inspector MCP工具

Requirements

• Node.js: ^22.7.5

Docker Container

You can also start it in a Docker container with the following command:

docker run --rm \
  -p 127.0.0.1:6274:6274 \
  -p 127.0.0.1:6277:6277 \
  -e HOST=0.0.0.0 \
  -e MCP_AUTO_OPEN_ENABLED=false \
  ghcr.io/modelcontextprotocol/inspector:latest

To go back to the deployed SDK version:

Quick Start (UI mode)

To get up and running right away with the UI, just execute the following:

npx @modelcontextprotocol/inspector

The server will start up and the UI will be accessible at http://localhost:6274.

Basic usage

npx @modelcontextprotocol/inspector --cli node build/index.js

Tool Input Validation Guidelines

When implementing or modifying tool input parameter handling in the Inspector:

• Omit optional fields with empty values - When processing form inputs, omit empty strings or null values for optional parameters, UNLESS the field has an explicit default value in the schema that matches the current value
• Preserve explicit default values - If a field schema contains an explicit default (e.g., default: null), and the current value matches that default, include it in the request. This is a meaningful value the tool expects
• Always include required fields - Preserve required field values even when empty, allowing the MCP server to validate and return appropriate error messages
• Defer deep validation to the server - Implement basic field presence checking in the Inspector client, but rely on the MCP server for parameter validation according to its schema

These guidelines maintain clean parameter passing and proper separation of concerns between the Inspector client and MCP servers.

Pass environment variables only

npx @modelcontextprotocol/inspector -e key=value -e key2=$VALUE2 node build/index.js

Pass both environment variables and arguments

npx @modelcontextprotocol/inspector -e key=value -e key2=$VALUE2 node build/index.js arg1 arg2

Configuration

The MCP Inspector supports the following configuration settings. To change them, click on the Configuration button in the MCP Inspector UI:

Note on Timeouts: The timeout settings above control when the Inspector (as an MCP client) will cancel requests. These are independent of any server-side timeouts. For example, if a server tool has a 10-minute timeout but the Inspector's timeout is set to 30 seconds, the Inspector will cancel the request after 30 seconds. Conversely, if the Inspector's timeout is 10 minutes but the server times out after 30 seconds, you'll receive the server's timeout error. For tools that require user interaction (like elicitation) or long-running operations, ensure the Inspector's timeout is set appropriately.

These settings can be adjusted in real-time through the UI and will persist across sessions.

The inspector also supports configuration files to store settings for different MCP servers. This is useful when working with multiple servers or complex configurations:

npx @modelcontextprotocol/inspector --config path/to/config.json --server everything

Example server configuration file:

{
  "mcpServers": {
    "everything": {
      "command": "npx",
      "args": ["@modelcontextprotocol/server-everything"],
      "env": {
        "hello": "Hello MCP!"
      }
    },
    "my-server": {
      "command": "node",
      "args": ["build/index.js", "arg1", "arg2"],
      "env": {
        "key": "value",
        "key2": "value2"
      }
    }
  }
}

Transport Types in Config Files

The inspector automatically detects the transport type from your config file. You can specify different transport types:

STDIO (default):

{
  "mcpServers": {
    "my-stdio-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["@modelcontextprotocol/server-everything"]
    }
  }
}

SSE (Server-Sent Events):

{
  "mcpServers": {
    "my-sse-server": {
      "type": "sse",
      "url": "http://localhost:3000/sse"
    }
  }
}

Streamable HTTP:

{
  "mcpServers": {
    "my-http-server": {
      "type": "streamable-http",
      "url": "http://localhost:3000/mcp"
    }
  }
}

Default Server Selection

You can launch the inspector without specifying a server name if your config has:

1. A single server - automatically selected:

```bash

With config file

npx @modelcontextprotocol/inspector --cli --config path/to/config.json --server myserver

To co-develop with the typescript-sdk package (assuming it's cloned in ../typescript-sdk; set MCP_SDK otherwise):

npm run dev:sdk "cd sdk && npm run examples:simple-server:w"

npm run unlink:sdk && npm i

> **Note for Windows users:**
> On Windows, use the following command instead:
>
> 

Production mode:

CLI Mode

CLI mode enables programmatic interaction with MCP servers from the command line, ideal for scripting, automation, and integration with coding assistants. This creates an efficient feedback loop for MCP server development.

npx @modelcontextprotocol/inspector --cli node build/index.js

The CLI mode supports most operations across tools, resources, and prompts. A few examples:

```bash

UI Mode vs CLI Mode: When to Use Each