AI
The exact inner mechanics of the AI remain a mystery. However, some general rules of its behaviour are known. Those were either deducted through observation of the AI's movements, or they have been stated by the creator himself on the forums.
Weighted Random
The AI constructs a list of actions it could take on each turn, along with a value of how strongly it feels it should do that action. It then does a weighted random against that list. This means that the AI is never perfectly predictable, but it does have tendencies.
General behaviour of the AI
Confirmed:
- It currently does not know how to use any card other than the reinforcement card. [1] [2]
- It does prefer to expand as long as it still sees neutral bonuses to expand to. [3]
- When deciding whether or not to complete a bonus, the AI currently uses (bonus value) * 3 - (armies we'd have to kill to take the bonus). If this comes out negative, it won't deem the bonus worthy in some cases. [4]
observed:
- It tends to attack with twice as many armies as the territory is showing. [5]
- It generally only places armies in a few spots and attacks from them. [6]
- It tends to prefer neutral territories over player controlled territories, but it mostly prefers to attack the weakest territories. [7]
- It tends to favor getting bonuses, and breaking enemy bonuses higher than making random other attacks. [8]
Behaviour of the AI in team games
- It will only attack teammates in two circumstances:
- If a bonus is entirely controlled by teammates and it has >= 50% of the territories. It will only do attacks of 2 then.
- If it's expanding into a new bonus that no teammates control. [9]
- The AI will not play cards when teamed with a human teammate unless it must play cards by rule. The only circumstance where an AI must play cards when teamed with a human teammate is if the last player on a team turns into an AI via boot or surrender, and cards must be used by that team that turn.
Changes
The AI's behavior has not been changed since it was introduced in 2009. Changing the AI's behavior, even slightly, would invalidate every single-player score that's been achieved. If the AI is to be improved in the future, it will likely be done in conjunction with a revamp of the single player levels.