Set Up Cursor for Full Codebase Chat

Use Cursor's codebase index to ask questions and make changes across your entire repo.

Prerequisites

• Cursor installed (cursor.com)
• A Git repository
• OpenAI, Anthropic, or Ollama API key

Step 1: Open your project

Open your repo in Cursor. It starts indexing automatically. For large repos, let it finish (check the status bar).

Step 2: Configure your model

Go to Settings → Models. Choose GPT-4, Claude 3.5 Sonnet, or a local Ollama model. Claude 3.5 is recommended for code understanding and multi-file edits.

Step 3: Use Cmd+L for codebase chat

Open the chat with Cmd+L. Type @codebase to give the model full repo context. Ask: "How does authentication work?" or "Where is the user discount logic?" The model answers with file references.

Step 4: Use Cmd+K for inline edits

Select a function or block. Press Cmd+K. Describe the change: "Refactor this to use async/await" or "Add input validation for null and empty string." Review the diff. Accept with Tab or reject.

Step 5: Multi-file edits with Agent

For larger changes, use Cursor Agent (Ctrl+Shift+I). Describe the task: "Add rate limiting middleware to all API routes." The agent reads relevant files, proposes changes across multiple files, and shows a unified diff. Review and accept.

Step 6: Add .cursorrules

Create a .cursorrules file in your repo root. Add project-specific rules: naming conventions, preferred patterns, libraries to use or avoid. Cursor reads this file and follows the rules in all suggestions.