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- Anthropic released Fable 5, a “Mythos-class” model with safeguards.
- Anthropic previously held off on publicly releasing Claude Mythos Preview, warning it was too skilled at hacking.
- Instead, Anthropic shared the model with a small group of companies and the US government to help bolster cybersecurity.
Anthropic is finally willing to give you some Mythos, but it comes with some safeguard strings attached.
On Tuesday, Anthropic said it was releasing a “Mythos-class” model called Claude Fable 5, but with safeguards so significant that it gave the model a different name.
“Without safeguards, Fable 5’s capabilities in areas like cybersecurity could be misused to cause serious damage,” Anthropic said in a statement accompanying the release. “We’ve therefore launched the model with safeguards that mean queries on some topics will instead receive a response from our next-most-capable model, Claude Opus 4.8.”
Anthropic is also continuing Project Glasswing, which it first announced in April, that gave early access to the first version of Mythos, Claude Mythos Preview, to an initially limited number of tech, cybersecurity, and financial companies. The AI company said “a small group of cyberdefenders and infrastructure providers” will get access to Claude Mythos 5, which is the same model as Fable 5, “but with the safeguards lifted in some areas.”
“It has the strongest cybersecurity capabilities of any model in the world,” the company said of Mythos 5. “Soon, we intend to expand access to Mythos 5 through a broader trusted access program.”
When Anthropic released Claude Opus 4.8 on May 28, the AI startup said it expected to “be able to bring Mythos-class models to all our customers in the coming weeks.” Anthropic said Fable 5 is part of “a tier of Claude models that sit above our Opus class in capability.”
The release comes at a critical time for Anthropic, which recently announced that it had confidentially filed a draft S-1, officially kicking off the march toward a blockbuster IPO.
OpenAI, Anthropic’s chief rival, announced on Monday that it too had confidentially filed its S-1. SpaceX, which includes Elon Musk’s xAI, is set to go public on Friday when it begins trading on the Nasdaq.
Anthropic’s initial announcement of Mythos spooked financial markets and governments worldwide, raising concerns that AI models had advanced to the point where they could now uncover major vulnerabilities in software and cybersecurity.
President Donald Trump recently signed an executive order that allows AI companies to voluntarily give the federal government access to frontier AI models up to 30 days before their release. The order explicitly prohibits the government from imposing a mandatory review on AI companies.
This is developing…
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