Node.js Debugger MCP
Allows Claude to directly debug a NodeJS server by setting breakpoints, inspecting variables and stepping through code.
What is Node.js Debugger MCP?
Node.js Debugger MCP is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to allows claude to directly debug a nodejs server by setting breakpoints, inspecting variables and stepping through code.
Allows Claude to directly debug a NodeJS server by setting breakpoints, inspecting variables and stepping through code.
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- nodejs_inspect
- set_breakpoint
- inspect_variables
- step_over
- step_into
Use Cases
Maintainer
Works with
Installation
NPM
npx -y @hyperdrive-eng/mcp-nodejs-debuggerManual Installation
npx -y @hyperdrive-eng/mcp-nodejs-debuggerConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Node.js Debugger MCP
The Node.js Debugger MCP server lets Claude connect directly to a running Node.js process via the V8 Inspector protocol and perform live debugging operations. Claude can set breakpoints at specific file and line locations, list all active breakpoints, and execute arbitrary JavaScript in the process context to inspect variables and connection state. This eliminates the manual cycle of adding console.log statements, restarting the server, and reading logs — Claude can instead interrogate the live runtime and explain what it finds.
Prerequisites
- Node.js 16+ installed with npx available
- Claude Desktop, Claude Code CLI, or Cursor as your MCP client
- A Node.js application you can start in debug mode with node --inspect
- No API keys required — the server communicates with the local debugger port
Start your Node.js app in debug mode
Launch your application with the --inspect flag so the V8 Inspector listens on the default port 9229. The debugger MCP connects to this port.
node --inspect server.jsAdd the MCP server to your client config
Register the @hyperdrive-eng/mcp-nodejs-debugger package in your MCP client configuration. For Claude Code CLI you can add it with a single command.
claude mcp add nodejs-debugger npx @hyperdrive-eng/mcp-nodejs-debuggerVerify the server is connected
In Claude Code, run /mcp to list active servers and confirm nodejs-debugger appears with a connected status.
/mcpSet a breakpoint via Claude
Ask Claude to set a breakpoint at the line you suspect is causing an issue. Claude will call the set_breakpoint tool with the file path and line number.
Inspect runtime variables
Once execution is paused at the breakpoint, ask Claude to inspect specific variables or evaluate expressions. Claude uses the nodejs_inspect tool to execute JavaScript in the paused process context and report back the values.
Node.js Debugger MCP Examples
Client configuration
Add this to your claude_desktop_config.json or ~/.cursor/mcp.json to register the Node.js debugger server.
{
"mcpServers": {
"nodejs-debugger": {
"command": "npx",
"args": ["@hyperdrive-eng/mcp-nodejs-debugger"]
}
}
}Prompts to try
Use these prompts in Claude after starting your Node.js app with --inspect and connecting the MCP server.
- "I'm getting a runtime error in my Express server. Help me debug it using the nodejs-debugger MCP"
- "Set a breakpoint at line 42 in src/routes/auth.js and tell me what variables are in scope when it hits"
- "List all active breakpoints currently set in the debugger"
- "Evaluate the expression 'req.session' at the current breakpoint and explain what you see"Troubleshooting Node.js Debugger MCP
Debugger cannot connect to the Node.js process
Ensure your app was started with 'node --inspect' (not just 'node'). The debugger connects to port 9229 by default. If you used --inspect=PORT, note that the current package targets the default port.
set_breakpoint has no effect — execution never pauses
Breakpoints only pause execution when the breakpointed code is actually reached. Trigger the code path in your app (e.g., make an HTTP request) after setting the breakpoint for it to take effect.
npx @hyperdrive-eng/mcp-nodejs-debugger fails to start
Clear the npx cache with 'npx clear-npx-cache' and try again. Also ensure you have Node.js 16+ and that your network can reach the npm registry to download the package on first run.
Frequently Asked Questions about Node.js Debugger MCP
What is Node.js Debugger MCP?
Node.js Debugger MCP is a Model Context Protocol (MCP) server that allows claude to directly debug a nodejs server by setting breakpoints, inspecting variables and stepping through code. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Node.js Debugger MCP?
Install via npm with the command: npx -y @hyperdrive-eng/mcp-nodejs-debugger. Then add the server configuration to your AI client's JSON config file (e.g., claude_desktop_config.json or .cursor/mcp.json).
Which AI clients work with Node.js Debugger MCP?
Node.js Debugger MCP works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Node.js Debugger MCP free to use?
Yes, Node.js Debugger MCP is open source and available under the MIT License license. You can use it freely in both personal and commercial projects.
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Quick Config Preview
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