Ask a frontier vision model for the pixel coordinates of a "Submit" button in a 1920x1080 screenshot and it will often miss by dozens of pixels. That miss is the difference between an agent that completes a checkout flow and one that clicks empty whitespace and loops until it hits a timeout. The fix is not a bigger model. It is a better interface between the model and the screen. That interface has two parts. Screen painting draws numbered marks onto the screenshot before the model sees it....