MCP Node.js Debugger

The MCP Node.js Debugger is a lightweight, runtime‑enabled debugging server that bridges AI assistants—such as Claude Code or Cursor—with an actively running Node.js process. By exposing the V8 inspector interface over MCP, it lets conversational agents query and manipulate the execution state of a Node.js application without leaving their chat window. This solves a common pain point for developers: the need to switch context between an IDE, terminal, and debugging console whenever a runtime error occurs.

At its core, the server listens for MCP requests that describe typical debugging actions: setting breakpoints, inspecting stack frames, evaluating expressions, or stepping through code. When the assistant sends a request, the server forwards it to the Node.js inspector and returns the result in a structured JSON payload. This round‑trip is fast enough that developers can ask for the value of a variable, change a breakpoint location, or continue execution while still engaged in natural language dialogue. The ability to control debugging from the same interface that generates or refactors code accelerates iteration cycles and reduces context switching.

Key capabilities include:

• Live breakpoint management – set, list, or remove breakpoints on the fly.
• State inspection – retrieve variable values, stack traces, and call frames at any moment.
• Expression evaluation – run arbitrary JavaScript snippets within the current context.
• Step control – step over, into, or out of functions while maintaining conversational state.

These features make the debugger ideal for real‑world scenarios such as troubleshooting production logs, exploring complex async flows, or teaching debugging concepts in pair programming sessions. For example, a developer can launch an Express server with , then ask the AI to “show me why this request is returning a 500 error” and receive both the stack trace and suggestions for fixing the issue—all within the chat.

Integration is seamless: adding the MCP server to Cursor or Claude Code requires only a single configuration line. Once connected, the assistant can invoke debugging commands directly from its command palette or conversational prompts. The server’s design follows MCP best practices, exposing a clean API that is agnostic to the underlying AI platform. This means future assistants can adopt the same debugger without any custom plumbing, ensuring a consistent debugging experience across tools.