Expo iOS Development MCP Server

Instructions

Implementation Reference

• src/simulator/devices.ts:166-190 (handler)

  Core handler function that erases the simulator device by shutting it down if necessary and calling simctl erase.

  export async function eraseDevice(nameOrUdid: string): Promise<void> {
    logger.info("simulator", `Erasing simulator: ${nameOrUdid}`);
  
    const device = await findDevice(nameOrUdid);
  
    if (!device) {
      throw createError("SIM_NOT_FOUND", `Simulator not found: ${nameOrUdid}`, {
        details: "Use simulator.list_devices to see available simulators",
      });
    }
  
    // Must be shut down before erasing
    if (device.state !== "Shutdown") {
      await shutdownDevice(device.udid);
    }
  
    const result = await simctl(["erase", device.udid]);
  
    if (result.exitCode !== 0) {
      const { code, message } = parseSimctlError(result.stderr);
      throw createError(code, message, { details: result.stderr });
    }
  
    logger.info("simulator", `Device ${device.name} erased successfully`);
  }

• src/mcp/server.ts:146-165 (registration)

  Registers the 'simulator.erase' tool with MCP server, providing description, input schema, and thin wrapper handler that delegates to eraseDevice.

  server.tool(
    "simulator.erase",
    "Erase all content and settings from a simulator (factory reset)",
    SimulatorEraseInputSchema.shape,
    async (args) => {
      try {
        await eraseDevice(args.device);
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify({ success: true, message: `Device ${args.device} erased` }),
            },
          ],
        };
      } catch (error) {
        return handleToolError(error);
      }
    }
  );

• src/mcp/schemas.ts:24-26 (schema)

  Zod schema defining the input for the simulator.erase tool: requires a 'device' string (name or UDID).

  export const SimulatorEraseInputSchema = z.object({
    device: z.string().describe("Device name or UDID to erase."),
  });