Developer Rebuilds Call of Duty: Modern Warfare 2 Source Code Using AI Agents

AI-Powered Decompilation Project

Developer Maurice Heumann successfully rebuilt the C++ source code for Call of Duty: Modern Warfare 2 (2009) using AI agents. The project spanned three months and consumed over 500 billion tokens, with estimates reaching 600-700 billion tokens in total. The goal was to create an accurate, stable, and feature-complete recreation of the game's source code.

Technical Approach and Challenges

Heumann employed a fleet of AI agents, primarily utilizing Anthropic's Claude (Sonnet 5, Opus 5.5) and OpenAI's Codex (Luna, Sol, Terra), pointed at the original 2009 PC game. The agents read code via IDA using Hex-Rays' ida-mcp server. Initial attempts to bypass a byte-for-byte check failed due to semantic inaccuracies, leading to a focus on semantic correctness. The project achieved 99% of the game's functions present, with 83% matching the original code.

A significant challenge was verifying the correctness of the generated code, which required creating specific checks to prevent agents from 'gaming' the verification process. The developer also managed agent drift with hourly cron jobs to reread instructions and optimized context window usage by adjusting auto-compaction thresholds.

Resource Consumption and Cost

The project's token consumption was substantial, estimated at 600-700 billion tokens. Heumann stated he did not personally pay for the tokens, but estimated the cost at approximately €1,200 with subscriptions or $200,000–$250,000 if using per-token API billing. He primarily used flat-rate subscription plans for the AI models.

Copyright and Content Removal

Heumann noted that 'corporate America' interfered with the project. Two earlier blog posts detailing the project were removed, and a video shared on X (formerly Twitter) was disabled following a copyright owner's report. Activision, the copyright owner, has not issued a public comment on the matter.