In Commander, can you include a card in your deck if it only mentions a color outside your commander's color identity in reminder text?

A card's color identity in Commander is determined by its mana cost, color indicator, and any mana symbols or color words that appear in its rules text — but reminder text is explicitly excluded from this determination. This is covered in CR 903.4, which governs Commander color identity, in conjunction with CR 207.2, which clarifies that reminder text (printed in italics within parentheses) has no functional rules meaning.

Because reminder text is purely explanatory and carries no rules weight, any color symbols or color references appearing only within reminder text do not contribute to a card's color identity. The card is treated as if that text simply does not exist for color identity purposes.

A classic example is Extirpate, which has the keyword Split Second. The reminder text for Split Second mentions 'mana abilities,' but contains no off-color mana symbols. A cleaner example: if a card with reminder text like '(It can't be blocked by green creatures)' were in your deck, that green reference in reminder text would NOT add green to the card's color identity, so a non-green Commander could still include it.

This rule prevents players from being penalized for reminder text that is there purely to help them understand a keyword, not to define the card's identity. So always check the actual mana cost, color indicator, and non-reminder rules text when assessing color identity.