Game Design Document AI: One Page That Stays True
The best use of AI for a game design document is to let it interview you, then write one short page that you keep next to your game. Treat that page as a living file your AI reads before each change, not as a long report nobody opens.
A game design document, or GDD, is the written description of how your game works. Studios write long ones because many people must agree. You have one person and one AI, so you need something shorter and much more exact.
Why AI is good at this, and where it is not
Ask an AI to "write a game design document" and it will happily produce ten confident pages, most of them invented. You now own a detailed plan for a game you never decided to make.
It is far better at two other things: asking questions, and finding contradictions. A chat can keep asking until the vague parts are gone, and it can hold every rule in view at once to spot two that clash. So use it as an interviewer and a checker, and keep the ideas for yourself.
What goes on the page
Here is a full example for Night Market Noodles, an invented game.
# Night Market Noodles
Pitch: You run a noodle stall for one busy night.
Loop: take an order, cook, serve, collect tips, buy an upgrade.
Rules:
- Up to 3 customers wait at once.
- Noodles cook in 6 seconds and burn after 10.
- A customer leaves after 20 seconds.
- A round is 6 minutes. Rent is 120 coins.
Win or lose: pay the rent at midnight, or the stall closes.
Not in this game: multiplayer, a story campaign, a shop outside the stall.
Open questions: Do tips grow with speed?
That is under 100 words, and each line can be built from. Two parts earn their place more than they appear to. Not in this game stops your AI from adding things when it feels helpful. Open questions gives doubts a home, so they do not turn into silent guesses.
Add one more thing to the page: a diagram of the loop, in Mermaid, a text format that mermaid.live turns into a picture. A list of rules can look fine while the loop has a hole in it. What happens if the customer leaves while your noodles cook? The diagram asks that out loud.
Keeping it true
An out-of-date page is worse than none, because your AI will trust it. Three habits keep it honest:
- Keep it in your project as
game-design.md, and tell your AI to read it before any change. - When a rule changes, change the page first and the game second.
- Re-run the contradiction check after big changes.
For the words and characters, use a story bible alongside this page. What is a core game mechanic? helps with the loop, and the mechanics pages show how exact a rule can get.
Paste this to your AI
Interview me about my game, one question at a time, until you can fill in this page: pitch in one sentence, what the player does again and again, rules with real numbers, how a round is won or lost, what is not in this game, open questions.
Then draw the main loop as a Mermaid diagram and walk through it. Ask me about every situation the rules do not cover, such as two things happening at once, and every place a player could get stuck. Update the page from my answers.
Write it all to game-design.md, at most 300 words plus the diagram. After each rule, add [mine] if I said it, or [yours] if you suggested it and I agreed. Anything I have not confirmed goes under open questions.
Finish by listing any two rules that cannot both be true, quoting both. If you find none, tell me what you compared.
Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP
How to check it worked
- Explain it to a friend in 30 seconds, with the page in hand. If you need to add things, they belong on the page.
- Start a fresh chat and ask about multiplayer. Your AI should point to "Not in this game".
- Look for rules with no [mine] or [yours]. Each one came from nowhere.
- Trace the diagram with a stuck customer. Every arrow should lead somewhere.