Writing for AI
Plan and document before you build
Great prompts help with one task. Great planning helps with a whole app. In this section, you'll learn to write simple documents that keep your AI builder on track from start to finish.
Why plan before you build?
Imagine building a house without a blueprint. You tell the builder "add a kitchen" one day and "move the stairs" the next. It gets messy and expensive fast.
Building with AI is the same. If you jump straight into "build me an app", the AI makes hundreds of guesses. Some will be wrong, and fixing them takes longer than planning would have.
- A plan tells the AI what to build and in what order.
- Documents keep that plan saved, so you don't repeat it in every chat.
- Small steps make every change easy to check and easy to undo.
| Feature | No plan | With a plan |
|---|---|---|
| First prompt | "Build me an app" | A clear PRD and step list |
| AI guesses | Many | Few |
| Surprises | Often | Rarely |
| New chat | Explain everything again | Point it to your docs |
The documents you'll write
All of these are short text files written in Markdown, a simple format AI reads very well. You don't need any special software.
- README — the front page of your project: what it is and how to use it.
- PRD (product requirements document) — what your app does, for whom, and what's out of scope.
- Notes for your AI — lasting rules like "use Tailwind" or "never touch the .env file".
What you'll learn
How to use this section
Each page builds on the one before, so I recommend going in order. Markdown comes first because every other document uses it. By the end, you'll know how to write a complete plan for any small app.
- Learn the format — Markdown basics
- Write the documents — README, PRD, and notes for your AI
- Put it together — turn an idea into a step-by-step build plan
Practice
Try these exercises to lock in what you just learned.
What's next?
Let's start with Markdown, the simple writing format used by every document in this section.