A2UI

Developers can use A2UI to let agents compose interactive interfaces from their applications’ existing components.

Availability

Available in the Python agent SDK, TypeScript agent SDK, and Dart SDK

Pricing model

Not established

Deployment

The client renders A2UI operations using its component catalog

Privacy

Not established

Licence

Described as an open standard

• A2UI describes interfaces as data for applications to render with their existing components. ^[1]
• A2UI is a declarative data format rather than executable code. ^[1]

  A2UI is a declarative data format rather than executable code.

• The client keeps a catalog of trusted components and checks agent output against it. ^[1]

  The client keeps a catalog of trusted components, so anything the agent invents outside that set is caught before it reaches the screen.

• A2UI payloads are flat lists of JSON messages that can be emitted incrementally. ^[1]
• The same response can render through React, Lit, Angular, SwiftUI, Jetpack Compose, or Flutter. ^[1]

  The same response renders through React, Lit, Angular, SwiftUI, Jetpack Compose (Android) or Flutter (multi-platform), and through community renderers for Vue, or even the terminal.

• The article provides setup instructions and links to A2UI documentation.
• A2UI Express is an inference format optimized for inference speed and accuracy. ^[2]

  Now agents can generate A2UI Express , an intermediate format optimized for inference speed and accuracy, and rely on deterministic code in A2UI's Agent SDKs to translate it into the JSON-based transport protocol.

• The SDK compiles the model's reply into validated A2UI messages. ^[2]

  The SDK generates the prompt instructions for that format and compiles the model's reply into standard A2UI messages.

• The inference format and compiler are generated from the catalog's JSON schema. ^[2]

  An inference format has two parts, and the SDK generates both from your catalog's JSON schema.

• A2UI Express is available in the Python, TypeScript, and Dart SDKs. ^[2]

  A2UI Express is available in the Python agent SDK ( a2ui-agent-sdk 0.9.0 on PyPI), in the TypeScript agent SDK ( @a2ui/agent on npm), and in the Dart SDK ( a2ui_agent 0.0.1-wip004 on pub.dev).

• The post reports that Express can reduce latency by up to 3x and use up to 3x fewer tokens than Direct JSON for the same kinds of UI. ^[2]