balanced - bias towards growth, taxable income, trade level bonuses (roads), walls and Exp bonus buildings
religious - bias towards growth, loyalty, taxable income, farming, walls and law
trader - bias towards growth, trade level, trade base, weapon upgrades, games, races and Exp bonus buildings
comfortable - bias towards growth, farming, games, races, Exp bonus and happiness
bureaucrat - bias towards taxable income, growth, pop health, trade, walls, improved bodyguards and law
craftsman - bias towards walls, races, taxable income, weapon upgrades, Exp bonuses, mines, health and growth
sailor - bias towards sea trade, taxable income, walls, growth, trade
fortified - bias towards walls, taxable income, growth, loyalty, defenses, bodyguards and law
These biases are towards building properties, rather than buildings themselves. The game does not know what a "Blacksmith" is, for example, it only knows that it is a building which provides a weapon upgrade, and hence a Craftsman AI would be more likely to build it than another AI personality type.
These are then combined with a troop production personality, as follows:
smith - exactly level
mao - biased towards mass troops, light infantry
genghis - biased towards missile cavalry and light cavalry
stalin - biased towards heavy infantry, mass troops and artillery
napoleon - biased towards a mix of light and heavy infantry, light cavalry
henry - biased towards heavy and light cavalry, missile infantry
caesar - biased towards heavy infantry, light cavalry, siege artillery