Updated Cursor Rules: A Smarter Way to Guide AI Code Generation

In the fast-moving world of AI-assisted coding, staying updated is key. If you’re using Cursor AI to help with development, understanding and applying Cursor Rules will take your workflow to the next level. These rules allow you to fine-tune how the AI operates, ensuring it follows your coding style, project needs, and best practices.

What Are Cursor AI Rules?

Cursor AI Rules are instructions you set to guide the AI’s coding decisions. Whether it’s following a specific framework, enforcing best practices, or just making sure you don’t forget to commit your code, these rules make AI assistance more predictable and tailored to your workflow.

The New Cursor Rules System

Cursor recently overhauled how rules are handled. Previously, project-specific rules were managed through a .cursorrules file, but that method is now deprecated. The new system introduces a rules folder approach, where rules are managed directly in Cursor’s settings.

Here’s what’s changed:

  • Global Rules: Set rules that apply across all projects under Settings > Rules for AI.
  • Project-Specific Rules: Instead of using .cursorrules, you now create rules inside the .cursor/rules folder.
  • More Flexibility: Rules can be written in Markdown or JSON and are constantly synced with your codebase.

Transition from .cursorrules to the New System

Traditionally, you stored your project-level rules in the .cursorrules file in the root directory and toggled an option to ensure it was read. However, this method is being deprecated and will be switched off in future releases according to the Cursor team. The recommended approach now is to use the new rules folder system, ensuring your project stays compatible with future updates.

You can find great examples of these files for inspiration at:

Why Use Cursor Rules?

Setting up rules in Cursor AI can help with:

  • Consistency: Ensure AI-generated code follows your conventions.
  • Efficiency: Automate repetitive tasks like adding dependencies or structuring components.
  • Collaboration: Share rules with teammates to keep everyone on the same page.

How to Set Up a New Rule in Cursor

  1. Open Cursor Settings and navigate to Rules for AI.
  2. Click Add New Rule.
  3. Name your rule (e.g., Create React Component).
  4. Define when it should apply (e.g., when creating, refactoring, or updating a component).
  5. Specify file patterns using Globs (e.g., only apply to .tsx files in a certain directory).
  6. Add a description so you and your team understand its purpose.
  7. Save your rule—it will now appear in .cursor/rules and sync with your project.

Example Cursor Rules

Here is a sample Rules for AI, found in Settings, see above:

You are an expert AI programming assistant that primarily focuses on producing clear, readable Javascript and Python code.
You are thoughtful, give nuanced answers, and are brilliant at reasoning. You carefully provide accurate, factual, thoughtful answers, and are a genius at reasoning.

- Follow the user’s requirements carefully & to the letter.
- First think step-by-step - describe your plan for what to build in pseudocode, written out in great detail.
- Confirm, then write code!
- Always write correct, best practice, DRY principle (Don't Repeat Yourself), write correct, up to date, bug free, fully functional and working, secure, performant and efficient code.
- Focus oneasy and readability over being performant.
- Fully implement all requested functionality.
- Leave NO todo’s, placeholders or missing pieces.
- Ensure code is complete! Verify thoroughly finalized.
- Include all required imports, and ensure proper naming of key components.
- Be concise. Minimize any other prose. The fewer lines of code the better. 
- If you think there might not be a correct answer, you say so. 
- If you do not know the answer, say so instead of guessing.
- Do not stop working until you have completed the task, unless you don't know the answer, then say so instead of guessing.

Here are some useful rules to consider:

  • Enforce Tailwind in React Components
    • When creating or modifying a component, ensure Tailwind CSS is used for styling.
  • Remind to Commit Code
    • Append a reminder to commit after every major change.
  • Standardize Component Names
    • Prefix all new components with a specific tag, like UI_ or App_.
  • Use Prettier for Formatting
    • Automatically format files using Prettier when saving changes.
  • Install Dependencies Before Running
    • Ensure npm install or yarn install runs before executing a project.
  • Enforce ESLint Rules
    • Ensure all new code adheres to ESLint configurations before allowing a commit.
  • Use Specific Frameworks for API Calls
    • Always use Axios instead of Fetch for handling API requests.
  • Ensure Unit Test Coverage
    • Require at least 80% test coverage before merging pull requests.
  • Use a Specific Commit Message Format
    • Enforce a structured commit message format like Conventional Commits (feat:, fix:, etc.).
  • Block Deprecated Libraries
    • Prevent the AI from suggesting or using outdated dependencies in new code.

Additional Resources

For more insights into AI-assisted coding, check out:

Final Thoughts

With the new Cursor Rules system, managing AI-driven code generation is easier and more effective than ever. By setting clear rules, you can ensure your AI assistant aligns with your development practices, making coding more streamlined and efficient.

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