AI

Seventy-two days. That is exactly how long the technology world spent in anxious anticipation.

On April 7, 2026, Anthropic quietly, almost unnoticed, released what many experts called “the most dangerous artificial intelligence model ever created.” Mythos.

A model capable of finding vulnerabilities in software. A model that can break through defenses programmers spent years building. A model that, if it falls into the wrong hands, could potentially disrupt banking systems, paralyze power grids, halt transportation networks, and cause widespread digital chaos.

Back in April, however, Anthropic acted cautiously. Instead of making Mythos publicly available—as some publicity-hungry startups might have done—the company granted access to only fifty organizations. These included operators of critical infrastructure: banks, energy providers, transportation networks, and government agencies.

Even then, access came with strict controls, usage restrictions, and monitoring of every request.

Now comes the next step.

On June 10, 2026, Anthropic introduced Claude Fable 5—the first Mythos-class model available to the broader public.

Well, “public” is a relative term.

The model is accessible through a paid API, subject to strict limitations, safety filters, and automatic redirection of dangerous requests to a less capable model, Claude Opus 4.8. Nevertheless, for the first time, ordinary developers, companies, and researchers can experiment with technology that was under lock and key only two months ago.

It is as if the U.S. government suddenly declassified all UFO files, or CERN opened the Large Hadron Collider to anyone who wanted to use it.

The technology is powerful enough to require extraordinary caution—and important enough that keeping it hidden indefinitely was no longer an option.

So what exactly is Mythos? Why is Claude Fable 5 considered dangerous? And why did Anthropic decide to release it despite the risks?