Wrote up some thoughts on Anthropic's Project Glasswing, where their latest Opus-beating model is available to partnered security research organizations only. Given the recent alarm bells raised by credible security voices I think this is a justified decision.
https://simonwillison.net/2026/Apr/7/project-glasswing/
Anthropic’s Project Glasswing—restricting Claude Mythos to security researchers—sounds necessary to me

Anthropic didn’t release their latest model, Claude Mythos (system card PDF), today. They have instead made it available to a very restricted set of preview partners under their newly announced …

Simon Willison’s Weblog

@simon woe to us when we find a way of giving the LLMs static analysis tools to aid them in this :)

e.g. think what an LLM that is trained to construct TLA+ to help in analysis could do

@Profpatsch The holy grail of AI+formal methods ☺️
@simon