I have only just begun playing around with evals for a harness I'm working on and so far I have just been doing runs of converting https://github.com/realworld-apps/realworld from one language to another
not super pleased with it
the unsatisfying answer I think is that crafting good eval environments for long runs takes a lot of time, and there are many things you'd want to verify that you cannot simply lint or test for
Letting another LLM decide quality probably isn't the only meterstick you want, either.