Prompting one agent is easy. Getting several of them to work on the same Flutter codebase without breaking it is not.
The shift happens when you stop prompting and start building a harness: skills that encode how your project actually works, subagents that own a slice of the work, hooks that enforce your rules, commands that make it repeatable. And then the hard problem isn't generating a widget. It's that three agents are working at once, while your specs, your review and your QA were all designed for one human at a time.
This is what we're building on production Flutter codebases at an agency: the anatomy of the harness, the Flutter-specific guardrails that stop agents from wrecking your widget tree and state, and how the PM, dev and QA roles shift once the bottleneck moves from writing code to describing and verifying it.