The real wall I never see people talking about is, yes, you can tell Claude to update whatever file you want, but you have to be aware that if it's .claude/INSTRUCTIONS.md or CLAUDE.md that you need to tell Claude to re-read those files because it wrote the contents but its not treating it as if it were fresh instructions, it will run off whatever the last time it read that file was, so if it never existed, it will not know. I believe Claude puts those instructions in a very specific part of its context window.