app-screen-mcp

Instructions

Implementation Reference

• src/index.ts:821-831 (handler)

  The pressButton handler method, which executes the 'idb ui button' command to trigger hardware button presses on the iOS simulator.

  private async pressButton(button: string, udid?: string) {
    const target = await resolveUdid(udid);
    try {
      await execAsync(`idb ui button --udid ${target} ${button}`);
      return {
        content: [{ type: 'text', text: `Pressed ${button} on ${target}` }],
      };
    } catch (error: any) {
      throw new McpError(ErrorCode.InternalError, `Failed to press button: ${error.message}`);
    }
  }

• src/index.ts:427-443 (schema)

  The JSON schema definition for the 'press_button' tool, defining the allowed button enum and optional UDID parameter.

  {
    name: 'press_button',
    description: 'Press a hardware button on the simulator',
    inputSchema: {
      type: 'object',
      properties: {
        button: {
          type: 'string',
          enum: ['HOME', 'LOCK', 'SIDE_BUTTON', 'SIRI'],
          description: 'Button to press',
        },
        udid: { type: 'string', description: 'Simulator UDID (optional, defaults to booted simulator)' },
      },
      required: ['button'],
      additionalProperties: false,
    },
  },

• src/index.ts:528-529 (registration)

  The registration/dispatch logic inside the CallToolRequestSchema handler that routes 'press_button' requests to the class method.

  case 'press_button':
    return this.pressButton(args.button as string, args.udid);