b4642b4338Update all documentation links from `modelcontextprotocol.github.io/ext-apps` to the new custom domain across README.md, docs/, and example READMEs. Add `cname` to the `peaceiris/actions-gh-pages` deploy action in `.github/workflows/docs.yml` so the CNAME file persists across deploys. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
74 lines
2.9 KiB
Markdown
74 lines
2.9 KiB
Markdown
# Example: Basic Server (Vanilla JS)
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An MCP App example with a vanilla JavaScript UI (no framework).
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> [!TIP]
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> Looking for a React-based example? See [`basic-server-react`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-server-react)!
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## MCP Client Configuration
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Add to your MCP client configuration (stdio transport):
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```json
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{
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"mcpServers": {
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"basic-vanillajs": {
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"command": "npx",
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"args": [
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"-y",
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"--silent",
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"--registry=https://registry.npmjs.org/",
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"@modelcontextprotocol/server-basic-vanillajs",
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"--stdio"
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]
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}
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}
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}
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```
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### Local Development
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To test local modifications, use this configuration (replace `~/code/ext-apps` with your clone path):
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```json
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{
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"mcpServers": {
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"basic-vanillajs": {
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"command": "bash",
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"args": [
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"-c",
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"cd ~/code/ext-apps/examples/basic-server-vanillajs && npm run build >&2 && node dist/index.js --stdio"
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]
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}
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}
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}
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```
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## Overview
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- Tool registration with a linked UI resource
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- Vanilla JS UI using the [`App`](https://apps.extensions.modelcontextprotocol.io/api/classes/app.App.html) class directly
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- App communication APIs: [`callServerTool`](https://apps.extensions.modelcontextprotocol.io/api/classes/app.App.html#callservertool), [`sendMessage`](https://apps.extensions.modelcontextprotocol.io/api/classes/app.App.html#sendmessage), [`sendLog`](https://apps.extensions.modelcontextprotocol.io/api/classes/app.App.html#sendlog), [`openLink`](https://apps.extensions.modelcontextprotocol.io/api/classes/app.App.html#openlink)
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- Theme integration via [`applyDocumentTheme()`](https://apps.extensions.modelcontextprotocol.io/api/functions/app.applyDocumentTheme.html), [`applyHostStyleVariables()`](https://apps.extensions.modelcontextprotocol.io/api/functions/app.applyHostStyleVariables.html), and [`applyHostFonts()`](https://apps.extensions.modelcontextprotocol.io/api/functions/app.applyHostFonts.html)
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## Key Files
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- [`server.ts`](server.ts) - MCP server with tool and resource registration
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- [`mcp-app.html`](mcp-app.html) / [`src/mcp-app.ts`](src/mcp-app.ts) - Vanilla JS UI using `App` class
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## Getting Started
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```bash
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npm install
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npm run dev
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```
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## How It Works
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1. The server registers a `get-time` tool with metadata linking it to a UI HTML resource (`ui://get-time/mcp-app.html`).
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2. When the tool is invoked, the Host renders the UI from the resource.
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3. The UI uses the MCP App SDK API to communicate with the host and call server tools.
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## Build System
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This example bundles into a single HTML file using Vite with `vite-plugin-singlefile` — see [`vite.config.ts`](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`](https://apps.extensions.modelcontextprotocol.io/api/interfaces/app.McpUiResourceCsp.html#resourcedomains) in the UI resource metadata.
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