I have just fought 4 days with Claude 4 Sonnet because it generates too much garbage for my usage, and I am considering stopping the AI usage altogether. No matter what system prompt, rules et. all you give, they don't want to do as I said, but instead do something which compiles (Rust) but is not performant or is extremely verbose and includes all kinds of unnecessary things. They have too much assumptions that some function is used/not used in async context, or it is okay to clone, or whatever. Is the Opus really that big leap?