app-screen-mcp

Instructions

Implementation Reference

• src/index.ts:761-775 (handler)

  Implementation of the tap_relative tool logic.

  private async tapRelative(rx: number, ry: number, udid?: string) {
    if (!Number.isFinite(rx) || !Number.isFinite(ry) || rx < 0 || rx > 1 || ry < 0 || ry > 1) {
      throw new McpError(
        ErrorCode.InvalidRequest,
        'rx and ry must be finite numbers between 0 and 1.'
      );
    }
  
    const target = await resolveUdid(udid);
    try {
      const size = await this.getScreenSize(target);
      const x = Math.round(size.width * rx);
      const y = Math.round(size.height * ry);
  
      await execAsync(`idb ui tap --udid ${target} ${x} ${y}`);

• src/index.ts:383-395 (schema)

  Tool registration and schema definition for tap_relative.

  {
    name: 'tap_relative',
    description: 'Tap using relative coordinates (rx, ry) in [0,1] where (0.5, 0.5) is center.',
    inputSchema: {
      type: 'object',
      properties: {
        rx: { type: 'number', description: 'Relative X in [0,1]' },
        ry: { type: 'number', description: 'Relative Y in [0,1]' },
        udid: { type: 'string', description: 'Simulator UDID (optional, defaults to booted simulator)' },
      },
      required: ['rx', 'ry'],
      additionalProperties: false,
    },