Every Django + React project needs the same code before it does anything of its own: serializers, permission classes, admin files, login pages, tables and forms. A boilerplate copies it into your project once. An AI agent writes it again in every project. Either way you pay twice: once to produce it, and again to maintain every copy. Karni keeps that code in versioned packages you install and upgrade, so your agent writes only your domain and karni upgrade brings each fix to every project.