Chapter 3 · Section 02

Set upyour machine

Four steps · about fifteen minutes

Before you begin

Five things to check
before we start

Fifteen minutes for all four steps. Thirty seconds now saves ten minutes later — tick what's true, the page remembers. If you're still installing when the room moves on, stop and pair with a neighbour: you'll do every exercise from their screen and finish your own install afterwards.

Pace yourself against the clock

Time left on the room timer — the countdown on the screen at the front.

12:00 left Claude Desktop is installed and you're signed in.
9:00 left The workshop folder exists, with its two rooms inside.
6:00 left personal-site is open in Claude Code.
3:00 left index.html shows your name in the browser. The point
0:00 Done? Help a neighbour.

Check

On Windows? Claude Code needs Git installed. You'll be prompted during step 1 or the first time you use Code — say yes, and take the default options. If you can install it before class, do.

Setup 1 of 4

Install Claude Desktop

One installer. The clicking takes a minute; the download takes as long as it takes, because sixty laptops are pulling the same file. You're installing the Claude desktop app; Claude Code is a tab inside it, and that tab is what can read and write files in a folder you choose. We're using the app rather than the command line so your attention stays on directing Claude.

Do this

  1. Download the Claude desktop app for macOS or Windows From claude.ai/download — take the version your laptop offers.
  2. Run the installer and open the app Accept the defaults. On a Mac you may need to drag it to Applications.
  3. Sign in with your MIT Claude account The login you used in Chapter 1 — not a personal account you may also have.
  4. On Windows: install Git if prompted Claude Code needs it. Take the default options in that installer too.

Done when

If something's wrong

My download is crawling, or it stopped

Expected — sixty laptops are pulling the same file. Give it two minutes. If it hasn't moved, cancel and restart the download once; a stalled transfer rarely recovers on its own.

If the second attempt stalls too, raise your hand and pair with a neighbour now rather than at step 3 — you can install at home tonight and lose nothing today.

The installer won't run, or my Mac says it's from an unidentified developer

On macOS: open System Settings → Privacy & Security, scroll to the bottom, and choose Open Anyway next to the blocked app. Then launch it again.

On Windows: if SmartScreen appears, choose More info → Run anyway.

If your laptop is managed by an employer and blocks both, raise your hand — pair with a neighbour for today and install at home.

My sign-in fails — and how long to spend on it

Sign out completely, then sign back in choosing the MIT option rather than an email and password you may have used personally. If your browser auto-fills a personal account, open a private window for the login step.

Still stuck? Raise your hand. Do not spend more than two minutes here — a helper can usually fix this in thirty seconds.

Windows: what exactly is Git, and do I have to understand it?

No. It's a piece of plumbing Claude Code uses to keep track of file changes on Windows. Install it, take the defaults, and forget about it. We're not teaching Git today — that's next session's material.

Setup 2 of 4

Create a workshop folder

The folder is the boundary — the agent works inside it and nowhere else. Choosing it is a permissions decision, so choose it deliberately.

Documents/ anywhere you can find again is fine
└─ vibe-coding-workshop/ everything for today
   ├─ personal-site/ the warm-up
   └─ mba-advisor/ the main exercise

Do this

  1. Open Finder (Mac) or File Explorer (Windows) Go to Documents, or anywhere you'll be able to find again.
  2. Make a folder called vibe-coding-workshop Lower case, hyphens, no spaces. It'll save you typing later.
  3. Inside it, make two more: personal-site and mba-advisor Two rooms on purpose: the page never sees the advisor's files.
Why two folders? Whatever folder you open is what Claude can read and write. Keeping the exercises apart means a mistake in one can't touch the other — and it makes the boundary visible instead of theoretical.

Done when

If something's wrong

Should I put this in OneDrive, iCloud, or Dropbox?

A synced Documents folder is fine and is what most of you already have. Just avoid putting it somewhere that syncs aggressively while you work — if you see files reappearing or locking, move the folder to your desktop instead.

Can I put it on my Desktop, or somewhere else entirely?

Yes. Anywhere you can navigate to confidently. Avoid hidden or system directories, and avoid anything with your employer's name on it.

Does the name actually matter?

Not to the software — but lower case with hyphens and no spaces is the convention you'll see everywhere in this world, and it avoids a class of small annoyances. Copy the names above and you'll match the rest of the room.

Setup 3 of 4

Open the folder in Code

This is where you hand Claude a workspace and decide how much it may do on its own. The mode you set in a moment is the permissions layer from Chapter 1, made concrete.

Do this

  1. In Claude, open the Code tab Look for Code in the sidebar or top navigation. If you can't see it after thirty seconds, raise your hand. This is the one step where hunting alone costs you the exercise.
  2. Choose to open a project folder Claude will ask you to pick a folder from your computer.
  3. Select the folder you made for the warm-up It's called personal-site if you used our name. Whatever you called it, pick that one — not all of Documents.
  4. Set the permission mode to Manual Look for the mode control near where you type. Choose the option that asks you before each edit — if the wording on your screen differs from ours, that is the one you want. Can't find it in thirty seconds? Raise your hand.

What the modes mean

Plan It thinks it through and proposes an approach. No files change.
Manual It proposes; you approve each edit before it happens. Choose this
Accept edits It edits freely; you review afterwards. Use it once you've earned trust.
This is the shield from Chapter 1. Permissions are what the system may do without asking. Start narrow and widen deliberately — that habit is worth more than any keyboard shortcut you'll learn today.

Done when

If something's wrong

I can't find the Code tab — and how long to spend on it

Thirty seconds of looking, then stop. Hunting for a tab is the most expensive way there is to lose this exercise.

Raise your hand, and sit with a neighbour rather than waiting; you can catch the install up afterwards.

While you wait: quit the app completely, reopen it, and check you're signed in to your MIT account — Code isn't available to every account type.

Windows: it's asking me to install Git

Say yes and take the defaults — this is the Git install the preflight mentioned, arriving now rather than at step 1. Give it a couple of minutes and don't cancel it partway.

If it's still going when the room moves on, raise your hand and pair with a neighbour — you can finish your own install afterwards.

I opened the wrong folder

No harm done — nothing has changed on your disk yet. Close the project and open the right one. If you opened something large like your whole home directory, definitely switch: a big folder makes Claude slower and vaguer, and it widens what it can touch.

It's asking for permission to access Documents or Desktop

That's your operating system, not Claude, and it's the right question to be asked. Allow it for the folder you chose. On macOS these live in System Settings → Privacy & Security → Files and Folders if you need to change your answer later.

I can't get this working at all

Sit with a neighbour now. You'll do every exercise today from their screen — watching someone direct the agent is most of the lesson.

Tick nothing, and come back to this page tonight: the guide will still be here and the folders take four minutes.

Setup 4 of 4

Prove that it works

One small, unambiguous success before anything that matters. If you're stuck here, raise your hand rather than re-reading.

Copy the prompt below, replace YOUR NAME with your actual name, then paste it into the box where you type in the Code tab — with personal-site open — and press Enter.

Hello prompt · replace YOUR NAME

Create one file named index.html. Make it display "Hello, YOUR NAME" in large text on a clean white page. Do not create any other files.

Approve the edit when Claude asks — that's Manual mode doing its job.

Done when — all three

If something's wrong

My page says YOUR NAME instead of my name

One line fixes it: tell Claude "My name is Alex, update index.html to use it." Nothing is broken.

Nothing happened, or I can't find the file

Check the folder in Finder or File Explorer rather than trusting the chat. If it isn't there, ask Claude directly: "Which folder are you working in, and what files are in it?" That one question resolves most of these.

The file opens in a text editor instead of a browser

Right-click it and choose Open With → Chrome / Safari / Edge. You're seeing the file's source, which means it exists and everything worked — it just opened in the wrong application.

My folder shows index, not index.html

That's Windows and macOS hiding the extension. The file is right. If you want to see extensions: View → Show → File name extensions on Windows, or Finder → Settings → Advanced on Mac — but you don't need to.

I said no when it asked permission

Sensible instinct, and the mode is doing its job. Just ask again: "Go ahead and create index.html" — then approve it this time. Nothing was written, so nothing is broken.

It made several files, or put things somewhere unexpected

Say so plainly: "You created extra files. Delete everything except index.html and show me what's left." Steering after the fact is the normal working mode, not a failure — and it's the skill the rest of the session is about.

It's asking me questions instead of building

Answer briefly and let it proceed. If it's over-thinking a four-word page, say "Keep it simple — one file, one line of text."

I've tried everything and no file appears

Sit with a neighbour now. You'll do every exercise today from their screen — watching someone direct the agent is most of the lesson.

Leave the last three boxes unticked and come back tonight: Claude is installed and your folders exist, so you'd be picking up at this step rather than at the beginning.

Your machine is a workshop now

You installed an agent, gave it a folder, set what it may do without asking, and watched it write a real file to your disk. That's the whole harness — context, tools, permissions, and you closing the loop.

Keep Claude open. The warm-up starts in the same folder.

Back before class? Take thirty seconds on the preflight — power, wifi, notifications closed — and check you're still signed in to your MIT account.