With web apps playwright-mcp[0] is essential IMO. It lets the AI Agent check its own work before claiming it's done.
With that it can see any errors in the console, click through the UI and take screenshots to analyse how it looks giving it an independent feedback loop.
Of course you need to check their work, but also the better your initial project plan and specifications are, the better the result.
For stuff with deterministic outputs it's easy to verify without reading every single line of code.