Show HN: AG-UI Protocol – Bring Agents into Frontend Applications

Introducing AG-UI; the Agent-User Interaction Protocol.

AG-UI is an open, lightweight, event-based protocol that standardizes how AI agents connect to fronted-end applications.

After a year of one-off, CopilotKit <> Agent frameworks collaborations, we decided to ship a standard, and open way for agents to connect to apps.

We are launching with day 0 integrations with LangChain, Mastra, CrewAI and AG2 with more partnerships on the way.

How AG-UI works: - Creates a unified, two-way bridge between backend agents and frontend apps - Works with any event transport (SSE, WebSockets, webhooks) - Supports 16 standardized event types for common agent-user interactions

Where AG-UI fits in the agent protocol landscape: - MCP: for agent←→tools communication - A2A/ACP: for agent←→agent communication - AG-UI: for agent←→human interaction in applications

We launched the protocol yesterday, and have been blown away by the reception. We have the first working group this Friday, to help expand and steer the direction of the protocol.

Check out the repo to get started!

I had kinda wondered about this for a while - I called it "MWP - model workload protocol" - a client-agnostic (sms, whatsapp, in-app, react components) way to display what an agent is doing

- working - thinking - calling tools - hit an error - needs human input - needs human approval

etc etc etc

I don't understand what it can be used for. Is this for accessibility? Or a new UI building paradigm?

Wow, after MCP, this is the new thing!

let me give it a try

This is super exciting and, in my opinion, is going to solve so many problems for agent builders.