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The MCP Inspector is a lightweight web application that connects to an MCP (Model Context Protocol) server and provides a visual interface to explore prompts, tools, resources, history, and notifications — so you can test and debug an MCP server without building a client first. Useful when you need to:
  • Browse available prompts and inspect prompt definitions.
  • Explore tools and resources registered on the MCP server.
  • Review server history, notifications, and execution traces.
Relevant links:

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Install & run

The inspector is published as an npm package and can be launched directly via npx. Depending on the package namespace, use one of these commands:
When started, the inspector launches a local web server and prints the URL to open in your browser. Example output:

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Connect the Inspector to an MCP server

  1. Open the URL reported by the inspector in your browser (for example http://localhost:8080/mcp/).
  2. In the Inspector UI, use the Connect control in the left column to enter the MCP server base URL (for example http://localhost:8080/mcp/) and click Connect.
  3. Once connected, the UI displays Prompts, Tools, Resources, History, and Notifications. You can click individual entries to view details and run or inspect calls.
A dark-themed dashboard titled "MCP Inspector v0.16.1" showing connection settings on the left and a central Prompts panel with entries like "find_best_flight" and "handle_disruption," plus history and server notifications. The left column shows a streamable HTTP URL (http://localhost:8080/mcp/) and a green "Connected" indicator.

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Quick reference

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Troubleshooting & tips

Ensure Node.js and npx are installed locally before running the inspector. If the inspector runs on a remote host, use that host’s reachable URL and open any required ports/firewall rules so your browser can access the web UI.
  • If the Inspector prints an address like http://localhost:8080/mcp/ but you are connecting from a different machine, replace localhost with the host IP or hostname reachable from your browser (or run the inspector on the workstation directly).
  • If the browser shows CORS or network errors, verify the MCP server URL is correct and that any proxies, firewalls, or VPNs allow access.
  • For automated testing or CI, you can run the inspector on a headless host and access it via a tunneled port or reverse proxy.

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Further reading

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