| Filename | Latest commit message | Latest commit date |
|---|---|---|
5bbf277882* chore: bump ext-apps to 1.1.0 Features: - registerAppResource now returns the registered resource (#370) - Accept UIResourceMeta in both resources/list and resources/read (#410) - callServerTool throws helpful error when called with a string (#449) - Add double-connect guard to prevent protocol message handling errors (#450) Bug fixes: - Only ignore messages that lack jsonrpc 2.0 in message-transport (#448) - Align basic-host dark mode styles (#438) Spec: - Change Host <> Sandbox communication protocol to SHOULD (#435) - Clarify UIResourceMeta in both list and read responses (#410) * fix(debug-server): add missing npm package config (main, bin, types, exports) Align debug-server package.json with all other server examples: - main: dist/server.js (was server.ts) - types: dist/server.d.ts - bin: mcp-server-debug -> dist/index.js - exports with types - files: only dist (remove source server.ts) |
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| .. | ||
| src | ||
| .gitignore | ||
| grid-cell.png | ||
| main.ts | ||
| mcp-app.html | ||
| package.json | ||
| README.md | ||
| screenshot.png | ||
| server.ts | ||
| tsconfig.json | ||
| tsconfig.server.json | ||
| vite.config.ts | ||
Example: Basic Server (React)
An MCP App example with a React UI.
Tip
Looking for a vanilla JavaScript example? See
basic-server-vanillajs!
MCP Client Configuration
Add to your MCP client configuration (stdio transport):
{
"mcpServers": {
"basic-react": {
"command": "npx",
"args": [
"-y",
"--silent",
"--registry=https://registry.npmjs.org/",
"@modelcontextprotocol/server-basic-react",
"--stdio"
]
}
}
}
Local Development
To test local modifications, use this configuration (replace ~/code/ext-apps with your clone path):
{
"mcpServers": {
"basic-react": {
"command": "bash",
"args": [
"-c",
"cd ~/code/ext-apps/examples/basic-server-react && npm run build >&2 && node dist/index.js --stdio"
]
}
}
}
Overview
- Tool registration with a linked UI resource
- React UI using the
useApp()hook - App communication APIs:
callServerTool,sendMessage,sendLog,openLink
Key Files
server.ts- MCP server with tool and resource registrationmcp-app.html/src/mcp-app.tsx- React UI usinguseApp()hook
Getting Started
npm install
npm run dev
How It Works
- The server registers a
get-timetool with metadata linking it to a UI HTML resource (ui://get-time/mcp-app.html). - When the tool is invoked, the Host renders the UI from the resource.
- The UI uses the MCP App SDK API to communicate with the host and call server tools.
Build System
This example bundles into a single HTML file using Vite with vite-plugin-singlefile — see vite.config.ts. This allows all UI content to be served as a single MCP resource. Alternatively, MCP apps can load external resources by defining _meta.ui.csp.resourceDomains in the UI resource metadata.