Your agent knows what it is doing. Your interface still shows a spinning chat bubble.

When an agent needs to show progress, request consent, collect structured input, or return an interactive result, many teams connect custom UI components to tool calls one workflow at a time. It works—until the agent, interface, and application state stop agreeing.

This session compares three emerging approaches to that problem. AG-UI streams agent state, events, and tool progress into the application. A2UI lets an agent describe a trusted interface using structured data. MCP Apps allows a tool to return an interactive experience inside a sandboxed surface. They overlap, but they solve different parts of the interaction layer.

In one end-to-end expense-approval demo, we will connect all three approaches. The interface will stream the agent’s plan, pause before a sensitive action, render a structured approval form, and return an interactive audit view showing what happened.

Attendees will leave able to explain where these protocols overlap, choose the right boundary for state and UI generation, implement consent-first actions, and design agent interfaces that remain testable and secure.

The goal is not to put every protocol into one application. It is to understand which piece fits the interaction you need.

Audience: Front-end, full-stack, and agent developers building interactive web applications.
Format: 45–60-minute technical talk with one end-to-end live demo.
Demo: An expense-approval agent using AG-UI state events, an A2UI form, and an MCP App audit view.
Technology reference: https://github.com/ag-ui-protocol/ag-ui
Materials: Talk-specific repository, slides, and recording are not yet published.
Vendor scope: Protocol-focused and vendor-neutral; web examples use React and TypeScript.