mcp-apps

<!-- LOGO --> <div align="center"> <picture> <source media="(prefers-color-scheme: dark)" srcset="media/mcp-white.svg"> <source media="(prefers-color-scheme: light)" srcset="media/mcp.svg"> <img src="media/mcp.svg" alt="MCP Apps" width="128"> </picture> <h1>MCP Apps</h1> <p> Build interactive UIs for MCP tools — charts, forms, dashboards — that render inline in Claude, ChatGPT and any other compliant chat client. <br /><br /> <a href="#why-mcp-apps">Why</a> · <a href="https://apps.extensions.modelcontextprotocol.io/api/documents/Quickstart.html">Quickstart</a> · <a href="https://apps.extensions.modelcontextprotocol.io/api/">API Docs</a> · <a href="https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/2026-01-26/apps.mdx">Spec</a> · <a href="CONTRIBUTING.md">Contributing</a> </p> </div>

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<p align="center"> <img src="media/excalidraw.gif" alt="MCP Apps demo" width="600"> <br><em>Excalidraw built with MCP Apps, running in Claude</em> </p>

Table of Contents

• •Build with Agent Skills
• •Supported Clients
• •Why MCP Apps?
• •How It Works
• •Getting Started
• •Using the SDK
• •Examples
• •Specification
• •Resources
• •Contributing

Build with Agent Skills

The fastest way to build an MCP App is to let your AI coding agent do it. This repo ships four Agent Skills — install them once, then just ask:

Install the Skills

Claude Code — install via the plugin marketplace:

/plugin marketplace add modelcontextprotocol/ext-apps
/plugin install mcp-apps@modelcontextprotocol-ext-apps

Other agents — any AI coding agent that supports Agent Skills can use these skills. See the agent skills guide for manual installation instructions.

Once installed, verify by asking your agent _"What skills do you have?"_ — you should see create-mcp-app, migrate-oai-app, add-app-to-server, and convert-web-app in the list. Then just ask it to create or migrate an app and it will guide you through the rest.

Supported Clients

<p align="center"> <a href="https://developers.openai.com/apps-sdk/mcp-apps-in-chatgpt/"><img src="https://img.shields.io/badge/ChatGPT-docs-74aa9c?logo=openai&logoColor=white" alt="ChatGPT"></a> <a href="https://claude.com/docs/connectors/building/mcp-apps/getting-started"><img src="https://img.shields.io/badge/Claude-docs-d97706?logo=claude&logoColor=white" alt="Claude"></a> <a href="https://code.visualstudio.com/blogs/2026/01/26/mcp-apps-support"><img src="https://img.shields.io/badge/VS_Code-docs-007ACC?logo=visualstudiocode&logoColor=white" alt="VS Code"></a> <a href="https://block.github.io/goose/docs/tutorials/building-mcp-apps/"><img src="https://img.shields.io/badge/Goose-docs-000000?logo=goose&logoColor=white" alt="Goose"></a> <a href="https://learning.postman.com/docs/postman-ai/mcp-requests/interact"><img src="https://img.shields.io/badge/Postman-docs-FF6C37?logo=postman&logoColor=white" alt="Postman"></a> <a href="https://www.mcpjam.com/blog/mcp-apps-example"><img src="https://img.shields.io/badge/MCPJam-docs-8B5CF6" alt="MCPJam"></a> </p>

[!NOTE]

MCP Apps is an extension to the

core MCP specification. Host

support varies — see the

clients page for the full list.

Why MCP Apps?

MCP tools return text and structured data. That works for many cases, but not when you need an interactive UI, like a chart, form, design canvas or video player.

MCP Apps provide a standardized way to deliver interactive UIs from MCP servers. Your UI renders inline in the conversation, in context, in any compliant host.

How It Works

MCP Apps extend the Model Context Protocol by letting tools declare UI resources:

1. Tool definition — Your tool declares a ui:// resource containing its

HTML interface

1. Tool call — The LLM calls the tool on your server
2. Host renders — The host fetches the resource and displays it in a

sandboxed iframe

1. Bidirectional communication — The host passes tool data to the UI via

notifications, and the UI can call other tools through the host

Getting Started

npm install -S @modelcontextprotocol/ext-apps

New here? Start with the Quickstart Guide to build your first MCP App.

Using the SDK

The SDK serves three roles: app developers building interactive Views, host developers embedding those Views, and MCP server authors registering tools with UI metadata.

There's no _supported_ host implementation in this repo (beyond the examples/basic-host example).

The MCP-UI client SDK offers a fully-featured MCP Apps framework used by a few hosts. Clients may choose to use it or roll their own implementation.

Examples

The `examples/` directory contains demo apps showcasing real-world use cases.

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Starter Templates

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Running the Examples

To run all examples locally using basic-host (the reference host implementation included in this repo):

git clone https://github.com/modelcontextprotocol/ext-apps.git
cd ext-apps
npm install
npm start

Then open http://localhost:8080/.

Every Node.js example is published as @modelcontextprotocol/server-<name>. To add one to an MCP client that supports stdio (Claude Desktop, VS Code, etc.), use this pattern:

{
  "mcpServers": {
    "<name>": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-<name>", "--stdio"]
    }
  }
}

For example, to add the map server: @modelcontextprotocol/server-map. The Python examples (qr-server, say-server) use uv run instead — see their READMEs for details.

To test local modifications with an MCP client, clone the repo, install, then point your client at a local build:

{
  "mcpServers": {
    "<name>": {
      "command": "bash",
      "args": [
        "-c",
        "cd ~/code/ext-apps/examples/<name>-server && npm run build >&2 && node dist/index.js --stdio"
      ]
    }
  }
}

Specification

<div align="center">

</div>

Resources

• •Quickstart Guide
• •API Documentation
• •Specification (2026-01-26)

(Draft)

• •SEP-1865 Discussion

Contributing

Contributions are welcome! Please read CONTRIBUTING.md for guidelines on how to get started, submit pull requests, and report issues.