AI bases are recorded by the map maker and saved to the map. They'll only build what the map maker included. Some maps were recorded with specific mods enabled but aside from that it would require recording a new AI for a given map. Recording AI's isn't that much more complicated than building a base as a player, but there are a few extra steps to save it. There's more information about that in the map making guide, or you can look up some AI making streams on YT.