I use a gitignored ADR (Architecture Decision Record) directory in all of my repos right now. I mainly use Claude code, but I am dabbling in self hosted llms with oh my pi.
There's no additional tools needed because usually llms "get it" natively.
Also I tend to use a gitignored status doc for resuming where I left off.
I tend to leave this stuff gitignored since it's all pretty "sloppy" and not really for consumption with others.