Browser
The program that turns an address into a page. It asks servers for files, draws what comes back, and runs the code that came with it. Chrome, Safari and Firefox are browsers.
An agent reading your code sees what should happen. The browser keeps a log of what did. When something looks broken, that log settles the argument, so ask for its contents instead of a theory about them.
Say it to your agent
“The save button does nothing. Open the page in Playwright, click save, and show me the request it sent and the status it got back, from the network log. Don't work it out from reading the code.”