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AG-UI

Agent internet protocolOpen Source

Open event-based protocol for agent and user interaction

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Overview

About AG-UI

This summary uses submitted and public product material. Only source-mapped claims are documentation reviewed.

AG-UI is an MIT-licensed protocol that standardizes the bidirectional connection between agent backends and user-facing applications, including streamed events, shared state, tool calls, and user interactions.

So agents can…

  • Stream progress and responses into applications in real time
  • Synchronize agent and frontend state across runtimes
  • Request approvals and drive interactive or generative interfaces

Listing decision

Why AG-UI is listed

AG-UI standardizes the boundary between agent backends and user-facing applications, so its primary role is an agent-internet protocol rather than an agent runtime or end-user application.

Before you choose

Fit and limitations

Best for

Teams connecting an agent backend to an interactive frontend that needs streamed output, shared state, tool calls, interrupts, or other bidirectional agent/user events.

Known limitations

AG-UI supplies the interaction contract, not a hosted agent or complete application; adopters still need compatible client and server implementations and must operate their own backend and security controls.

Not yet verified

The reviewed first-party sources do not publish a formal conformance certification program or an independent interoperability benchmark.

Sources

Sources and verification

First-party unless marked otherwise. Each link supports only its adjacent claim.

  1. AG-UI Overview — protocol scope and interaction model

    AG-UI is an open, bidirectional, event-based protocol for connecting agentic backends to user-facing applications, with streaming, shared state, tool calls, and human interaction primitives.

    official documentation · accessed Sep 3, 2026
  2. AG-UI Server guide — HTTP and event-stream implementation

    The first-party server guide shows an HTTP endpoint accepting AG-UI requests and streaming typed events over server-sent events.

    official documentation · accessed Sep 3, 2026
  3. AG-UI repository license — MIT

    The maintained AG-UI repository publishes the protocol implementation and documentation under the MIT License.

    official license · accessed Sep 3, 2026
  4. CopilotKit repository — maker of AG-UI

    CopilotKit identifies itself as the company behind the AG-UI Protocol.

    official repository · accessed Sep 3, 2026

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