The engine
Inside Boxwood.
Eight engines, one search. What separates them is how far ahead it looks — and nothing else.
Specification
Small on purpose.
A material-count negamax with alpha-beta pruning, running on the main thread. It evaluates position by material alone — no king safety, no pawn structure, no opening book. It will punish a hanging piece and it will not outplay you positionally.
It runs in the page because it has to. Framer sites send no COOP or COEP headers, so SharedArrayBuffer is unavailable and a worker-based engine cannot start. Levels seven and eight search three ply and are noticeably slower on a phone.