Rulebreaker Rules
Rulebreaker is an ability word, not a keyword. Each Rulebreaker commander bends exactly one Commander deckbuilding rule, spelled out in its own reminder text.
The mechanic
How Rulebreaker works
The five things to understand about Rulebreaker before building.
Rulebreaker is an ability word
Rulebreaker has no rules meaning on its own. It is printed in italics before reminder text that spells out each commander's specific exception. The exception is only what the reminder text says — nothing more.
It only applies while the card is your commander
A Rulebreaker exception is active only when that card is your commander. The same card in the 99 (or anywhere else) grants no deckbuilding exception.
It changes deckbuilding, not gameplay
The exception is a pregame deckbuilding rule. It does not change a card's color identity, and it has no effect on how spells and abilities work during the game.
Each commander breaks one specific rule
Every Rulebreaker commander bends exactly the restriction its reminder text names — a card category, a color, or a deck-size rule. No Rulebreaker removes all Commander restrictions.
Governed by the Commander rules
Commander deck construction is defined by the Comprehensive Rules (section 903). Rule 903.5e governs the pregame deckbuilding exception that Rulebreaker commanders rely on. The official sources below are authoritative.
Comprehensive Rules
Key Commander deckbuilding rules
The rule references that Rulebreaker interacts with. Select a rule to expand its summary.
A card's color identity is the set of colored mana symbols in its mana cost and rules text, plus any color indicators or characteristic-defining abilities. Rulebreaker exceptions do not change a commander's color identity.
A Commander deck normally contains exactly 100 cards, including the commander. Whtz, the Bibliophile's exception removes the maximum size for its deck.
Other than basic lands (and cards that say otherwise), a Commander deck may contain no more than one copy of any card. Rulebreaker does not change this.
A card can be included in a Commander deck only if every color in its color identity is also in the commander's color identity. Many Rulebreaker exceptions relax this for a specific card category.
Rule 903.5e governs how Rulebreaker abilities work: it lets them function before the game begins (during deck construction), and only while the card with the Rulebreaker ability is your commander. Each reminder text names the exact restriction it modifies.
Official Sources
Primary references
The authoritative Wizards of the Coast sources for the Rulebreaker mechanic and card wording.
- Mystery Booster Commander Edition Release Notes
- Mystery Booster Commander Edition Update Bulletin
- Tolabow, Loch Rascal Rules Text Update
Card text on this site uses current Oracle wording from Scryfall. The official Comprehensive Rules remain the authoritative reference.