I got tired of coding agents telling me the frontend work was done when nobody had opened the frontend.

You've probably seen the routine. The agent changes some code, runs the formatter, the type checker, and the tests, everything comes back green, and you get some version of "Implemented and verified."

But verified how, exactly? A passing test suite is useful evidence, but it isn't the same as opening the app and using the thing that just changed.

I've had plenty of changes where the code made sense and the tests passed, and the UI still had the kind of problem a person spots in about three seconds. A control overlapping something else. A selected state that exists in the store but isn't highlighted on screen. Reset working for one path and not another. A filter that updates state but leaves the old data on the page. Save looking fine until you refresh. A map layer drawn in the wrong order.…