As the current tools when your removing grass have a habit of knocking holes in the ground as well may I suggest adding a scythe.
The scythe would only effect the grass and have no damaging effects on blocks, this would make it easier and faster to clear out larger areas when foundation building.
I think Ideally grass should be removed when a block is placed on top. I know that at the moment it pokes through, but I don’t think that’s intended. Still, a scythe would be a useful tool when harvesting farms later in the game, particularly if it had an area of effect where it gathered a few blocks in semi-circular area in front of the user. This added effect doesn’t have to keep it from being used as a weapon, either