cider-nrepl should be a good code read barebones completions and compliment-based completions are different nrepl ops - there's no automatic upgrade contexts are computed client-side, you can refer to cider (elisp) for an example Hope it helps!

I have a hard time reading elisp, but no worries - I already have a completions code on my side, just wanted to be sure that I wasn't doing the wrong thing 🙂. I though there was a possibility of an automatic upgrade, so that's why I asked!

If you mean nREPL's basic completion functionality, then it doesn't use Compliment directly. The latest master version of nREPL uses simplified Compliment code (without support for contexts).

BTW, you don't need to read Elisp, cider-nrepl is in Clojure: https://github.com/clojure-emacs/cider-nrepl/blob/master/src/cider/nrepl/middleware/complete.clj

I referred to supplying a context https://github.com/clojure-emacs/cider/blob/24b060ab8ac28922b0dddeed104572e98fc8a6ea/cider-completion-context.el

You can actually instruct nREPL to use compliment if you have it on the classpath via *completion-fn*. Perhaps at some point we’ll change nREPL to pick up compliment automatically, given it doesn’t have much (any?) competition in the completion space these days.