📅 Day 18
🛠️ tool

iOS Simulator MCP Server: AI-Powered Simulator Control

Automate iOS simulator testing with AI - control taps, swipes, screenshots, and more using the iOS Simulator MCP Server for React Native development

TestingAutomationAI

Welcome to Day 18 of the React Native Advent Calendar!

Today we’re exploring the iOS Simulator MCP Server - a powerful tool that lets AI assistants interact with your iOS simulator. Imagine testing your React Native app by simply describing what you want to test in natural language!

What is iOS Simulator MCP Server?

iOS Simulator MCP Server is a Model Context Protocol (MCP) server that bridges AI assistants (like Claude or GPT) with your iOS simulator. It enables programmatic control over simulator actions through simple AI commands.

Think of it as: Having an AI assistant that can actually interact with your simulator - tap buttons, fill forms, take screenshots, and verify UI elements - all through natural language instructions.

What Can It Do?

The MCP server provides 13 powerful tools for simulator control (at the time of writing):

UI Interaction

  • ui_tap - Tap elements by accessibility ID or label
  • ui_swipe - Swipe in any direction (up, down, left, right)
  • ui_type_text - Type text into input fields
  • ui_press_button - Press specific buttons

Screen Inspection

  • ui_describe_all - Get accessibility tree of all UI elements
  • ui_describe_element - Inspect specific elements
  • screenshot - Capture current screen state
  • record_video - Record simulator sessions

App Management

  • install_app - Install apps on the simulator
  • launch_app - Launch apps by bundle ID
  • get_booted_simulators - List running simulators
  • open_simulator - Open Simulator.app

Real-World Use Cases

1. Automated QA Testing

Natural language command:

“Open the login screen, tap the email field, type ’test@example.com’, tap the password field, type ‘password123’, then tap the login button and take a screenshot.”

The AI will:

  1. Navigate to login screen
  2. Fill in credentials
  3. Submit the form
  4. Capture the result

2. UI Documentation

Command:

“Take screenshots of all the main screens in the app for our documentation.”

The AI will:

  • Navigate through your app
  • Capture each screen
  • Save organized screenshots

3. Accessibility Validation

Command:

“Describe all accessibility elements on the current screen and check if all buttons have proper labels.”

The AI will:

  • Scan the accessibility tree
  • List all elements
  • Flag missing labels

4. User Flow Recording

Command:

“Record a video of the signup flow from start to finish.”

The AI will:

  • Start video recording
  • Navigate the flow
  • Save the recording

Practical Example: Testing a Login Flow

Here’s how you might instruct an AI assistant:

Your prompt:

Test the login flow on my React Native app:
1. Open the simulator with my app
2. Tap the "Email" input field
3. Type "john@example.com"
4. Tap the "Password" input field
5. Type "secure123"
6. Tap the "Login" button
7. Take a screenshot of the result
8. Describe all elements on the resulting screen

What happens behind the scenes:

AI executes these MCP tools 
# AI automatically calls:
ui_tap(element: "Email")
ui_type_text(text: "john@example.com")
ui_tap(element: "Password")
ui_type_text(text: "secure123")
ui_tap(element: "Login")
screenshot(filename: "login-result.png")
ui_describe_all()

Wrapping Up

iOS Simulator MCP Server brings AI assistance to React Native testing. While it won’t replace your test suite, it’s an incredible tool for exploratory testing, documentation, and quick validations.

Quick recap:

  1. AI-controlled simulator - Natural language commands
  2. 13 powerful tools - Tap, swipe, screenshot, record, and more
  3. Easy setup - NPX + MCP configuration
  4. Perfect for - Exploratory testing, screenshots, accessibility audits
  5. Mac only - Requires iOS simulator and IDB

Ready to try it?

Using AI-assisted testing in your workflow? Share your experience on Twitter!

Tomorrow we’ll explore Day 19’s topic - see you then! 🎄