GENie is a build system generator that creates native project files (Makefile, Visual Studio, Xcode, Ninja, etc.) from Lua-based project descriptions. It embeds Lua 5.3.0 as its scripting engine and uses a hierarchical configuration system (solution/project/platform/configuration) to manage build settings. The tool processes user-defined Lua scripts (typically premake4.lua) to generate tool-specific build files through registered actions. Architecture consists of a C host layer handling platform abstractions, Lua modules for core functionality (solution/project/config management, action/option system), toolchain-specific compilers/linkers, and generator actions for each build system. Key entry points are src/host/premake_main.c (main) and the embedded Lua API. Data flow involves: CLI args → Lua state initialization → user script execution → action-specific file generation. External dependencies are limited to system libc and platform APIs; Lua is fully embedded.