AG-UI, the Agent-User Interaction Protocol, is an open protocol that sets out how an AI agent running on a server talks to the app a person is using.
In plain words
As an agent works, it sends a stream of events of about 16 standard types, and the app shows them as they arrive, such as text word by word or a tool's results. The link runs both ways, so a person can join in mid-run, and a run can be cancelled and resumed. Events can go over WebSockets or other transports. MCP links agents to tools and A2A links agents to each other; AG-UI links them to people. It grew out of CopilotKit and uses the MIT licence.
A quick example
Imagine a travel app with a chat panel. A user asks for a weekend plan, and the agent on the server streams its answer word by word while showing each search it runs. Halfway through, the user cancels and asks for a cheaper option.
Where you'll meet it
- Showing an agent's live progress inside an app.
- Letting people work alongside an agent while it runs.
Related
Sources
- DocsAG-UI: The Agent-User Interaction Protocol (README), AG-UI on GitHub · read 14 Nov 2026
- DocsAG-UI Overview, AG-UI Docs · read 14 Nov 2026
Checked by WhatIsAI against the sources above · 14 Nov 2026. Spotted an error? Report it.