Vibe EngineeringSMIT · AI Agentic Engineering
Class 2 · 2.1

Welcome — and your first build

The definitive AI coding course opens the way it means to continue: not with a syllabus, but by building something real in the next ten minutes. Buckle up.

🎯 Goal: generate a working app from one sentenceRead: 7 min🧰 Tool: Cursor (free trial)

01Instant gratification, on purpose

Most courses begin with objectives, introductions, and logistics. This one doesn’t. The very first thing you do is roll up your sleeves and build something. There will be plenty of time for theory later — and Class 3 is full of it — but the fastest way to understand what AI coding agents can do is to point one at a blank folder and watch it work.

The one rule for today

Every project in this course is chosen to have real commercial value. Today is the single exception. Today we just have fun — because there’s no better way to feel the power of these tools than to build a game out of nothing.

02Meet Cursor

We start with Cursor — hugely popular, easy to use, and it has a free trial. If you’ve already burned your trial, you can simply watch, or follow along in any other agentic tool. Cursor is built on top of VS Code, so if you’ve used that editor, the windows and menus will feel familiar.

3 min

Download & install

Go to cursor.com and grab the build for your platform — Mac, Windows, or Linux. On Windows, accept the agreement and keep the default that adds Cursor to your PATH. On Mac, drag it into Applications.

Sign in or sign up

First launch prompts you to sign in. Create a free account if you don’t have one — the trial is all we need for now. Can’t see the screen? Use File → New Window.

Open a project

“Open a project” really means choose a folder. Make a projects folder, create a new folder inside it called Instant, and open it. When you see INSTANT in the top-left, you’re in.

Files your project tree Editor where code appears Agent chat with an AI today’s star
Cursor’s three panes: file tree, editor, and — on the right — the agent you’ll talk to.

03Build a game from one sentence

On the right-hand pane you talk to an LLM — your coding sidekick. Below the box you can pick a model (on higher plans; otherwise it’s set to auto and Cursor chooses). Then you type your request:

prompt to the agent
Please build a website for a 3D first-person shooter game
in an arena against one computer opponent, controlled by
arrow keys and space bar to shoot.

Send it. The agent springs to life: planning, exploring, then writing files. You watch index.html appear, maybe a stylesheet, maybe a script. It might ask permission for certain actions — say yes if you’re happy — or it might just go, depending on your settings.

Double-click and play

When it finishes, open index.html in your browser. Arrow keys to move and turn, space to shoot. A playable first-person shooter — built from a single sentence, with zero code written by you.

Now make it better — by talking

The real lesson is iteration. Keep the conversation going and the agent revises the same files:

Prompt 1

“That’s great. Please add some detail to the opponent so it looks more like an enemy.”

Prompt 2

“Please add a heads-up display (HUD) and also make the difficulty harder.”

Result

A tougher game with a HUD and a meaner enemy — no code, just plain-English feedback.

Your run will look different from mine

Run this ten times and you get ten different games — sometimes one file, sometimes three; sometimes the shooting works first try, sometimes it doesn’t. That unpredictability is real, and it’s the whole point of Class 3’s exercise. If something breaks, just tell the agent what went wrong, or delete the Instant folder and start again with a different model or prompt.

04A teaser of going pro

To show where this is heading, the same prompt was run through a technique called a Ralph Loop with Claude Code — set off zero-shot (one instruction, no human feedback) and left to run. The result was a polished shooter with a health system, a live mini-map, kill counter, and a genuinely cool weapon. You’ll be able to do this yourself within days. We’ll cover Ralph Loops properly on Class 3.

Key takeaways

  • The fastest way to understand agents is to use one — build first, theorize later.
  • An agent takes a goal in plain English and plans, writes files, and iterates for you.
  • Non-determinism is normal: the same prompt yields different results every time.
  • You steer entirely through conversation — describe what you want and what’s wrong.