 on July 1 after fixing a vulnerability with a new safety classifier that blocks 99% of bypass attempts. The model is available globally with 50% weekly usage limits through July 7, then switches to usage credit pricing. The US government approved the release after a two-week review, with Commerce Secretary Howard Lutnick citing alignment with national AI leadership.

The United States government and Anthropic have announced that Claude Fable 5 is available beginning Wednesday, July 1. The advanced model is available to users around the world. Mythos will be available to a set of organizations in the United States. The United States Secretary of Commerce, Howard Lutnick, tweeted: “Over the past two weeks, we have worked closely with Anthropic to analyze and approve Fable 5 to ensure alignment across the US Government and strengthen America’s leadership in AI.” Perhaps not unexpectedly, his tweet was met with complaints about the delay. Anthropic Fixes Flaw With A New Classifier The official announcement by Anthropic relates that the vulnerability that was reported by Amazon has been addressed with a new classifier that should catch 99% of the attempts. A classifier in this context is an automated security layer that decides whether a user’s prompt is a harmless query or an attempt to circumvent guardrails for malicious purposes. Users will be notified if their requests are blocked and will also re-route the request to Even so, we moved quickly to address the reported bypass. Working closely with the government, we trained an improved safety classifier that targets and blocks the behavior described in the report. Users will be notified if a request to Fable 5 is blocked, and the request will instead be sent to Opus 4.8. In a sign that Anthropic may not be totally satisfied with the new safeguard, their announcement also warns that “benign requests” may be flagged “during routine coding and debugging tasks” but they also promise to improve their classifier in order to reduce false positive incidents. Fable 5 Will Be Available With New Usage Limits Access to Fable 5 will be available with up to 50% weekly usage limits through July 7, after which it switches to usage credit pricing. Anthropic’s official announcement explained https://www.anthropic.com/news/redeploying-fable-5 the access timeline: “Fable 5 will be available starting tomorrow, Wednesday, July 1, to users globally on the Claude Platform, Claude.ai, Claude Code, and Claude Cowork. For Pro, Max, Team, and select Enterprise plans,1 Fable 5 will be included for up to 50% of weekly usage limits through July 7, after which it will be available via usage credits. We will re-enable access on AWS, Google Cloud, and Microsoft Foundry as quickly as possible. We have also restored access to Mythos 5 for a set of US organizations, following the US government’s approval on June 26. We continue to coordinate with the government to expand access to the broader set of domestic and international partners in the Glasswing program.” Featured Image by Shutterstock/RixAiArt