Short answer: you don't need a 50-page specification. Write a one or two-page brain dump in plain words: the screens your app needs, what each kind of user can do, and the terms your app works with. Write down even the obvious things, and leave questions where you have no answer. Then paste it into the AI and ask it to grill you with questions. When you've answered them all, it writes an idea.md file your agent can build from.
Before you start
You should have Claude Code, Git, Docker and, most importantly, the MVP System Design skill installed. If not, follow the setup first.
Start small
Don't start with your dream app. For your first project, pick something small that you understand well: a task tracker, a budgeting app, a game for your child.
Do a brain dump
Open a Word or Google doc and write your idea down. No special format, just plain text, in the order below. I'll show it on the app I build through the course.
QuestGuild is a web app, and later a mobile app, where parents set up quests and rewards for their kids. Kids see their quests, complete them and claim rewards. It turns everyday routines into a game.
Think about the screens first
Most projects start with what people will see, so we do too.
A landing page. If you are building an MVP for the world, not an internal tool, you need one. It's the first page your future users see: whether you post content or run ads, you'll send people there. Technically it's simple, a couple of buttons: sign up, log in, join a waitlist. Making it sell is a whole science of its own, which this course doesn't cover. For QuestGuild I write: a landing page with a sign-up button and a login button.
A workspace. That's the part of the app people get after they sign up, and where the brain dump really matters. List in plain words the features you want.
QuestGuild has two kinds of users, parents and kids. Kids can't do everything parents can, and they need a slightly different interface, so there are two workspaces: a parent one and a child one.
Write down every feature, even the obvious ones
The better your description, the more accurate the result. My parent workspace:
- create, edit and delete kids' accounts (to "manage" something usually means all three)
- create, edit and delete quests, the tasks
- create, edit and delete rewards: kids earn coins and XP for quests, spend coins on rewards and level up with XP
- a profile with settings and a subscription, because I want to sell subscriptions and make money
My child workspace:
- sign up and connect to a parent's account
- respect children's privacy laws, which are strict in some countries
- see the quests and complete them
- see the rewards and claim them
At this point you already have a lot to work with. If you don't have a clear picture of how the app should be structured, you can stop here and hand it to the AI.
One step further: name your terms
If you can, look at what you've described and write down the terms your app works with. For QuestGuild: parent account, kid account, quest, reward, coin, XP. Then think about what each one is made of:
| Term | What it has | Open question |
|---|---|---|
| Parent account | email, name, picture or icon | — |
| Kid account | name, picture or icon | kids aged 7 to 12 often have no email: how do they sign up? |
| Quest | name, description, icon, one-time or recurring, value in coins and XP | — |
A recurring quest saves work: "brush your teeth" can be one daily quest instead of a new one every day. And where you have no answer, like how kids sign up, leave the question in the doc and let the AI suggest something.
My final brain dump is one or two pages. Depending on how prepared you are, this stage can take a while, and that's fine.
Hand it to the AI and let it grill you
Paste the whole brain dump into the chat and add:
Grill me on this idea. Ask me questions about the implementation details. When we are done, create a single Markdown file that documents the idea.
The AI asks a lot of questions on different topics, and you answer each one. Every answer is a decision about how your app works. One of mine:
Question: a kid claims a reward, 30 minutes of tablet time or a pizza night. What happens to the coins, and does the parent confirm?
My answer: a switch per reward. For each one, the parent decides whether to confirm first, or whether the coins move as soon as the kid says it's done.
When all the questions are answered, you get idea.md: the whole idea in detail, with a diagram.
Review it, then commit it
Read the file. If something is off, ask the agent to change it, discuss it, ask why it was done that way. Take your time.
When you're happy, ask the agent to set up a Git repository and commit the file to the main branch. What that means comes in the next video; for now, just do it.
Before this: set up Claude for vibe coding. All videos as articles: articles.