ag-ui: A standard protocol for connecting AI agents to the frontend

An open-source protocol that standardizes communication between AI agents and user interfaces. Through approximately 16 standard event types, the agent backend sends state in real time, allowing the frontend to receive it and implement real-time streaming chat or generative UIs.

While MCP provides tools to agents and A2A handles inter-agent communication, AG-UI serves the role of bringing agents into user applications. It supports various event transmission methods such as SSE, WebSockets, and webhooks, ensuring interoperability across diverse environments through loose event format matching.

It is officially integrated with major agent frameworks such as LangChain, CrewAI, Microsoft Agent Framework, and Google ADK. It provides SDKs for over 10 languages, including Kotlin, Golang, Rust, and Java, and can be used in various client environments such as CopilotKit, Slack, and Microsoft Teams.

It is useful for teams developing agent-based applications that want to integrate UIs in a standardized way without writing complex connector code. It is released under the MIT license and includes a reference HTTP implementation and a basic connector to facilitate a quick start.