I specifically have instructions for claude explaining the purpose of the project in pretty much all repos. Just a simple PROJECT.md is enough - and referenced from AGENTS.md

There I usually lay out stuff like "this is a personal greenfield project" and "don't bother with multi-user support" etc. Or Claude will default to creating something WEBSCALE for a simple tool that won't run outside of my local LAN-only Proxmox setup. And that'll also skip massive database migration support for a project that's 3 days old - the agent doesn't know that. I'm just dropping it on the project after a full memory wipe.