I haven't used an AGENTS or CLAUDE file as much lately. I'm not sure how much more it helps, but generally I try to have one or more project md files. These are curated to whatever I am currently working on. Perhaps references to certain modules, commands, schemas for DB, etc.

This way the agent doesn't get too much context it doesn't necessarily need.

Again, not sure how much more effective or efficient it is but it seems to do better for my needs at least.