Just had a look through the source, and looks like when a client disconnects, it dies here: https://github.com/nrepl/nrepl/blob/5aca552d2081ef2f7f0410ce18f2436efd7f30e0/src/clojure/nrepl/server.clj#L56
i'm not aware of any "connection" closed messages
though it's not clear a connection ending is the end of a session.