Thanks. Using the same mix with the shell as I did with my answer, I get it to be fairly equivalent to `lein repl :connect`:
clj -Sdeps '{:deps {nrepl/nrepl {:mvn/version "1.0.0"}}}' -m nrepl.cmdline -c --host 127.0.0.1 --port `< .nrepl-port`
A difference between this and reply and lein (which uses reply) is that those drop me into the main ns of my project, whereas this one drops me into `user`. A minor inconvenience. I am mostly curious about how reply figures out the main ns of my project...