ag-ui is an agent-frontend interoperability layer and communication protocol designed to connect AI agent backends with web and mobile user interfaces. It provides a standardized event-driven framework for exchanging messages, session state, and tool calls, utilizing a generative UI framework to render dynamic interface components and structured content triggered by an agent.
The project distinguishes itself through an SSE-based event streamer that delivers real-time incremental model responses and reasoning telemetry. It enables bi-directional state synchronization and allows remote agents to trigger local client-side tool execution for accessing device hardware or private data.
The system covers a broad range of capabilities including session and conversation context management, schema-driven tool integration, and human-in-the-loop coordination. It also provides protocol event inspection for debugging and supports API request authentication via bearer tokens, API keys, or basic authentication.
A command-line tool is available for project scaffolding to quickly establish connectivity between clients and servers.