I agree. I actually used Claude to rewrite some famous kernels (in OCaml): https://github.com/aryx/IX/tree/main/kernels with xv6, plan 9, oberon, singularity, Squeak on the bare Metal. So easier now to experiment in OS design.
This is nice, but when your language will grow, why would you use that instead of lex/yacc? It's hard to beat a nice BNF grammar; In fact they felt the need to put the BNF grammar for the things they were parsing at the end of the README, because it's far more readable that those >* skip <* stuff.