AI agents that automate web workflows operate within the browser’s web layer, the DOM that Playwright and the Chrome DevTools Protocol (CDP) expose. AgentCore Browser provides a secure, isolated browser environment for this, and it works well for the vast majority of automation: navigating pages, filling forms, clicking elements, extracting content. But the web layer has a hard boundary. Anything that the operating system renders (native dialogs, security prompts, certificate choosers, context menus, even Chrome settings) sits outside the DOM entirely.