It's great for me. I have a claude.md at the root of every folder generally, outlined in piped text for minimal context addition about the rulesets for that folder, it always creates tests for what it's doing and is set to do so in a very specific folder in a very specific way otherwise it tries to create debug files instead. I also have set rules for re-use so that way it doesn't proliferate with "enhanced" class variants or structures and always tries to leverage what exists instead of bringing in new things unless absolutely necessary. The way I talk to it is very specific as well, I don't write huge prose, I don't set up huge PRDs and often I will only do planning if its something that I am myself unsure about. The only time I will do large text input is when I know that the LLM won't have context (it's newer than it's knowledge window).

I generally get great 1-shot (one input and the final output after all tasks are done) comments. I have moved past claude code though I am using the CLI itself with another model although I was using claude code and my reason for switching isn't that claude was a bad model it's just that it was expensive and I have access to larger models for cheaper. The CLI is the real power not the model itself per-se. Opus does perform a little better than others.

It's totally made it so I can do the code that I like to do while it works on other things during that time. I have about 60-70 different agent streams going at a time atm. Codebases sizes vary, the largest one right now is about 200m tokens (react, typescript, golang) in total and it does a good job. I've only had to tell it twice to do something differently.