This is a language that explicitly sacrifices important stuff like the strength of automatic checks possible and performance in lieu of developer ergonomics. Even if you support that particular choice, chosing the language when you won't be writing or reading most of the code is a pretty poor tradeoff.
I actually find, for some reason, that LLMs seem to be able to be more "creative" when it comes to Ruby (having used LLMs across 4-5 languages). I don't mean hallucinating, but crafting solutions I would not have thought of, even if I've ensured that I've inserted my original thinking at the beginning.
I wonder if there is something about the combination of the expressiveness of Ruby and the way LLMs are closely tied to human language that brings that out. Of course, usual caveat: n of 1 on my own experience, and a dose of bias.
There are indeed so many compelling arguments against using Ruby these days (e.g. performance, type safety, an increasingly small user base), & yet I continue to reach for it because of this effortless expressiveness (& the maturity of the ecosystem).
I know the bot's not sophisticated enough to metaprogram anything, it writes straightforward code that's easy enough on the eyes, if not to my standards of style.
The idea is eventually I want to build the tooling to where I can actually start writing code again. That code will be ruby.
Testing anything in Ruby is dead simple, and agents are very good at writing the tests.
The REPL is also a big win for agents. Reproducing a bug, or exploring how to build a feature, agents can get a lot of mileage out of a rails console.
A lot of the developer ergonomics are just as helpful to agents.
The performance of Ruby sucks, though.