What are AI Rules in Modern IDEs?

Why Use AI Rules?

AI rules offer several key benefits:

• Consistency: Enforce coding standards and maintain patterns across your codebase
• Productivity: Speed up development with faster, more accurate code generation
• Context Awareness: Help AI understand your project's specific requirements
• Team Collaboration: Share coding standards and best practices across your team
• Quality Control: Reduce technical debt and maintain code quality

Setting Up Global Rules

Global rules are configuration files that define AI behavior across all your projects, with each IDE implementing them differently:

• Windsurf: Uses global_rules.md with a 6,000 character limit, accessed through Settings > Edit Rules
• Cursor: Configured via Cursor Settings > General > Rules for AI, supporting both legacy .cursorrules and new .cursor/rules system
• VSCode Copilot: Uses .github/copilot-instructions.md in repository root, focusing on project-specific contexts

Key characteristics:

• Apply across all projects or repositories
• Support markdown formatting
• Can include coding standards and preferences
• May have character limits (e.g., Windsurf's 6,000 char limit)
• Some IDEs support both global and repository-specific rules

Project-Specific Rules

Project rules provide granular control over AI behavior in different parts of your codebase:

Cursor

1. Create .cursor/rules directory in project root
2. Add .mdc files for different rule sets:
   • *.mdc for path-specific rules

# .cursor/rules/typescript.mdc

- Use TypeScript for all new code
- Follow clean code principles
- Implement comprehensive error handling
- Use async/await over callbacks

VSCode Copilot

1. Create .github directory in project root
2. Add copilot-instructions.md file
3. Define instructions in Markdown format
4. Commit and push to repository

Windsurf

1. Create .windsurfrules in project root
2. Define rules using MDC format
3. Restart Windsurf to apply changes

Best Practices

1. Rule Organization

   • Keep rules concise and focused
   • Group related rules together
   • Use clear, descriptive language
   • Include examples where helpful

2. Version Control

   • Commit rule files to version control
   • Document rule changes in commits
   • Review rules during code reviews

3. Team Collaboration

   • Share rule documentation
   • Maintain consistency across team
   • Regular review and updates

4. Verification To ensure rules are working:

   • Test AI features after changes
   • Verify code generation follows rules
   • Monitor team feedback