Capcom is rebuilding RE Engine to work with AI

Capcom has begun reworking RE Engine, the in-house engine behind Resident Evil, Monster Hunter and Street Fighter. The project is codenamed REX, and the company has stated its goal as "creating games together with AI". The engine is being rebuilt so that both people and AI can work with it comfortably.

The plan was presented by programmer Satoshi Ishida at the company's own technical conference, Capcom Open Conference RE: 2026, held last week. According to him, RE Engine should eventually become a "game engine of the AI era", where models write programs themselves and run test sessions in search of errors.

Why Capcom is rebuilding the engine

Ishida listed three problems the company already faces in development:

• games have grown so large in data volume that even simple operations take a long time;
• teams are growing, and every member needs to be confident using the engine;
• bringing AI into workflows has, in Ishida's words, become "a mandatory condition for optimising development in the future".

In his talk, Ishida also discussed the RE:Dox, RE:Log and RE:Flows components.

One language for humans and neural networks

The key technical decision concerns the code. As part of REX, the entire system has been brought in line with the rules of the world's most widespread programming language. The benefit, according to Ishida, is twofold: it is easier for people to work with the engine, and easier for AI to read and understand such code. With a single language at the foundation, models will be able to make sense of programs, write them automatically and check builds for errors on their own.

Judging by a report from the Japanese outlet GameBiz, REX is focused on development efficiency, tooling and quality control. Capcom will make some of the new AI tools open — for training models.

Where Capcom draws the line

How far the company will go with generating art and assets is still unclear. Earlier this year, Capcom stressed that it would not use assets created by generative AI in its games. The REX announcement does not contradict this: what Ishida showed relates to code, tools and testing.

What this means for the industry

The announcement fits a notable trend: engine developers are increasingly adapting their engines to work with AI agents, not just to individual generative features. For a major publisher's in-house engine this is a particularly striking step: such technologies accumulate their own code and knowledge over years, understood mainly by their authors. The decision to bring the system to a common language and describe modules uniformly is probably tied precisely to making the engine transparent to models.

If the approach works, programmers and QA departments stand to gain the most: automated testing and the generation of utility code touch the most routine part of large-scale production. Things will be harder for those whose work amounts to manually checking builds. Also open is how the studio will reconcile its bet on AI in development with its refusal to use generated content in games.