Two weeks after telling the Pentagon, the courts, and anyone listening that Mythos is too dangerous for general release, Anthropic released Mythos. The wrapper is called Claude Fable 5. The trick is a set of classifiers that intercept anything in the four categories the company has been most public about (cybersecurity, biology, chemistry, and the distillation attacks that would let a competitor lift the model’s weights through clever querying) and quietly punt the response back to Claude Opus 4.8. Anthropic says the punt fires in under five percent of sessions. The other ninety-five percent, you are talking to the same model the federal government was, two weeks ago, very concerned about.
Pricing tells the rest of the story. Fable 5 is $10 per million input tokens and $50 per million output tokens, which is twice the cost of Opus 4.8 and roughly half the cost of the Mythos Preview that enterprise customers were already paying for under NDA. Through June 22, it is free inside Pro, Max, Team, and seat-based Enterprise plans. After June 23, those tiers will require usage credits to keep accessing it. The day-one AWS Bedrock listing is the more interesting deployment signal. Mythos Preview was a quiet handshake-only rollout on Bedrock in late May. Fable 5 is on the front page.
Stripe’s testimonial, which Anthropic put in the launch post, claimed the model “compressed months of engineering into days.” Cognition put it at the top of FrontierCode. Hebbia put it at the top of its finance benchmark. Whether any of those numbers survive a quarter of real production usage is the question every CTO will be answering at their next board meeting. The non-negotiable footnote: Anthropic is now requiring a 30-day data retention window on all Fable 5 and Mythos 5 traffic, even from customers who previously had zero-retention contracts. The company says the data is for jailbreak defense and false-positive tuning, not for training. The legal and compliance teams at the enterprise customers who signed those original zero-retention agreements are presumably reading the new terms today.