What manaruler does
Four things. This page describes what each one does, and where it stops.
Deck legality, checked properly
Give manaruler a decklist and it tells you whether the deck is legal, and if it is not, which cards break which rule. The check reads the card catalogue and applies the format's construction rules directly. It does not ask a language model for an opinion, so the same list gets the same verdict every time you run it.
Standard and Historic are both supported, which between them cover most of what a newer Arena player is building.
- Minimum deck size
- 60 cards in constructed play. Comprehensive Rules 100.2a
- Copies of one card
- Four, counted by English card name. Basic lands are the exception and have no limit.
- Sideboard
- Up to 15 cards, checked alongside the main deck.
- Set legality
- Every card is checked against the format it is claimed for, not just the deck's size and shape.
Rules answers with the rule attached
Ask in ordinary words. manaruler searches the Comprehensive Rules, finds the passages that actually apply, and gives you an answer written for a person rather than for a judge.
Every answer carries the rule it came from, so you can read the original text yourself and decide whether you believe it. That is the whole point: the citation is not a footnote, it is the feature.
“What happens the moment I hit 0 life?”
You lose the game. The game checks for this on its own, before anyone gets the chance to take another action, so there is no window to cast one last spell and save yourself.
Comprehensive Rules 704.5a
Decks that travel with you
Import a decklist in the format Arena already gives you when you export one. Keep it, rename it, change it, and export it back out in the same format when you want to play it again.
Your decks are yours. There is no proprietary format to get stuck in, and nothing you import stops being a plain list you can copy back out.
A collection you keep on purpose
What it does
You add the cards you own by pasting in a list. manaruler remembers it, and can compare any deck against it to show you which cards the deck needs that you do not have yet.
That comparison counts by card identity rather than by printing, so a copy you own from an older set still counts toward a deck that lists the newer one.
What it does not do
There is no automatic Arena sync. manaruler does not read your Arena installation, does not watch your log files, and never connects to your Arena account.
Everything in your collection is there because you typed or pasted it in. If that changes, this page will say so.
Where this is up to
All four capabilities above are built and running. The web pages you would click to use them are not finished yet, so for now they are reached through manaruler's own interface rather than through a deck builder you can open. This page will stop saying that when it stops being true.