Microsoft adopts new AG-UI standard for AI agent user interfaces

AG-UI (Agent-User Interaction Protocol) is an open, lightweight, event-based protocol that standardizes real-time, bidirectional communication between AI agent backends and user interfaces. Microsoft announced native integration with its Agent Framework (MAF) on January 29, 2026, confirming compatibility with LangGraph and CrewAI [1,2].

Developers can use SDKs such as agent-framework-ag-ui (pip installable) to expose endpoints and avoid building custom streaming logic [1]. AG-UI complements the Model Context Protocol (MCP) by handling agent-to-user flows while MCP manages agent-to-tool interactions. CopilotKit integrates both to embed MCP Apps' interactive HTML UIs [4]. The specification is available at docs.ag-ui.com and on GitHub [1].

Why It Matters

• Build reusable frontends that work across LangGraph, CrewAI, and MAF backends without custom integrations.
• Stream real-time events for visibility into tool calls, text output, and state deltas to simplify debugging and monitoring.
• Support human-in-the-loop workflows via INTERRUPT events to pause runs for approvals or interventions, improving safety controls.
• Reduce vendor lock-in and cut bandwidth by sending state deltas instead of full snapshots, accelerating interactive agent deployments.