MCP Inspector

MCP Inspector is a developer tool for testing and debugging MCP (Model Context Protocol) servers.

Think of it like Postman, but for MCP servers.

Postman
   ↓
Test HTTP APIs
 
MCP Inspector
   ↓
Test MCP servers

What can you do with it?

Suppose you built an MCP server with tools:

My MCP Server
├── get_weather
├── search_files
├── create_task
└── send_email

MCP Inspector lets you connect to that server and inspect/test things like:

• 🔧 Tools — what tools the server exposes

• 📋 Tool inputs — what arguments a tool expects

• 📤 Tool results — what the tool returns

• 📚 Resources — resources exposed by the server

• 💬 Prompts — prompts exposed by the server

• 🔌 Connection/protocol behavior

• ❌ Errors and debugging information

Example

Imagine your MCP tool is:

calculate_sum

with:

{
  "a": 10,
  "b": 20
}

You can use Inspector to call it manually:

Tool: calculate_sum
 
a: 10
b: 20
 
        ↓
 
Result: 30

This is useful because you can verify that your MCP server works correctly before connecting it to Claude, Cursor, OpenCode, etc.

Mental model

             MCP Inspector
                  │
                  ↓
          ┌───────────────┐
          │   MCP Server  │
          ├───────────────┤
          │ Tools         │
          │ Resources     │
          │ Prompts       │
          └───────────────┘

So if you’re developing an MCP server, Inspector is basically a debugging/testing UI for the MCP protocol.

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MCP Agent My-Journey-In-Codeless