Every XP project has several different roles, each with its own unique rights and responsibilities. XP attempts to improve communication between customers and developers. It accomplishes this by sharply dividing the work between the two. If you want to get any work done, you’ll have to talk to each other!
XP gives developers authority to make technical decisions. This is their area of expertise. XP gives the customer authority to make business decisions. This is his area of expertise. These spheres of influence complement each other. Following these clear lines of authority will improve your chances of success.