The Phoenix.new environment includes a headless Chrome browser that our agent knows how to drive. Prompt it to add a front-end feature to your application, and it won’t just sketch the code out and make sure it compiles and lints. It’ll pull the app up itself and poke at the UI, simultaneously looking at the page content, JavaScript state, and server-side logs.

Is it possible to get that headless Chrome browser + agent working locally? With something like Cursor?

Playwright has an MCP server which I believe should be able to give you this.

When Roo Code uses Claude, it does this while developing. It renders in the sidebar and you can watch it navigate around. Incredibly slow, but that’s only a matter of time.