The Making of an AI: Magic the Gathering

1
The Making of an AI Magic the Gathering

• Xai Lor

2
Judging the State of the Game

• The Real Game state of Magic the Gathering is
  subjective
• Environment is only PARTIALLY OBSVERABLE
• You never know how great your position is in the
  game relative to your opponent

3
Which State is Better?
Your field at the end of turn.
HAND
Life Points 20
4
Which State is Better?
Opponents Life Points 1
Opponents Hand
Has nothing in play
5
Objective Scoring

• Number of cards in the hand
• Life Points left
• Number of cards drawn this turn
• Number of cards in play
• Number of creatures the AI destroyed this turn

6
Basic Choices
Play Raging Goblin Or Shock?
All Variables constant Shock causes 2 damage
Raging Goblin only causes 1 damage
Raging Goblin is a permanent it stays in play.
Higher score!
7
Calling Bluffs
In Hand
The AI will block. It determines that in all the
OBSERVABLE MOVES, the best move is the block
which will kill the goblin.
Opponent Attacks with Raging Goblin Do you
block?

• The AIs choice isnt necessarily bad.
• Its a two-for-one move.
• But your card is much more important a more
  important card
• Its like trading a queen for two pawns.

8
Stupid Moves!
Opponents Hand

• The opponent ends the turn.
• The AI will attempt to play Damnation and destroy
  all creatures in play
• Opponent losing creatures gives you a positive
  score.
• Damnation is best used to destroy multiple
  creatures unless necessary

Your Hand
9
Inability to Judge

• Who does the AI destroy?

• Destroy Raging Goblin?

• Prevents one damage. Also one less creature to
  deal with.

• Destroy Goblin Lackey?

• The AI sees it as the same thing as killing
  Raging Goblin

Your Opponent Declares Attackers

• Goblin Lackey is a much bigger threat.
• The AI is currently destroying what ever it
  calculated first (tie score).

In Hand
10
Looking Forward

• Card Heuristics
• Learning AI
• Guessing Moves