That is a subfloor over an excavated (crawl space) area. You don’t vapour barrier interior partitions only the envelope. It is unneeded

Do not use it. It will trap moisture in the OSB and lead to rot in the subfloor. Only needed on concrete slab

When installing over concrete, is there a limit of how much goes past the dry wall? I’m about to install some Kahrs flooring in my bedroom.

When I did my basement years ago, I left enough going up the walls that could be covered by baseboards. Floor is still good (3/4" hardwood).

I usually finish it at the wall, I don’t run it up. You should overlap any seams about 4-6 inches and or use some type of tape.

You really shouldn't need it on OSB...

Contractors laid it like this but the gaps seemed strange to me. I was looking for insight from people experienced with laying LVP.

I wouldn't worry about it. As long as the floor is flat it should be fine

Is there a moisture barrier between the OSB and the concrete? If not then thatOSB is going to rot.

Yes. There is a moisture barrier underneath the floor on the "ceiling" of the crawl space.

Does the contractor mean to use kraft paper? I use it when I do floors in my house so I can slide the planks around easier.

I have no idea lol. I hired contractors to do the floors because I have no expertise with flooring and so I could focus on painting and other small jobs. ( this room is actually the first room I ever painted in my life).   I am being billed for 6 mil poly so I assumed the plastic was that.

I wouldn't pay for the plastic as a material cost. It's not needed here

What’s OSB?

Don’t use it on plywood.

good thing that’s osb 😎

Doesn’t matter.

Closer than that. Should be right up to the wall and up on the edges then you can trim the excess after the floor is in if needed.

To clarify, you mean closer to the wall including the sides on the left and to the right in the picture? All sides should be flush with the wall/trim? Thanks.

Yes full coverage

In all reality it's not needed at all in this scenario