TL;DR Intruder, a GCHQ-accelerated UK cybersecurity startup, launched AI pentesting agents that replicate manual pen testing methodology in minutes. The broader market is racing to automate vulnerability discovery as AI compresses the gap between offence and defence. A manual penetration test costs between 10,000 and 50,000 dollars. It takes weeks to schedule, days to execute, and produces a report that is out of date before the ink dries. Intruder, a London-based cybersecurity company that graduated from GCHQ’s Cyber Accelerator, has launched AI pentesting agents that replicate the methodology of a human pen tester and deliver results in minutes. The company’s chief executive, Chris Wallis, will present the technology at KnowBe4’s KB4-CON conference on 13 May. The pitch is simple: the depth of a manual pentest, available on demand, at a fraction of the cost. The timing is not accidental. The cybersecurity industry is watching AI transform the attack side of the equation faster than the defence side can adapt. Anthropic’s Claude Mythos Preview found thousands of zero-day vulnerabilities across every major operating system and browser in a single evaluation pass. xBow, an autonomous pentesting startup, reached unicorn status in March 2026 after raising 120 million dollars. The question is no longer whether AI will replace human pen testers. It is whether the replacement will happen fast enough to close the gap between the vulnerabilities AI can find and the speed at which organisations can fix them. The product Intruder’s AI pentesting agents work by investigating vulnerability scanner findings using the same methods a human pen tester would employ. When the scanner flags a potential issue, the AI agent interacts directly with the target system, sending requests, analysing responses, and probing for exposed data to determine whether the finding represents a genuine exploitable flaw or a false positive. The investigations cover