The AI designs and builds ships with newer technology as it progresses. There are other options for missile defence besides railguns and not every AI fleet will have effective AM protection because some have different roles.
The AI looks at every shot you fire and everything your ships do and adjusts accordingly, using same tactical intelligence information that is available to the player. It is a LOT more sophisticated than your suggestion above. However, as with any AI, it is never going to come close to a human player in a tactical situation because a human can weight different factors in a given situation and plan accordingly. Also, the more complex the game, the more difficult to create an AI that can adjust to any situation. If I made Aurora much simpler, the AI would handle it far better.
Consider how basic the rules are for Chess or Go or Poker and consider how much effort and how many years were required to build an effective computer opponent. I suggest playing the game longer until you have encountered a lot more situations and then think about the AI code that would be required to handle all of them given the huge variety of different factors and potential systems involved.
I understand. Sorry, I didn't want my error message to sound like a rebuke to you personally! I understand perfectly well that Aurora is a very difficult game, and it is almost impossible to make an adequate AI in it that would be comparable to a human in abilities.
I previously played Gary Grigsby's War in the East - a game about the Second World War, where each support division / regiment is a separate unit with many parameters, and a map of the Second World War (Eastern Front) where every 10km (+ -) is a separate hex with its own parameters. It is also a very complex game, and there it was also almost impossible to create an AI even approximately comparable to a human.
Simply, specifically in this situation, it seems to me that we are talking about some kind of error in logic. I'm sure it doesn't have to be that way. I understand that AI is not perfect, that it can be stupid, separate its fleets, not calculate forces, design ships not in the most optimal way ...
But when the AI, after the conclusion of a truce, does not react to the fact that I destroy its ships with missiles, or when it sends fleets that have no anti-missile defense at all (despite the fact that it has separate missile defense ships!) - to my ships with missiles - this is very strange.
The point is that the AI has designed a certain type of ship:
having: 17 Railgun DMG 3 * 4 80904 km ROF 150.
And almost all of its combat fleets consist only of ships of this type.
I don't know what kind of equipment they have inside, but they are definitely not capable of firing at my missiles. Even on slow (16000 km / s).
Either there is a mistake that the AI does not install anti-missile sensors on these ships, and therefore is simply not able to see them, or the AI does everything correctly in terms of ship templates (having separate missile defense ships - I also do this, and do not put sensors 1 on my main warships), but does not add ships of the main combat class - missile defense destroyers to its fleets.
I guess this is fair to AI. To be on the safe side, I increased the difficulty of the game to 120%. Suddenly it will help.