Amazon Bedrock AgentCore is a fully managed service that helps you deploy, manage, and scale AI agents in production. One of its key components, the AgentCore Gateway, provides a centralized entry point for routing and securing agent-to-tool communications. When an AI assistant makes a request to an MCP server through the Gateway, that request must be verified before it’s processed. This is known as inbound authentication. Only authorized users and agents can access the tools and services exposed by the MCP server. Organizations typically manage user identities through an identity provider (IdP), such as Okta, Microsoft Entra ID, or Amazon Cognito, which authenticates users and issues security tokens that verify who they are.

This post demonstrates how to implement Open Authorization (OAuth) Code flow as an inbound authorization mechanism for MCP servers hosted on Amazon Bedrock AgentCore Gateway. By the end of this guide, you will have a production-ready setup where each AI assistant request is authenticated with a valid user identity token issued from your organization’s identity provider.

In an inbound authorization code flow OAuth setup, the AgentCore Gateway acts as an MCP resource server that requires a valid identity token before allowing AI clients to access any tools.

The following diagram shows the end-to-end architecture for the authorization code flow with AgentCore Gateway, including the identity provider, AI client, and MCP server interactions.

The solution involves the following components working together to complete the authentication flow: