A2UI enables AI agents to generate rich, interactive user interfaces that render natively across web, mobile, and desktop without executing arbitrary code. It solves the problem of how AI agents can safely send rich UIs across trust boundaries by providing a declarative approach to UI generation.

The protocol features a secure by design declarative data format that prevents UI injection attacks, an LLM-friendly flat streaming JSON structure designed for easy generation, and framework-agnostic rendering that works across Angular, Flutter, React, and native mobile platforms. It also supports progressive rendering that streams UI updates as they're generated, allowing users to see interfaces building in real-time.

A2UI works through a six-step process: users send messages to AI agents, agents generate A2UI messages describing the UI structure and data, messages stream to client applications, clients render using native components, users interact with the UI sending actions back to agents, and agents respond with updated A2UI messages. This streaming protocol allows for incremental UI generation without requiring perfect JSON in one shot.

The protocol enables AI agents to build complete applications and interfaces, such as generating custom forms based on image analysis or selecting appropriate components like charts and maps for different types of queries. It supports custom components offered by clients, allowing for interactive elements like Google Maps and data visualizations.

A2UI is designed for developers building AI-powered applications, particularly those working with LLMs and AI agents that need to generate user interfaces. It integrates with various rendering frameworks and supports custom component development for specific application needs.