# Zerocode > An agent that rewrites itself: one SBCL process, shells attach to it, the > model's one tool is evaluating Lisp in it and keeping what it defines. Every page is markdown at its own address, `.md`. - [Quickstart and build](https://zerocode.ulas.tech/docs/quickstart.md): install the release, or build from source with SBCL 2.6.8 and Quicklisp, and the layout a build needs. - [README](https://zerocode.ulas.tech/docs/readme.md): what it is, what is different, how a release is packed. - [Cells](https://zerocode.ulas.tech/docs/cells.md): the contract a cell folder signs — packages, the layer, what a cell may and may not touch. - [Updates](https://zerocode.ulas.tech/docs/updates.md): the layout an installed organism updates itself in, and how a staged release is verified. - [Fork notes](https://zerocode.ulas.tech/docs/fork.md): what this build changes against upstream and what it keeps on purpose. - [Release host](https://zerocode.ulas.tech/dl/): the channel pointers, tarballs and their sha256 sidecars the installer and `zerocode update` read. - [Install script](https://zerocode.ulas.tech/install.sh): the Linux and macOS one-liner.