A2UI: A Protocol for Agent-Driven Interfaces

Summary

A Protocol for Agent-Driven Interfaces A2UI enables AI agents to generate rich, interactive user interfaces that render natively across web, mobile, and desktop—without executing arbitrary code. ️Status: Early Stage Public Preview A2UI is currently in v0.8 (Public Preview). The specification and implementations are functional but are still evolving. We are opening the project to foster collaboration, gather feedback, and solicit contributions (e.g., on client renderers). Expect changes. At a Glance A2UI is currently v0.8, Apache 2.0 licensed, created by Google with contributions from CopilotKit and the open source community, and is in active development on GitHub. The problem A2UI solves is: how can AI agents safely send rich UIs across trust boundaries? Instead of text-only responses or risky code execution, A2UI lets agents send declarative component descriptions that clients render using their own native widgets. It's like having agents speak a universal UI language. In this repo you will find A2UI specifications and implementations for renderers (eg: Angular, Flutter, etc.) on the client side, and transports (eg: A2A, etc.) which communicate A2UI messages between agents and clients. Secure by Design Declarative data format, not executable code. Agents can only use pre-approved components from your catalog—no UI injection attacks. LLM-Friendly Flat, streaming JSON structure designed for easy generation. LLMs can build UIs incrementally without perfect JSON in one shot. Framework-Agnostic One agent response works everywhere. Render the same UI on Angular, Flutter, React, or native mobile with your own styled components. Progressive Rendering Stream UI updates as they're generated. Users see the interface building in real-time instead of waiting for complete responses. Get Started in 5 Minutes How It Works User sends a message to an AI agent Agent generates A2UI messages describing the UI (structure + data) Messages stream to the client application Client renders u...