The Deps and CLI Guide is actually pretty clear.

Basically, the formula is:

1. Create a top level ns (e.g. foo).
2. In that ns, create a standard main function. Note that it will only terminate if you explicitly call (System/exit) yourself.
3. Invoke the application as clj -m name-of-ns, e.g. clj -m foo.

To use these elsewhere:

1. Commit to git.
2. Add an alias to your deps.edn file. The alias can be whatever you want. Declare your dependency with the :deps key and specify the actual invocations with :main-opts.
3. Invoke the alias as clj -A:alias.

You can now invoke as:

• clj -m ls
• clj -m list-instances