AI agents can do more than chat. With the right protocol, an agent can render an interactive chart inline in your conversation, update a shared canvas in real time, or pause mid-execution to ask for your approval before proceeding. These interactions (generative UI, shared state, and human-in-the-loop) need a standard way for agent backends to communicate dynamic events to frontends.

AG-UI (Agent-User Interaction Protocol) is an open protocol that defines this standard. It works with multiple agent frameworks (Strands Agents, LangGraph, CrewAI) and frontend libraries (React, Angular, Vue). With AG-UI, your agent code and your frontend code stay decoupled. You pick the best framework for your backend and the best library for your frontend, and AG-UI connects them.

Amazon Bedrock AgentCore is part of the Amazon Bedrock family of services for generative AI. AgentCore is an agentic platform for building, deploying, and operating AI agents securely at scale, using any framework and any model.

This post walks through how AG-UI integrates into the Fullstack AgentCore Solution Template (FAST) to build interactive agent frontends on Amazon Bedrock AgentCore. We then show how CopilotKit extends this with generative UI, shared state, and human-in-the-loop interactions, all deployed on Amazon Bedrock AgentCore.

Amazon Bedrock AgentCore Runtime provides a secure, serverless, and purpose-built hosting environment for deploying and running AI agents or tools. AgentCore Runtime supports several agent protocols. Model Context Protocol (MCP) connects agents to tools, Agent2Agent (A2A) connects agents to other agents, and AG-UI connects agents to users. When you deploy an agent container with the AG-UI protocol flag, AgentCore acts as a transparent proxy. It handles authentication (Signature Version 4 [SigV4] or OAuth 2.0 through Amazon Cognito), session isolation, scaling, and observability. Your container exposes POST /invocations for AG-UI requests and GET /ping for health checks on port 8080. AgentCore passes requests through unchanged. For more details, see Deploy AGUI servers in AgentCore Runtime.

FAST is a ready-to-deploy starter project. It connects AgentCore Runtime, Gateway, Identity, Memory, and Code Interpreter with a React frontend and Amazon Cognito authentication, all defined with AWS Cloud Development Kit (AWS CDK). It ships with agent patterns for Strands Agents, LangGraph, and the Claude Agent SDK. FAST v0.4.1 added two AG-UI patterns (agui-strands-agent and agui-langgraph-agent) that share a single frontend parser. For a full walkthrough of FAST’s architecture and deployment, see Accelerate agentic application development with a full-stack starter template for Amazon Bedrock AgentCore.