I've got everything working — both back-end and front-end, thank you for your help! I've also finished renaming all namespaces, and now can enjoy coding with polylith. One last thing left: in our backend-api project there is a bunch of kaocha tests. I'm trying to run them with polylith-kaocha, having a project configured like this: "backend-api" {:alias "api" :test {:create-test-runner polylith-kaocha.test-runner/create}} But I'm getting this error from the poly tool: Invalid test runner configuration for project backend-api. Unable to load test runner constructor polylith-kaocha.test-runner/create. I have followed instructions from polylith-kaocha and added the installes to the :poly alias of the main deps.edn, and to the :test alias of the project deps.edn. What am I missing? UPDATE: Tests do run when launched from command line with clojure -Srepro -M:poly test, the error is within the poly tool. UPDATE 2: I figured it out. In order to run from the tool, I need to start the tool with clojure -Srepro -M:poly shell. Is this ok?