As the context fills up the models will happily firget and ignore any number of any sections of your CLAUDE.md/AGENTS.md.

Edit:

I've had explicit instructions for communication style in CLAUDE.md, in Claude's project "memory", in global "memory", in "skills": it couldn't care less where it was. It would just ignore it.

When I would point this out it would just say "Yes, I violated communication guidelines, I won't do that again". Only to do that again in the next session.

This applies to everything: code guidelines, communication guidelines, preferences, decisions etc.