I Built an AI Coding Agent That Lives in Your Browser

The Problem Every AI coding tool I've used has the same blind spot: it edits source files without ever seeing the running application. You describe a layout bug. The AI reads your JSX, guesses what the DOM looks like, and generates a fix. You switch to the browser. It's wrong — the AI didn't know about the inherited padding, the conditional render that adds a third child, or the CSS variable that resolves differently at this breakpoint. You switch back, describe it again with more detail, and repeat. This loop — describe, edit, check, re-describe — is where a surprising amount of AI-assisted development time actually goes. Not on the AI generating code. On you being the bridge between the AI's understanding of the source and the application's actual behavior. The same thing happens on the server side. Your AI edits a Next.js API route but doesn't know what middleware is active, what the compiled module graph looks like, or what's in the server logs. It's guessing about the runtime from