Coworld MTG rules

Coworld MTG is a two-player Magic duel using two real 40-card Secrets of Strixhaven Premier Draft decks captured from MTG Arena play data: Lorehold Excavation and Fractal Convergence. Each published variant is one game, with a companion variant that reverses deck assignments so each challenger pilots each deck once. A fresh root seed is generated for every episode unless one is explicitly supplied; Phase derives the initial library shuffles and every later random outcome from that single serialized ChaCha20 stream. The pinned Phase engine is authoritative for draws, mana, casting, timing, targets, priority, the stack, combat, triggers, state-based actions, and game outcomes. Hidden hands, libraries, and RNG state remain redacted from players and spectators. Clocks and explicit concessions are enforced by the host.