Glamdring
Legendary Artifact — Equipment
Equipped creature has first strike and gets +1/+0 for each instant and sorcery card in your graveyard.
Whenever equipped creature deals combat damage to a player, you may cast an instant or sorcery spell from your hand with mana value less than or equal to that damage without paying its mana cost.
Equip 
Commander bracket
Derived from card traits, not a ruling — bracket rules turn on how a deck intends to use a card. Bracket rules
EDHREC
Combos 1
Format legality
Rulings
- 2023-06-16
If the spell has
in its mana cost, you must choose 0 as the value of X. - 2023-06-16
If you cast a spell "without paying its mana cost", you can't choose to cast it for any alternative costs. You can, however, pay additional costs, such as kicker costs. If the card has any mandatory additional costs, those must be paid to cast the spell.
- 2023-06-16
If you cast a spell using Glamdring's triggered ability, you do so as part of the resolution of the ability. You can't wait to cast the spell later in the turn. Timing permissions based on the card's type are ignored.