Right Screen, Wrong Transition: World Models as Verifiers for GUI Agents
The paper introduces LGWM, a decoder-free world model that predicts the next screen representation directly in the observation space. This allows verification of GUI agent transitions to be reduced to a simple vector comparison between predicted and observed representations. By predicting in the same space as observations, LGWM enables detectors to distinguish harmful transitions from benign ones without needing complex semantic models or training.