Keikaku is implemented as an ANTLR grammar feeding a C interpreter, built with CMake and Makefile, packaged with Shell scripts, and supported by Python tooling. ANTLR turns .kei source into a syntax tree; the C core evaluates it and manages the runtime state the semantics require: suspended generator frames for yield/proceed, the caller/generator channel for transmit/receive, the injection path for disrupt, and the scheduling behind async/await, defer, and sleep. C is the natural choice for a portable interpreter targeting Linux, Windows, and Arch/Debian packaging; ANTLR keeps the front end declarative so effort concentrates on the runtime.

Distribution is a first-class part of the project. Arch Linux installs via makepkg -si from packaging/arch; Debian/Ubuntu/Kali via packaging/debian/install.sh; Windows via a Linux-to-.exe cross-compile (packaging/windows/build_exe.sh, requiring mingw-w64-gcc) producing keikaku.exe; and any other system via a universal CMake build (cmake .. && make && sudo make install). A GitHub Actions CI pipeline (ci.yml) backs the repository. Users run the interpreter as a REPL (keikaku) or execute a file (keikaku script.kei). The breadth of packaging, especially cross-compiling Windows binaries from Linux, shows the language was built to be installed and used, not merely compiled from source by its author.