StainFlow: Entity-Stain Tracking and Evidence Linking for Process Rewards in GUI Agents

In three linesStainFlow is a process reward model for GUI agents using entity-stain tracking. It objectively decomposes tasks into phases via visual entity state evolution, and dynamically constructs evidence windows for key step verification. Results: +3.2% RL success and +1.8% trajectory completion accuracy on AndroidWorld and OGRBench.

Summary generated by Claude — human-verified