Watch the Simulator, not Terminal. After you prompt your agent, the result appears on the iPhone preview. That is the only surface that matters.
Keep it running. In Prototo Desktop, just keep the app open. In the terminal flow, do not quit the window running npx proto start. If you close it, follow Open Prototo again.
You do not repeat your design system. Your agent reads DESIGN.md every time. Describe the screen: layout, content, feel. The colours and fonts you already chose during setup come along on their own.
Be specific. “Add a card” gets a guess. “Add a card with a glass background, merchant name at the top, amount large in the centre” gets what you pictured. More examples in How to prompt Prototo.
Change screens in plain language. You do not edit files. Say what to change: “on the settings screen, move sign out to the bottom and make it red.”
Your agent checks its own work. After each screen it writes, it takes a screenshot of the live iPhone, type-checks the project, and reads the current errors itself. If you change the navigation (tabs, root layout), it can restart the app on its own too. You rarely need to relay what you see.
If a screen looks broken, ask the agent to fix it. In the agent window:
fix any errors in the Settings screenReplace Settings with your screen name. You do not need to read the error.
When nothing else works, reset. In Prototo Desktop, click Reload above the iPhone. In the terminal flow, run this in your project folder:
npx proto resetThis restarts the environment and reopens the Simulator. It fixes most stuck states. Details in Troubleshooting.