Anthropic releases Mythos-like AI model to the public two months after private rollout rocked Wall Street

Two months after Anthropic rolled out Mythos to a limited number of users, citing concerns about the artificial intelligence model’s potential to do damage in the wrong hands, the company said it’s ready to release an equally powerful model to the public.

Anthropic on Tuesday announced Claude Fable 5, a Mythos-class model that will be available to its enterprise customers and paid subscribers. The company said the broad release is possible because of new safeguards that block responses in specific high-risk areas, including cybersecurity and biology.

“For us, it’s really around what we call ‘race to the top,’ being able to provide this technology in a valuable fashion, and at the same time providing the right safety guardrails so that it can do asymmetrically more benefits than harm,” Dianne Penn, Anthropic’s head of product management for research, told CNBC in an interview.

Anthropic captivated Wall Street and government officials in April with the unveiling of Mythos, which excels at identifying security flaws within software. The company said it did not plan to make the model generally available, and it has limited the rollout to a select group of companies as part of a cybersecurity initiative called Project Glasswing.

But with the launch of Claude Fable 5, Anthropic is honoring its stated “eventual goal” to deploy Mythos-class models at scale. It’s also capitalizing on growing momentum and investor interest in its technology ahead of a potentially massive IPO, which is expected to take place as soon as this year.

Anthropic said Claude Fable 5 shows “exceptional performance” across software engineering and knowledge work tasks. On some benchmarks, it scored more than 10% higher than Claude Opus 4.8, another model the company announced late last month, according to a blog post.

Claude Fable 5 represents a “significant jump” in capability, which is why Anthropic had to implement additional guardrails to prevent misuse, Penn said. If a user asks a high-risk question, like how to make ricin, a toxin, for instance, the model will block its response and fall back to Claude Opus 4.8 to deliver a safe answer.

“What we wanted to do was to be very intentional about building new types of classifiers and new types of safety guardrails in place for this launch,” Penn said.

Anthropic also launched an updated Mythos model on Tuesday called Claude Mythos 5. It’s the same underlying model as Claude Fable 5, but with the safeguards lifted in some areas, according to a blog post.

Claude Fable 5 comes just days after Anthropic said it confidentially filed its IPO prospectus with the Securities and Exchange Commission, setting up a potentially historic share sale after the company experienced a period of explosive growth this year.

Anthropic said in May that its revenue run rate has ballooned to $47 billion, up from roughly $10 billion in annual revenue last year. It recently closed a funding round at a$965 billion valuation, topping its chief rival, OpenAI, which was valued at $852 billion in late March.

OpenAI is also gearing up for a major IPO, announcing on Monday that it confidentially filed its prospectus with regulators.

Elon Musk’s SpaceX, which merged with his AI startup xAI earlier this year, is slated to make its record-breaking public markets debut on Friday.

The fierce competition means Anthropic CEO Dario Amodei will be under pressure to justify the startup’s valuation to investors, and Claude Fable 5 could become a valuable new money-maker for the company. The model costs $10 per million input tokens and $50 per million output tokens, which is twice as expensive as Claude Opus 4.8.

Penn said that pricing is “very top of mind” for customers, but that they’re not just seeking out lower costs. She said users are looking for higher accuracy and higher benefit for the money that they spend, and that early Claude Fable 5 customers have noted an improvement in spend per task.

“You just get a higher ROI by having more intelligent models,” Penn said.

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