The EU4 devs have been using forum suggestions to aid gaps in AI

One fan in particular managed to reverse engineer AI behaviour in a way that was easier to understand than the code itself

Paradox Grand Strategy: From the Carnival of Lust to the Enlightened Times - The Something Awful Forums

30% Terra Invicta on

AI Abusing Mission System to Hyper-Develop : r/eu4

Europa Universalis (Video Game) - TV Tropes

Why do I always get institutions so late? The Ai seems to be way faster at getting them, even though I use the advancement effort : r/eu4

Very Hard difficulty - AI agressivnes and bonuses

Stellaris Dev Diary #239 - AI++ : r/Stellaris

Why are the AI provinces never invested in Infrastructure? It is an indispensable investment to develop provinces as early as 15 devs, AI's must be wasting a ton of power developing their

Collections: Teaching Paradox, Europa Universalis IV, Part I: State of Play – A Collection of Unmitigated Pedantry

Nevermind i was wrong. The AI is indeed stupid enough to declare war on you despite your many alliances : r/eu4

EU4 - Development Diary - 26th of May 2016

Can we please make the AI not delete its entire army the second they are in a deficit

Europa Universalis IV - Development Diary 19th of July 2022, Page 5

Paradox Plaza

Europa Universalis IV - Development Diary 14th of June 2022, Page 5