What are MDC files in Cursor?

MDC (.mdc) files are Cursor's newer multi-rule format. Instead of one massive .cursorrules file, you place multiple targeted .mdc files inside the `.cursor/rules/` directory (e.g., frontend.mdc, testing.mdc).

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Cursorrules vs Windsurf Rules: Developer Guide [2026]

Q: Can I use .cursorrules in Windsurf?

Technically no, Windsurf's Cascade engine specifically looks for `.windsurfrules`. However, the contents are largely interchangeable. You can generally rename the file and the AI will follow the identical instructions.

Master AI skills with our definitive guide to `.cursorrules` and `.windsurfrules`. Compare the formats and download top 2026 templates.

Quick Answer

While Cursor and Windsurf use different filenames (`.cursorrules` vs `.windsurfrules`), the core concept is identical: plain-text markdown files injected into the AI's system prompt. The biggest difference in 2026 is that Cursor officially supports modular .mdc files (`.cursor/rules/*.mdc`) allowing for context-aware, granular rules.

Feature Comparison

Feature	Cursor IDE	Windsurf IDE
Primary Filename	.cursorrules	.windsurfrules
Multi-file Support	.cursor/rules/*.mdc	Global rules via IDE settings
Primary AI Engine	Composer / Chat	Cascade
Best Format Style	Markdown + XML tags	Standard Markdown

How to Write the Best Rules (For Both)

Whether you use Cursor or Windsurf, LLMs respond best to structured XML-like tags blended with standard Markdown lists.

# Project Profile
You are a Staff-level React developer specializing in Next.js 14 App Router.

## Technologies
- Next.js 14 (App Router)
- Tailwind CSS
- shadcn/ui
- Typescript

<guidelines>
- ALWAYS use functional components with standard const arrow functions.
- NEVER use class components.
- PREFER 'lucide-react' for all icons.
</guidelines>

Cursor's .mdc Paradigm

In mid-2025, Cursor shifted towards `.mdc` files. You place these inside `.cursor/rules/`. They allow you to add "globs" at the top of the file (e.g., `*.ts`), ensuring the rule is only loaded when editing TypeScript files, saving precious token context.

Windsurf's Setup

Windsurf relies primarily on the single root `.windsurfrules` file. However, you can also establish global instructions in the IDE settings that apply across all workspaces, which Cursor traditionally handles via "Rules for AI".

Frequently Asked Questions

Can I use .cursorrules in Windsurf?

Technically no, the Windsurf Cascade engine specifically looks for the `.windsurfrules` filename. However, the contents are completely interchangeable. Just rename the file.

Is SKILL.md the same thing?

Yes. `SKILL.md` is simply the universal alias for AI coding rules designed to be IDE-agnostic and machine-readable across platforms.

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