Uploaded May 2026 | Updated September 2026, 6 hours ago
Agents are disproportionately better at building websites than mobile apps — and it's because Claude Desktop and Codex ship with an in-app browser their MCPs can already see, click, and screenshot. iOS gets none of that. Evan Bacon, head of AI at Expo, decided to fix it by putting the iOS simulator inside the browser.
0:00 Intro — why agents can't build iOS apps
0:16 See what agents get for free on the web
1:33 Put the iOS simulator in the browser
1:52 Run npx serve-sim in one command
2:50 Click, touch, and tail logs from the MCP
3:12 Give the simulator a real camera
4:16 Watch the camera demo (almost) work live
5:27 Stream a webcam into the simulator
5:52 Emulate location, inspect web views, and more
6:15 Greg Brockman noticed — try it yourself
The iOS simulator doesn't have a camera. It can't emulate location well. Screenshots come back full-res and burn tokens. So if you want an agent to develop a camera app in a loop, you historically had to plug in a real phone and wave it around. In this MCP Night demo, Evan walks through serve-sim — a single `npx` command that runs the iOS simulator inside any agent's in-app browser, complete with touches, console logs, inspect element (contributed by someone on the OpenAI team), and an injected binary that pipes your real webcam into the simulator's camera feed. It works in Claude Desktop, Cursor, and Codex. Same chat app Evan demos is built with Expo, but serve-sim works with any React Native or native iOS project. Greg Brockman tweeted about it. The point: agents can finally develop mobile apps the way they already develop web apps.
Evan Bacon on X: https://x.com/baconbrix
Agents are disproportionately better at building websites than mobile apps — and it's because Claude Desktop and Codex ship with an in-app browser their MCPs can already see, click, and screenshot. iOS gets none of that. Evan Bacon, head of AI at Expo, decided to fix it by putting the iOS simulator inside the browser.
0:00 Intro — why agents can't build iOS apps
0:16 See what agents get for free on the web
1:33 Put the iOS simulator in the browser
1:52 Run npx serve-sim in one command
2:50 Click, touch, and tail logs from the MCP
3:12 Give the simulator a real camera
4:16 Watch the camera demo (almost) work live
5:27 Stream a webcam into the simulator
5:52 Emulate location, inspect web views, and more
6:15 Greg Brockman noticed — try it yourself
The iOS simulator doesn't have a camera. It can't emulate location well. Screenshots come back full-res and burn tokens. So if you want an agent to develop a camera app in a loop, you historically had to plug in a real phone and wave it around. In this MCP Night demo, Evan walks through serve-sim — a single `npx` command that runs the iOS simulator inside any agent's in-app browser, complete with touches, console logs, inspect element (contributed by someone on the OpenAI team), and an injected binary that pipes your real webcam into the simulator's camera feed. It works in Claude Desktop, Cursor, and Codex. Same chat app Evan demos is built with Expo, but serve-sim works with any React Native or native iOS project. Greg Brockman tweeted about it. The point: agents can finally develop mobile apps the way they already develop web apps.
Evan Bacon on X: https://x.com/baconbrix
