Anthropic’s Claude Fable raises crypto security concerns

Anthropic released Claude Fable on June 9, 2026, the public version of a Mythos-class AI model the company says can autonomously discover and chain zero-day exploits. The company is offering access to enterprise and security-focused customers rather than general consumers.

Access for Claude Fable is priced at roughly twice the cost of Anthropic’s most advanced Claude Opus tiers. An analyst at Bull Theory estimated internal pricing for the original Mythos build had been about five times higher than Opus; the public price is lower but remains aimed at institutional buyers.

Anthropic ran a closed preview of the Mythos model in April through Project Glasswing with cloud and security partners including AWS, Microsoft, Apple and CrowdStrike. Early tests in that program showed the model could identify previously unknown vulnerabilities across major operating systems and web browsers and link them into automated exploit chains.

Anthropic says the public release includes added safeguards to limit misuse while preserving the model’s coding, reasoning and defensive security capabilities. The company has not published technical details of those guardrails. A confidential regulatory filing and a recent large funding round indicate a commercial focus on higher-tier enterprise offerings.

Security teams and crypto firms say models with these capabilities can shorten the window between vulnerability discovery and exploit. Automated analysis can scan smart contracts, node software and wallet code faster than manual review. Security professionals also plan to use similar tools to run deeper audits and accelerate patching.

Leaks from developer tools and backend sightings, along with strong trader interest in prediction markets, had generated speculation ahead of the June 9 release. Anthropic may expand Project Glasswing in the coming weeks and invite additional partners, including organizations in the crypto industry, as exchanges and security teams watch for new tooling and integration announcements.

‘Claude Fable will be roughly twice as expensive as today’s most advanced Claude Opus models,’ an analyst at Bull Theory estimated.