OpenAssetTools is a native C++20 modding toolchain for older Call of Duty games (IW3-IW5, QOS, T4-T6). It provides CLI tools (Linker, Unlinker, ImageConverter, RawTemplater, ZoneCodeGenerator) and a desktop GUI (ModMan) for manipulating game 'zone' (fastfile) archives. The system supports round-trip conversion: extracting binary assets to raw formats (JSON, DDS, IWI, CSV, GLTF, etc.) and compiling them back into custom zone files. It incorporates a sophisticated per-game abstraction layer with factories for loading, writing, compiling, and dumping assets, alongside a reusable parsing framework used for menu scripts, techsets, state maps, and structured data definitions. The codebase is large (2500+ files) and shows signs of active development despite being a work-in-progress, with high code duplication across game versions and some reverse-engineering fragility.