> note how often Opus 5 now says things like "task X was blocked by the classifier, I will not attempt to circumvent that"

Interesting. I had an issue with Opus 4.7 / 4.8, where it would sometimes flake out on a task, and give me some nonsense explanation why it was not feasible or wouldn't work. At one point I told it directly, that I understand how modern LLM systems are structured, and I suspect my prompt triggered one of the various classifiers in the background, which put up a yellow or red flag, and I want the model to stop gaslighting me.

We ended up agreeing and committing to memory system explicit instructions that the model is free to refuse but must be up front about the reason, and never pretend to try and then fail in stupid way. Only then I started getting the occasional direct refusal.