Computer-use agents can’t guess, improvise, or ask a coworker. That makes them the most honest usability testers we’ve ever had.The first time I watched an agent fail on a vendor portal, I recognized the failure immediately. Not because I understood the model. Because I’d failed in exactly the same place myself.For example, I watched a run where an agent reached a form that had two buttons labeled “Continue” and “Submit”, chose the wrong one, and the run stalled. This wasn’t the agent’s fault, it was bad UX.I design products at Deck, where we build infrastructure for computer-use agents: software that logs into websites and operates them the way a person would, clicking, typing, and navigating. Most of the portals our agents work in were never designed to be automated. They’re utility accounts, vendor payment pages, and back-office tools with no API, built for humans and often barely...