Anthropic has unveiled Claude Fable 5, a new AI model it claims is the most powerful it has ever made widely available - which is like saying a new roller coaster is the scariest one they’ve actually let the public ride.
The company says Fable 5 “shows exceptional performance in software engineering, knowledge work, and vision,” with its lead over other models growing as tasks become longer and more complex. In other words, it’s great at things humans already do, but faster and without needing coffee breaks.
Fable 5 marks the first broad release from Anthropic’s Mythos class of AI models, after the company previously said the family was so capable at cybersecurity tasks that it was too dangerous to release publicly. Because nothing says “trust us” like an AI company keeping its best model locked in a digital vault for safety reasons.
Anthropic said the release was “made possible by new safeguards that block responses in specific high-risk areas,” with the system falling back to Claude Opus 4.8 - a model it praised for “honesty” when it launched last month. Because when your AI is too smart for its own good, you give it a built-in babysitter.
Anthropic singled out cybersecurity and biology as two domains where the safeguards may block responses, both areas widely considered sensitive topics for advanced AI systems. The company said that in testing, 95 percent of Fable sessions ran entirely on Fable responses, without falling back to Opus 4.8 - so the safety net is mostly decorative.
The company is also releasing Claude Mythos 5, but provided few details on what that means. In a blog, Anthropic said Mythos 5 is the same underlying model as Fable 5, “but with the safeguards lifted in some areas.” Because why have one confusingly named model when you can have two?
For now, access appears limited to the steadily expanding group of organizations granted access to Claude Mythos Preview through Anthropic’s - not entirely watertight - private Project Glasswing initiative. Those users will be able to upgrade to Mythos 5, Anthropic said, adding that it plans to “expand access over time through a more systematic trusted-access program.” Which is corporate speak for “we’ll let you in when we’re sure you won’t break anything important.”
Anthropic did not respond on the record to The Verge’s request for comment explaining how either model relates to Claude Mythos Preview or why the models are numbered “5” when there do not appear to be any previously released Mythos or Fable models. So we’re left guessing whether this is a numbering system or a marketing department that lost count.
Pricing for both models is significantly higher than its former flagship model - double rates for Claude Opus 4.8, though it’s half what users pay for Mythos Preview - at $10 per million input tokens and $50 per million output tokens, Anthropic said. Because the best way to prove your AI is powerful is to charge an arm and a leg for it.