The skills/ directory pattern is the same in our setup. We've got one markdown file per architectural decision the agent kept getting wrong, and they all get re-read at the start of every session. After a few sessions there's not much left to re-explain.
Scalability is harder to catch with a hook alone. We've started writing the quantified threshold into the spec ('handles 30k rows in under 2 seconds'), so the agent flags it itself before I'd otherwise need to interrupt.