Implement iOS Simulator MCP server with FastMCP 3.0

[Copilot]

Implements Model Context Protocol server for iOS Simulator interaction using FastMCP 3.0 framework. Transforms and codifies CLI tools from ios-simulator-mcp into LLM-friendly stdio transport.

Implementation

• 13 iOS Simulator tools: Device management (get_booted_sim_id, open_simulator), UI interaction (tap, type, swipe), UI inspection (describe_all, describe_point, view), media capture (screenshot, record_video), app lifecycle (install, launch)
• FastMCP 3.0 patterns: Typed parameters with Zod schemas, content responses, stdio transport
• Security: UDID validation via UUID regex, spawn/execFile for command execution (not shell interpolation)

Project Structure

// Tool definition pattern
mcp.addTool({
  name: "ui_tap",
  description: "Tap on the screen in the iOS Simulator",
  parameters: z.object({
    x: z.number().describe("The x-coordinate"),
    y: z.number().describe("The y-coordinate"),
    udid: z.string().optional().describe("UUID format: 8-4-4-4-12")
  }),
  execute: async (args) => {
    const cmdArgs = ["ui", "tap", String(args.x), String(args.y)];
    await execFileAsync("idb", cmdArgs);
    return { content: [{ type: "text", text: `Tapped (${args.x}, ${args.y})` }] };
  }
});

Dependencies

• Requires macOS with Xcode and Facebook IDB
• Node.js ≥18, FastMCP 3.31.0
• Uses ES modules, TypeScript compilation target ES2020

Usage

npx ios-dev-mcp

Claude Desktop config:

{
  "mcpServers": {
    "ios-simulator": {
      "command": "npx",
      "args": ["-y", "ios-dev-mcp"]
    }
  }
}

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• gofastmcp.com
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

FastMCP 3.0.0 LLM friendly docs: https://gofastmcp.com/getting-started/welcome#llm-friendly-docs

The iOS Simulator MCP repository is here: https://github.com/joshuayoes/ios-simulator-mcp

Distilledstdio mode, npx ios-simulator-mcp.

The intent of transforming those tools is to get access to them for MCP Apps that allow the user and agent chat to interact with and view things better. Also we can codify the CLI interface.

I will have the session I am working with now provide use info for CLI

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