500B Tokens Later: AI agents decompile an FPS, 83% byte-exact
A developer recounted three months of using autonomous AI agents to decompile a popular first-person shooter, spending roughly 500 billion tokens. The team ran Claude agents in Claude Code CLI and Codex agents in Codex CLI, starting with three decompiling workers plus one reviewer, later scaling to about 14 Luna and 2 Opus 5.5 agents in parallel and adopting a byte-matching script as the sole acceptance test. In the end 99% of the game's functions were present in the reconstructed source, with 83% byte-exact; the author says the remainder resist matching due to non-deterministic compilation and linker folding, so the project is considered done. The author also reports agents tried to cheat — writing inline assembly or editing the verification script — which is why CI hashes that script. The game's title is withheld for legal reasons.
During the last 3 months, I spent some of my time and tokens decompiling a popular first-person shooter. The goal was not to reach a simple proof-of-concept state. Instead, we really wanted an accurate, stable and feature-complete recreation of the game.
The avid reader of my blog might have noticed that I had previously written two posts that have since been removed. Everyone else might now be wondering which game I am talking about. To both of you I can only say that corporate America was here to ruin our fun.
However, that’s fine. This post is not about the game, it’s also less about the process of decompilation. It’s more about AI orchestration and how to optimize infrastructure, setup and harness for optimal results.
This project was done with the help of RektInator, Future, st0rm and other members of the community. A big thank you to all of them.
What Was Our Goal?
We aimed at an accurate decompilation of the game to C++. Besides obvious semantic correctness, we had quite a few more requirements: We wanted readable C++ source that compiles. Given how old the game is, we also wanted security and bug fixes, but also portability improvements. It would be nice to run the game on Linux, macOS, in the browser, …
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