How does the light play on the counter? That's what matters as far as installation goes. As far as how they attached it, I've seen worse. I have worse. :) Apparently we aren't supposed to ever look up there.

Also be sure that the electrical connection is to code, coming out of the wall like that. It's similar to what my GC did and it seems sketchy to me, but I don't know much about that sort of thing.

I'm presuming the cable coming out of the wall is a normal 110v circuit. If so it is not acceptable, is not to code, and presents a potential fire and shock hazard. Any connections involving such circuits are required to be enclosed in an electrical box. What you got was a nice, low profile connection that is a hazard. No inspector would pass that installation. If your contractor is telling you this is normal/standard, I'd be concerned about what other non-code things he has done that you are unaware of. Insist that this be corrected. Those connections can be enclosed in a shallow "pan box" which is only 1/2" deep . And the connections need to be done with wire nuts, not electrical tape.

What if it is low voltage (12 or 24)?

There’s no transformer so it has to be low voltage coming out of the wall. He just used NM cable for some reason.

greg-

There is no transformer visible, but there could be one somewhere, in which case my earlier presumption that it was regular household current -- based on the cable used -- is wrong. Why someone would use Romex and tape the connections in this situation is baffling and, to me, not workmanlike. The OP should be asking the contractor if this is indeed connected to a low voltage transformer...and reveal the location. And, if so, hopefully it's not entombed in the wall....

They went cheap. They sell a better light with a small housing around it and a diffuser so you don't get the pin-point look reflecting off the counter and/or backsplash.

@kudzu9 thank you I will ask him. He has some personal connection with this electrician. I have gotten I to many arguments with him over every little thing. This he is digging his heels in. I have one week until the reno is done. I’m scared he’s going to walk along with my money and my quartzite slabs that are being installed end of this week. I am not good with confrontation and I’m sick over it. Everything about this looks wrong.

With the light rail installed, you will never see any of that. Yes, it is normal to notch or drill through the cabinets to install the tape lighting. I prefer to drill with a right angle attachment. It’s neater.

120V or 12V it's still sloppy, unworkmanlike, and unsafe. About the only thing 12V does for you is provide for less of a shock hazard.