IUDEX ARCANUM is an AI rules judge for Magic: The Gathering and other trading card games — instant rulings backed by the exact Comprehensive Rules citations. Life, turn and stack tracking are always free with no sign-up; sign in to ask the Judge, build decks, and look up cards.
Free life & turn tracking needs no account. The AI Judge, deck builder & card tools run on pay-as-you-go credit. · All features → · See how it works →
A sample of the AI Judge's real output — sign in to ask your own. Create a free account →
Ask any rules question and get an instant ruling with cited Comprehensive Rules numbers, a confidence level, and a Dispute/Override flow for table calls. The feature that settles the argument.
Two-player life totals, poison, commander damage, custom counters, turn phases and a phase timer — a clean digital scorepad for any trading card game.
Describe a format, colors, budget and playstyle — or use your saved collection — and get a full, legal decklist with strategy and a sideboard.
Push spells and abilities onto the stack, resolve in order, and step through every phase of the turn. Camera support to point at the board.
Look up any card's oracle text, format legality, rarity, and official rulings in seconds.
Snap a photo to estimate whether a card is genuine or a proxy, and grade its condition on the TCGplayer scale — handy for trading outside official stores.
The rules judge and deck builder understand the major constructed and singleton formats:
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