Clojurians Log v2

I’m looking for the simplest, most idiomatic Calva way to create an nrepl session on 7888 for clojure-mcp to connect to. Currently I am spawing a second nrepl server on the desired port? Why 2 nrepl servers? Is this desireable?

Also, the nrepl server alias reccomended on clojure-mcp repo has

:jvm-opts ["-Djdk.attach.allowAttachSelf"]
;; this allows nrepl to interrupt runaway repl evals 

Asked about this here too https://clojurians.slack.com/archives/C068E9L5M2Q/p1758045218004339 My heads swimming in config options 😵‍💫 I’m trying to have a simple calva-jack in that will work clojure-mcp with stable config that i can use in different projects.

Not exactly an answer to the question you asked but my recommendation is to start your REPL manually and have Calva connect to it. I was a big fan of jack-in for a while, but I found Calva wanted me to reload the window for extension updates more often than I would otherwise start a REPL -- and reloading kills the jack-in REPL. So I switched to starting my REPL manually -- I have a repl shell script and a bunch of aliases in my user deps.edn file (see my dot-clojure repo on GitHub for that script, those aliases, and the code I use to start a REPL). That allows me to start a REPL from the command-line -- usually a terminal inside VS Code -- and connect to it and be able to reload Calva's window without losing the REPL process and I have Calva configured to auto-connect if there's a .nrepl-port file (which starting the nREPL server lays down). This allows you a lot more control over exactly what's on your classpath and what JVM options to use etc. My VS Code / Calva / Joyride config is all in my vscode-calva-setup repo on GitHub.

Same experience as Sean because I need to choose the JVM version and I couldn’t find a way to set this with VSCode. Calva has a command which will save to your clipboard the exact command they use for the jack-in. So you don’t have to add all the nREPL config in your deps file.

How I start my REPL: https://github.com/seancorfield/dot-clojure/blob/develop/bin/repl#L14

:dev/repl adds my own custom code that adaptively figures out what to do based on what's on the classpath (from the aliases).

@seancorfield thanks for the guidance, and the links. I have been burned by the window reloading all the time. So once you start a project repl, if it includes an nrepl server for Calva to connect to, do you also set the port and use that nrepl server for clojure-mcp to talk to, or do you start a second nrepl server for that?

@pez, if i did want to continue to use jack-in in Calva, is there a way to pre-set the nrepl port? I’m assuming the custom command line string in the repl jack-in config json is the only way?

I'm not using clojure-mcp but, if I was, I would specify the port in my dev/repl code I expect, based on some CLI options...

(I'm using Copilot in VS Code, since we pay for it at work, and then I can use "any" model with it -- but I'm mostly using Claude Sonnet 4, in agent mode)