I meant: why tell Claude to edit CLAUDE.md to add the "don't add a signature" rule, instead of just writing a "don't add a signature" rule into CLAUDE.md direct

I meant: why tell Claude to edit CLAUDE.md to add the "don't add a signature" rule, instead of just writing a "don't add a signature" rule into CLAUDE.md directly? The necessary rule can't be much longer than the prompt generating it, surely.