In-browser domain policy enforcement
In Stagehand v4, domain policy enforcement runs inside the browser extension rather than client-side, enabling true blocking of unauthorized pop-ups before they load—eliminating the v3 workaround of closing tabs after they open.
Supporting evidence
Introducing Stagehand v4: The SDK for browser agents.
Original excerpt
In v4, target management lives in the extension. You set your domain policy and the enforcement runs inside the browser, so a blocked pop-up gets blocked and shows a blocked page. We removed the workaround.