People keep saying AI coding agents can only build basic, cookie-cutter apps. I decided to prove them wrong.
For my first major public demo, I spent some time pushing
@Replit 's AI agent to its absolute limit. The result? I rebuilt macOS entirely on the web. No templates. No imported UI libraries. 100% vibecoded using natural language.
As the AI Chief of Staff at Replit, I spend my days building enterprise-grade platforms for our internal teams, but I wanted to see how far a solo developer could take a passion project just by talking to an AI.
What’s inside:
💻 A functional VS Code replica with an integrated terminal and multi-agent AI copilot.
🔌 Custom MCP servers hooked up to fetch, PostgreSQL, Stripe, and GitHub.
🤖 A rebuilt "Siri" that actually controls the OS -changing wallpapers and opening apps via voice or text.
🕹️ Parallels Desktop running Windows XP, Ubuntu, and games like Mario Kart.
📱 AND... I asked Agent 3 to turn it into an iOS mobile app in one shot. It actually worked.
The ceiling for software creation has been completely blown open with Agent 3. And 4 those who know... greater things are coming soon :)
We are way past basic web apps.
What are you building? 👇