The default lockfile will still exist. The difference is when you want a custom one, you point it to some named resolve, rather than this special mechanism just for tools. How you generate that named resolve is up to you (but we can give you obvious guidance, such as seeding a

requirements-toolname.txt

from the default requirements). But notably you can also point to one of your user lockfiles, so, for example, you get the same version of pytest as a tool and as a library.