Both things happens from time to time. Gemini has written a plan which again directly said that as a human user I will need to verify changes myself because “We don’t have a reliable Playwright integration running here”. I’ve asked “Do you know that you have a browser sub-agent for verification of changes?”. Instead of answering the question gemini started to proceed the plan stating that “The user approved the fixes”
This is pretty typical. By default, and seemingly in contradiction to the settings, it will aggressively interpret responses as approval to take action unless you very clearly state otherwise. Get used to typing, “reply only, no changes”, or setup rules and/or workflows to give it more guidance.
And yes, you have to tell/remind it the browser agent exists.