What was done
Gustavo Canepa applies his Gran Turismo 4 matching tools to the older PS2 game, with Claude agents matching functions against the original compiler output.
Gustavo Canepa is building a matching decompilation of Gran Turismo 3: A-Spec (PS2), with Claude agents doing most of the matching. His README reports 3,557 of 11,407 functions matched, 31.2%, as of October 2026. It is early work.
How it was done
GT3 is the engine generation before Gran Turismo 4 and was built with an older compiler, ee-gcc 2.9. The project reuses the tools from his GT4 decompilation. Agents write C++ for each function, and the compiler and a judge script check that it produces the same instructions as the original. The commit history also mentions runs with other models, including Gemini.
Results
The README says 6.3% of the code bytes match, 8.5% of the matched sources are clean, and the full build still reproduces the original executable. The repository holds no game data. It is a decompilation only, with no playable port.