> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-5e9cc07a-preview-3rdpar-1767989943-c9a4f5f.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Third-party MCP servers

> Connect Agent Builder to popular third-party MCP servers

You can connect Agent Builder to third-party MCP servers to extend your agents with additional tools and integrations. This page covers how to add custom MCP servers and provides configuration details for popular third-party servers.

## Add a third-party MCP server

To connect a third-party MCP server to Agent Builder:

<Steps>
  <Step title="Navigate to MCP server settings">
    In the [LangSmith UI](https://smith.langchain.com), select **Settings** in the lower left sidebar, then choose the **MCP Servers** tab.
  </Step>

  <Step title="Add the server">
    Click **Add server** and enter:

    * **Name**: A descriptive name for the server
    * **URL**: The MCP server endpoint URL
  </Step>

  <Step title="Configure authentication">
    Select an authentication type based on the server's requirements:

    * **Headers**: Add key-value pairs sent with every request. Use `{{SECRET_NAME}}` placeholders to reference [workspace secrets](/langsmith/agent-builder-setup#add-workspace-secrets).
    * **OAuth 2.1 (Auto)**: Select this for servers that support OAuth. You'll be prompted to log in with your account for that service.

    <Tip>
      For specific authentication details, see the configuration details for each [supported server](#supported-servers).
    </Tip>
  </Step>

  <Step title="Add headers (optional)">
    If your MCP server requires additional headers, click **Add headers** and enter the key and value.
  </Step>

  <Step title="Save and verify">
    Click **Save server**. Agent Builder will discover available tools from the server.
  </Step>
</Steps>

## Supported servers

### Arcade

[Arcade](https://arcade.dev) provides a gateway for connecting to various tools and services.

**Configuration details**

| Setting       | Value                                                                                                                                  |
| ------------- | -------------------------------------------------------------------------------------------------------------------------------------- |
| **URL**       | Dynamic. Create an MCP gateway in your [Arcade dashboard](https://arcade.dev), select the tools you want, then copy the generated URL. |
| **Auth type** | Headers or OAuth 2.1 (Auto). See below for specific details.                                                                           |

**Option 1: Headers authentication**

Add the following headers:

| Header           | Value                       |
| ---------------- | --------------------------- |
| `Authorization`  | `Bearer {{ARCADE_API_KEY}}` |
| `Arcade-User-Id` | Your email address          |

Store your Arcade API key as a [workspace secret](/langsmith/agent-builder-setup#add-workspace-secrets) named `ARCADE_API_KEY`.

**Option 2: OAuth authentication**

1. Select **OAuth 2.1 (Auto)** as the auth type when adding the server.
2. Log in with your Arcade account when prompted.

To learn more about Arcade MCP integration, see the [Arcade documentation](https://docs.arcade.dev/en/resources/integrations).

### Parallel

[Parallel](https://parallel.ai) provides search and task automation tools.

**Configuration details**

| Setting       | Value                                |
| ------------- | ------------------------------------ |
| **URL**       | `https://search-mcp.parallel.ai/mcp` |
| **Auth type** | Headers                              |

Add the following header:

| Header          | Value                         |
| --------------- | ----------------------------- |
| `Authorization` | `Bearer {{PARALLEL_API_KEY}}` |

Store your Parallel API key as a [workspace secret](/langsmith/agent-builder-setup#add-workspace-secrets) named `PARALLEL_API_KEY`.

For more information, see the [Parallel documentation for search MCP](https://docs.parallel.ai/integrations/mcp/search-mcp) and [task MCP](https://docs.parallel.ai/integrations/mcp/task-mcp).

### Notion

[Notion](https://notion.com) provides tools for interacting with your Notion workspace.

**Configuration details**

| Setting       | Value                        |
| ------------- | ---------------------------- |
| **URL**       | `https://mcp.notion.com/mcp` |
| **Auth type** | OAuth 2.1 (Auto)             |

1. Select **OAuth 2.1 (Auto)** as the auth type when adding the server.
2. Log in with your Notion account when prompted.

For more information, see the [Notion MCP documentation](https://developers.notion.com/docs/mcp).

***

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</Callout>

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