d03123bb5c* docs: add local development MCP client configuration to READMEs Add instructions for configuring MCP clients to use locally-cloned and modified servers. This allows developers to test local changes with MCP clients like Claude Desktop or VS Code. - Top-level README: Added 'Local Development' section after npx config - All TypeScript examples: Added 'Local Development' subsection with bash one-liner that builds and runs the server - Python examples (qr-server, say-server): Added local path config * docs: include all servers in local development config * docs: use bash wrapper for Python server configs to enable tilde expansion
93 lines
3.1 KiB
Markdown
93 lines
3.1 KiB
Markdown
# Example: System Monitor App
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A demo MCP App that displays real-time OS metrics with a stacked area chart for per-core CPU usage and a bar gauge for memory.
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<table>
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<tr>
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<td><a href="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/01-initial-state.png"><img src="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/01-initial-state.png" alt="Initial state" width="100%"></a></td>
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<td><a href="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/02-cpu-data-accumulated.png"><img src="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/02-cpu-data-accumulated.png" alt="CPU data accumulated" width="100%"></a></td>
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<td><a href="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/03-extended-cpu-history.png"><img src="https://modelcontextprotocol.github.io/ext-apps/screenshots/system-monitor-server/03-extended-cpu-history.png" alt="Extended CPU history" width="100%"></a></td>
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</tr>
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</table>
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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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"system-monitor": {
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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-system-monitor",
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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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"system-monitor": {
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"command": "bash",
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"args": ["-c", "cd ~/code/ext-apps/examples/system-monitor-server && 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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## Features
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- **Per-Core CPU Monitoring**: Stacked area chart showing individual CPU core utilization over a 1-minute sliding window
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- **Memory Usage**: Horizontal bar gauge with color-coded thresholds (green/yellow/red)
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- **System Info**: Hostname, platform, and uptime display
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- **Auto-Polling**: Automatically starts monitoring on load with 2-second refresh interval
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- **Theme Support**: Adapts to light/dark mode preferences
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## Running
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1. Install dependencies:
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```bash
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npm install
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```
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2. Build and start the server:
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```bash
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npm run start:http # for Streamable HTTP transport
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# OR
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npm run start:stdio # for stdio transport
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```
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3. View using the [`basic-host`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-host) example or another MCP Apps-compatible host.
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## Architecture
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### Server (`server.ts`)
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Exposes a single `get-system-stats` tool that returns:
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- Raw per-core CPU timing data (idle/total counters)
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- Memory usage (used/total/percentage)
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- System info (hostname, platform, uptime)
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The tool is linked to a UI resource via `_meta.ui.resourceUri`.
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### App (`src/mcp-app.ts`)
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- Uses Chart.js for the stacked area chart visualization
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- Polls the server tool every 2 seconds
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- Computes CPU usage percentages client-side from timing deltas
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- Maintains a 30-point history (1 minute at 2s intervals)
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- Updates all UI elements on each poll
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