Agent ↔ user interface
Agent User Interaction Protocol (AG-UI)
An event-based protocol that streams agent runs, state, tool calls and user input between an agent backend and a user-facing app.
- Status
- Stable, v1.0 (September 2026)
- Governance
- CopilotKit and the AG-UI open source community
- Sources
- Project siteSpecification
- Latest release (checked daily)
- 1.0.2 on 2026-10-05 · npm @ag-ui/core · all releases
What to know
- AG-UI 1.0 is the first release with a normative behavioural spec written in BCP 14 language; 0.x defined only message shapes.
- Version 1.0 adds run outcomes (success, interrupt, cancelled), an interrupt and resume pattern, and subagent attribution.
- Official SDKs exist for TypeScript, Python and .NET.
- The docs position it alongside MCP (tools) and A2A (agent to agent) as the agent-to-user layer.
- Repositories went public on 2025-04-09.
When to use it
Use it when you build a frontend that has to show a live agent run (streaming text, tool calls, shared state, approvals) and you want to swap agent frameworks without rewriting the UI.
Related standards
MCP · Model Context ProtocolA2A · Agent2Agent ProtocolSKILL.md · Agent SkillsAGENTS.md · AGENTS.mdACP · Agent Client ProtocolPAP · Personal Agent ProtocolA2UI · A2UIMCP Apps · MCP AppsTAP · Trusted Agent ProtocolPACT · Personal Agent Consent & Trust Protocol (PACT)ANP · Agent Network ProtocolOASF · Open Agentic Schema FrameworkWebMCP · WebMCPllms.txt · llms.txtAgent Spec · Open Agent Specification
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Reviewed Oct 7, 2026. Spotted something out of date? Email hello@agentatlas.dev.