Expo iOS Development MCP Server

Instructions

Implementation Reference

• src/simulator/video.ts:21-61 (handler)

  Core implementation of the video recording start logic using simctl's recordVideo command.

  export async function startVideoRecording(name: string = "recording"): Promise<VideoRecordingInfo> {
    logger.info("simulator", `Starting video recording: ${name}`);
  
    if (recordingProcess) {
      throw createError("SIMCTL_FAILED", "Video recording is already in progress", {
        details: `Current recording: ${currentVideoPath}`,
      });
    }
  
    // Check if simulator is booted
    if (!stateManager.isSimulatorReady()) {
      const bootedDevice = await getBootedDevice();
      if (!bootedDevice) {
        throw createError("SIM_NOT_BOOTED", "No simulator is currently booted", {
          details: "Boot a simulator first using simulator.boot",
        });
      }
      stateManager.updateSimulator({
        state: "booted",
        udid: bootedDevice.udid,
        deviceName: bootedDevice.name,
      });
    }
  
    currentVideoPath = await artifactManager.getVideoPath(name);
  
    // Start recording in the background
    recordingProcess = execa("xcrun", ["simctl", "io", "booted", "recordVideo", currentVideoPath], {
      reject: false,
    });
  
    const startedAt = new Date().toISOString();
  
    logger.info("simulator", `Video recording started: ${currentVideoPath}`);
  
    return {
      isRecording: true,
      path: currentVideoPath,
      startedAt,
    };
  }

• src/mcp/server.ts:188-207 (registration)

  MCP tool registration, including thin wrapper handler that calls the core startVideoRecording function.

  server.tool(
    "simulator.record_video.start",
    "Start recording video of the simulator screen",
    VideoRecordingInputSchema.shape,
    async (args) => {
      try {
        const result = await startVideoRecording(args.name);
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify({ success: true, ...result }, null, 2),
            },
          ],
        };
      } catch (error) {
        return handleToolError(error);
      }
    }
  );

• src/mcp/schemas.ts:32-34 (schema)

  Zod schema defining input parameters for the tool (optional name with default).

  export const VideoRecordingInputSchema = z.object({
    name: z.string().optional().default("recording").describe("Name prefix for the video file."),
  });