CAS uses GitHub to store and version your context files — this keeps your work portable and under your control, independent of any AI model or vendor. Here's how to set it up from scratch on Windows or Mac. Linux users: you know what to do.
GitHub is where your CAS shell lives — your files, your repository, your account. It's free.
Go to github.com/signup and create a free account. Verify your email address before moving on.
Already have a GitHub account? Skip to step 2.
GitHub Desktop is a free app that manages your repositories without requiring the command line. Download it at desktop.github.com, install it, and sign in with your GitHub account.
Comfortable with Git on the command line? Skip this step and clone the repo directly in step 3.
Go to the CAS Shell Template on GitHub. Click Use this template → Create a new repository.
my-cas-shell or your nameThen in GitHub Desktop: File → Clone Repository, find your new repo in the list, and choose where to save it on your computer.
The setup script installs git hooks that scan for secrets before any commit or push — so you never accidentally put an API key or password inside your context files.
.\setup.ps1 and press Enter.Y and press Enter.bash setup.sh and press Enter.You should see a confirmation message that the hooks are installed. If you get a permissions error on Windows, open PowerShell as Administrator and try again.
Open your repository folder and open CONTEXT.md in any text editor. Update the YAML frontmatter at the top of the file:
owner: — your nametype: — personal, business, or professionaldomain: — a short description of your work or focus areacreated: — today's date in YYYY-MM-DD formatThe file includes instructions for every field. Fill in what you have now — you can add more later.
No text editor installed? Notepad works on Windows. TextEdit works on Mac. VS Code is worth installing if you plan to use CAS regularly — it handles Markdown files well.
How you load your context depends on the tool you're using. There are two paths:
Claude Code, Cursor, and similar agent-based tools can read your shell folder directly. Point the tool at your repository folder and it will read your context files live at the start of every session.
Your CONTEXT.md and session logs are read automatically — no pasting required.
ChatGPT, Gemini, Claude.ai, and other chat interfaces cannot read files from your computer. For these, open SETUP_PROMPT.md in your text editor, select all and copy (Ctrl+A, Ctrl+C on Windows — Cmd+A, Cmd+C on Mac), then paste it into a new conversation.
The model gets a snapshot of your context for that session. Paste again at the start of each new conversation.
Chat AI gives you useful partial access — the model understands your context and can work with it. Agent tools like Claude Code give you full access: the model can read, reference, and suggest updates to your actual files as you work.
You now have a versioned, portable CAS shell that works with any AI assistant. When you're ready for an expert-built shell with pre-loaded frameworks and prompt cards, the library is here.