Opus 4.6 just dropped, and it shipped with a seriously cool experimental feature: Claude Code Agent Teams. In this video I literally give Opus an entire dev team to build a fitness tracker app called Claude Fit from a simple PRD. I spin up five specialized teammates—UX/UI designer, back-end dev, technical architect, database expert, and my favorite: a devil’s advocate that questions everything—then I let them run in parallel while I jump between their individual chats. The big takeaway is how Agent Teams differ from sub-agents. Sub-agents are basically one-way workers: they do a task in their own context and report back to the parent, but they can’t see or coordinate with each other. Agent Teams are more like putting a bunch of specialists in the same room: they share a task list, they can message each other peer-to-peer, and they coordinate automatically—especially useful for complex builds like starting a project from scratch. I also show you how to enable Agent Teams in your Claude Code settings.json, how to prompt for specific roles and models, how human-in-the-loop works (interrupt, redirect, ask questions), and how delegation mode lets the team lead rely purely on teammates. We finish by running the app and the UI honestly looks great—fonts, colors, and even animations feel like a real fitness tracker.