Cursor Best Practices

Cursor is a powerful AI-enabled IDE, forked from VS Code. With proper configuration and usage, it can significantly boost your development speed and code quality. Configuration is done through a combination of Rules, .cursor/rules/*.mdc files, and context documents like instructions.md.

There are multiple layers of rules you can use to instruct Cursor how to behave:

• User Rules: Global to your Cursor environment. Defined in settings and always applied.
• Project Rules: Stored in .cursor/rules/ as .mdc files and version-controlled per project.
• Legacy .cursorrules: Still supported but deprecated.

Rule Precedence

Cursor evaluates rules in the following order of priority:

1. Local (manual): Explicitly included with @ruleName
2. Auto Attached: Files matching glob patterns are referenced
3. Agent Requested: AI chooses to include if needed
4. Always: Automatically included in all contexts

User Rules (Global Settings)

User Rules are defined via Cursor Settings > Rules. These are plain text instructions applied to all projects.

Example:

Please reply in a concise style. Avoid unnecessary repetition or filler language.

Use User Rules to set:

• Response language or tone
• Personal coding preferences
• General principles you want the AI to follow globally

❗ User rules do not support metadata or .mdc formatting. They are plain text only.

Project Rules: .mdc Files

Project-specific rules live in the .cursor/rules/ directory. Each rule is saved as a .mdc file and can be scoped with globs, included automatically, or triggered manually.

✅ Example .mdc Rule File:

---
description: RPC Service boilerplate
globs:
  - src/services/**/*.ts
alwaysApply: false
---

- Use our internal RPC pattern when defining services
- Always use snake_case for service names

🔍 Rule Types:

You can use @filename.ts to reference relevant files for the rule.

To scaffold a new rule in Cursor: use Cmd + Shift + P > “New Cursor Rule”.

Understanding the Benefits of .cursorrules (now .mdc)

Even though the legacy .cursorrules file is deprecated, the concept and structure behind it still serve as the foundation for project-based rule design. The updated .mdc format continues to support these same benefits:

• AI Response Customization: Configure Cursor to respond more accurately to your specific requirements, resulting in better code generation.
• Standardization: Establish unified coding guidelines to maintain consistency across your codebase.
• Enhanced Project Understanding: Supply the AI with architectural patterns, common libraries, and naming conventions to improve context relevance.
• Development Efficiency: Reduce the need for manual corrections by encoding workflows and expectations.
• Collaborative Harmony: Shared .mdc rules ensure that all team members benefit from the same rule sets and development style.
• Project-Centric Solutions: Guide the AI with details about the tech stack, design decisions, and workflow expectations for better assistance.

What Should You Include in Your .mdc Rule Files?

• System prompt
• Project Description
• Key Principles
• Project Structure
• Tech Stack / Project Dependencies
• Naming Conventions
• Coding Standards
• UI/UX Guidelines
• Language-specific guidelines
• Environment-specific guidelines
• State Management
• Testing
• Security
• Git Usage
• Documentation and Comments
• Development Workflow
• Build Process
• CI/CD
• Anything else critical from a technical standpoint

These sections can be distributed across multiple .mdc files depending on scope and purpose.

Context Files

These provide project-specific details Cursor uses to guide development.

instructions.md

A full specification of your project:

• Features
• Technologies
• Structure
• Build steps

Split into multiple files if needed (e.g., frontend.md, database.md).

Example Prompt to Generate instructions.md

You are a senior Business Analyst... [include a structured prompt for LLM assistance]

roadmap.md

Outlines milestones and future features to help guide long-term planning and incremental development.

Composer Overview

Composer is Cursor's AI coding assistant for writing and refactoring code interactively.

Modes

• Agent Mode (⌘.): Auto-pulls context, executes commands, edits files.
• Normal Mode: File and context-aware assistance.

Context Commands

• @Files – include specific files
• @Folders – include folders
• @Code – reference specific code blocks
• @Docs – reference documentation
• @Web – search online

Full list of @-commands →

Cursor Ignore Files

Use .cursorignore to exclude files from indexing. This prevents Cursor from loading unnecessary files into context.

# .cursorignore
legacy-code/
debug.log

.gitignore is respected automatically. This affects indexing only, not chat or composer access.

Tips & Best Practices

• Write focused, composable .mdc rules.
• Keep rules concise: under 500 lines.
• Reuse rule blocks instead of duplicating prompts.
• Give rules concrete names and descriptions.
• Use @filename.ts references to provide useful anchors.
• Write instructions.md before starting AI-based work.
• Always ask Cursor to confirm understanding of tasks first.

Resources

• https://cursor.directory/ – Community rule examples
• https://dotcursorrules.com/ – More templates
• https://github.com/PatrickJS/awesome-cursorrules – Community repo
• Official Cursor Docs – Rules
• Cursor Overview Video