Notes on Cross-Platform Computer Use Agents for macOS and Windows — Selection with Hermes Agent and cua-driver as of September 2026

Notes from comparing Computer Use agents that can operate native apps on both macOS and Windows as of September 2026. Among official apps, only the ChatGPT and Claude desktop apps clear the bar of two-OS support plus full-OS control. On the open-source side, Nous Research's Hermes Agent paired with trycua's cua-driver is the strongest starting point, with UI-TARS, Agent S, and Open Interpreter as adjacent candidates. This article focuses on what feature-matrix comparisons tend to hide: the actual scope of the 'no-foreground contract' for background operation, TCC and Accessibility on macOS, UIPI and Session 0 on Windows, multi-monitor limits, and Japanese IME behavior.