ext-apps/examples/system-monitor-server
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Olivier Chafik 89a684546b
fix(examples): resolve DIST_DIR path for npm package execution (#277)
* fix(examples): resolve DIST_DIR path for npm package execution

When servers are compiled to dist/server.js and published to npm,
`import.meta.dirname` already points to dist/, so joining with "dist"
results in dist/dist/ which doesn't exist.

This fix detects whether we're running from TypeScript source or
compiled JavaScript and adjusts the path accordingly:
- From source (server.ts): use dist/ subdirectory
- From compiled (dist/server.js): use current directory

Fixes ENOENT errors like:
"ENOENT: no such file or directory, open '.../dist/dist/mcp-app.html'"

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix(pdf-server): mark pdfjs-dist as external in bundle

The pdf.worker.mjs file wasn't being found when running from npm
because bun bundled pdfjs-dist but didn't include the worker file.

By marking pdfjs-dist as external, it uses the installed package
from node_modules at runtime where the worker is available.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-15 12:23:13 +00:00
..
src Improve consistency and organization of examples for AI learning 2026-01-13 20:48:02 -06:00
.gitignore Improve consistency and organization of examples for AI learning 2026-01-13 20:48:02 -06:00
grid-cell.png feat(basic-host): URL params, fullscreen mode, unified layout (#266) 2026-01-14 22:09:41 +00:00
main.ts feat: compile example servers to JavaScript for npm consumption (#259) 2026-01-14 23:46:17 +00:00
mcp-app.html Add color-scheme meta tag to all example apps 2025-12-15 11:42:18 -08:00
package.json feat: compile example servers to JavaScript for npm consumption (#259) 2026-01-14 23:46:17 +00:00
README.md docs: add tool visibility and restructure _meta.ui (#131) 2025-12-16 21:47:40 +00:00
screenshot.png feat(basic-host): URL params, fullscreen mode, unified layout (#266) 2026-01-14 22:09:41 +00:00
server.ts fix(examples): resolve DIST_DIR path for npm package execution (#277) 2026-01-15 12:23:13 +00:00
tsconfig.json Add system-monitor-server example 2025-12-04 14:32:41 -06:00
tsconfig.server.json feat: compile example servers to JavaScript for npm consumption (#259) 2026-01-14 23:46:17 +00:00
vite.config.ts Add system-monitor-server example 2025-12-04 14:32:41 -06:00

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.

Initial state CPU data accumulated Extended CPU history

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:

    npm install
    
  2. Build and start the server:

    npm run start:http  # for Streamable HTTP transport
    # OR
    npm run start:stdio  # for stdio transport
    
  3. View using the 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