# block-goose-mcp-ui-future-agentic-interfaces-2025-08-25

## Veille

Block/Goose — MCP-UI and the Future of Agentic Interfaces: interactive web components in AI agent conversations via Model Context Protocol (block.github.io)

## Titre Article

Block's Goose and the Future of Agentic Interfaces via Model Context Protocol

## Date

2025-08-25

## URL

https://block.github.io/goose/blog/2025/08/25/mcp-ui-future-agentic-interfaces/

## Keywords

Block, Goose, MCP, Model Context Protocol, agentic interfaces, future of UI, Square, developer tools, AI agents, interface evolution, tool integration, context management

## Authors

Block (Square) Engineering team

## Ton

**Profile:** Developer advocacy | Tech institutional | Educational-Promotional | Intermediate

Block's Goose team (post authored by Ebony Louis, Developer Advocate) adopts an enthusiastic developer-advocacy voice, structured around an episode of the "Wild Goose Case" podcast with the creators of MCP-UI (Ido Salomon and Liad Yosef, Monday.com) and Andrew Harvard (Block). The opening through concrete pain points ("walls of text," copy-pasted URLs) establishes relatable frustrations. The problem → solution → architecture → demos → vision structure guides progressive understanding. The technical language remains accessible (sandboxed iframes, post messages, remote DOM) and concrete examples (Shopify, airplane seats, restaurants) ground the abstract protocol. The optimistic tone, free of naive hype (the acknowledged challenge is adoption), is typical of Block's open source advocacy aimed at the agent-developer community.

## Pense-betes

- **Goose**: Block's open source AI agent, among the first platforms to support MCP-UI
- **MCP-UI = protocol + SDK**: rich, interactive web components embedded directly into agent conversations
- **Creators**: Ido Salomon and Liad Yosef (Monday.com), with Andrew Harvard (Block); featured in the "Wild Goose Case" episode
- **Problem addressed**: text-only interfaces unsuited to the general public — walls of text, copy-pasting, multiple tabs
- **Philosophy**: don't discard decades of web UI/UX expertise, augment it with AI instead
- **Security**: components rendered in sandboxed iframes, host communication only via post messages
- **Three content types**: external URLs, raw HTML, remote DOM (separate workers)
- **Demos**: interactive Shopify catalog, visual airplane seat-selection map, restaurant discovery with ordering
- **Network effect**: an MCP-UI component implemented once works across all compatible agents (Goose, VS Code extensions, future mobile assistants)
- **Vision**: accessibility revolution (the agent builds the UI to user preferences), generative UI eventually
- **Simple start**: `createUIResource({ type: 'html', content: '<h1>Hello World</h1>' })`

## RésuméDe400mots

Block's Goose blog publishes a deep dive into **MCP-UI**, a technology that, according to the team, does away with the "endless walls of text" of AI agent conversations. The article draws on an episode of the "Wild Goose Case" podcast bringing together the creators of MCP-UI, **Ido Salomon and Liad Yosef of Monday.com**, and **Andrew Harvard of Block**, to explore how this technology reshapes the future of agentic interfaces.

**The text-only interface problem**

Asking an agent for help with a purchase today results in a wall of text: product names, prices, descriptions, followed by copy-pasted URLs and multiple tabs — the user redoes all the work. As Ido Salomon puts it, everyone has experienced that "rage quit" moment in front of an assistant that returns nothing but text. These interfaces work for early adopters, not for the general public.

**MCP-UI: protocol and SDK**

MCP-UI (Model Context Protocol User Interface) makes it possible to embed **rich, interactive web components** directly into agent conversations. The underlying philosophy is simple: why discard decades of web UI/UX expertise when it can instead be augmented with AI? Liad Yosef notes that more than a decade of web interfaces refined for human cognitive limits should not disappear with the rise of agents. The system leverages the embedded resources of the MCP specification: an MCP server can return UI components instead of plain text. Four key contributions: rich components (catalogs, seat maps, forms), **brand preservation** (Shopify keeps its own experience), secure integration, and **cross-platform compatibility**.

**Technical foundations**

Security is paramount: components are rendered in **sandboxed iframes** that communicate with the host only via post messages, preventing third-party code from manipulating the parent application. Three content types are supported: external URLs, raw HTML, and remote DOM (rendered in separate workers). Getting started is minimal: `createUIResource({ type: 'html', content: '<h1>Hello World</h1>' })`.

**Demonstrations and ecosystem**

The demos show visual shopping (interactive Shopify catalog with add-to-cart), trip planning (seat selection on a visual map, automatic destination weather), and restaurant discovery (cards with photos, ratings, menus, direct ordering) — all without leaving the conversation. Success rests on four stakeholder groups: agent developers (such as the Goose team), MCP server developers, service providers (Shopify, Square), and end users. The approach creates a **network effect**: a component implemented once works across all compatible agents.

**Vision**

Beyond prettier interfaces: an **accessibility revolution** ("what could be more accessible than an agent that knows you and builds the UI to your preferences?") and, eventually, **generative UI** producing interfaces tailored to each user's needs.

## GrapheDeConnaissance

- Ebony Louis —publie→ article MCP-UI agentic interfaces (DOCUMENT, 0.98)
- MCP-UI —est_basé_sur→ Model Context Protocol (TECHNOLOGIE, 0.97)
- Ido Salomon —a_créé→ MCP-UI (TECHNOLOGIE, 0.95)
- Liad Yosef —a_créé→ MCP-UI (TECHNOLOGIE, 0.95)
- Ido Salomon —travaille_chez→ Monday.com (ORGANISATION, 0.97)
- Liad Yosef —travaille_chez→ Monday.com (ORGANISATION, 0.97)
- Andrew Harvard —travaille_chez→ Block (ORGANISATION, 0.96)
- MCP-UI —utilise→ iframes sandboxées (CONCEPT, 0.93)
- MCP-UI —remplace→ interfaces textuelles des agents IA (CONCEPT, 0.92)
- Goose —utilise→ MCP-UI (TECHNOLOGIE, 0.95)
- Shopify —utilise→ MCP (TECHNOLOGIE, 0.9)
- MCP-UI —permet→ préservation de l'expérience de marque (CONCEPT, 0.88)
- MCP-UI —permet→ interfaces UI génératives personnalisées (CONCEPT, 0.85)

---
Canonical: https://www.thekb.eu/en/fiches/block-goose-mcp-ui-future-agentic-interfaces-2025-08-25/