Anthropic has been using the Claude Mythos model internally since February 24th, 2026.

Anthropic's Mythos LLM is so capable at computer security tasks that Anthropic did not release it publicly, instead granting access only to critical software makers.

Anthropic's Claude Mythos model is a much bigger, more expensive, slower, but more powerful model compared to Opus.

Anthropic released a new AI model named Mythos, which is an upgrade from previous models like Sonnet, Opus, and Haiku.

Anthropic will not widely release its Claude Mythos Preview model because of its potential to cause harm if misused.

In early internal use, Claude Mythos preview reached unprecedented levels of reliability and alignment, leading to broader use with less frequent human interaction than prior models.