I think the point here, though, is that the user needs to be explicit on the command line: they have to specify one of `--wet` or `--dry`; specifying neither is an error. It's not clear from your code if you do that, or if you interpret `--dry-run` as `DryRunMode.Dry` and the absence of an option as `DryRunMode.Wet`.

While I kinda like this idea in principle, I haven't really seen any CLI apps that require an explicit option for both modes, so it might be a bit of unexpected UX for people.

I noticed that after I posted and had read a bit more; but you're also using F# which has proper ADTs. I'm typically writing support scripts in Python or the like, and even very good libraries like click[1] nevertheless reflect the idioms popular in the language.

I really came back to this post because I was struggling with Gradle and if there is a more perfect illustration of how a dry run mode could help than that, I don't know what it could be. Gradle builds are a fucking mystery, every time, and there's no excuse for it.

[1]: https://palletsprojects.com/p/click/