AgentIndex icon
AgentIndex
ToolsMCP ServersHOTCategoriesTrendingNewBest ListsCompareGuides
Submit Tool
ToolsMCP ServersHOTCategoriesTrendingNewBest ListsCompare
Home/
API Integration/
ext-apps
ext-apps logo

ext-apps

Active·★ 3.0k·NOASSERTION·Updated 2026-09-25
★ Essential★ Trending

MCP Apps is an extension to the Model Context Protocol that lets a tool return an interactive interface, such as a chart, form, design canvas or video player, which renders inline in the conversation of a compliant chat client like Claude or ChatGPT. The mechanism: a tool declares a `ui://` resource that holds its HTML, the model calls the tool, the host fetches the resource and shows it in a sandboxed iframe, and the host and the UI exchange data in both directions, including the UI calling other tools through the host.

The npm package `@modelcontextprotocol/ext-apps` serves three roles: app developers building the View (with React hooks under `/react`), host developers embedding Views in a chat client (`/app-bridge`), and MCP server authors registering tools with UI metadata. The repo ships four Agent Skills for coding agents (create an app, migrate an OpenAI App, add UI to an existing server, convert a web app), installable as a Claude Code plugin, plus examples and starter templates. The README notes that this is an extension to core MCP and that host support varies, so check the clients page.

© 2026 AgentIndex.app|Built by a 10-year iOS Developer.
Best by use caseAboutContactAdvertisePrivacy PolicyTerms of UseQYSGitHubBuy me a coffee ☕

Browse by Category

MCP ServersCode AssistantWorkflow AutomationRAG / Knowledge BaseMulti-AgentBrowser AutomationLLM InfraDev ToolingObservability

Not affiliated with Anthropic, OpenAI or Microsoft.

Guides

This write-up is based on the project's README and public repository data. We have not hand-tested the tool. Data as of 2026-10-18.

License
Not detected by GitHub
Latest release
v2.0.3 · 2026-09-25
Last commit
2026-09-25
Contributors
48
Forks
404
Open issues and PRs
230
First published
2025-11-21

Source: GitHub, npm and PyPI public APIs.

#Interactive UIs#LLM Integration#Agent Skills#Chat Client Extensions#UI Development#Model Context Protocol#SDK
$ Install
$ npm install -S @modelcontextprotocol/ext-apps
↗ Visit site★ GitHub
01

Features

01Build interactive UIs (charts, forms, dashboards) for MCP tools.
02Inline rendering of UIs within various chat clients.
03Offers Agent Skills for streamlined app development and migration.
04Provides an SDK for UI development, host embedding, and server-side tool registration.
02

Why choose it

+Official MCP extension that standardises interactive UIs instead of per-client custom solutions
+Clear mechanism: `ui://` resources rendered in a sandboxed iframe with two-way messaging
+SDK covers the View, the host and the server sides, with React hooks
+Ships Agent Skills, examples and starter templates to get going quickly
03

Trade-offs

!Only works in hosts that support the extension; the README says support varies
!Needs front-end work (HTML views) on top of the MCP server code
!Hosts render the UI in an iframe, so view code has to be written with that sandbox in mind
!The repository's license is not detected by GitHub; confirm it before use
04

Maintenance check

ActiveChecked: 2026-10-17
Last commit
2026-09-25
Commits, last 90 days
47
Releases, last 90 days
5
Latest release
v2.0.3 (2026-09-25)
Open issues
231
Recent issues with at least one comment
6/15
Commits per week, last 12 weeks
Commits per week, last 12 weeks: 1, 0, 1, 0, 0, 0, 20, 0, 8, 0, 0, 0

Oldest week on the left; the latest four weeks are orange. Source: GitHub commit activity.

Status rule: archived on GitHub = Archived; last commit within 90 days = Active; 91 to 365 days = Slowing; older = Stale. All figures come from the GitHub API on the date shown.

05

Compatibility

ChatGPT
Chat Client
Verified via docs
Claude
Chat Client
Verified via docs
VS Code
IDE Extension
Verified via docs
Node.js
Runtime
Verified via docs
Python
Language
Verified via docs
06

Quick start

1
$ npm install -S @modelcontextprotocol/ext-apps
07

Use cases

↳Visualizing complex data through interactive charts and dashboards.
↳Integrating interactive design canvases or multimedia players into chat environments.
↳Providing custom forms for data input and interaction within LLM conversations.
↳Enabling real-time monitoring and dynamic content display directly in chat clients.
08

Alternatives

⚡Top VS:
VSmcp-server-arangodb★46→VSruby-sdk★937→VSpython-sdk★24.6k→

Comments

Log in to leave a comment

No comments yet. Be the first!

On this page
01Features02Why choose it03Trade-offs04Maintenance check05Compatibility06Quick start

Most discussed open issues

  • #671 Bug Report: MCP Apps UI Resource Not Rendering in Claude Desktop / claude.ai24 comments · 2026-05-27
  • #674 Set up public MCP Apps platform tests14 comments · 2026-05-27
  • #387 Support `frameDomains` → `frame-src` CSP Mapping for External Iframe Embeds8 comments · 2026-01-28
  • #431 Accessibility7 comments · 2026-02-05
  • #420 MCP Apps - start server issue7 comments · 2026-02-02

Issue titles are quoted from GitHub. Open the link to check whether a problem still applies to the version you use.

VS
mcp-server-cloudflare
★4.4k
→
mcp-server-arangodb logo
mcp-server-arangodb★ 46
This is a TypeScript-based MCP server that provides database interaction capabilities through ArangoDB.
VSCompare→
ruby-sdk logo
ruby-sdk★ 937
The official Ruby SDK for the Model Context Protocol.
VSCompare→
python-sdk logo
python-sdk★ 24.6k
The official Python SDK for Model Context Protocol servers and clients
VSCompare→
mcp-server-cloudflare logo
mcp-server-cloudflare★ 4.4k
No description provided.
VSCompare→
Figma-Context-MCP logo
Figma-Context-MCP★ 16.0k
MCP server to provide Figma layout information to AI coding agents like Cursor
VSCompare→
mcp logo
mcp★ 9.8k
AWS MCP Servers — helping you get the most out of AWS, wherever you use MCP.
VSCompare→
whatsapp-mcp logo
whatsapp-mcp★ 6.7k
WhatsApp MCP server
VSCompare→
mcp-dotnet-samples logo
mcp-dotnet-samples★ 201
A comprehensive set of samples of creating and using MCP servers and clients with .NET
VSCompare→
See all alternatives →
07
Use cases
08Alternatives
modelcontextprotocol /
ext-apps
↗

SDK and spec for interactive UIs inside MCP tools (MCP Apps)

3.0k404
Last commit3w ago
StatusActive
CategoryAPI Integration
Contributors48
Latest releasev2.0.3
Links
Documentation↗Discussion↗Issues↗Releases↗
Cloud Infrastructure
Ad

Deploy on DigitalOcean

Host your MCP servers, Docker containers, and AI agents with $200 free credit over 60 days.

Claim $200 Free Credit