Runtime Mix.Task - set long task description?

I have a Mix.Task I am writing. This is a generic Task runner task, where what it does depends entirely on the project configuration. As such I want running mix help check to use a runtime set long task description.

With a configuration like this:

def project do
[
  #...
  checks: [
    {"test", "mix", ~W"test --force --warnings-as-errors"},
    {"cspell", "npx", ~W"--package=cspell@8.16.0 --yes -- cspell ."},
    {"compile (no warnings)", "mix", ~W"compile --force --warnings-as-errors"},
  ]
  #...
]
#...

I want to show this as the help

Runs the following checks:
  - test
  - cspell
  - compile (no warnings)

I expect doing this would require getting Mix.Task.moduledoc changed to optionally call a callback on the task?

Alternatively if anyone knows of a better way to do what I am doing I am all ears. I believe I can not use an alias, both because I want to call external commands, and because I want to e.g. run test in the test enironment, then compile in the dev environment.