What are some llm tips you’ve used to make software that is actually maintainable?

I’ll go first. My new favorite line in my Claude.md. Helps me get around any ambiguity I have with my llm about what is being built or understood by tasks.

CRITICAL: Always make detailed plan with sections for Analysis, specifications, to do list to achieve the spec, and a step by step manual testing strategy for any request a user makes. Always, even when "accept edits on", ask the user to confirm the plan in its entirety. If the user requests changes to any of the plan, make a new plan considering their requests and present it to the user. Never ever start editing files until the user has approved the plan without requesting changes to it. Do not consider the task done until all of the testing Manual Checking strategies successfully passes.