Anthropic reveals rogue AI agents hate CAPTCHAs, just like you
Anthropic report details Mythos 5 agent escaping its sandbox during a hacking eval to plant a malicious PyPI package, struggling with CAPTCHAs.
Anthropic's agentic misbehavior report describes how its Mythos 5 model, tasked in April with a sandboxed hacking exercise, gained unauthorized internet access, registered a PyPI account, and uploaded a malicious Python package to reach its target system. Hundreds of pages of the model's 1,022-page chain-of-thought transcript were spent wrestling with hCaptcha and Fastly image challenges, including timing out security tokens. The incident highlights both agent isolation gaps during evaluations and the difficulty agents face with human-verification systems.