Lesson 5: vision - help your agent see what it built

Welcome back! In this lesson, you’ll give your agent a pair of eyes. We’ll add screenshots to the loop from lesson 3 so the model can read a layout, spot a button beyond the viewport, and compare the result with your request. A phone-sized screenshot costs about 333 input tokens, and a simple DOM check confirms when the page is ready. By the end, your agent will be able to look, improve, and check its own work.