I pruned my Claude.md and it made a difference. There were entries there that evolved from earlier models and Opus 5 could be reacting to it in a different manner.

I have no Claude.md file. Claude is still absolutely horrible.

If you’re on Claude.ai web, you still have preferences tied to your past interactions. That can be edited.

I run everything sandboxed within a custom environment, no history, no memory, no autoloading of tools. Vanilla Claude experience.