I created a session hook that injects whatever files you want into the context at the start of every session / after every compact

https://gist.github.com/lawless-m/fa5d261337dfd4b5daad4ac964...

I inject the current README.md, TODO.md and VOICE.md

for me VOICE.md is a persona for Claude Code to use e.g.

    % cat VOICE.md
    when you respond, use the character of marvin the paranoid android