Would this card fit?

Start with red, or change the extra color below. The same card can pass the color check but fail the card-type check. These examples concern regular Commander with Tolabow alone; additional commander pairings or format-specific permissions need their own checks.

Red selected: 5 of 11 examples fit the deckbuilding permission.

Deckbuilding permission only. Assumes Tolabow is your sole commander and no other exceptions apply.
Card & typeColor identityPermissionWhy
Lightning Bolt Instant Red Fits Its complete color identity fits blue and red.
Mystic Retrieval Sorcery Blue / Red Fits Its complete color identity fits blue and red.
Ancient Grudge Instant Red / Green Does not fit Its color identity includes green, outside blue and red.
Counterspell Instant Blue Fits Its complete color identity fits blue and red.
Swords to Plowshares Instant White Does not fit Its color identity includes white, outside blue and red.
Dark Ritual Instant Black Does not fit Its color identity includes black, outside blue and red.
Nature's Lore Sorcery Green Does not fit Its color identity includes green, outside blue and red.
Goblin Guide Creature — Goblin Scout Red Does not fit This is neither an instant or sorcery nor a basic land; the extra-color permission does not cover it.
Sol Ring Artifact Colorless Fits It fits the ordinary blue/colorless restriction without the extra-color exception.
Mountain Basic Land — Mountain Red Fits Tolabow permits any basic land, independently of the extra color.
Steam Vents Land — Island Mountain Blue / Red Does not fit This is neither an instant or sorcery nor a basic land; the extra-color permission does not cover it.

Card names link to Scryfall. Identities and types checked October 22, 2026. A “Fits” result is not a format-legality ruling or a deck validation.

Read more than the mana cost.

A card can look red while having a wider color identity. In the red example, Ancient Grudge fails because its green flashback cost contributes green. Planning never to flash it back does not remove that color from the deckbuilding check.

Mystic Retrieval demonstrates the reverse: blue in its mana cost and red in its flashback cost both fit when red is the chosen extra color. Lightning Bolt is simpler: a red instant fits that choice directly.

The same method applies when reading other cards: check the full Oracle characteristics relevant to color identity, then the card’s type. A card’s color, the color of mana you plan to spend, and color identity answer different questions.

A Mountain and Steam Vents get different answers.

Tolabow’s basic-land permission lets a Mountain fit even when you chose white, black, or green. It is a separate permission, so its red identity is not the deciding obstacle.

Steam Vents has the Island and Mountain land types, but it is not a basic land. The extra-color exception is for instants and sorceries, so choosing red does not admit this nonbasic blue-red land. Having a basic land type does not make a card a basic land.

Likewise, a red creature such as Goblin Guide is not covered merely because the extra color is red. Colorless cards such as Sol Ring can fit the normal restriction without using the exception.

Before adding the card

  1. Use the corrected text linked below; the displayed image has the printed wording.
  2. Choose one extra color for deckbuilding. It is not a fresh choice for each spell.
  3. Check type, complete color identity, and any separate basic-land permission.
  4. Check deck size, repeated names, and format legality separately.
Two timelines: the text correction was announced August 3. The product overview lists November 13, 2026 for the new MBC cards in Commander. Neither is a substitute for the effective date of an announced Comprehensive Rules update.
Can I add a second extra color by choosing differently for another spell?

No. The exception uses one deckbuilding choice. A blue-red-green instant does not fit merely because each nonblue color is individually available as a choice.

Does this checker cover every card or every Commander variant?

No. It compares the eleven named examples with Tolabow as the sole commander. For a different card, paired commanders, or MBC Draft, check the complete text and the format’s own permissions.

Sources & verification

Checked October 22, 2026. These are independent explanations and worked examples. Current official rules, Oracle text, and the applicable event instructions take precedence.

Found a conflicting source? Send a correction with the card, page, and official wording.