A2UI 1.0 is released

AG-UI and A2UI 1.0

Watch an agent build a real interface. A2UI describes it, AG-UI carries it, and CopilotKit renders it, then sends what the user does back to the agent.

Build with A2UI 1.0 Read the spec

AG-UI agent → renderercreateSurface
{"version": "1.0", "createSurface": {"surfaceId": "flight_picker", …}}

Booked: 09:40 nonstop to SFO

Similar names, different jobs

One describes the UI. The other moves it.

A2UI 1.0

What to render

A declarative spec from Google. Agents describe an interface using components from a catalog your app trusts, safe to render on web, mobile and desktop.

{ "id": "root",
  "component": "Card",
  "child": "picker" }

AG-UI

How it travels

The Agent-User Interaction protocol. A two-way, event-based connection between any agent backend and your app. It carries messages, state, tools and generative UI, including A2UI.

See it in action

One agent, many interfaces

A tour of the A2UI Playground. Ask a question, and the answer comes back as the right interface: a picture grid, a report, a live calculator, a chart, or data you can download, all built from A2UI 1.0.

Inside the A2UI Playground · 4:42

What's new in A2UI 1.0

What 1.0 adds

callAgentFunction

Two-way function calls

The UI can call functions on the agent and get a response back, and the agent can call functions in the UI for rendering.

AG-UI binding

AG-UI in the spec

The 1.0 spec names AG-UI as a standard transport, alongside A2A and MCP.

instructions

Catalogs that teach the model

A catalog carries its own prompt guidance, and controls which functions the agent or the UI may call.

@path · @call

Clearer data binding

Bindings are marked with @, so they're never confused with data.

allowedChildren

Stricter component trees

Catalogs can say which components nest inside which, and renderers reject anything else.

live · hidden

Better accessibility

Components can announce live updates to screen readers, and hide decorative pieces.

How they work together

From agent to interface and back

01
Agent describes UI
Emits A2UI 1.0 messages
02
AG-UI carries it
Streams it to the app as events
03
CopilotKit renders
In your React app, from your catalog
04
User acts
Clicks, forms, choices

Actions and function calls flow back to the agent over AG-UI. New in 1.0: the UI can call functions on the agent.

Generative UI specs

Where A2UI sits

Controlled

Pre-built components you wire up

Declarative · A2UI 1.0

The agent describes it, your catalog renders it

Open · MCP Apps

Sandboxed, free-form surfaces

Other specs, such as MCP-UI and Open-JSON-UI, travel over AG-UI too.

The A2UI Composer, powered by CopilotKit

Browse agent-generated A2UI components in the gallery, then open any of them in the Composer.

Open the Composer

Live on DeepLearning.AI

Build Interactive Agents with Generative UI

A2UI is one of three approaches taught in Atai Barkai's hands-on short course on DeepLearning.AI — alongside controlled components and MCP Apps.

Take the course →

Are you ready?

Ready to build with A2UI 1.0?

Explore the A2UI spec and start building agentic applications with CopilotKit and AG-UI.