MCP Inspector

docs/2024-11-05/tools/inspector New page · 140 lines, new page

# MCP Inspector ## Getting started ### Installation and basic usage #### Inspecting servers from npm or PyPI #### Inspecting locally developed servers ## Feature overview ### Server connection pane ### Resources tab ### Prompts tab ### Tools tab ### Notifications pane ## Best practices ### Development workflow ## Next steps

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# MCP Inspector

> In-depth guide to using the MCP Inspector for testing and debugging Model Context Protocol servers

The [MCP Inspector](https://github.com/modelcontextprotocol/inspector) is an interactive developer tool for testing and debugging MCP servers. While the [Debugging Guide](/docs/2024-11-05/tools/debugging) covers the Inspector as part of the overall debugging toolkit, this document provides a detailed exploration of the Inspector's features and capabilities.

## Getting started

### Installation and basic usage

The Inspector runs directly through `npx` without requiring installation:

```bash theme={null}
npx @modelcontextprotocol/inspector <command>
```

```bash theme={null}
npx @modelcontextprotocol/inspector <command> <arg1> <arg2>
```

#### Inspecting servers from npm or PyPI

A common way to start server packages from [npm](https://npmjs.com) or [PyPI](https://pypi.org).

<Tabs>
  <Tab title="npm package">
    ```bash theme={null}
    npx -y @modelcontextprotocol/inspector npx <package-name> <args>
    # For example
    npx -y @modelcontextprotocol/inspector npx @modelcontextprotocol/server-filesystem /Users/username/Desktop
    ```
  </Tab>

  <Tab title="PyPI package">
    ```bash theme={null}
    npx @modelcontextprotocol/inspector uvx <package-name> <args>
    # For example
    npx @modelcontextprotocol/inspector uvx mcp-server-git --repository ~/code/mcp/servers.git
    ```
  </Tab>
</Tabs>

#### Inspecting locally developed servers

To inspect servers locally developed or downloaded as a repository, the most common
way is:

<Tabs>
  <Tab title="TypeScript">
    ```bash theme={null}
    npx @modelcontextprotocol/inspector node path/to/server/index.js args...
    ```
  </Tab>

  <Tab title="Python">
    ```bash theme={null}
    npx @modelcontextprotocol/inspector \
      uv \
      --directory path/to/server \
      run \
      package-name \
      args...
    ```
  </Tab>
</Tabs>

Please carefully read any attached README for the most accurate instructions.

## Feature overview

<Frame caption="The MCP Inspector interface">
  <img src="https://mintcdn.com/mcp/4ZXF1PrDkEaJvXpn/images/mcp-inspector.png?fit=max&auto=format&n=4ZXF1PrDkEaJvXpn&q=85&s=83b12e2a457c96ef4ad17c7357236290" width="2888" height="1761" data-path="images/mcp-inspector.png" />
</Frame>

The Inspector provides several features for interacting with your MCP server:

### Server connection pane

* Allows selecting the [transport](/specification/2024-11-05/basic/transports) for connecting to the server
* For local servers, supports customizing the command-line arguments and environment

### Resources tab

* Lists all available resources
* Shows resource metadata (MIME types, descriptions)
* Allows resource content inspection
* Supports subscription testing

### Prompts tab

* Displays available prompt templates
* Shows prompt arguments and descriptions
* Enables prompt testing with custom arguments
* Previews generated messages

### Tools tab

* Lists available tools
* Shows tool schemas and descriptions
* Enables tool testing with custom inputs
* Displays tool execution results

### Notifications pane

* Presents all logs recorded from the server
* Shows notifications received from the server

## Best practices

### Development workflow

1. Start Development
   * Launch Inspector with your server
   * Verify basic connectivity
   * Check capability negotiation

2. Iterative testing
   * Make server changes
   * Rebuild the server
   * Reconnect the Inspector
   * Test affected features
   * Monitor messages

3. Test edge cases
   * Invalid inputs
   * Missing prompt arguments
   * Concurrent operations
   * Verify error handling and error responses

## Next steps

<CardGroup cols={2}>
  <Card title="Inspector Repository" icon="github" href="https://github.com/modelcontextprotocol/inspector">
    Check out the MCP Inspector source code
  </Card>

  <Card title="Debugging Guide" icon="bug" href="/docs/2024-11-05/tools/debugging">
    Learn about broader debugging strategies
  </Card>
</CardGroup>