Mock cyber attacks used to cost about $30,000, take two weeks, and tell companies what their defenses looked like six months ago. Then Anthropic’s Mythos showed up, exposing thousands of zero-day vulnerabilities. A (yes, as in the letter) uses AI to continuously break into its own customers’ systems—finding real attack paths and fixing them—before actual hackers get the chance. The New York-based autonomous offensive security startup, emerged from stealth with $37 million in funding from Lightsp...