CommandbenchEDHREC deck builder rules check
Search a commander, then add cards. The checker blocks anything outside that color identity, a second copy of a nonbasic, and card 101. It does not rank cards the way EDHREC does.
What EDHREC's Recs page does instead
EDHREC asks for a commander at minimum. With only that legend selected, the suggestions match the average list. Add more of the 99 and the suggestions narrow toward decks that already look like yours. That is collaborative data. This page is the rules layer you run before or after that.
Read how color identity and the tax work if a card is rejected and you want the rule, not only the error line.
Questions
Does this deck builder copy EDHREC recommendations?
No. EDHREC's Recs page imports your list and suggests cards from similar public decks. This checker only tests Commander construction: one or two commanders, color identity, singleton, and 100 cards. Card data comes from Scryfall.
What does the second commander slot do?
It unions the two color identities and counts both cards toward 100. It does not verify Partner, Background, Friends Forever, or Doctor's Companion. Confirm the pair is legal before you play it.
Where is the deck saved?
In this browser, under a local storage key. Nothing is uploaded. Clearing site data clears the list.