Box MCP Server

Aembit supports the official Box MCP server, which lets AI agentsAI Agent: A software workload that authenticates to systems, requests credentials, and accesses resources, either on behalf of a person or on its own. Aembit secures AI agents with the same identity-first model it uses for any workload. User-driven agents such as Claude Desktop also carry a blended identity that ties access to both the user and the agent.Learn more read and manage Box files and folders through MCPModel Context Protocol: A standard protocol for AI agent and server interactions that defines how AI assistants communicate with external tools and data sources.Learn more(opens in new tab) tools.

This page describes how to configure Box as an MCP serverMCP Server: A server that implements the Model Context Protocol to provide tools, resources, or data to AI agents and MCP clients.Learn more(opens in new tab) behind the Aembit MCP Identity GatewayMCP Identity Gateway: A component that brokers MCP traffic between MCP clients and target MCP servers, validating authorization and presenting Aembit-managed credentials on each request.Learn more.

This guide builds the Gateway-to-Server PolicyGateway-to-Server Policy: The Access Policy that authorizes the MCP Identity Gateway to access an MCP server on behalf of authenticated users—the Gateway itself is the Client Workload. Also called right-side auth; each MCP server behind the Gateway needs its own.Learn more—the second of the two Access PoliciesAccess Policy: Access Policies define, enforce, and audit access between Client and Server Workloads by cryptographically verifying workload identity and contextual factors rather than relying on static secrets.Learn more the MCP Identity Gateway requires. You create the first, the Client-to-Gateway PolicyClient-to-Gateway Policy: The Access Policy that validates which MCP client can connect to the MCP Identity Gateway and authenticates users through your Identity Provider. Also called left-side auth; you create one per MCP client and Gateway combination.Learn more, during Gateway setup.

Looking for direct Box API access?

This page covers MCP tool access through Aembit’s MCP Identity Gateway. To broker credentials for the Box API as a traditional Server WorkloadServer Workload: Server Workloads represent target services, APIs, databases, or applications that receive and respond to access requests from Client Workloads.Learn more, see the Box Server Workload guide instead.

Prerequisites

Before you begin, ensure you have the following:

• A Box account with access to the Box Developer Console (a free developer account is sufficient)
• A configured Aembit MCP Identity Gateway

Box doesn’t support OAuth Dynamic Client Registration, so you also create a Box custom app in the Box Developer Console. This guide walks through that in Create the Box custom app, before you configure the Credential Provider.

Requirements and considerations

Before you configure Box, review these requirements and behaviors specific to Box’s MCP server.

• Use User-Based Auth. Aembit supports User-Based Auth for Box.
• No Dynamic Client Registration. Box needs the OAuth app you create in the Box Developer Console.
• User-Based Auth requires PKCE turned off. Unlike most servers, Box’s User-Based flow fails with PKCE enabled. Set PKCE Required to Off on the MCP User-Based Access Token Credential Provider.

Create the Box custom app

Box doesn’t support OAuth Dynamic Client Registration, so an administrator must create one custom app before users can authenticate. You do this setup once per Box account.

1. Go to the Box Developer Console and click New Custom App.
2. Select User Authentication (OAuth 2.0) as the authentication method, then name the app and create it.
3. Copy the Client ID and generate a Client Secret from the app’s Configuration tab.
4. Leave the Developer Console open. After you create the Credential Provider in Aembit, you’ll return here to add its callback URL under OAuth 2.0 Redirect URI.

A free Box developer account is enough to create this app—a paid enterprise account isn’t required.

Configure the Credential Provider

Create an MCP User-Based Access Token Credential ProviderCredential Provider: Credential Providers obtain the specific access credentials—such as API keys, OAuth tokens, or temporary cloud credentials—that Client Workloads need to authenticate to Server Workloads.Learn more in Aembit.

1. Log into your Aembit Tenant.

2. Go to Credential Providers in the left sidebar and click + New.

3. Configure the following fields:

   Field	Value
   Name	A user-friendly name
   Credential Type	MCP User-Based Access Token
   MCP Server URL	https://mcp.box.com
   Client ID	The Client ID you copied earlier
   Client Secret	The Client Secret you copied earlier
   PKCE Required	Off
   Lifetime	1 year

   For MCP Server URL, click Discover to populate the Authorization URL and Token URL.

   Leave PKCE Required set to Off. Box is the only supported server whose User-Based flow fails with PKCE enabled.

4. Click Save.

5. Copy the read-only Callback URL from the Credential Provider.

Finish configuring the Box app

This step uses the custom app you create in the prerequisites.

1. Return to your app in the Box Developer Console and open the Configuration tab.
2. Under OAuth 2.0 Redirect URI, add the read-only Callback URL you copied from the MCP User-Based Access Token Credential Provider. Its path ends in /userauth/<credential-provider-id>/callback.
3. Save the app configuration.

Authorize the Credential Provider

There’s no administrator authorization step for this credential type. Each user completes their own Box sign-in and provides consent the first time they access Box through the Gateway, and Aembit stores and refreshes each user’s tokens individually.

Create the Server Workload

1. Go to Server Workloads in the left sidebar and click + New.

2. Configure the following fields:

   Field	Value
   Name	A user-friendly name
   Host	mcp.box.com
   Application Protocol	MCP
   Port	443 with TLS
   URL Path
   Authentication method	HTTP Authentication
   Authentication scheme	Bearer

3. Click Save.

Create an Access Policy

This section creates the Gateway-to-Server Access Policy, which authorizes the MCP Identity Gateway to access Box on behalf of authenticated users.

Create an Access Policy linking the MCP Identity Gateway (as the Client WorkloadClient Workload: Client Workloads represent software applications, scripts, or automated processes that initiate access requests to Server Workloads, operating autonomously without direct user interaction.Learn more), the Credential Provider you created, and the Server Workload for Box.

The Gateway is the Client Workload

In this policy, the Client Workload is the MCP Identity Gateway itself—not the AI agent or individual users. The AI agent connects through the separate Client-to-Gateway policy, and the Credential Provider enforces per-user access.

For step-by-step instructions, including the Client Workload settings that identify the Gateway, see Create the gateway-to-server Access Policy.

Verify

After authorization completes, the Aembit AI Access Authorized page lists the Box MCP Server as Ready. The AI agent can then call Box MCP tools through the Gateway.