Set up Claude Code on a real project

This is the first project of the Claude Code course. Finish Units 1 and 2 before you start.

You'll take everything from Units 1 and 2 and put it to work on a real codebase: install and sign in to Claude Code, then give this project a CLAUDE.md and permission rules that make Claude genuinely useful from the very first session.

This is also the repository you'll keep building on as the course continues — each level's project adds to it, all the way to a shareable plugin at the end.

What you'll deliver

On your branch of this repo:

• a working CLAUDE.md at the project root
• a .claude/settings.json with your permission rules
• a short NOTES.md explaining your choices

...plus Claude Code installed, signed in, and confirmed to load your CLAUDE.md.

You are not changing the app code. The Express API below is here so you have a real project to set Claude up on.

What's already in the repo

• package.json — scripts for dev, test, and lint
• server.js — the entry point; starts the API
• routes/ — users.js and health.js, one file per resource
• db/store.js — a tiny in-memory data helper
• tests/users.test.js — a sample test
• .env.example — sample config; real secrets would live in .env (which is git-ignored)
• .gitignore — already ignores node_modules, .env, and .claude/settings.local.json

Run it once to see it work:

npm install
npm run dev      # starts the API on http://localhost:3000
npm test         # runs the sample tests
npm run lint     # checks code style

Before you start

1. Finish Units 1 and 2.
2. Have Claude Code installed and signed in. Check with:

   claude --version
   

3. Get this repo onto your machine and open a terminal in the project folder. Opening a terminal (the app where you type commands):
   • Mac - press Cmd + Space, type "Terminal", press Enter.
   • Windows - open "Terminal" or "PowerShell" from the Start menu.
   • Linux - open your "Terminal" app (often Ctrl + Alt + T).Getting into the project folder - copy the repo to your machine, then move into it:

   git clone <your-repo-url>
   cd <repo-folder>

cd means "change directory". To check you're in the right place, run ls (Mac/Linux) or dir (Windows) - you should see server.js, package.json, and the routes, db, and tests folders.

Tasks

1. Get Claude running in the repo

Start Claude in the project folder:

claude

Confirm you're signed in and Claude can see the project — ask "What's in this project?" and check the answer matches the files above.

2. Generate a first CLAUDE.md

Run:

/init

Let Claude read the codebase and draft a CLAUDE.md. (No /init? Ask: "Create a CLAUDE.md for this project.")

3. Shape your CLAUDE.md

Edit the file so it has these four parts, each lean and specific:

• a one-line description of what the project does
• Commands — at least two you run often (here: npm run dev, npm test, npm run lint)
• Conventions — at least two real rules ("use X, not Y"), written so Claude can follow them without asking a question
• Architecture — a few lines on how the project is organised (the server.js entry point, one route file per resource in routes/, data access through db/store.js)

Then trim it: cut anything obvious from the code, any one-off notes, and anything sensitive. Shorter is stronger.

4. Add permission rules

Create .claude/settings.json (or run /permissions and add rules there) with at least:

• one allow rule for a safe command you run often (the test command is a good choice)
• one deny rule for something sensitive or destructive (reading .env, or a force-push)
• optionally, one ask rule for something you want to confirm each time (git push)

Example shape:

{
  "permissions": {
    "allow": ["Bash(npm test:*)"],
    "ask": ["Bash(git push:*)"],
    "deny": ["Read(./.env)", "Bash(git push --force:*)"]
  }
}

Commit .claude/settings.json so the rules are shared. The repo's .gitignore already keeps .claude/settings.local.json out — that one is personal and stays on your machine.

5. Verify it works

• Start a fresh session and run /memory — confirm your CLAUDE.md shows as loaded.
• Run /permissions — confirm your allow / deny / ask rules are there.
• Ask Claude something that relies on the file, such as "How do I run the tests here?", and check it answers from your CLAUDE.md without you explaining.

6. Write your NOTES.md

In a short NOTES.md, answer in a few sentences each:

• What did you put in your CLAUDE.md, and what did you deliberately leave out, and why?
• Which permission rules did you add, and what could go wrong without your deny rule?

Definition of done

• claude --version runs (installed and signed in)
• CLAUDE.md committed at the project root with a description, 2+ commands, 2+ conventions, and an architecture note
• No secrets, no pasted long documents, and no one-off tasks in the CLAUDE.md
• .claude/settings.json committed with at least one allow rule and one deny rule
• /memory shows the CLAUDE.md loaded and /permissions shows your rules (mention this in NOTES.md)
• NOTES.md committed with your reasoning

Submit

1. Create a branch:

   git checkout -b set-up-claude
   

2. Stage and commit your work:

   git add CLAUDE.md .claude/settings.json NOTES.md
   git commit -m "Set up Claude Code: CLAUDE.md and permissions"
   

3. Push your branch:

   git push -u origin set-up-claude
   

4. Open a Pull Request against the main repository, not your fork, and submit it through the platform, which copies your branch for review.

Before you submit, make sure that:

• only the intended files are in the PR — no secrets, and no .claude/settings.local.json
• every line in your CLAUDE.md earns its place
• your NOTES.md explains your choices

---

How this is checked: a reviewer opens your branch and works down the Definition of Done. The aim isn't a perfect file — it's a CLAUDE.md and permission set that would genuinely save time on this project, with clear reasoning behind what you kept and what you cut.