Yep - this has worked well for me too. I do it a little differently:

I have a /review-sessions command & a "parse-sessions" skill that tells Claude how to parse the session logs from ~/.claude/projects/, then it classifies the issues and proposes new skills, changes to CLAUDE.md, etc. based on what common issues it saw.

I've tried something similar to DISCOVERIES.md (a structured "knowledge base" of assumptions that were proven wrong, things that were tried, etc.) but haven't had luck keeping this from getting filled with obvious things (that the code itself describes) or slightly-incorrect things, or just too large in general.