A serverless Agent-to-Agent (A2A) gateway on AWS addresses the operational burden of managing agent communication across teams, vendors, and infrastructure. Without a centralized layer, each new agent integration adds point-to-point connections, separate credentials, and custom routing logic, with a deployment of 20 agents requiring up to 190 point-to-point connections. The gateway pattern places a single entry point in front of agents, regardless of whether they run on Amazon Elastic Container Service (Amazon ECS), AWS Lambda, Amazon Bedrock AgentCore Runtime, a non-AWS cloud, or a hybrid environment. It handles routing and enforces fine-grained permissions centrally, building on the A2A protocol. The solution has three layers: a Management layer with a centralized agent registry and discovery; a Control layer using JSON Web Token (JWT) scopes and a Lambda authorizer; and an Execution layer with single-domain routing, OAuth backend authentication, and Server-Sent Events (SSE) streaming support. Amazon API Gateway (REST API) serves as the single-entry point, with a Lambda authorizer inspecting JWT scopes and generating IAM policies for specific agent paths. Lambda functions implement authorizer, registry, search, proxy, and admin logic, while Amazon DynamoDB stores data.