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CK3 Dev Diary #104: AI AI AI

Greetings!

One of the trickiest bits about GSGs is making a good AI. You want it to pose a challenge and play well, but you don’t want it to ruin the player’s fun by acting out of character. We’ve read a lot of discussions and threads in various places across the community, and we understand that there is room for improvement. Over the summer we’ve been working on a few aspects of the AI, specifically the economy (and a little bit of diplomacy). We’ve not focused on warfare, except for one thing which we’ll get to later.

All changes outlined in this Dev Diary will be released in a future update.

For the player to feel motivated to do well, the AI must show that it can do well alongside you. It doesn’t have to be fantastic or play optimally (in fact, that’s usually immersion-breaking), but it must be capable of progress. We want the AI in CK3 to be able to provide a good challenge and do well enough to motivate you to do even better. Also, we want it to do this without cheating.

Before delving deeper into what we’ve done, I’d like to explain some of the challenges we set out to solve for the Economy:
  • Economically, all AIs currently play the same. We want their personality to affect how an AI decides to spend their hard-earned gold, and on what. You should be able to look at an AIs personality traits and, roughly, be able to tell what they’re up to.
  • A player understands that there are certain ways of using gold that are optimal and appropriate regardless of their situation; that there are certain risks worth taking. We want the AI to understand this, employing decisions that make them prosper and are suitable to the stage the game is in.
  • We want the AI to build more buildings, so that the world becomes more and more developed over time. Right now, only players realize the value that buildings bring in the long run, while AIs spend most of their gold on wars.
  • The power of a ruler lies within their domain. The AI, much like the player, should strive to build a base of power and cultivate it over time.

…and here are some of the challenges we set out to solve for Diplomacy:
  • AI realms tend to fall apart, and never reform. Vast seas of counts and dukes, unwilling to accept the overlordship of neighboring kings. We want the AI to be able to diplomatically expand, much like the player is able to. New realms with great monarchs should rise out of the ashes of former empires.
  • A stable realm is a prosperous realm, and there are many tools for achieving this. The AI should not hold back when using available methods of stabilization, be they diplomatic schemes or underhanded council actions.
  • The AI should understand that Tyranny is sometimes appropriate. It’s for the greater good of the realm. Within reason, of course - personality and relationships must play a large role here. As it stands, the AI will never willingly take on Tyranny, under any circumstance.

…and for Warfare:
  • In real life, the Mongols were an existential threat. Currently, in CK, they are not. We want them to be. There is one pivotal change that enables this: the ability to gather armies closer to their target.

The Economy, fools!​

The key to success in CK3 is a strong and stable economy, and such a thing is driven by buildings (and, partly, MaA). We’ve set out to change how the AI uses its gold so that it builds up its realm more. We’ve taken considerations to make sure that the AI does this in a way so that it, for example, doesn’t become too easy to defeat for the player. The backbone of this work rests upon a framework of Economic Archetypes.

Economic Archetypes​

There are four economic archetypes that AI rulers can fall into, of which three are significant: Warlike, Cautious, and Builder. If a character falls into none of these archetypes, they will be Unpredictable and use aspects of other archetypes in a semi-random fashion.

Warlike​

warlike_archetype_example.png

[Image - Warlike Personality Example]
The Warlike archetype wants to be ready to declare war, always. This is the archetype that is most similar to how the AI behaves in the game right now. They will put their gold into a war chest before considering other options. If a Warlike archetype is at peace for an extended period of time, they will use the gold in their war chest to develop the realm - but they will first and foremost prepare for war, even in the early game.

Bold and greedy AI’s tend to be Warlike. Common traits include Wrathful, Impatient, Sadistic, Ambitious, Vengeful, Irritable, and Zealous. Tribal rulers and cultures with the Bellicose Ethos are also drawn to this archetype, as well as any character in the Iberian struggle that wants to escalate towards the hostility phase.

Cautious​

cautious_archetype_example.png

[Image - Cautious Personality Example]
Not to be confused with cowardly, the Cautious archetype wants to be prepared for having war be declared upon them. They are somewhat averse to declaring offensive wars, instead preferring a slow buildup. This archetype will save up a minimum buffer of gold, depending on their tier. When choosing to invest gold into buildings or MaA, they will evaluate the state of their military, how long they’ve been at peace, how many allies they have, and their level of dread - depending on these factors, they will feel ‘safe’ and invest more gold than they would otherwise, while keeping the aforementioned minimum buffer.

Non-bold AIs tend to be Cautious. Common traits include Patient, Calm, Craven, Paranoid, and Content. Rulers with the Fickle or Lunatic trait will never be cautious. Rulers with the Stoic Ethos or the Stalwart Defenders Cultural Tradition are also drawn to this archetype.

Builder​

builder_archetype_example.png

[Image - Builder Personality Example]
The Builder archetype wants to invest all of its gold into the realm. They will empty their treasury in order to build buildings and MaA as quickly as they can, and will also tend to construct more economical buildings and new holdings than other archetypes. They are bold and a bit reckless, only saving up a war chest if they are under a direct threat (such as a strong faction). This is the rarest of all archetypes.

Bold AIs with a propensity for building and no particular inclination for war fall into this archetype. Common traits include Calm, Patient, Diligent, Generous, Stubborn, Profligate, and Improvident. Where Warlike AI’s want to expand their realm, the Builder wants to build up their domain. Rulers with the Domain Focus also tend to fall into this category.

Unpredictable​

neither_archetype_example.png

[Image - Unpredictable Personality Example]
The Unpredictable archetype doesn’t have a propensity towards anything in particular, and might decide upon any strategy. They can decide to boom their economy much like the Builder archetype, but they do so randomly (weighed up by traits such as Diligent or Architect), and the amount will be modified by how bold they are. Otherwise, they will want to build up their realms to a minimum degree (higher than a Warlike archetype), keep a decent buffer (lower than a Cautious archetype), and go to war at a normal pace.

AIs who do not qualify for any of the above categories will fall into this archetype.

Economic Stages​

The AI divides its economic game into three stages; Capital Development, Domain Development, and Late Development. The first two of these are ‘early’ stages that should be all but over roughly 100 years into the game.

Each of these stages modifies how the AI spends its gold, which is then again modified by the economic personalities above.

Early Capital Development​

The most important holding to develop is your capital, I’m sure you all agree. The AI will strive quite hard to fill all of the empty slots in its capital before doing many other things, as first-level buildings have a significantly higher return of investment than upgrades do. At this stage, the archetypes matter less, but this phase is also over somewhat quickly.

This has a quite significant effect on the AI overall. By being able to kickstart their economy earlier than before, you will see them doing much better in the mid-late game. In the current version, you see a lot of provinces with open building slots well into the late game: even places of prominence, such as Paris, can sometimes be devoid of buildings - after these changes, this will be exceedingly rare.

Early Domain Development​

In the second stage, the AI wants to develop its secondary counties by constructing first-level buildings there too. Truth be told, many AI’s elect to buy MaA or keep developing their capital during this phase as the choice of what to do/construct is semi-random and weighted - but this really just results in more powerful rulers overall.

At this stage, the archetypes are manifesting, with Warlike AI’s saving war chests (albeit for shorter periods than in the Later stage!), Cautious AI’s saving up buffers, etc.

When first-level buildings are present in an AI’s entire domain, they move on to the Later Economic Behavior.

Later Economic Behavior​

During this stage, the archetypes will manifest fully. Builder AI’s will constantly build up their realm. Cautious AI’s will want a buffer, allies, and a powerful military, Warlike AI’s will only invest their gold if they’ve been at peace for many, many years - and so on.

Interestingly enough, despite the AI being disincentivized from declaring frequent wars (previously all AIs were constantly gearing up for war), there are no fewer wars in the world. The wars that are declared are, however, more intense and exciting, as the AIs are generally more built up and have a stronger economic backbone.

While the Economy part of this update isn’t the only thing contributing to what you’re about to see, here’s a comparison of the Live version of the game compared to the upcoming update. The sample size is 200 years, and there are no major deviations except for the Mongol Empire not having collapsed yet in the Live comparison.
comparison_stats_ai.png

[Image - Various Comparisons between the Live Version (1.6.1.2) and the upcoming update (1.7.0)]
Counts+ in this context means Counts, Dukes, Kings, and Emperors.

Diplomatic Matters​

One of the AI’s faults is that it underuses the tools given to it, choosing to use them only sporadically and without much direction. The AI acting out its personality is all well and good, but in many instances, personality didn’t even matter at all, for example when choosing to revoke a title. We’ve done many small things that together add up to a vastly improved experience.

Domain Consolidation​

The AI is now going to strive towards having a strong capital and domain, prioritizing first and foremost the consolidation of lands within their De Jure Capital Duchy. For example, the king of France will want to hold Isle-de-France and all counties within the duchy of Valois.

In order to do this, they are now willing to take on a modicum of Tyranny via revoking or retracting, modified by their personality. For reference, the AI has never before willingly taken on Tyranny and has always waited for a revocation reason. All AIs will want their capital county and at least a small domain (3 or so), regardless of personality, but Just and Generous AIs will stop after that point. Depending on the AI’s rationality, they will be willing to take on more or less Tyranny. Wise and rational rulers will want to let their Tyranny decay completely before taking a tyrannical action again, while more irrational rulers are willing to keep their Tyranny high in order to consolidate their domain.

In order to consider revocation, the AI looks to its reserves of gold and military strength, making sure to not get into Tyranny wars it doesn’t think it can win (of course, it still happens that a ruler is overthrown via Tyranny, but it’s rarer!).

Of course, relationships are accounted for, so you won’t see the AI revoking from their friends, lovers, children, etc.

In practice, this means that the average AI ruler is much more powerful, and you won’t see things such as the king of France being content with having one single domain county in Brittany, just because they don’t have a revoke reason on the current ruler of Isle-de-France. In combination with the previously mentioned economic changes, this results in economically powerful AI rulers.
scotland_consolidated_domain.png

[Image - Alba having consolidated their capital duchy]

The AI has also been taught to revoke secondary baronies in the counties it owns, which is especially useful for Clan rulers, as they can hold temples. This makes it so that much of the Clan sphere has a stronger economy, especially early on, and is able to match European and Indian feudal realms which generally have more favorable terrain.

Vassalization​

One of the things that we’ve changed a lot is how vassalization works and how the AI uses it. This isn’t a pure AI change, as we’ve also rebalanced all the modifiers that affect whether a character wishes to accept your overlordship or not. But, yes, simultaneously we’ve taught the AI to consider these facts and try to make their neighbors into vassals.

A sub-goal here was to make vassalization into a viable alternative to military conquest, while also dialing back the most powerful sources of vassal acceptance and adding more interactive modifiers. While I won’t go into all of the detail here, I’ll say that the modifiers from Diplomatic Court and True Ruler have been lowered, while modifiers such as Average Powerful Vassal Opinion (-20/+20) have been added to promote alternatives to only being militarily powerful. We’ve also tweaked the opinion modifiers for Clan rulers so that Feudal rulers don’t have a fundamental advantage when it comes to vassalization (by offering low Contracts).

The AI will now much more frequently check if neighbors would accept vassalization, and they will actively seek to sway or befriend neighbors if the AI considers them targets for diplomatic expansion. This means that the player does not have a monopoly on vassalizations any longer; if you take too long, AI rulers will sweep in and offer overlordship to your small independent neighbors.

In practice, this means that areas stay shattered and stagnant for less time, while also creating more interesting realms where different cultures (and even faiths) are represented in the vassal strata. As an example, you might see a great unifying Sultan appear somewhere in Persia and diplomatically sweep up the remains of a shattered Seljuk Empire.
vassalize_example.png

[Image - Example of new vassalization modifiers]

Holy Wars​

As it turns out, rulers of the same faith as the defender in a Holy War would never join in their defense, despite the game claiming they would. This is our bad: a set of triggers were looking at the wrong character, and thus no one would consider joining. This is now changed, and we’ve put some effort into ensuring that the rulers who join up against you feel right.

Protecting the boundaries of your faith is important, and the AI is now aware of this. Depending on personality and economic readiness, they will now assist their brothers-in-faith against encroaching heathens. Zealous and bold AI’s are the first to join, while you can be certain that cynical and cowardly rulers will not. Vassals of your target won’t join in, though vassals of neighboring rulers might - generally, you need only look within the immediate area as you declare wars. Extremely zealous rulers, though, might decide to join in from further away.

In practice, you have to prepare well before declaring a holy war, but taking stock of your neighbors will help you here - personalities are telling, so you shouldn’t be overly surprised when someone aids your target.

From a game perspective, this makes it much less likely for the Middle East to be completely overtaken by either Catholics or Orthodox Christians (which seemed to happen in at least 90% of all observer games that ran until the end date). Major religious upsets are now rarer, but when they happen they are all that much more likely to stick, as they’ve probably been launched by strong rulers during an opportune time.

Realm Stability​

AI rulers should now be somewhat more aware of the state of their realm, and proactively try to improve its stability. There are many flavors of stability, some more underhanded than others…

Firstly, the AI is now much more likely to sway, and when they choose who to sway they are much more likely to pick important characters. For example, they will sway their realm priest, spymaster, and angry powerful vassals much more often, and also keep swaying them for a longer time. This also goes for the befriend scheme, should it be available. In the comparison screenshot at the end of the economy section, you’ll note that there are significantly more AIs with bishops/realm priests who endorse them.

AI rulers with a more… unsavory disposition will use the Find Secrets council task, which the AI previously didn’t use. They’ll tend to target their vassals or rivals, if the chance of being found out isn’t too great. They’ll then blackmail and use the ensuing hooks to improve vassal contracts. Rulers who have unlocked the Fabricate Hook scheme will also much more often use it on vassals whose contracts can be modified. Over the generations, this means that the contracts AI rulers have with their vassals tend to be much better than they used to.

contracts_1389.png

[Image - Sample vassal contracts, France 1389]

In general, we’ve taken a pass on when AIs will use certain Council Tasks. They will avoid certain things completely (using bestow royal favor on vassals-of-vassals), and more proactively switch to tasks that support them in the short term (support schemes when any hostile scheme is active, Organize Army when gold is running very low, etc).

There’s a whole lot more that we’ve taught the AI to do, most of them small - but small things add up. They will send non-primary children to be educated by vassals they want to appease (it’s 15 opinion per child after all!), make their children learn the languages of their subjects to prepare them for a smooth succession, hire seneschals if they have more than one county with very low control, etc, etc. It really does add up.

All of these changes lead to AI realms being more stable and better at recovering from bad wars or messy successions. Of course, there’s still a lot of the hallmark CK3 chaos that we all know and love - it’s just not all there is, now!

Let's compare two areas, one from the Live version, and one from the upcoming update. They are 200 years from game start (in fact, these are the same saves used for comparison stats earlier in the DD).
comparison_1.png

[Picture - Comparison between an area in Live and the Update]
Do note that these changes do not mean you’ll see the same realms in every game. It’s still as it’s always been, where you might have a powerful Burgundy in the south or a Wales controlling the British Isles; it’s just that, now, the emerging Burgundian and Welsh realms will be much stronger and able to thrive! Additionally, given the AI is now consolidating a larger, more centralized domain, partition splits are nicer and border gore is reduced.

Ikh Mongol Uls​

No matter what changes we’ve made to the Mongols in the past, they always fall on one single point: when they grow large enough, it takes them too long to march their troops to their target, and thus lose too many troops to attrition and too much warscore to time.

We’ve taught the AI to raise their troops closer to the target of their wars. They will seek to raise in a safe county within their realm that is close, but not bordering, to the wargoal. While this is the most impactful for the Mongols, all Duke or above rulers will now do this. What this means for the Mongols: they will no longer march all the way from far eastern Mongolia after every conquest. This change alone magnifies their potential for conquest tenfold (at least). They now fulfill their purpose; they shake up the world and reshape the lands they conquer. More than ever, you must now seriously consider if you wish to submit to the Great Khan…

In addition to the new raising behavior, we have improved the way the Mongols pick their targets (making them less likely to gallop into the mountains of Tibet or immediately crash against a massively strong Byzantine empire), and we’ve changed how successor khanates work. The Golden Horde, Ilkhanate, Chagatai, etc, were never long for this world after they spawned. There were many reasons for this: they didn’t get a proper domain, no de jure lands, no gold, etc. While they still dissolve with some regularity (as they should) they now sometimes persist, and even thrive, as we’ve improved their starting positions by assigning them some starting resources, domain, and De Jure land depending on what they’ve managed to conquer.

While it isn’t overly common that the Mongols exceed their historical conquests, here’s an example of how far they can spread under somewhat-ideal circumstances (long-lived Khans).
mongol_1.png

[Image - Initial state of the world]

mongol_2.png

[Image - Some years in: note that Tibet was taken because Ü had land in mongolia]

mongol_3.png

[Image - The newly-shattered Persia gets absorbed]

mongol_4.png

[Image - Strategically avoiding a Byzantium that is almost their strength, the Mongols go towards eastern europe]

mongol_5.png

[Image - After taking all of eastern Europe, they turn to Arabia and the Fatimids]

mongol_6.png

[Image - Eventually, Hungary falls after an intense war]

mongol_7.png

[Image - The Khan dies and successor khanates spawn in. Who knows how long they’ll last?]

That’s it for now. The full update notes with all the details will come soon, so stay tuned!
 

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Love it! I was working on many of these same things in my mod Major Re-balance. Looks like you guys did a much better job doing many of the same things and more.

One thing I saw mentioned was the duchy buildings not being touched yet in 1.7. That was relatively easy to get into a decent state in my mod tho, just introduce some cultural preferences for the buildings
 
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If the AI never used find secrets how were they blackmailing me so often?

Either way these changes look good. Little concerned about the AI realms being too "stable" though. Then again, realm stability is a setting that doesn't effect ironman so it might not be that big of a deal. I just like a little bit of shaky ground for all empires and not blobs.

EDIT: Will "Tactical" army movement AI be looked at? Especially pathfinding? The Crusades for Jerusalem almost always fail due to the AI getting confused by the geography of the region.

EDIT 2: Will the AI be more willing to stoop to murder more often? Feels like even with a court full of -100 I practically always require a rival to actually start a murder plot against me. Also, can the special player protection from having multiple assassination plots against them at a time be removed, at least on normal difficulty? Bodyguards, food tasters, cup-bearers all feel much less useful with how rare the player is a target for assassination. Especially compared to CKII.
 
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I think this was within the diary, but if it wasn't: we've taken some measures to prevent recently diplomatically vassalised subjects from joining in on independence and dissolution factions.
If a ruler would accept a vassalization that would make them immediately unhappy with their liege, it seems like the "measure" should be that they should not accept that vassalization, not that they should be artificially pacified for a while after accepting.
 
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scotland_consolidated_domain.png
View attachment 870171
[Image - Alba having consolidated their capital duchy]
Two new icons teased in this image. If you notice between the lifestyle and kills icon, there is a new book icon. Also, a new positive coping trait of a dog. Anybody have speculation as to what these might be?

My guess for the book might be a chronicle/biography, but perhaps it is the long awaited "will-and-testament" feature? I suspect the dog trait isn't simply just the temporary modifier of having a pet dog upgraded to trait form. Perhaps it is something like, "animal lover" and it lets you recruit pet's as you wish. Or maybe even "Dog Breeder" as a hobby and past-time.
 
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This looks like a really attentive and well-thought out improvement to the game's lackluster AI and, as with the experiments with faction reworks, I really like the direction this is heading. I particularly like the economic archetypes, and that it seems care has been taken not only to make the AI good at the game, but also to allow the AI to make reasonable and interesting roleplaying decisions. For me, that's a really encouraging sign, and already I can't wait to get my hands on 1.7.
 
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If the AI never used find secrets how were they blackmailing me so often?
Both other Spymaster tasks have the possibility to discover secrets as a Side Effect, even though it's not shown for "Disrupt Schemes".
It's setup in a weird way actually, they can discover minor secrets if they have at least -8 intrigue (seriously, why -8?) and major secrets if they have at least 8 intrigue.
"Support Schemes" can only discover minor secrets because of a bug though.
 
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Greetings!

One of the trickiest bits about GSGs is making a good AI. You want it to pose a challenge and play well, but you don’t want it to ruin the player’s fun by acting out of character. We’ve read a lot of discussions and threads in various places across the community, and we understand that there is room for improvement. Over the summer we’ve been working on a few aspects of the AI, specifically the economy (and a little bit of diplomacy). We’ve not focused on warfare, except for one thing which we’ll get to later.

All changes outlined in this Dev Diary will be released in a future update.

For the player to feel motivated to do well, the AI must show that it can do well alongside you. It doesn’t have to be fantastic or play optimally (in fact, that’s usually immersion-breaking), but it must be capable of progress. We want the AI in CK3 to be able to provide a good challenge and do well enough to motivate you to do even better. Also, we want it to do this without cheating.

Before delving deeper into what we’ve done, I’d like to explain some of the challenges we set out to solve for the Economy:
  • Economically, all AIs currently play the same. We want their personality to affect how an AI decides to spend their hard-earned gold, and on what. You should be able to look at an AIs personality traits and, roughly, be able to tell what they’re up to.
  • A player understands that there are certain ways of using gold that are optimal and appropriate regardless of their situation; that there are certain risks worth taking. We want the AI to understand this, employing decisions that make them prosper and are suitable to the stage the game is in.
  • We want the AI to build more buildings, so that the world becomes more and more developed over time. Right now, only players realize the value that buildings bring in the long run, while AIs spend most of their gold on wars.
  • The power of a ruler lies within their domain. The AI, much like the player, should strive to build a base of power and cultivate it over time.

…and here are some of the challenges we set out to solve for Diplomacy:
  • AI realms tend to fall apart, and never reform. Vast seas of counts and dukes, unwilling to accept the overlordship of neighboring kings. We want the AI to be able to diplomatically expand, much like the player is able to. New realms with great monarchs should rise out of the ashes of former empires.
  • A stable realm is a prosperous realm, and there are many tools for achieving this. The AI should not hold back when using available methods of stabilization, be they diplomatic schemes or underhanded council actions.
  • The AI should understand that Tyranny is sometimes appropriate. It’s for the greater good of the realm. Within reason, of course - personality and relationships must play a large role here. As it stands, the AI will never willingly take on Tyranny, under any circumstance.

…and for Warfare:
  • In real life, the Mongols were an existential threat. Currently, in CK, they are not. We want them to be. There is one pivotal change that enables this: the ability to gather armies closer to their target.

The Economy, fools!​

The key to success in CK3 is a strong and stable economy, and such a thing is driven by buildings (and, partly, MaA). We’ve set out to change how the AI uses its gold so that it builds up its realm more. We’ve taken considerations to make sure that the AI does this in a way so that it, for example, doesn’t become too easy to defeat for the player. The backbone of this work rests upon a framework of Economic Archetypes.

Economic Archetypes​

There are four economic archetypes that AI rulers can fall into, of which three are significant: Warlike, Cautious, and Builder. If a character falls into none of these archetypes, they will be Unpredictable and use aspects of other archetypes in a semi-random fashion.

Warlike​

View attachment 870166
[Image - Warlike Personality Example]
The Warlike archetype wants to be ready to declare war, always. This is the archetype that is most similar to how the AI behaves in the game right now. They will put their gold into a war chest before considering other options. If a Warlike archetype is at peace for an extended period of time, they will use the gold in their war chest to develop the realm - but they will first and foremost prepare for war, even in the early game.

Bold and greedy AI’s tend to be Warlike. Common traits include Wrathful, Impatient, Sadistic, Ambitious, Vengeful, Irritable, and Zealous. Tribal rulers and cultures with the Bellicose Ethos are also drawn to this archetype, as well as any character in the Iberian struggle that wants to escalate towards the hostility phase.

Cautious​

View attachment 870167
[Image - Cautious Personality Example]
Not to be confused with cowardly, the Cautious archetype wants to be prepared for having war be declared upon them. They are somewhat averse to declaring offensive wars, instead preferring a slow buildup. This archetype will save up a minimum buffer of gold, depending on their tier. When choosing to invest gold into buildings or MaA, they will evaluate the state of their military, how long they’ve been at peace, how many allies they have, and their level of dread - depending on these factors, they will feel ‘safe’ and invest more gold than they would otherwise, while keeping the aforementioned minimum buffer.

Non-bold AIs tend to be Cautious. Common traits include Patient, Calm, Craven, Paranoid, and Content. Rulers with the Fickle or Lunatic trait will never be cautious. Rulers with the Stoic Ethos or the Stalwart Defenders Cultural Tradition are also drawn to this archetype.

Builder​

View attachment 870168
[Image - Builder Personality Example]
The Builder archetype wants to invest all of its gold into the realm. They will empty their treasury in order to build buildings and MaA as quickly as they can, and will also tend to construct more economical buildings and new holdings than other archetypes. They are bold and a bit reckless, only saving up a war chest if they are under a direct threat (such as a strong faction). This is the rarest of all archetypes.

Bold AIs with a propensity for building and no particular inclination for war fall into this archetype. Common traits include Calm, Patient, Diligent, Generous, Stubborn, Profligate, and Improvident. Where Warlike AI’s want to expand their realm, the Builder wants to build up their domain. Rulers with the Domain Focus also tend to fall into this category.

Unpredictable​

View attachment 870169
[Image - Unpredictable Personality Example]
The Unpredictable archetype doesn’t have a propensity towards anything in particular, and might decide upon any strategy. They can decide to boom their economy much like the Builder archetype, but they do so randomly (weighed up by traits such as Diligent or Architect), and the amount will be modified by how bold they are. Otherwise, they will want to build up their realms to a minimum degree (higher than a Warlike archetype), keep a decent buffer (lower than a Cautious archetype), and go to war at a normal pace.

AIs who do not qualify for any of the above categories will fall into this archetype.

Economic Stages​

The AI divides its economic game into three stages; Capital Development, Domain Development, and Late Development. The first two of these are ‘early’ stages that should be all but over roughly 100 years into the game.

Each of these stages modifies how the AI spends its gold, which is then again modified by the economic personalities above.

Early Capital Development​

The most important holding to develop is your capital, I’m sure you all agree. The AI will strive quite hard to fill all of the empty slots in its capital before doing many other things, as first-level buildings have a significantly higher return of investment than upgrades do. At this stage, the archetypes matter less, but this phase is also over somewhat quickly.

This has a quite significant effect on the AI overall. By being able to kickstart their economy earlier than before, you will see them doing much better in the mid-late game. In the current version, you see a lot of provinces with open building slots well into the late game: even places of prominence, such as Paris, can sometimes be devoid of buildings - after these changes, this will be exceedingly rare.

Early Domain Development​

In the second stage, the AI wants to develop its secondary counties by constructing first-level buildings there too. Truth be told, many AI’s elect to buy MaA or keep developing their capital during this phase as the choice of what to do/construct is semi-random and weighted - but this really just results in more powerful rulers overall.

At this stage, the archetypes are manifesting, with Warlike AI’s saving war chests (albeit for shorter periods than in the Later stage!), Cautious AI’s saving up buffers, etc.

When first-level buildings are present in an AI’s entire domain, they move on to the Later Economic Behavior.

Later Economic Behavior​

During this stage, the archetypes will manifest fully. Builder AI’s will constantly build up their realm. Cautious AI’s will want a buffer, allies, and a powerful military, Warlike AI’s will only invest their gold if they’ve been at peace for many, many years - and so on.

Interestingly enough, despite the AI being disincentivized from declaring frequent wars (previously all AIs were constantly gearing up for war), there are no fewer wars in the world. The wars that are declared are, however, more intense and exciting, as the AIs are generally more built up and have a stronger economic backbone.

While the Economy part of this update isn’t the only thing contributing to what you’re about to see, here’s a comparison of the Live version of the game compared to the upcoming update. The sample size is 200 years, and there are no major deviations except for the Mongol Empire not having collapsed yet in the Live comparison.
View attachment 870170
[Image - Various Comparisons between the Live Version (1.6.1.2) and the upcoming update (1.7.0)]
Counts+ in this context means Counts, Dukes, Kings, and Emperors.

Diplomatic Matters​

One of the AI’s faults is that it underuses the tools given to it, choosing to use them only sporadically and without much direction. The AI acting out its personality is all well and good, but in many instances, personality didn’t even matter at all, for example when choosing to revoke a title. We’ve done many small things that together add up to a vastly improved experience.

Domain Consolidation​

The AI is now going to strive towards having a strong capital and domain, prioritizing first and foremost the consolidation of lands within their De Jure Capital Duchy. For example, the king of France will want to hold Isle-de-France and all counties within the duchy of Valois.

In order to do this, they are now willing to take on a modicum of Tyranny via revoking or retracting, modified by their personality. For reference, the AI has never before willingly taken on Tyranny and has always waited for a revocation reason. All AIs will want their capital county and at least a small domain (3 or so), regardless of personality, but Just and Generous AIs will stop after that point. Depending on the AI’s rationality, they will be willing to take on more or less Tyranny. Wise and rational rulers will want to let their Tyranny decay completely before taking a tyrannical action again, while more irrational rulers are willing to keep their Tyranny high in order to consolidate their domain.

In order to consider revocation, the AI looks to its reserves of gold and military strength, making sure to not get into Tyranny wars it doesn’t think it can win (of course, it still happens that a ruler is overthrown via Tyranny, but it’s rarer!).

Of course, relationships are accounted for, so you won’t see the AI revoking from their friends, lovers, children, etc.

In practice, this means that the average AI ruler is much more powerful, and you won’t see things such as the king of France being content with having one single domain county in Brittany, just because they don’t have a revoke reason on the current ruler of Isle-de-France. In combination with the previously mentioned economic changes, this results in economically powerful AI rulers.
View attachment 870171
[Image - Alba having consolidated their capital duchy]

The AI has also been taught to revoke secondary baronies in the counties it owns, which is especially useful for Clan rulers, as they can hold temples. This makes it so that much of the Clan sphere has a stronger economy, especially early on, and is able to match European and Indian feudal realms which generally have more favorable terrain.

Vassalization​

One of the things that we’ve changed a lot is how vassalization works and how the AI uses it. This isn’t a pure AI change, as we’ve also rebalanced all the modifiers that affect whether a character wishes to accept your overlordship or not. But, yes, simultaneously we’ve taught the AI to consider these facts and try to make their neighbors into vassals.

A sub-goal here was to make vassalization into a viable alternative to military conquest, while also dialing back the most powerful sources of vassal acceptance and adding more interactive modifiers. While I won’t go into all of the detail here, I’ll say that the modifiers from Diplomatic Court and True Ruler have been lowered, while modifiers such as Average Powerful Vassal Opinion (-20/+20) have been added to promote alternatives to only being militarily powerful. We’ve also tweaked the opinion modifiers for Clan rulers so that Feudal rulers don’t have a fundamental advantage when it comes to vassalization (by offering low Contracts).

The AI will now much more frequently check if neighbors would accept vassalization, and they will actively seek to sway or befriend neighbors if the AI considers them targets for diplomatic expansion. This means that the player does not have a monopoly on vassalizations any longer; if you take too long, AI rulers will sweep in and offer overlordship to your small independent neighbors.

In practice, this means that areas stay shattered and stagnant for less time, while also creating more interesting realms where different cultures (and even faiths) are represented in the vassal strata. As an example, you might see a great unifying Sultan appear somewhere in Persia and diplomatically sweep up the remains of a shattered Seljuk Empire.
View attachment 870172
[Image - Example of new vassalization modifiers]

Holy Wars​

As it turns out, rulers of the same faith as the defender in a Holy War would never join in their defense, despite the game claiming they would. This is our bad: a set of triggers were looking at the wrong character, and thus no one would consider joining. This is now changed, and we’ve put some effort into ensuring that the rulers who join up against you feel right.

Protecting the boundaries of your faith is important, and the AI is now aware of this. Depending on personality and economic readiness, they will now assist their brothers-in-faith against encroaching heathens. Zealous and bold AI’s are the first to join, while you can be certain that cynical and cowardly rulers will not. Vassals of your target won’t join in, though vassals of neighboring rulers might - generally, you need only look within the immediate area as you declare wars. Extremely zealous rulers, though, might decide to join in from further away.

In practice, you have to prepare well before declaring a holy war, but taking stock of your neighbors will help you here - personalities are telling, so you shouldn’t be overly surprised when someone aids your target.

From a game perspective, this makes it much less likely for the Middle East to be completely overtaken by either Catholics or Orthodox Christians (which seemed to happen in at least 90% of all observer games that ran until the end date). Major religious upsets are now rarer, but when they happen they are all that much more likely to stick, as they’ve probably been launched by strong rulers during an opportune time.

Realm Stability​

AI rulers should now be somewhat more aware of the state of their realm, and proactively try to improve its stability. There are many flavors of stability, some more underhanded than others…

Firstly, the AI is now much more likely to sway, and when they choose who to sway they are much more likely to pick important characters. For example, they will sway their realm priest, spymaster, and angry powerful vassals much more often, and also keep swaying them for a longer time. This also goes for the befriend scheme, should it be available. In the comparison screenshot at the end of the economy section, you’ll note that there are significantly more AIs with bishops/realm priests who endorse them.

AI rulers with a more… unsavory disposition will use the Find Secrets council task, which the AI previously didn’t use. They’ll tend to target their vassals or rivals, if the chance of being found out isn’t too great. They’ll then blackmail and use the ensuing hooks to improve vassal contracts. Rulers who have unlocked the Fabricate Hook scheme will also much more often use it on vassals whose contracts can be modified. Over the generations, this means that the contracts AI rulers have with their vassals tend to be much better than they used to.

View attachment 870173
[Image - Sample vassal contracts, France 1389]

In general, we’ve taken a pass on when AIs will use certain Council Tasks. They will avoid certain things completely (using bestow royal favor on vassals-of-vassals), and more proactively switch to tasks that support them in the short term (support schemes when any hostile scheme is active, Organize Army when gold is running very low, etc).

There’s a whole lot more that we’ve taught the AI to do, most of them small - but small things add up. They will send non-primary children to be educated by vassals they want to appease (it’s 15 opinion per child after all!), make their children learn the languages of their subjects to prepare them for a smooth succession, hire seneschals if they have more than one county with very low control, etc, etc. It really does add up.

All of these changes lead to AI realms being more stable and better at recovering from bad wars or messy successions. Of course, there’s still a lot of the hallmark CK3 chaos that we all know and love - it’s just not all there is, now!

Let's compare two areas, one from the Live version, and one from the upcoming update. They are 200 years from game start (in fact, these are the same saves used for comparison stats earlier in the DD).
View attachment 870174
[Picture - Comparison between an area in Live and the Update]
Do note that these changes do not mean you’ll see the same realms in every game. It’s still as it’s always been, where you might have a powerful Burgundy in the south or a Wales controlling the British Isles; it’s just that, now, the emerging Burgundian and Welsh realms will be much stronger and able to thrive! Additionally, given the AI is now consolidating a larger, more centralized domain, partition splits are nicer and border gore is reduced.

Ikh Mongol Uls​

No matter what changes we’ve made to the Mongols in the past, they always fall on one single point: when they grow large enough, it takes them too long to march their troops to their target, and thus lose too many troops to attrition and too much warscore to time.

We’ve taught the AI to raise their troops closer to the target of their wars. They will seek to raise in a safe county within their realm that is close, but not bordering, to the wargoal. While this is the most impactful for the Mongols, all Duke or above rulers will now do this. What this means for the Mongols: they will no longer march all the way from far eastern Mongolia after every conquest. This change alone magnifies their potential for conquest tenfold (at least). They now fulfill their purpose; they shake up the world and reshape the lands they conquer. More than ever, you must now seriously consider if you wish to submit to the Great Khan…

In addition to the new raising behavior, we have improved the way the Mongols pick their targets (making them less likely to gallop into the mountains of Tibet or immediately crash against a massively strong Byzantine empire), and we’ve changed how successor khanates work. The Golden Horde, Ilkhanate, Chagatai, etc, were never long for this world after they spawned. There were many reasons for this: they didn’t get a proper domain, no de jure lands, no gold, etc. While they still dissolve with some regularity (as they should) they now sometimes persist, and even thrive, as we’ve improved their starting positions by assigning them some starting resources, domain, and De Jure land depending on what they’ve managed to conquer.

While it isn’t overly common that the Mongols exceed their historical conquests, here’s an example of how far they can spread under somewhat-ideal circumstances (long-lived Khans).
View attachment 870176
[Image - Initial state of the world]

View attachment 870177
[Image - Some years in: note that Tibet was taken because Ü had land in mongolia]

View attachment 870178
[Image - The newly-shattered Persia gets absorbed]

View attachment 870179
[Image - Strategically avoiding a Byzantium that is almost their strength, the Mongols go towards eastern europe]

View attachment 870180
[Image - After taking all of eastern Europe, they turn to Arabia and the Fatimids]

View attachment 870181
[Image - Eventually, Hungary falls after an intense war]

View attachment 870182
[Image - The Khan dies and successor khanates spawn in. Who knows how long they’ll last?]

That’s it for now. The full update notes with all the details will come soon, so stay tuned!
After the update, will the last patch save work?
 
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AI rulers with a more… unsavory disposition will use the Find Secrets council task, which the AI previously didn’t use. They’ll tend to target their vassals or rivals, if the chance of being found out isn’t too great. They’ll then blackmail and use the ensuing hooks to improve vassal contracts. Rulers who have unlocked the Fabricate Hook scheme will also much more often use it on vassals whose contracts can be modified. Over the generations, this means that the contracts AI rulers have with their vassals tend to be much better than they used to.

Will unsavory AI rulers also learn to identity powerful or ambitious vassals as threats and try to murder or kidnap them?

I actually wished the AI would adopt the player tactic of keeping vassals in prison more, if it has the personality for this.
 
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In real life, the Mongols were an existential threat. Currently, in CK, they are not.
In my last game, the Mongol Empire lasted twelve years before the Khan drank himself to death, and his realm shattered... and those realms shattered, too. I had to go digging through the character archives just to find the drunken fool who died childless.
 
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I love these improvements and I'm absolutely ready to get back after a few months of taking a break. When I read that the team actually is able to make the ai play like a human but decided not too, as it makes the game feel one dimensional, I had an idea, that maybe would make for a good addition.

the AI isn't here to win, it's here to roleplay, they make decisions based on their personalities, not what is necessarily optimal. Making the AI make all optimal choices would make for a very one-dimensional game
This is a good call, of course, but I'd like to see an ai ruler play optimally in a sort of "Child of destiny -light" way if they are a genius. The better their intelligence trait the more likely they should be to play like a human (try-hard) would. This would bring more meaning to the genius trait which right now only increases stats. I was long wishing for something akin to ck2's child of destiny because they really made each game they appeared in different and gave us an interesting character to view who maybe had a story just as interesting as the player character. They could even have absolutely insane rags to riches stories. This also made the game feel more real by taking away the feeling that its just a version of our tomeline with known events like the Mongols being the endgame crisis at point x. Having a random conqueror pop up at any time to just establish a new empire that completely changed a region of the world was great.

But what I always disliked about it was that it could only be accomplished by cheating. Me cheating by heavily increasing child of destiny spawn rates but more importantly the game cheating by bestowing bonusses out of nowhere on these characters.

But now these new ai changes could bring a fresh new experience by adding conquerors, reformers, master administrators, builders and so on by understanding what makes optimal, meta play, so basically how I assume most players play after a while instinctively by remembering what works, and then using these strategies themselves. And all of this by using just the games features instead of cheats. Or maybe a bit of cheats but things that can be reasonably understood as a great vision a human being can reasonably have.

Maybe combine it with their education trait. Intelligent+ brilliant strategist means they make optimal men at arms, play aggressively and get the great conquest and subjugation casus belli. Intelligent + midas touched means they actually develop like a human player, be peaceful but use optimal money builds, intelligent + mastermind theologian means they get an event to build a grand cathedral in their capital and tech rush. And Genius trait gets an increases chance to play the game optimally at around.
 
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This is where consolidating a power within their primary title comes from. They will make an effort to do so.

That being said, it has to be pointed out that the AI isn't here to win, it's here to roleplay, they make decisions based on their personalities, not what is necessarily optimal. Making the AI make all optimal choices would make for a very one-dimensional game. The AI cares about succession, just not in the same way the player does.
Well.. they should be here to win, with personalities. They are characters that seem goals and glory right? They aren't props..
 
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Hey this looks awesome! super excited to play it. I hope the Ai sending marriage proposals to the player outside of the struggle was taken under consideration seeing as were on the topic of Ai behavior after all.
 
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Nice updates. But AI need also be better to handle successions. No use developing land if it falls apart because you got several kids who wants their share.
The AIs should use the focus in learning where you can choose to not have more kids if they have an heir.
they should also take the next trait so they know when they will die and disinherit if they have more than one kid so all their holdings pass on tomain heir.
AIs largest problem is that the realm falls appart because it cannot handle succession
 
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Nice updates. But AI need also be better to handle successions. No use developing land if it falls apart because you got several kids who wants their share.
The AIs should use the focus in learning where you can choose to not have more kids if they have an heir.
they should also take the next trait so they know when they will die and disinherit if they have more than one kid so all their holdings pass on tomain heir.
AIs largest problem is that the realm falls appart because it cannot handle succession
I think one of the best things the devs could do is to unshackle the AI from Permanent Gavelkind All the Time, Every time...
 
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Probably so far the DD which got me most excited! So needed and from what we have seen, major problems well hit on the nail and done without both letting the AI simply cheat or making them characterless min-maxers :)

Nice updates. But AI need also be better to handle successions. No use developing land if it falls apart because you got several kids who wants their share.
The AIs should use the focus in learning where you can choose to not have more kids if they have an heir.
they should also take the next trait so they know when they will die and disinherit if they have more than one kid so all their holdings pass on tomain heir.
AIs largest problem is that the realm falls appart because it cannot handle succession
At most AI characters with a very special personality should act that way - but please not all or even most of them...
 
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First of all, thank you everyone at Paradox who worked on this. A lot of stuff in here that players like myself have wanted addressed and I'm seeing some really great solutions. Secondly are some questions below.

1. Is the 1066 start date going to have a lot more buildings already built to compensate for the time they would have been building under the new AI?
2. Does the new building behavior apply to vassals or only independent rulers? Basically looking to see if our vassals will be making themselves and the entire realm stronger. I hope so as this would give players more strategy about who they want to make a vassal and which land to give them. I'd want builders in the interior of my realm, and warlike or cautious if I want them to expand my borders or defend them.

Once again, great job everyone at Paradox!
 
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