- TypeScript 76.4%
- MDX 19.3%
- JavaScript 4.3%
| Filename | Latest commit message | Latest commit date |
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eaea3f9e07* feat: store and expose hostContext in App class Fixes #129 - The App class now stores the initial hostContext received during initialization and exposes it via getHostContext(). Changes: - Add _hostContext private property to App class - Store result.hostContext in connect() method - Add getHostContext() getter method (parallel to getHostCapabilities()) - Update onhostcontextchanged setter to merge partial updates into stored context - Add default notification handler to update context even when user hasn't set onhostcontextchanged This enables apps to: - Access toolInfo immediately after connection (only in initial context) - Render with correct theme/locale without waiting for first notification - Synchronously access viewport, timezone, and other initial state 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com> * fix: use sendHostContextChange for partial update accumulation test Address PR review feedback: The test was using setHostContext with full context spreads which didn't clearly demonstrate partial update accumulation. Now uses sendHostContextChange directly to send truly partial updates (only theme, then only viewport), making it clear the App correctly merges multiple partial notifications. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com> --------- Co-authored-by: Claude <noreply@anthropic.com> |
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@modelcontextprotocol/ext-apps
This repo contains the SDK and specification for MCP Apps Extension (SEP-1865).
MCP Apps are a proposed standard inspired by MCP-UI and OpenAI's Apps SDK to allow MCP Servers to display interactive UI elements in conversational MCP clients / chatbots.
Overview
This SDK serves two audiences:
App Developers
Build interactive UIs that run inside MCP-enabled chat clients.
- SDK for Apps:
@modelcontextprotocol/ext-apps— API Docs - React hooks:
@modelcontextprotocol/ext-apps/react— API Docs
Host Developers
Embed and communicate with MCP Apps in your chat application.
- SDK for Hosts:
@modelcontextprotocol/ext-apps/app-bridge— API Docs
There's no supported host implementation in this repo (beyond the examples/basic-host example).
We have contributed a tentative implementation of hosting / iframing / sandboxing logic to the MCP-UI repository, and expect OSS clients may use it, while other clients might roll their own hosting logic.
Installation
npm install -S @modelcontextprotocol/ext-apps
Or edit your package.json manually:
{
"dependencies": {
"@modelcontextprotocol/ext-apps": "^0.0.1"
}
}
Examples
Start with these foundational examples to learn the SDK:
examples/basic-server-vanillajs— Example MCP server with tools that return UI Apps (vanilla JS)examples/basic-server-react— Example MCP server with tools that return UI Apps (React)examples/basic-host— Bare-bones example of hosting MCP Apps
The examples/ directory contains additional demo apps showcasing real-world use cases.
To run all examples together:
npm install
npm run examples:start
Then open http://localhost:8080/.