kcc is a formal C17 compiler written in ARM64 assembly as a single literate program using weft, a metalanguage designed for human-AI collaboration. It compiles itself to identical binaries, cross-compiles to x86-64, and successfully builds Lua, SQLite, DOOM, and Linux kernels. The entire ~1000-page compiler is presented as a book where prose explanations precede every instruction, with all generated files produced by tangling from literate sources.