MCP Node.js Debugger

MCP Node.js Debugger is an MCP server that provides runtime debugging access for running Node.js applications to AI programming tools like Cursor and Claude Code. It connects directly to the Node.js inspector protocol via a local debug port when an application runs with the standard inspect flag. Node.js software developers, backend engineers, and QA engineers use this tool to allow LLM agents to investigate runtime behavior directly rather than relying solely on static code analysis. Once connected, it enables client assistants to set dynamic breakpoints, inspect the call stack, evaluate arbitrary JavaScript snippets in execution context, and query active variables during live execution. This server helps diagnose elusive runtime bugs such as broken database connections, missing environment variables, and unhandled asynchronous exceptions without leaving the AI editor interface.

Category: Developer Tools & Code Intelligence

Tags: debugging, inspector, nodejs, runtime

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How to install and configure MCP Node.js Debugger

1. Configure Cursor by adding the debugger to ~/.cursor/mcp.json under mcpServers with the key nodejs-debugger, command npx, and args ["@hyperdrive-eng/mcp-nodejs-debugger"]. Alternatively, for Claude Code, run claude mcp add nodejs-debugger npx @hyperdrive-eng/mcp-nodejs-debugger. 2. Start your target Node.js application in debug mode from a separate terminal window by passing the --inspect flag: node --inspect {file.js}. 3. Verify your connection in Claude Code using /mcp or inspect the MCP status indicator inside Cursor. 4. Direct your AI client to start debugging your application at runtime.

What you can do with MCP Node.js Debugger

• Setting programmatic breakpoints in active Node.js server files to inspect variable state during specific HTTP requests. - Inspecting live database connection strings and environment variables at runtime to diagnose connection failures. - Evaluating dynamic JavaScript expressions directly inside the running Node.js process using the inspect tool. - Listing and managing all active breakpoints during an AI-guided debugging session in Claude Code or Cursor. - Isolating unexpected runtime exceptions by capturing detailed call stacks and execution context during application execution.

Key facts

• https://github.com/hyperdrive-eng/mcp-nodejs-debugger
• Developer Tools & Code Intelligence, Monitoring & Observability
• debugging, inspector, nodejs, runtime

Part of MCP Servers

What is MCP Node.js Debugger?

MCP Node.js Debugger is an Model Context Protocol server that gives AI coding environments access to Node.js applications at runtime. It interfaces with the Node.js inspector protocol to set breakpoints, read variables, evaluate expressions, and capture error contexts directly from an active process.

How do I install MCP Node.js Debugger?

You can install it in Claude Code by running claude mcp add nodejs-debugger npx @hyperdrive-eng/mcp-nodejs-debugger. For Cursor, add a new server definition to ~/.cursor/mcp.json pointing command to npx and args to the @hyperdrive-eng/mcp-nodejs-debugger package name.

Which MCP clients work with MCP Node.js Debugger?

The project documentation specifically supports and demonstrates setup with Cursor and Claude Code. Any Model Context Protocol client capable of spawning Node.js processes using stdio or npx can also communicate with this server.

How must I start my application to use MCP Node.js Debugger?

You must start your Node.js application in debug mode using the inspect flag. In your terminal, run node --inspect followed by your script name. This opens the default Node.js inspector WebSocket port so the MCP server can attach.

What tools are exposed by MCP Node.js Debugger?

Based on runtime usage examples, the server provides tools including set_breakpoint to attach to target files and lines, list_breakpoints to see existing breakpoints, and nodejs_inspect to evaluate JavaScript expressions inside the running process context.