Two very different kinds of software in one session: a browser game your friends can play, and a program that does a real chore on your computer. Along the way you learn the dialogue pattern that makes agents build what you actually meant.
Build and publish a small browser game, then build a program that organizes files on your computer — both by directing Codex through the describe → plan → approve dialogue.
You need: your laptop with Codex from Day 1 · your Netlify account · about 90 minutes.
A game is software with three parts: rules (what's allowed), state (what the game remembers — score, lives, positions), and reaction (what happens when you act). The agent writes all the code; your job is the design: what makes it fun, what makes it fair, when it ends. Pick your concept:
Click each card to see what that game teaches you. Pick whichever you'd actually show a friend — you'll build it in the next step.
Describe the game — and demand a plan
Watch the dialogue pattern first. Three moves: describe the result, add the details that matter to you, ask for a plan before code.
New folder my-game, new Codex thread, and send your version — your game, your rules:
I want a [snake / quiz / catcher] game in the browser.
Rules: [how you play, in 2–3 plain sentences]
Score: [what counts as a point, when the game ends]
Feel: [one sentence about looks or mood]
One HTML file, plain HTML/CSS/JS, no libraries, everything in this folder.
Before you build, show me your plan in 5 bullets and wait for my OK.Step done when: you read the plan, corrected at least one bullet (there's always something), and approved it.
Play it — that's verification
Open index.html in your browser and actually play, looking for the gap between rules-as-described and rules-as-built: does the score count right? does the game end when it should? does anything feel unfair?
Step done when: you've played 3 rounds and written down (or remembered) 2 things to change.
Tune it — game design by conversation
Send your two changes as plain requests. Tuning is where a game becomes yours:
The game gets hard too fast — make the speed grow twice as slowly.
Add a "best score" that survives page reload.
When I lose, show a funny message instead of just "game over".✦ You just did game design. The programming happened somewhere below you, where it belongs.
Step done when: both of your changes are in and verified by playing.
Websites and games live in the browser. A program just does work: rename a hundred files, sort a folder, produce a report. No visuals, pure usefulness — and it's where agents save you the most hours at your actual job.
Make a safe copy to practice on
Our program will organize a messy folder. Never point a new program at real files — ask Codex to build a playground first:
Create a folder here named "playground" and fill it with 30 fake files of mixed types: some .jpg, .pdf, .docx, .mp3, .zip, with realistic messy names. These are for safely testing a program we'll write next.Step done when: you open playground in Explorer and see the mess — 30 fake files, ready to be organized.
Describe the program — same dialogue pattern
Write a program that organizes the "playground" folder: create subfolders by file type (Images, Documents, Music, Archives, Other) and move each file into the right one.
Two safety rules: it must only ever touch the "playground" folder, and it must first PRINT what it plans to move — and ask me before actually moving anything.
Show me your plan in 4 bullets and wait for my OK.The two safety rules are the lesson: limit where it can act, and dry-run before real run. You'll use both rules for every program you ever commission.
Step done when: plan approved; the program printed its intentions and asked permission.
Run it and verify in Explorer
Let it move the files, then look with your own eyes: open playground — five tidy subfolders, everything where it belongs? Try dropping in 3 new fake files and running it again.
✦ That program is yours forever. Point it at your real Downloads folder whenever you're ready — you know the safety rules now.
Step done when: the playground is organized, and a second run handles new files correctly.
Turn it into a real program — one double-click .exe
Right now the organizer runs only when the agent runs it. A real program is a file: double-click, it works, no agent needed. Ask Codex to package it:
Package the organizer as a standalone Windows program: one .exe file I can double-click, no installation needed on the computer that runs it. Use PyInstaller — install whatever you need yourself. When it's built, tell me the exact path of the .exe and how to test it.Copy the .exe to your Desktop and double-click it. Point it at the playground folder and watch it work — with no agent running.
Same idea, different wrapper: ask for “a double-clickable app for macOS”. The agent builds a .app or a .command file. On first launch use right-click → Open — macOS also distrusts new programs once.
✦ That file is a real program. You can send it to anyone with Windows — no agent, no setup. Your software.
Step done when: the double-clicked .exe organizes the playground while no agent is running.
Publish your game, note the chore your future tool will kill, and read the tokens article before tomorrow.
homework complete — mark the day done below
Tick when the homework above is finished — it syncs to your account.
Describe the result → add the details that matter to you → demand a plan and approve it before code exists. Correcting a plan costs seconds; correcting a finished build costs a rebuild.
Limit where it can act (only the playground folder) and dry-run first (print the intended moves and ask permission before touching anything). Any program that changes real things earns trust on a copy first.
The agent wrote and ran the code; you owned the decisions and the checking. Rules, fairness, safety limits, "is this right?" — those stayed with you in every build. That division of labor is the profession.