Expert AI 2.0

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Author: Chondrite
Last revision: 4 Feb at 08:14 UTC


Compatible with 1.4.2

Do you want to play vanilla HOI IV but can’t find the challenge you need because the AI plays the game at a beginner level? This mod is for you. Nearly everything about the AI that is possible to mod has been overhauled (with over fifty thousand lines of script added) to create a more efficient AI.

That includes division designs, division production, equipment production, variants, research, diplomacy, construction, naval invasions, ideas and more. In other words how well the AI manages its country overall. There is absolutely massive room for improvement in these areas in the vanilla game. What is NOT fixed is how the AI moves its divisions, fleets and such except for tweaks here and there. This area is largely unmoddable although there are some significant improvements here as well.

Other than just making the AI more efficient, this mod also adds completely new AI features. The AI is for example capable of creating different types of armies from game to game instead of doing the same thing every time: one game it may build heavy armor and close air support, in another game it may build medium armor and tactical bombers (there are thousands of combinations of various AI focuses). This includes correctly prioritising research, template and variant XP spending and so on. It is able to adapt its division designs to its doctrine (which it can also change) and to its circumstances (facing high armor divisions? it will add more piercing to its armor and AT infantry).

If this is still not challenging enough for you, there is also an in-depth configuration tool that allows you to set various difficulty levels that far exceed the default game difficulty settings as well as allows you to manually configure what the AI should build plus change other settings. This can be done at any point in the game (type ‘event EAI_M.1000’ into the console).

This mod works best with historical focuses. The overall progression of the game has been made more historical (Italy joins Axis after Germany has broken through the French front etc.) and the AI is more efficient with national focuses.

Make sure you at least read the rest of this page before using this mod. Above is just a brief summary of the mod so read the Mod Details thread if you want to know more.

See the compatible mods here. This mod has extremely limited compatibility with other non-cosmetic mods due to the extensive rework of the AI.

  • Expanded Technologies. More late game techs as well as rebalancing of the game, especially in areas where the AI is weak.

Compatible mods.

Paradox forum thread.[]

Patch notes.

Suggestions & feedback.

Bug Reports.

Mod details.

Read before using:
  • If you are an experienced player and want a challenge especially as a major, you should still give the AI bonuses (see recommended settings here).
  • The AI takes certain shortcuts to be on a more level playing field with the player (listed in the ‘details’ thread). This mod is about having a competetive AI right now and not after a couple of major DLCs – these shortcuts allow the AI to do things that are simple for an experienced player to manage rather than give it an unfair advantage over the player.
  • This mod is meant to be played with historical focuses enabled but there should not be any game breaking issues that occur on non-historical. Historical focus setting in this mod does more than just changes the order in which the AI takes national focuses and which decisions it makes in events.
  • This mod is not balanced around playing with minor nations. If going on a conquest spree with minors is impossible or at least much harder, then it is working as intended.
  • 1939 start is not is not supported due to how much work it is to adapt to this mod.
  • There are A LOT of aspects that I have tweaked and it’s possible that I have made an odd choice somewhere. If you have suggestions on effective strategies that could be used by the AI, let me know.

  • Not achievement compatible.
  • Multiplayer compatible when every player has this mod enabled.
  • This is a major overhaul that edits nearly every important file, therefore this is not compatible even with non-AI overhauls or mods that add or change technologies, advisors, new equipment etc. Compatible mods.


"Does this help performance by fixing AI division spam?"

The AI won’t spam thousands of divisions in the late game, so yes. There is however a performance cost to all the additional AI scripting in this mod. In short, the game is a little slower from the beginning but lags out less during the late game.

"I picked Germany, set sliders to max and steamrolled all of Europe/world by 1939."

This is a sandbox game so you can play any way you like. However there are several problems with this: 1) Germany is by far the easiest nation, 2) the sliders only very marginally help the AI (so use more buffs through the EAI config), 3) there’s a reason why many MP games use a massive list of house rules. The game is completely unbalanced without them and if human players can’t deal with it then the AI sure as hell can’t.

"Something ahistorical happened on historical mode."

It’s not my intention to force the game to play out exactly historically whether it’s Germany always losing by 45 or China not getting annexed by Japan. I usually focus on improving the AI for countries that don’t perform as well as they historically should but I will never give them free troops or factories and such. Customise the difficulty if you want to see some nation perform better.

"Can you make this compatible with my favourite mod X?"

It is unlikely that I will integrate other mods into Expert AI (or the other way around) for the time being. This mod is created around the vanilla Hearts of Iron 4 with painstaking effort to make an AI that understands how to play efficiently with the tools that it has.

Want to use some part of this mod in your own public mod? Ask for permission.


Inspired by the ‘AI Research and Division Tweaks’ mod.

Thanks to everyone who have given feedback, made suggestions or reported problems.

Thanks to the following people for testing, contributions or specific ideas: Yossarian, VDNKh, RunsOnDiesel, Stjern, Scrublord, Zijistark, Axe99, Locomotive, Fabius.

Russian localization by santyrion. Ahistorical AI focus logic by mrkettyo.