Build and Run Your First App

The moment is here: you describe a tiny app, Claude Code builds it, and you open a preview and see it working. That's the full loop. We'll also learn one important safety rule: never paste passwords or secret keys.

Like assembling furniture from instructions, then sitting on it to check it's sturdy — you build, then you run and check.

Preview / run: Opening what Claude Code built and seeing it actually work on screen.
Secrets & safety: Never paste real passwords or secret keys into an app or chat.