Neovim MCP Server

MCP (Model Context Protocol) server that integrates Neovim buffers with Claude Code, enabling seamless buffer awareness and real-time updates.

Features

Resources (Auto-available Context)

• nvim://current-buffer - Currently active buffer with path and content
• nvim://open-buffers - List of all open buffers with metadata

Tools (Claude Can Invoke)

• list_nvim_buffers() - List all open buffers in nvim instances running in current directory
• get_current_buffer() - Get the currently active buffer
• get_buffer_content(path) - Get content of a specific buffer by path
• update_buffer(path, content) - Update buffer content directly in nvim (changes appear immediately!)
• open_file(path) - Open a file in nvim (useful after creating new files)
• reload_buffer(path) - Reload a buffer from disk
• reload_all_buffers() - Check and reload all buffers that changed on disk

Setup with Claude Code

Option 1: Using the CLI (Recommended)

Run the following command in your terminal:

claude mcp add --transport stdio nvim -- npx nvim-mcp-server

This will automatically add the server to your ~/.claude.json configuration.

Option 2: Manual Configuration

Alternatively, manually edit ~/.claude.json:

{
  "mcpServers": {
    "nvim": {
      "command": "npx",
      "args": ["nvim-mcp-server"]
    }
  }
}

After adding the configuration, restart Claude Code for changes to take effect.

Verify Setup

Check that the server is configured correctly:

claude mcp list

Or use /mcp within Claude Code to check server status.

Usage

Once configured, the MCP server will automatically:

1. Detect Neovim instances running in the current directory
2. Expose buffer context to Claude via resources
3. Enable buffer operations via tools

Example Workflows

1. Refactor Current File

You: "Refactor the current file to use async/await"

Claude:
- Reads nvim://current-buffer resource automatically
- Sees you're working on src/api.js
- Refactors the code
- Calls update_buffer() to push changes to nvim
- Changes appear instantly in your editor!

2. Check Open Buffers

You: "What files do I have open in nvim?"

Claude:
- Calls list_nvim_buffers() tool
- Shows you all open buffers

3. Update Specific Buffer

You: "Add error handling to src/utils.js"

Claude:
- Calls get_buffer_content("src/utils.js")
- Adds error handling
- Calls update_buffer() to apply changes
- You see updates in nvim immediately

4. Create and Open New File

You: "Create a new component called Button.jsx"

Claude:
- Creates the file using Write tool
- Calls open_file("src/components/Button.jsx")
- File opens in your nvim automatically
- You can continue editing right away!

How It Works

1. Discovery: Uses $TMPDIR to find nvim socket files
2. Filtering: Only connects to nvim instances running in the current directory
3. RPC Communication: Uses the neovim npm package to communicate via msgpack-rpc
4. MCP Integration: Exposes nvim buffers as MCP resources and tools

Socket Discovery

The server finds nvim sockets using:

• macOS: $TMPDIR/nvim*/0 (typically /var/folders/.../T/nvim*/0)
• Linux: $TMPDIR/nvim*/0 or /tmp/nvim*/0
• Falls back to /tmp if $TMPDIR is not set

Benefits

Real-Time Updates

Traditional:

Claude writes to file → You reload in nvim

With MCP:

Claude updates buffer via RPC → Changes appear instantly

Context Awareness

Claude automatically knows:

• Which file you're currently editing
• All files you have open
• Can make changes directly in your editor

Seamless Integration

• No file writes needed (updates are in-memory)
• Works with unsaved buffers
• Normal nvim undo/redo works
• Triggers autocmds (LSP, linting, etc.)

Troubleshooting

No Neovim instances found

• Make sure you're running the command from the same directory as your nvim instance
• Check that nvim is running: ps aux | grep nvim
• Verify socket exists: ls $TMPDIR/nvim*/0

Buffer updates not appearing

• Ensure the buffer path matches exactly (use absolute paths)
• Check that the buffer is listed: :ls in nvim
• Verify the MCP server has permissions to access the socket

MCP server not connecting

• Restart Claude Code after adding the MCP configuration
• Check Claude Code logs for errors
• Verify the path in the config is absolute and correct

Development

Test the server manually:

node index.js

The server communicates via stdio, so you'll need an MCP client (like Claude Code) to interact with it properly.

Debug mode:

The server logs errors to stderr, which you can see in Claude Code's MCP server logs.

Running tests:

npm test              # Run all tests
npm run test:watch    # Watch mode
npm run test:ui       # Interactive UI
npm run test:coverage # With coverage report

Publishing

The project includes automated release scripts for publishing to npm.

Prerequisites:

• Clean git working directory
• Tests must pass
• npm authentication configured (npm login)

Release commands:

Patch release (1.0.0 → 1.0.1):

npm run release:patch

Minor release (1.0.0 → 1.1.0):

npm run release:minor

Major release (1.0.0 → 2.0.0):

npm run release:major

Specific version:

npm run release 1.2.3

What the release script does:

1. Validates git working directory is clean
2. Runs all tests
3. Bumps version in package.json
4. Creates git commit with version bump
5. Creates git tag (e.g., v1.0.1)
6. Publishes to npm
7. Pushes commit and tags to git

If any step fails, the script will abort and rollback changes.

Requirements

• Node.js 16+
• Neovim with RPC support (any recent version)
• Running nvim instance in the directory where you invoke Claude

License

MIT