> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# MCP Inspector

> Debug and test your GetMCP server interactively before connecting any AI client.

MCP Inspector is an official developer tool from Anthropic that gives you a live, interactive view into any MCP server. Connect it to your GetMCP server to browse tools, call them manually, inspect raw JSON-RPC messages, and verify everything works — before you involve Claude, Cursor, or any other client.

Think of it as Postman, but purpose-built for the MCP protocol.

<img src="https://mintcdn.com/infiwebs/X3D8lQwdysxDpY3z/images/mcp-inspector-overview.png?fit=max&auto=format&n=X3D8lQwdysxDpY3z&q=85&s=6cf7029300f1a4adf808fb870e7058ef" alt="MCP Inspector connected to a GetMCP server — placeholder" width="1920" height="971" data-path="images/mcp-inspector-overview.png" />

***

## Why Use It

* **Verify tools are configured correctly** — see exactly what `tools/list` returns to AI clients
* **Test tool calls manually** — fill in arguments and see the raw response your API returns
* **Debug authentication** — confirm your server URL, inbound auth, and Custom Headers all work
* **Inspect protocol messages** — see the exact JSON-RPC requests and responses
* **Catch problems before users do** — faster than connecting Claude Desktop and asking it questions

***

## Prerequisites

* Node.js 18+ installed ([nodejs.org](https://nodejs.org))
* A GetMCP server that is set to **Active** status
* Your server's MCP endpoint URL (from the server detail page)

***

## Launch Inspector

MCP Inspector runs entirely in your browser via `npx` — no installation required:

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

Your browser opens automatically at `http://localhost:5173`.

***

## Connect to Your GetMCP Server

<Steps>
  <Step title="Select transport">
    In the **Transport** dropdown, select **Streamable HTTP**.
  </Step>

  <Step title="Enter your server URL">
    Paste your GetMCP server URL into the **URL** field:

    ```
    https://yoursite.com/mcp/{server-slug}
    ```

    Your URL is on the server detail page in GetMCP admin.
  </Step>

  <Step title="Add authentication headers (if required)">
    If your server has inbound authentication enabled, click **Add Header** and enter:

    | Header          | Value               |
    | --------------- | ------------------- |
    | `Authorization` | `Bearer YOUR_TOKEN` |

    Leave this blank if your server uses `none` auth type.
  </Step>

  <Step title="Click Connect">
    Click the **Connect** button. Inspector runs the `initialize` handshake and negotiates the protocol version. A green status indicator confirms the connection.

    <img src="https://mintcdn.com/infiwebs/X3D8lQwdysxDpY3z/images/mcp-inspector-connection.png?fit=max&auto=format&n=X3D8lQwdysxDpY3z&q=85&s=af828a40a733a137b6ba4706952d8db6" alt="MCP Inspector connection status — placeholder" width="376" height="685" data-path="images/mcp-inspector-connection.png" />
  </Step>
</Steps>

***

## Browse Your Tools

Click the **Tools** tab to see every tool `tools/list` returns — exactly what Claude or Cursor sees when they connect.

<img src="https://mintcdn.com/infiwebs/X3D8lQwdysxDpY3z/images/mcp-inspector-tools-list.png?fit=max&auto=format&n=X3D8lQwdysxDpY3z&q=85&s=ea46b2cf65d73403dfed3572158f65d1" alt="Tools list in MCP Inspector — placeholder" width="718" height="587" data-path="images/mcp-inspector-tools-list.png" />

For each tool you can see:

* **Name** — the `snake_case` identifier
* **Description** — what you wrote (this is what the AI reads)
* **Input Schema** — the JSON Schema defining accepted parameters

***

## Call a Tool

<Steps>
  <Step title="Click a tool name">
    Select a tool from the list. The input form renders automatically from the tool's JSON Schema.
  </Step>

  <Step title="Fill in the arguments">
    Enter values for each parameter. Required fields are marked.

    <img src="https://mintcdn.com/infiwebs/X3D8lQwdysxDpY3z/images/mcp-inspector-tool-form.png?fit=max&auto=format&n=X3D8lQwdysxDpY3z&q=85&s=c4063f35c6abee87f6ad7c8cb6dbeccf" alt="Tool call form — placeholder" width="717" height="593" data-path="images/mcp-inspector-tool-form.png" />
  </Step>

  <Step title="Click Run">
    Inspector sends a `tools/call` JSON-RPC request and displays the full response.

    <img src="https://mintcdn.com/infiwebs/X3D8lQwdysxDpY3z/images/mcp-inspector-tool-response.png?fit=max&auto=format&n=X3D8lQwdysxDpY3z&q=85&s=6352f0980ba6059ebab3ed269c9d3396" alt="Tool call response — placeholder" width="693" height="964" data-path="images/mcp-inspector-tool-response.png" />
  </Step>
</Steps>

The response panel shows the raw JSON-RPC response — including the API data returned in `result.content[0].text`. You can see exactly what an AI client receives.

***

## Browse Resources and Prompts

**Resources tab** — Lists all resources via `resources/list`. Click any resource to call `resources/read` and see its content.

**Prompts tab** — Lists all prompt templates via `prompts/list`. Click a prompt, fill in argument values, and call `prompts/get` to see the fully rendered prompt text.

***

## Inspect Raw Messages

Click the **History** or **Messages** panel to see every JSON-RPC request and response as raw JSON. This is the exact protocol traffic your GetMCP server exchanges with AI clients.

Useful for:

* Confirming the `initialize` capability negotiation is correct
* Checking that tool input schemas are valid JSON Schema
* Verifying error response formats when something goes wrong

<img src="https://mintcdn.com/infiwebs/X3D8lQwdysxDpY3z/images/mcp-inspector-history.png?fit=max&auto=format&n=X3D8lQwdysxDpY3z&q=85&s=c350d6173fbc91a28514df08082a10de" alt="MCP Inspector History Panel" width="761" height="440" data-path="images/mcp-inspector-history.png" />

***

## Troubleshooting

<AccordionGroup>
  <Accordion title="Connection fails immediately">
    * Confirm your WordPress site is reachable over HTTPS
    * Check the server status is **Active** in GetMCP admin
    * Verify the URL — the slug must be exact
    * Flush WordPress permalinks: **Settings → Permalinks → Save Changes**
  </Accordion>

  <Accordion title="401 or 403 on connect">
    Your server has inbound authentication enabled. Add the `Authorization` header in Inspector's header configuration before clicking Connect. The value must match exactly what you set in the server's Authentication tab.
  </Accordion>

  <Accordion title="Tools list is empty">
    All tools are set to **Paused** status. Go to GetMCP admin → Tools tab and set at least one tool to **Active**.
  </Accordion>

  <Accordion title="Tool call returns an error response">
    The error message is in `result.content[0].text`. Common causes:

    * API key missing or expired — check Custom Headers in the tool's Advanced Settings
    * API endpoint URL typo — verify the endpoint in the tool editor
    * Missing required parameter — confirm your test arguments match the input schema
  </Accordion>

  <Accordion title="Inspector won't start (npx error)">
    Ensure Node.js 18 or higher is installed: `node --version`. If outdated, download from [nodejs.org](https://nodejs.org).
  </Accordion>
</AccordionGroup>

***

<Note>
  MCP Inspector is maintained by Anthropic as part of the official MCP project. Source code and docs: [github.com/modelcontextprotocol/inspector](https://github.com/modelcontextprotocol/inspector)
</Note>