AI Reference
Cursor
AI-native IDE built as a fork of VS Code. Composer, Rules, and codebase-aware chat.
Last updated: October 2026
Definition: Cursor is an AI-native code editor built as a fork of VS Code. AI is built into the core — Composer for multi-file agentic edits, codebase-aware chat, and inline generation. It's the most-used AI IDE in 2026.
📊 By the Numbers (2026)
| Metric | Value |
|---|---|
| Daily active users | 1M+ |
| Paying customers | 1M+ |
| Fortune 500 adoption | 64% |
| ARR (May 2026 est.) | $4B |
Install
# macOS
brew install --cask cursor
# Windows
winget install --id=Anysphere.Cursor -e
# Or download from cursor.comCursor's Four Modes
| Mode | Use when |
|---|---|
| Agent | Multi-file, autonomous tasks |
| Ask | Codebase questions, no changes |
| Manual | Targeted, precise edits |
| Custom | Your own workflows |
Choose Your Model
- Claude Sonnet 4.6 — best balance of quality and cost
- Claude Opus 4.6 — best for complex reasoning
- GPT-5.4 — strong general purpose
- Gemini 3 Pro — long context tasks
- Grok Code — fast, code-specialized
Pro tip: Start with Sonnet — it balances quality and cost. Reserve Opus for the hardest tasks.
Set Up Rules
Create .cursor/rules/ and add a project rules file:
# Project: My App
## Stack
- React 19 + Vite + Tailwind CSS
- TypeScript strict mode
## Conventions
- Functional components only
- Named exports
- Tailwind utility classes, no inline styles
## Testing
- Vitest for unit tests
- Playwright for E2EKeep Rules under 500 lines. Concrete examples work better than vague guidance.
Build with Composer
Open Composer with Cmd+I or Ctrl+I. Try:
Build a simple LLM cost calculator:
- Input: token count, model type
- Output: estimated cost
- React + Tailwind
- Add form validation and clean UIComposer proposes changes across multiple files with a visual diff.
Keyboard Shortcuts
Cmd/Ctrl + I # Open Composer
Cmd/Ctrl + K # Inline edit
Cmd/Ctrl + L # Open chat
Tab # Accept completion
Esc # Reject suggestion⚠️ Common Mistakes
- Not setting up Rules. Cursor follows generic patterns without project rules.
- Burning credits on premium models. Use Sonnet for daily work; Opus for hard problems.
- Accepting multi-file changes without review. Composer can introduce subtle bugs.
- Ignoring the free Hobby tier. Test Cursor before committing to a paid plan.
- Expecting VS Code extensions to work perfectly. Cursor is a fork — some extensions lag.
❓ Frequently Asked Questions
What is Cursor?
Cursor is an AI-native code editor built as a fork of VS Code. AI is built into the core, including Composer for multi-file agentic edits, codebase-aware chat, and inline generation.
Is Cursor free?
Cursor has a free Hobby tier with limited agent requests. Paid plans start at $20/month for Pro, which includes unlimited tab completions and extended agent limits.
What is Cursor Composer?
Composer is Cursor's agentic mode that makes multi-file edits across your project. Open it with Cmd+I or Ctrl+I, describe what you want, and it proposes changes with a visual diff.
What are Cursor Rules?
Rules are persistent instructions in .cursor/rules/ that guide Cursor's behavior across conversations. They define coding conventions, frameworks, and patterns.
What models does Cursor support?
Cursor supports Claude Sonnet and Opus, GPT-5 series, Gemini 3 Pro, and Grok Code. You can switch models per conversation or per task.