AG-UI

Rather than every agent framework inventing its own chat UI wiring, AG-UI defines a shared vocabulary: roughly 16 standard event types that stream from any agent backend to any frontend over SSE, WebSockets, or webhooks. The protocol, created by the CopilotKit team, covers token-by-token message streaming, tool calls rendered as typed UI components, bidirectional state synchronization via event-sourced diffs, and human-in-the-loop interrupts that let users approve, edit, or retry an agent's steps before they proceed. SDKs ship for TypeScript and Python plus community ports in Kotlin, Go, Dart, Java, Rust, Ruby, C++, and .NET, and integrations exist for Microsoft Agent Framework, Google ADK, AWS Strands Agents, LangGraph, CrewAI, Pydantic AI, Agno, LlamaIndex, and Mastra. An interactive Dojo site demonstrates each capability with code walkthroughs. Everything is MIT licensed with no hosted dependency, so the protocol works equally with API models or local ones, and the repo has passed 15,000 GitHub stars.