Prototo runs across two Terminal windows and the iOS Simulator. Once you understand this, the whole product makes sense. 
You
 │
 ├── proto CLI       ← scaffolds, starts, manages everything hidden
 │
 └── Claude Code CLI ← the design tool

iOS Simulator         ← the canvas

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Window 1 — Prototo

proto start
This starts Prototo and opens the iOS Simulator. Leave this window running. You never type in it again.

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Window 2 — Claude Code

cd myapp
claude
This is the design tool. Everything you describe here appears in the Simulator. Claude Code reads DESIGN.md before every generation — so it already knows your colours, typography, spacing, and component library. You never repeat context.

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The Simulator

This is the canvas. The only thing you look at. Tap to test interactions. Watch it update after every prompt. When it looks right, share it.

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The complete workflow

proto start          → Simulator opens       (Window 1, leave it)
cd myapp && claude   → Claude Code opens     (Window 2, stay here)
describe a screen    → Simulator updates     (look here)
describe a change    → Simulator updates     (look here)
proto share          → QR code appears       (send to stakeholders)
Five lines. No more complexity than this. One prompt tool. One output surface. The paradigm stays clean — you never context-switch between design surfaces.