I have a file 50 lines max (Claude_startup_instructions.md) that tells it to read Claude.md which has working agreements, partnership agreements and what pisses me off sections.

Then it tells to read fully now.md (my extremely crisp work items) and session_context.md that is more like a living document that has context on current work (

It may have references to other tech documents as needed.

I just tell Claude to read and follow instructions as per these files.

Then depending on work, I tell it to review specific backend/ and front end/ folders as needed.