If you use Claude Code then I am pretty sure you know what is CLAUDE md Your CLAUDE md is set up right But your token bill is still huge CLAUDE md is not lazy loaded It gets sent on every single message, every session, whether you needed it or not So the fix isn't adding more rules to it It's making the rules you already have actually cheap and enforce I added just 3 lines to mine and output tokens dropped noticeably ╰┈➤When editing code, output ONLY the changed lines or the single modified block — never reprint the whole file. ╰┈➤No setup guides, no recaps of what you changed, no explanations unless I explicitly ask. ╰┈➤Keep responses tight. If one line answers it, give one line That's it. No 2000 token essay of "best practices." Just rules that remove waste on every reply Second thing I keep seeing People running Opus for everything, even one line fixes and simple questions Opus is for the hard stuff. Architecture calls, big refactors Sonnet handles almost all day to day coding at a fraction of the cost Haiku is fine for quick lookups and small edits Match the model to the task Your CLAUDE md handles the output side Model choice handles the input side Do both and the difference in your bill is not small What's one CLAUDE md rule that actually changed how Claude behaves for you?