I maintain Elixir and Rails applications. In my opinion, almost all LLMs handle Elixir better. I suspect, though do not know, being an immutable functional language and composing applications in a functional style makes it easier for the models to "reason" about the code and state. I learned very quickly that this is my preferred language for that very reason.

Additionally, the features available in the BEAM and OTP mean the agents have built-in tools for many things that would require reaching for 3rd-party libraries or even additional services. This means less variability in design as the models will happily use all the language features human developers would have to learn about and understand over time to use effectively. Not that this isn't important, but I believe models do a better job steering you to obvious and optimal solutions with Elixir.

The new type system is only going to make it better.