Prototo Desktop puts the whole product in one window. Your coding agent on the left (you pick Claude Code or Codex during setup). A live iPhone on the right. Flow, Preview, Record, and Publish buttons up top.

Download Prototo for Mac , open it, and create a project. That is the setup.

Prototo Desktop (one window)
 ├── Agent terminal     ← the design tool (left pane)
 ├── live iPhone        ← the canvas (right pane)
 └── Flow · Preview · Record · Publish   ← screen map, phone preview, record a clip, share a link

Describe a screen in the terminal. Watch it appear on the iPhone beside it. Want to change one thing on it? Turn on the accessibility overlay in the preview’s dock, tap the element, and it lands in your prompt ready for the change (point and edit). Lost track of what you’ve built? Click Flow (or press ⌘⇧F) to see every screen in your prototype and how they link, where the terminal was. Click a screen and the iPhone jumps to it, with its file in your prompt, ready for the next change. Esc takes you back. Want feedback on the whole thing? Click Export flow in the Flow view (it needs at least 3 screens): Prototo captures every screen and gives you a link to your flow (prototo.app/f/…), a canvas with each screen in a phone frame and how they link. Scroll to move around, pinch to zoom into the details, double-click a screen to bring it up close. Anyone can open it in a browser, no app needed, and you don’t have to publish the prototype first. Click Preview to scan a QR and hold the prototype on your real iPhone while you build, no publish needed (how it works). When it looks right, click Publish for a link anyone can run natively on their iPhone with the free Prototo app, or Record to send a clip to Studio.

On a Team plan, Publish asks where a prototype goes: Team, so everyone on your team sees it, or Just me. The Team button opens your team on prototo.app, where you can remix anything the team has published (how remix works). Everything else in the app works the same whether you’re signed in or not.

The app keeps everything else out of sight: it starts Prototo for you, opens the Simulator hidden, and reconnects your last project when you come back.

Updating Prototo

Prototo updates itself every time you open it, before anything else runs. You’ll see “Updating Prototo” while it checks for a new version, downloads it, and installs it, then it reopens itself. If it can’t reach the internet, it gives up after a short wait and opens anyway.

Opening a project updates it too. You’ll see “Updating your prototype” with the update’s own progress underneath, usually about a minute.

If you had published that project before, click Publish once after the update so your link opens on the new Prototo app. The link itself never changes.

If a project update fails, you don’t lose your place. The terminal and the live iPhone keep working, so you can keep building and previewing. A message explains: “Publish and Export flow wait until this project is on the latest Prototo. The Simulator preview still works.” Click Try again, or Not now to keep working without updating yet.

The paradigm stays clean: one prompt surface, one output surface. You never context-switch between design tools.