Cursor for Game Makers: Rules, Agent and MCP

Set up Cursor for your game with a project rule that says how your game is built, and tell Agent to show what it tried before it says something is done. Agent can change files and run commands by itself, so that rule does most of the work of keeping it on track.

File locations below come from the Cursor documentation as of 2 November 2026. The product changes often, so compare them with the current docs.

What does Cursor Agent do?

Agent is the assistant in Cursor. According to the docs it can search your files, read and change them, run commands, search the web and control a browser to test things and take screenshots.

For a game, running commands is the useful part. If the rules of your game can be tried without opening the game, Agent can try them by itself. What happens on screen is harder for it to judge, so ask it to keep the rules apart from graphics and sound. When things break anyway, read My game keeps breaking.

How do I write a project rule?

Project rules are files in the .cursor/rules/ folder, and they must end in .mdc. The docs say a plain .md file in that folder is ignored. A few lines at the top of the file decide when the rule applies:

• alwaysApply: true includes it in every chat.
• description lets Agent decide when the rule is relevant.
• globs attaches the rule when certain files are in use.

For most game projects, one rule that always applies is enough:

---
description: How this game is built
alwaysApply: true
---

- Game rules live in src/rules/. Keep graphics out of that folder.
- The story lives in story-bible.md. Read it before you write any story.
- Before you say something is done, show me what you tried and what happened.
- Never just say something fits. Show me where that is written. If you cannot, say "I do not know".
- Do not use names, art, text or numbers from other games.

A simpler option is a file called AGENTS.md in your project folder. It is plain text with no lines at the top.

Rules are instructions and not guarantees, so still ask what Agent tried.

How do I build a feature with Agent?

A way of working that holds up:

1. Write a short note about the feature: what it does, which numbers it uses, what must always be true and what happens in odd cases.
2. Ask Agent to tell you how it understood the note, quoting the lines it is working from. This is where you catch a misunderstanding cheaply.
3. Ask Agent to build the feature.
4. When it says it is done, ask what it tried and what happened. How it tries things is up to Agent. If it could not try something, it should say so.
5. Play it. Only playing tells you whether it feels right.

What are checkpoints good for?

Agent saves snapshots of your project, and you can go back to one. The docs say checkpoints are stored locally and separate from Git, and that you should use Git for permanent history. Git is a tool that keeps every saved version. Use checkpoints to back out of a bad attempt, and ask Agent to save working versions in Git.

How do I connect Spielerando?

MCP is a way to plug extra knowledge into Cursor. The MCP guide explains it, and what to look at before you connect any server.

Log in on our site by e-mail or Google, then create a key on the keys page. Put this in .cursor/mcp.json in your project:

{
  "mcpServers": {
    "spielerando": {
      "url": "https://spielerando.com/api/mcp",
      "headers": {
        "Authorization": "Bearer ${env:SPIELERANDO_KEY}"
      }
    }
  }
}

The ${env:...} part keeps the key out of the file. Ask Agent to help you set SPIELERANDO_KEY on your computer. To use the server in all your projects, put the same text in ~/.cursor/mcp.json.

Our server gives your AI our wiki, examples and tested values. Usage is counted in tokens, though no AI runs on our side. It never takes or runs your game or your code.

What should stay with me?

• Play every change that affects how the game feels. A game can work and still not be fun.
• Read what Agent decided where your note said nothing.
• Look at the licence and origin of anything it adds, including code it says it wrote from memory.
• Do not ask it to rebuild someone else's game. See Can you copy game mechanics?
• Keep secret keys out of files that get shared.