Anthropic is opening Claude Mythos 5.1 to vetted cyber defenders through 3 access tiers that absorb Project Glasswing.

Until now, only Glasswing members got Mythos, while the Cyber Verification Program loosened filters on Opus and Sonnet for vetted security teams.

Anthropic ran Opus 5.5 through its CyScenarioBench attack scenarios 50 times per tier, and without program access every run stopped at the first prompt.
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Claude now gives more hacking help the more Anthropic trusts you and the more dangerous the systems you are allowed to attack.

A hospital security team or a lone researcher gets help analyzing malware and fixing flaws, but Claude won't help them attack anything.

A penetration-testing firm can also have Claude break into client systems it is hired to test, though ransomware stays blocked.

Only organizations vetted with the US government can use Claude to probe power grids, flight systems and interbank networks.

The expansion follows Anthropic's finding that Zhipu AI's freely downloadable GLM-5.3 built working exploits in 50 of 410 attempts, nearly matching Mythos Preview's 56.

Anyone can strip that model's safety refusals, as Anthropic did for about $4,400 of compute, so attackers already have near-Mythos exploit skills and so in many sense withholding Mythos mostly handicaps defenders.