I fixed this in the most recent version of MTG Forge, but the computer AI used to stumble when playing mono-colored decks. The AI seemed slow and would actually play the same land twice, the cards ID numbers were the same. The problem was in the code that smoothed the computer’s land, also known as mana threading. The code presumed a two color deck. I fixed the code and now it will worked with 1,2,3,4 or 5 color decks. With a 2 color deck the computer’s mana is threaded like 1,2,1,2,1,2.
The computer’s land is threaded in a very particular order. The computer’s opening hand has no lands and then draws a land for the next 5 turns. You may be asking yourself, why? The idea is to increase the number of spells the computer has an opportunity to play. On the computer’s first turn he has 7 spells and 1 land. So hopefully he has a one mana spell in his hand. On the computer’s second turn, he draws a land and plays it. So now he has 6 or 7 spells in his hand, depending if he played a spell. The computer’s hand is all spells, increasing the “quality” of cards he has. Being technical, I guess the computer has “virtual card advantage,” but I don’t really know, lol.
The computer draws an additional land on his 8th and 11th turn. The computer will never have more than 7 lands in play at a time, assuming he doesn’t play cards that fetch lands. Threading the computer’s land like Forest, Mountain, Forest, Mountain, gives it an advantage. Assuming a 2 color deck, the computer can play any double-costed spell like RR as early as turn 3 and always by turn 4.