Do builders have to install the plugs for phone connections?
I’m a builder. I do install at least two jacks per house. Usually 3 because of the sat dishes. I don’t have to. I just always have. No wires should have been left hanging out of the box. He should put a cover over them and wrapped the wires inside the box. If you don’t plan on getting service ask him to put covers on or provide them to you so you can do it. These are cheap. You can buy at stores like Lowes or Home Depot. He doesn’t have to put the jacks in unless spelled out in your spec sheet. Many today never get a home phone service. To keep you happy he probably will if you ask him nice. Check and make sure the phone company doesn’t do it for free with a new service. This isn’t something to make a big deal about. Try to maintain a good relationship with your builder. You may need him for something far more important.