What is a .cursorrules File? Complete Guide for 2026

If you use Cursor AI for coding, you've probably noticed that it sometimes writes code that doesn't match your project's conventions. It might use the wrong styling approach, import from the wrong libraries, or structure components differently than you prefer. That's where .cursorrules files come in.

What is a .cursorrules File?

A .cursorrules file is a plain text file placed in your project's root directory that tells Cursor AI how you want it to write code. Think of it as a "style guide" for your AI coding assistant.

When Cursor detects a .cursorrules file in your project, it automatically reads it and follows the instructions when generating code, making suggestions, or refactoring existing code.

Why Do You Need One?

Without a rules file, Cursor uses its default behavior — which might not match what you want. Here's what a rules file helps with:

• Consistent code style — ensures the AI follows your team's conventions
• Framework-specific patterns — tells the AI which patterns to use (e.g., App Router vs Pages Router in Next.js)
• Library preferences — specifies which libraries to use and which to avoid
• Error handling standards — defines how errors should be handled across the project
• TypeScript strictness — enforces strict typing rules

How to Create a .cursorrules File

There are two ways to create a .cursorrules file:

Option 1: Use Our Free Generator (Recommended)

The easiest way is to use the RulesForAI Generator. Select your framework, customize the options, and download a ready-to-use file in seconds.

Option 2: Write It Manually

Create a file named .cursorrules in your project's root directory. Write your rules in plain text or Markdown format. For example:

# Role
You are an expert React developer using TypeScript.

# Tech Stack
- React 19
- TypeScript (strict mode)
- Tailwind CSS

# Conventions
- Use functional components with hooks
- Use TypeScript interfaces for all props
- Prefer const over let
- Use early returns to reduce nesting

# Avoid
- Do not use class components
- Do not use the any type
- Do not use inline styles

.cursorrules vs Other Formats

Different AI coding tools use different rules file formats:

Our universal generator supports all five formats — generate once, export for any AI IDE.

Best Practices

• Be specific — vague rules lead to vague code. Say "Use TypeScript strict mode" instead of "Use TypeScript."
• Include your stack — list the exact libraries, frameworks, and versions you use.
• Say what to avoid — explicitly list anti-patterns and things you don't want.
• Keep it updated — update your rules file when your project's conventions change.
• Commit to version control — share rules with your team by committing the file to Git.

Get Started

Ready to create your own .cursorrules file? Use our free generator to build one in seconds:

Guides for Other AI IDEs

Not using Cursor? We have guides for all 15 AI coding tools:

• Complete Guide to AI Rules Files for Every IDE — setup, format, and examples for all 15 IDEs
• Best AI Coding Rules for Every IDE in 2026 — comparison and recommendations