Keynote: MCP Apps: Extending the Frontier - Ido Salomon, Creator MCP-UI & Liad Yosef, Co-creator, MCP Apps

by Liad Yosef, Ido Salomon

Day 1 · Broadway Ballroom (6th Floor) · Keynote Sessions · 20 min · 3 min read

Applied AI

TL;DR

Four months after its creation, MCP Apps became an open standard adopted by OpenAI, Anthropic, and VS Code. Co-creators Ido Salomon and Liad Yosef showed how HTML-based views allow servers to send interactive UI instead of text, keeping brand identity. Over 100 apps and dozens of hosts now support it. ChatGPT's 800 million weekly users represent 160 times the App Store's launch market.

From Concept to Adoption in Four Months

▶ Watch (1:07)

OpenAI released its apps SDK four days after Ido Salomon pitched MCP UI at the London Dev Summit. The chicken‑and‑egg problem ended. Within three months, VS Code, Cursor, Copilot, GitHub, ChatGPT, Postman, Goose, and Claude adopted the MCP Apps spec. The MCP UI work group, co‑led by Salomon and Liad Yosef, produced a draft a month later. Public meetings occur every three weeks.

How MCP Apps Replaces Text with Interactive HTML

▶ Watch (5:33)

MCP Apps uses existing MCP primitives. Instead of returning text from a tool call, a server returns a reference to an HTML resource. The host renders that resource in a sandbox. User clicks and other events are sent back as tool calls, not directly to the server. This keeps the model informed of every action. The result: a Canva UI or a PostHog funnel chart appears inside the chat, preserving the brand’s look and feel.

The Philosophy: Atomic Interfaces for the Agentic Web

▶ Watch (9:56)

Salomon described MCP Apps as a new web paradigm. Instead of opening a dozen browser tabs to plan an event, a user asks an assistant. The assistant fetches small UI chunks from Google Calendar, Amazon, and other services. Each chunk keeps its brand identity. The assistant composes them into a single interface. The user never leaves the chat. This eliminates the need for the model to generate UI from scratch.

Next Steps: Reusable Views and App Tools

▶ Watch (12:55)

The work group is addressing several gaps. Reusable views would allow updating existing UI instead of re‑rendering. A proposal called App Tools flips the model – the agent uses the app’s own tools to fill forms and update in place. The group is also debating whether HTML is sufficient for mobile native experiences. All changes are reflected in the official Aerth Apps SDK.

Notable Quotes

It’s a new philosophy. Ido Salomon · ▶ Watch (9:56)

But what if the apps, the connectors that are being connected to these chat could actually send their own UI to the chat instead of just text? Ido Salomon · ▶ Watch (4:29)

The nice thing about having an official SDK is that you build it once and it runs everywhere. Liad Yosef · ▶ Watch (12:24)

Key Takeaways

MCP Apps standardizes sending interactive HTML over MCP, adopted by OpenAI, Anthropic, and VS Code in three months.
Servers keep full control of UI and brand identity; user actions always flow through the model.
The open spec adds reusable views and App Tools; the Aerth Apps SDK enables write‑once‑run‑anywhere.

About the Speaker(s)

Liad Yosef is a seasoned AI lead and software architect. He co-built MCP-UI, co-authored MCP Apps on the MCP Steering Committee, and co-created GitMCP. Previously he was AI Lead in Shopify’s CEO office, leading agentic interfaces.

Ido Salomon is a seasoned AI lead and software architect. He created MCP-UI and AgentCraft, co-authored MCP Apps on the MCP Steering Committee, and co-created GitMCP. He previously led end-user AI at Palo Alto Networks.

Filed under

Applied AI