In discussion of Civilization VI’s changes from its predecessor, the new city planning features have gotten the bulk of attention, and deservedly so. But there are other systems that also got major overhauls. This rundown goes over diplomacy, specifically diplomacy in single-player games and how the new AI behaves.
Whereas in Civilization 5 the different AI leaders all had specific personalities, in 6 all those are much more clearly-defined and visible to the player. Every AI player has two agendas; one is always the same for that leader (So Teddy Roosevelt always has his “Big Stick Policy” agenda), while the other one is randomized and (initially) hidden.
Each agenda can be thought of as three things: Goal-seeking (what the AI tries to do), likes, and dislikes. So Ghandi’s Peacekeeper agenda means that it tries to never start wars other than reconquest wars; he automatically likes players who don’t go to war; and he hates players who go to war. Gorgo’s With Your Shield or On It agenda means that she tries to start wars, doesn’t make concessions in war if she can, likes other leaders who fight wars, and dislikes leaders who agree to punitive peace treaties or never go to war in the first place. So if you’re on a continent with Gorgo and Ghandi, you have to not start any wars so as to not antagonize Ghandi, and also you have to start wars so as to keep Gorgo happy. Pretty quickly you can recognise that the agenda system is often about choosing who you are going to make an enemy of.
Some agendas are not about whether or not you do certain things, but rather about how well you’re doing in some areas. Hojo Tokimune’s Bushido means that he likes civilizations that have a strong military and strong faith and culture output. What does “strong” mean? It actually means that you’re keeping up with the AI itself in that arena. If your army is bigger than Hojo’s and yet you’re matching him in culture and faith, he’ll be impressed. Otherwise he’ll be disappointed and more inclined to attack you.
There are two big asterisks about this: First, there are hidden agendas that look at the size of your army, your gold income, your science output, and your overall population. You can expect to have an AI leader with one of those hidden agendas in most games, and importantly, if a leader in your game has one of those agendas, they’ll prioritize the corresponding yield. This means that if Philip has the Money Grubber agenda, he’ll be building commercial hubs like mad and generally trying to maximize gold income, and you might think you have pretty decent gold income, but he might still think you’re headed for fiscal disaster because you’re not keeping up with him on that front.
Second, because those agendas are based around keeping up with the AI, at higher difficulties, you will trigger negative reactions from the AI more often. This is actually a key component of Civilization VI’s game balance; according to the devs, the AI has the same behavior on any difficulty from Warlord on up, it just gets an increasing bonus to tile yields. The harder AI doesn’t have to be more aggressive; you’re more likely to fall behind it and cause it to be aggressive by having an empire that’s not competing well with theirs. On King and up, Trajan will scold you about not grabbing enough territory much sooner and more often, but it’s not because he’s harsher on higher difficulties. Rather, he just has a bigger advantage over the human player that lets him make more settlers, and faster, so you’ll fall behind more quickly.
Complementing the agendas is the new concept of access levels. At the start of the game, when you first meet another civilization, your access level with them is zero; meaning you get no information at all about them besides an aggregate of how much they like you. You can improve your access level in several ways: Sending delegates (in the early game) and envoys (in the mid to late game); declaring friendship or becoming allies; sending a trade route to one of their cities; planting spies in their cities. The devs clearly felt this system was important enough that one of the leaders, Catherine de’ Medici of France, has an ability that revolves around access: if you play as her, you get one extra access level with every opponent. Playing some France games is actually very helpful in getting the hang of the diplomacy system in Civilization VI.
Leaders will often tell you that they’re displeased about something you’re doing even if you don’t theoretically have enough access to know what their hidden agenda is, so even without access you can get a picture of why you’re antagonizing the AI. But it’s not guaranteed, and if you have low access, the AI will sometimes seem ineffable. And having higher access with the AI will give you extra information about what they’re building, what they’re planning, and what’s going on in their empire. If one of the AI’s cities are besieged, you will learn that when it happens, which is particularly useful.
Pet Peeves and Goal-Seeking Behavior: How the AI Acts
Agendas are not the end-all-be-all of AI behavior in Civilization VI. Like in the previous game, the AI also reacts to certain aggressive moves by asking you to stop them: Moving troops in neutral territory near their border, settling cities near their territory, using spies against them, and converting their cities. If you trigger one of those warnings, they’ll give you a chance to promise that you’ll stop, or tell them off, or ignore the request entirely. As you might expect, promising that you’ll stop and then not stopping is the worst thing you could do.
It’s important to note that only leaders who have founded a religion seem to care if you’re converting their cities. In a standard sized game with 8 civilizations, three of them will not found a religion and are therefore safe to try and convert.
As you might expect, the AI leaders also tend to like you more if you share their government or religion, and how you relate to their friends and enemies will also influence their opinion of you.
Casus Belli: Going to war in the late game
One of the major changes in Civilization VI is to how warmonger penalties apply. First, warmongering will no longer just affect how the AI sees you; it also affects your own population, as fighting battles in an unjustified war will create more war weariness. War weariness applies to your cities as negative amenities, meaning your cities will need more amenities to stay productive through constant war. When you’re at peace, war weariness will slowly go away.
Second, warmonger penalties increase throughout the game. This is tied to advancing through the eras, and importantly it’s tied to the aggressor’s era, not the defender. So advancing through the ages will only change the consequences for declaring war, not the consequences others will face for declaring war on you. Warmonger penalties in fact don’t exist at all in the ancient era.
Certain mid-game civics will unlock casus belli, or justifications for war, that you can use to declare war on your neighbors with lessened consequences. Declaring a surprise war (that is, just attacking someone out of the blue) is heavily penalized from the classical era onwards. Declaring a “formal war”, which requires that you have denounced your target for at least five turns, is less onerous and will be your go-to way to declare war in the classical and medieval eras. Basically, it’s just like a surprise war, but you’re giving your opponent time to prepare, so it’s more of a fair fight.
Later on, casus belli come into play, allowing you to declare wars under specific circumstances with much lower penalties.
The AI does try to avoid heavy warmonger penalties, so if you’re getting denounced, don’t take that as a meaningless gesture; it means that the AI has opened up the possibility of attacking you in five turns, and you should prepare accordingly. The midgame casus belli are all punitive and relate to something you’re doing: Taking someone’s cities (or their ally’s), attacking their city-state friends, converting their cities. But in the late game, the colonial war and territorial war come into play, somewhat re-enabling the ability to declare war on anyone out of the blue, so be careful if you’re lagging far behind in tech or if you have an extensive border with someone: Suddenly they can declare a quasi-surprise war on you again.
From my observation, the AI will go to war whenever it thinks it can gain something, AND it sufficiently dislikes the target. How much dislike is “enough” depends on the size of the warmonger penalty it’ll get. This means that in the ancient era, be prepared to get attacked out of the blue by the AI – it doesn’t need justifications to attack and there are no penalties, so it can and will strike even if it doesn’t dislike you all that much; it’s nothing personal, it’s just trying to grab some early-game advantage. And yes, the AI does game the system a little and try to get their early war out of the way while there’s no warmonger penalty in play. I often experience a pile-on where AI opponents attack me in the tail end of the ancient era to try and get some advantages before that window closes – just like a real player would.
Later on, though, as the warmonger penalties get more severe, the AI seems to prefer formal wars, and it seems much less inclined to attack players that it’s indifferent about.
Computer players do fight wars with concrete aims in mind. They’ll try to expand after being boxed in, or try to secure key resources. The AI doesn’t seem to make punitive attacks against the human player; instead it’s trying to get an advantage. The best way of summing up how the AI behaves is that it’s something between a simulation of behavior and a pure, goal-driven AI that just tries to win the game. The AI in Civilization VI is trying to win, but it’s also following a sort of honor code: It wants to win while role-playing its stated personality.
Putting it all together: A practical guide to diplomacy
So, from looking at all those systems, what can we conclude?
Figure out a war strategy. The two extremes, of playing as a pacifist or going for a warmongering conquest game, are both available, of course. But there’s also the middle strategy of fighting early, mid, or late game wars in order to give yourself room, capture key resources, or just slow down dangerous opponents to facilitate a victory by other means. In VI, this strategy seems more viable than it was in V.
You can’t please everybody. As I noted previously, agendas often contradict one another. They often contradict your game strategy, asking you to focus on aspects of the game you can’t afford to focus on given the victory you’re pursuing. And they are sometimes just impossible to satisfy – Montezuma is, by design, impossible to keep happy unless you are willing to forgo improving luxury resources in your cities.
When deciding to try and avoid war with an AI opponent, ask yourself: How much am I giving up to do this? You can build holy sites to please a Devout leader, but then again you could also just build encampments and prepare to defend yourself against them.
Early game rushes pay off. This is, quietly, a really big departure from previous games. It used to be that you couldn’t really assault a city before getting your first siege weapons online, but now it’s the other way around: Cities are utterly vulnerable until they build walls, and then you need siege weaponry. Combine that with the free-for-all of no warmonger penalties in the ancient era, and suddenly building 4-5 warriors and marching to war seems comparable to building a settler and making a second city. The Aztecs, Germany, and Greece under Gorgo are all about this strategy, since they rely on war to feed their early economy. Remember, warmonger penalties are based on the aggressor’s tech level. Declaring war on the turn before you research that critical Classical era tech is fair game.
Keep an eye out for opportunities: Chances are, even if you’re avoiding warmonger penalties, you’ll have to build defenses and an army to deal with potentially belligerent neighbors. But every military unit you build and don’t use is a waste of resources. Try to keep on top of what casus belli you have available to you and what alliances you could form to get access to them. Just make sure you’re not marching your poor musketmen into a quagmire.
In conclusion, here’s the key thing that sets Civilization VI’s AI apart from the one in previous iterations of the series: It’s not trying to mimic a human player or simply defeat you; rather, it’s another game system for you to understand, puzzle out, and overcome. Just like city planning or policies, you can game the AI and optimize it. And to win games, you’ll have to.