# MCP Inspector — Debug MCP Servers Visually

> Official MCP Inspector for testing and debugging MCP servers. 9.3K+ stars. Web UI, tool/resource/prompt inspection, request testing.

## Install

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

# MCP Inspector — Debug MCP Servers Visually

> Official visual testing and debugging tool for MCP servers. 9.3K+ GitHub stars. Connect, inspect, test — all in a web UI.

## Quick Use

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

Opens a web UI at `http://localhost:6274`. Connect to any MCP server and:
1. See all available tools, resources, and prompts
2. Send test requests with custom parameters
3. View full request/response JSON
4. Debug connection issues in real-time

**Test a specific server:**
```bash
npx @modelcontextprotocol/inspector npx -y @modelcontextprotocol/server-filesystem /tmp
```

## Intro

MCP Inspector is the official debugging tool from the Model Context Protocol team. If you're building or using MCP servers, this is your DevTools equivalent.

Key features:
- **Zero install**: Run with `npx`, opens in your browser instantly
- **Server discovery**: Auto-detects available tools, resources, and prompts from any MCP server
- **Interactive testing**: Send requests with custom JSON parameters, see full responses
- **Connection diagnostics**: Shows transport details, error messages, and connection state
- **History**: Keeps a log of all requests/responses for debugging sessions
- **Multiple transports**: Supports stdio, SSE, and HTTP transports

Essential for:
- Developing custom MCP servers (test before deploying)
- Debugging why an MCP tool isn't working in Claude Code or Cursor
- Understanding what tools a third-party MCP server provides
- Validating MCP server responses match expected schemas

## FAQ

**Q: Do I need to install anything?**
A: No. `npx @modelcontextprotocol/inspector` runs it directly. No global install needed.

**Q: Can I test my own MCP server?**
A: Yes. Point it at any MCP server command. It will launch the server, connect via the appropriate transport, and let you interact with it.

**Q: Does it work with servers that need environment variables?**
A: Yes. You can pass environment variables through the CLI or configure them in the web UI.

## Works With

- Any MCP server (stdio, SSE, HTTP transport)
- Claude Code, Cursor, Windsurf MCP server development
- Node.js 18+, runs in any modern browser

## Source & Thanks

- GitHub: https://github.com/modelcontextprotocol/inspector (9.3K+ stars)
- License: Open Source (Model Context Protocol team)
- Part of the official MCP ecosystem


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Source: https://tokrepo.com/en/workflows/14bc1166-2ccc-462e-8d4a-e2efc5eb82ca
Author: MCP Hub