# MCP Inspector — Debug and Test MCP Servers

> Official debugging tool for MCP servers. MCP Inspector provides a web UI to connect, test tools, inspect messages, and validate responses from any MCP server interactively.

## Install

Merge the JSON below into your `.mcp.json`:

## Quick Use

```bash
npx @modelcontextprotocol/inspector
# Opens web UI at http://localhost:5173
```

```bash
# Connect to a specific MCP server
npx @modelcontextprotocol/inspector npx -y @modelcontextprotocol/server-filesystem /tmp
```

## What is MCP Inspector?

MCP Inspector is the official debugging and testing tool for MCP (Model Context Protocol) servers. It provides a web-based UI where you can connect to any MCP server, browse available tools and resources, send test requests, and inspect the full message exchange. Essential for MCP server development and troubleshooting.

**Answer-Ready**: MCP Inspector is the official MCP server debugging tool by Anthropic. Web UI to connect, browse tools, test requests, and inspect messages for any MCP server. Essential for MCP development and troubleshooting. Part of the official MCP SDK.

**Best for**: MCP server developers and users debugging MCP connections. **Works with**: Any MCP server (stdio or SSE transport). **Setup time**: Under 1 minute.

## Core Features

### 1. Server Connection

```bash
# Connect via stdio
npx @modelcontextprotocol/inspector node my-server.js

# Connect via SSE
npx @modelcontextprotocol/inspector --transport sse http://localhost:3000/sse
```

### 2. Tool Browser

The web UI shows all tools exposed by the connected MCP server:
- Tool name and description
- Input schema (JSON Schema)
- Required and optional parameters

### 3. Interactive Testing

```
1. Select a tool from the list
2. Fill in parameters via form UI
3. Click "Execute"
4. See full request/response JSON
```

### 4. Resource Browser

Browse resources and resource templates exposed by the server. Read resource contents directly from the UI.

### 5. Message Inspector

Full request/response log showing:
- JSON-RPC messages
- Timing information
- Error details and stack traces

## Use Cases

| Use Case | How |
|----------|-----|
| Developing MCP servers | Test tools as you build them |
| Debugging connections | See exact messages exchanged |
| Validating schemas | Verify tool input/output schemas |
| Learning MCP | Explore how MCP servers work |
| QA before deployment | Test all tools before production |

## FAQ

**Q: Do I need to install anything?**
A: No, `npx @modelcontextprotocol/inspector` runs without installation.

**Q: Does it work with any MCP server?**
A: Yes, supports both stdio and SSE transports. Works with all standard MCP servers.

**Q: Can I use it to test Claude Desktop MCP configs?**
A: Yes, point it at the same command from your Claude Desktop config to verify the server works correctly.

## Source & Thanks

> Part of the official [Model Context Protocol](https://github.com/modelcontextprotocol) SDK by Anthropic.
>
> [modelcontextprotocol/inspector](https://github.com/modelcontextprotocol/inspector) — Official MCP debugging tool

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## Quick Use

```bash
npx @modelcontextprotocol/inspector
```

Launch the MCP server debugger with a single command.

## What is MCP Inspector?

Anthropic's official MCP server debugging tool. A web UI to connect, browse tools, send test requests, and inspect messages.

**TL;DR**: Official MCP debugging tool. Web UI connects to any MCP server — browse tools, test requests, inspect messages. Essential for development and troubleshooting.

**Best for**: MCP server developers and users.

## Core Features

### 1. Server Connection
Supports both stdio and SSE transports.

### 2. Tool Browser
View all tool names, descriptions, and parameter schemas.

### 3. Interactive Testing
Fill parameters, execute tools, see full request/response.

## FAQ

**Q: Need to install anything?**
A: No — runs directly with npx.

**Q: Works with any MCP server?**
A: Yes — supports both stdio and SSE.

## Source & Thanks

> [modelcontextprotocol/inspector](https://github.com/modelcontextprotocol/inspector) — Official Anthropic tool

---
Source: https://tokrepo.com/en/workflows/mcp-inspector-debug-test-mcp-servers-302d7709
Author: MCP Hub