AI agents rebuild Call of Duty: Modern Warfare 2 source code with 83% byte-for-byte accuracy

A developer has rebuilt the source code for Call of Duty: Modern Warfare 2 using AI agents, showing that modern models can reverse-engineer legacy software at scale. This achievement matters because it demonstrates a viable path for preserving older games that might otherwise become unplayable as original infrastructure fades. The project proves that AI can handle the complexity of a 2009-era shooter, offering hope for digital archiving efforts.

Developer uses 500 billion tokens to reverse-engineer 2009 shooter into playable C++

Maurice Heumann led the effort to decompile the Activision title into C++ over a three-month period. He coordinated a fleet of 17 parallel AI agents to manage the workload. The team relied on Anthropic Claude models and OpenAI Codex models to generate the necessary code. This setup allowed the project to process more than 500 billion tokens during the reconstruction phase.

The decompilation process has reached a high level of fidelity, with 99% of the game's functions now present in the new codebase. Eighty-three percent of those functions match the original executable byte-for-byte. Heumann noted that the game is fully playable and that almost all visible bugs have been resolved. Only a few minor issues remain before the project is considered complete.

Heumann described the current state of code generation as cheap, advising that bad outputs should simply be discarded. The project has faced copyright enforcement actions that removed earlier blog posts and disabled related videos. Due to these restrictions, the developer is keeping the decompiled code private for personal use only. This limitation highlights the ongoing tension between software preservation and intellectual property rights.

The technical success of this decompilation stands in contrast to the legal hurdles that have silenced public documentation of the work. The project confirms that AI agents can successfully reconstruct complex legacy software when given sufficient compute and time. The code remains available only to the developer, preserving the game's functionality without distributing the modified files.