ext-apps/examples/system-monitor-server/README.md
Olivier Chafik cce8d5c7a3
docs: add MCP client configuration to example READMEs
Add stdio transport configuration snippets near the top of each example
README to help users quickly set up the servers in their MCP clients.

- Node.js examples use npx with the published npm packages
- Python qr-server uses uv with local path
- Removed Claude Desktop-specific references from qr-server
2026-01-16 14:00:57 +00:00

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# Example: System Monitor App
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.
<table>
<tr>
<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>
<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>
<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>
</tr>
</table>
## MCP Client Configuration
Add to your MCP client configuration (stdio transport):
```json
{
"mcpServers": {
"system-monitor": {
"command": "npx",
"args": [
"-y",
"--silent",
"--registry=https://registry.npmjs.org/",
"@modelcontextprotocol/server-system-monitor",
"--stdio"
]
}
}
}
```
## Features
- **Per-Core CPU Monitoring**: Stacked area chart showing individual CPU core utilization over a 1-minute sliding window
- **Memory Usage**: Horizontal bar gauge with color-coded thresholds (green/yellow/red)
- **System Info**: Hostname, platform, and uptime display
- **Auto-Polling**: Automatically starts monitoring on load with 2-second refresh interval
- **Theme Support**: Adapts to light/dark mode preferences
## Running
1. Install dependencies:
```bash
npm install
```
2. Build and start the server:
```bash
npm run start:http # for Streamable HTTP transport
# OR
npm run start:stdio # for stdio transport
```
3. View using the [`basic-host`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-host) example or another MCP Apps-compatible host.
## Architecture
### Server (`server.ts`)
Exposes a single `get-system-stats` tool that returns:
- Raw per-core CPU timing data (idle/total counters)
- Memory usage (used/total/percentage)
- System info (hostname, platform, uptime)
The tool is linked to a UI resource via `_meta.ui.resourceUri`.
### App (`src/mcp-app.ts`)
- Uses Chart.js for the stacked area chart visualization
- Polls the server tool every 2 seconds
- Computes CPU usage percentages client-side from timing deltas
- Maintains a 30-point history (1 minute at 2s intervals)
- Updates all UI elements on each poll