The official debugging UI for MCP servers. Not a server you add to a client.
- Not yet tested by us
- ★ 11.2K GitHub stars
- 295.1K downloads a week
- Last commit 25 Oct 2026
At a glance
Inspector is maintained by the Model Context Protocol project. It starts a small web app that connects to one server, lists its tools, prompts and resources, and lets you call each tool with your own arguments while showing the JSON going back and forth.
Use it before blaming your client: if a server misbehaves in Inspector, the problem is the server or its config.
- Made by
- The Model Context Protocol project (modelcontextprotocol)
- Latest version
- 2.12.0 (21 Oct 2026)
- npm package
- @modelcontextprotocol/inspector
- GitHub stars
- 11.2K
- Downloads
- 295.1K a week
- Last commit
- 25 Oct 2026
- Runs on
- Your computer
Our check: Written from the project's own documentation. We have not run this config ourselves yet.
What's in the pod: its tools
MCP Inspector groups its tools like this, and which ones load depends on how you set it up.
Web- A browser app for connecting to a server, listing its tools, resources and prompts, and calling them by hand.
--cli- A scriptable command line client: connect, list, call and check results, ideal for CI and quick agent feedback.
--tui- An interactive view in the terminal, for when you are on SSH or prefer the keyboard.
mcpdo- Experimental: connect once, then run many commands against that named connection.
Grouped and described by us. The README on GitHub lists the inputs each tool takes.
Set it up
- Run it with the server command after it: npx @modelcontextprotocol/inspector npx -y @playwright/mcp@latest
- Open the local address it prints in your browser.
- Click Connect, then List Tools, and try a tool with your own input.
New to this? See the setup guides for Claude Code, Cursor, Claude Desktop and ChatGPT.
Settings
Names are exactly as the project spells them. Required ones are marked.
| Setting | What it does |
|---|---|
npx @modelcontextprotocol/inspectorConfig · required | Starts the web interface. Add your server's command after it to connect straight away.npx @modelcontextprotocol/inspector node build/index.js |
--cliCommand line flag | Uses the command line client instead of the browser. |
--tuiCommand line flag | Uses the terminal interface. |
--configCommand line flag | Loads server definitions from a config file, in the same shape most MCP clients use. |
--format jsonCommand line flag | Prints CLI results as JSON so you can test a server with jq in a script. |
What it can touch
It can read
- Whatever the server you are testing exposes: its tools, resources and prompts
It can change
- Only what the tools you call by hand change
- Saves OAuth tokens and env values in your system keychain where one exists
Safer setup: Test servers against throwaway data, since calling a tool here does exactly what it would do for an agent.
Before you start
- Node.js 22 or newer
If it does not work
- It will not install or start
- Version 2 needs Node 22.19 or newer. Check node --version.
- Secrets are not saved between runs on Linux or in a container
- There is no keychain there. Install libsecret or follow the project's guidance for machines without one.
- Old v1 flags stop working
- Version 2 changed several CLI flags and split --config from --catalog. Read the v1 to v2 migration guide.
Peas in a pod: similar servers
How MCP Inspector lines up against other developer tools servers on the shelf.
| Server | Tools | Runs on | Licence | Stars |
|---|---|---|---|---|
| MCP Inspector | – | Your computer | – | 11.2K |
| XcodeBuildMCP | 24 | Your computer | MIT | 6.5K |
| Peekaboo | 3 | Your computer | MIT | 5.4K |
| Kubernetes MCP Server | 14 | Your computer | Apache-2.0 | 2.2K |
| IDA Pro MCP | 48 | Your computer | – | 13.2K |
Questions
Is this an MCP server?
No. It is the official test client for MCP servers, used by people who build or debug them. It is listed here because almost every server author needs it.
Can I use it in CI?
Yes. The CLI mode with JSON output and clear exit codes is meant for smoke-testing a server in a pipeline.
Does it support remote servers with OAuth?
Yes. It can connect over HTTP and walk through the OAuth sign-in, storing tokens in your keychain.
Is it free?
Yes. New code is Apache 2.0 licensed as the MCP project moves from MIT.
Something wrong on this page? Tell us.
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