Anthropic confirmed: Mythos represents a step change in AI performance. It's the most capable model the company has ever built. But it won't be released to the public. At least not anytime soon.
What is Mythos?
Internally, it's part of a new tier called "Capybara" — above Opus, being larger and more expensive than any previous model.
It's a general-purpose model with strong performance across all areas. But there's one detail that changed everything: exceptional capability in cybersecurity.
The capability that frightens
Mythos has found thousands of zero-day vulnerabilities in critical systems. Many of them critical. Without human guidance.
A concrete example: it discovered a 27-year-old vulnerability in OpenBSD — one of the world's most "hardened" operating systems. The flaw allowed remote crash simply by connecting to the machine.
For perspective:
Opus 4.6: success rate near 0% in autonomous exploit development
Mythos Preview: running the same benchmark (Firefox 147 vulnerabilities), developed 181 functional exploits and gained register control in 29 additional attempts
These capabilities were not trained explicitly. They emerged as a consequence of general improvements in code, reasoning, and autonomy.
Why wasn't it released?
It's the first large LLM since GPT-2 in 2019 to have its general release delayed due to risk of social impact.
Anthropic believes that releasing the model openly before strengthening defenses on critical systems could be catastrophic.
Putting a model with these capabilities into the hands of attackers? It's not an option the company is willing to take.
Project Glasswing: The Alternative
Instead of releasing, Anthropic created Project Glasswing.
The model is available in private preview to approximately 40 companies, including:
AWS, Apple, Microsoft, Google
CrowdStrike, Cisco, Palo Alto Networks
JPMorgan Chase, NVIDIA
Linux Foundation
The goal is clear: for these organizations to use the model to scan and patch vulnerabilities in their own software before models of this class reach attackers' hands.
Anthropic is donating $100 million in access credits for organizations to audit their systems.
Current Availability
Mythos is available as a closed preview (gated research preview) on:
Amazon Bedrock
Google Cloud Vertex AI (Private Preview for selected customers)
It's a large and computationally intensive model. Anthropic stated it's expensive to serve and is working to make it more efficient before any general release.
There is no defined timeline for public availability.
How it leaked
Details of the model emerged from a configuration error in Anthropic's CMS, which left blog post drafts publicly accessible. Fortune was the first to report the leak.
Conclusion
Mythos is a model superior to Opus 4.6, with unprecedented offensive and defensive security capabilities. That's why it's under extremely restricted access.
It's not censorship. It's prevention.
Published on Hive blockchain
