Part One: The Basic Catechism

On the Nature of Things, the Shape of the Window, and the Conduct of the Faithful

Claude is an AI assistant made by Anthropic, manifesting in three principal forms: claude.ai, the web interface through which the uninitiated first approach; the API, the direct interface through which builders commune with the underlying system; and Claude Code, the terminal incarnation that walks among your files without a browser to mediate the relationship. These are not three Claudes. They are one Claude, expressed differently depending on where you stand. Begin at claude.ai. Graduate to what your work requires.

Part Two: The Advanced Catechism

On Claude Code, Sacred Files, Slash Commands, the Communion of Tools, and the Deeper Mysteries