About manaruler
A Magic companion that tries to be right, and to show its work.
What it is
manaruler is a small web app for people who play Magic: The Gathering on Arena and are still working out how the game actually works. It answers rules questions in everyday language, checks whether a deck is legal, keeps decks you can import and export, and tracks the cards you tell it you own.
It is built around a single constraint: never give an answer without being able to show where the answer came from. Most of the design decisions on this site fall out of that one rule.
Who it is for
Built for
People who started playing recently. People coming back after a few years away. Anyone who has watched something resolve in Arena, lost the game because of it, and had no idea why.
The tone here is aimed at that person deliberately. Nothing on this site assumes you already know what a state-based action is.
Not built for
Tournament preparation. manaruler carries no metagame data, no matchup statistics, no win rates and no tier lists, so it will not tell you what to play this weekend.
That is a choice about focus, not a gap waiting to be filled. Getting the rules right for newer players is the whole job.
How it decides things
Three commitments, in descending order of how much trouble they would cause if they were broken.
- Legality is deterministic
- Deck legality comes from a rules engine reading the card catalogue, not from a language model. Two identical decks get the identical verdict, this month and next.
- Rules answers are cited
- Answers are drawn from the Comprehensive Rules and shown with the passage and rule number they came from, so you can check them against the source instead of trusting this site.
- Your collection is yours to state
- Nothing is inferred about what you own. Your collection contains exactly what you put into it, and nothing reads your Arena installation or your account.
- Card data has a source
- Card names, types and printings come from Scryfall's public card data, kept in sync rather than typed out by hand.
Fan content and attribution
manaruler is unofficial Fan Content, not approved or endorsed by Wizards of the Coast. See our Disclosures page for the full Wizards of the Coast Fan Content Policy notice, the Scryfall attribution, and the affiliate-link disclosure.
Have a look at what it does
The features page describes each capability in more detail, including the parts that are not finished yet.