AG-UI (Agent–User Interaction Protocol) is an open, event-based protocol for the communication between AI agents and user-facing frontends. It standardizes how streaming text, tool calls and agent state are exchanged — complementary to the MCP standard for tools and data sources.

---

The protocol defines a small set of event types (message streaming, tool calls, state snapshots and deltas based on JSON Patch) that can be transported over Server-Sent Events, WebSockets or webhooks. This allows the same frontend to talk to different agent runtimes, including a dedicated adapter for LangGraph.

We use AG-UI in MUCGPT and RIS-KI as specified software standard for the communication between agent backend and user interface.

---