ext-apps/examples/system-monitor-server
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Olivier Chafik 9f09932baf
feat: use structuredContent with outputSchema in example servers (#220)
* build app-with-deps

* make registerAppTool more interchangeable w/ server.registerTool

* feat: use structuredContent in all example servers

All servers now return structuredContent alongside JSON text content.
All mcp-apps now read structuredContent directly (no JSON.parse fallback).

Updated servers:
- basic-server-vanillajs
- budget-allocator-server
- cohort-heatmap-server
- customer-segmentation-server
- integration-server
- scenario-modeler-server
- system-monitor-server
- threejs-server
- video-resource-server
- wiki-explorer-server

* feat: add outputSchema to all example servers

Define output schemas for structuredContent validation:
- basic-server-vanillajs: { time: string }
- budget-allocator-server: BudgetDataResponseSchema
- cohort-heatmap-server: CohortDataSchema
- customer-segmentation-server: customers/segments schema
- integration-server: { time: string }
- scenario-modeler-server: templates/defaultInputs schema
- system-monitor-server: SystemStatsSchema
- threejs-server: { code, height }
- video-resource-server: { videoUri, description }
- wiki-explorer-server: { page, links, error }

* prettier:fix

* make registerAppTool more interchangeable w/ server.registerTool

* feat: use structuredContent in all example servers

All servers now return structuredContent alongside JSON text content.
All mcp-apps now read structuredContent directly (no JSON.parse fallback).

Updated servers:
- basic-server-vanillajs
- budget-allocator-server
- cohort-heatmap-server
- customer-segmentation-server
- integration-server
- scenario-modeler-server
- system-monitor-server
- threejs-server
- video-resource-server
- wiki-explorer-server

* feat: add outputSchema to all example servers

Define output schemas for structuredContent validation:
- basic-server-vanillajs: { time: string }
- budget-allocator-server: BudgetDataResponseSchema
- cohort-heatmap-server: CohortDataSchema
- customer-segmentation-server: customers/segments schema
- integration-server: { time: string }
- scenario-modeler-server: templates/defaultInputs schema
- system-monitor-server: SystemStatsSchema
- threejs-server: { code, height }
- video-resource-server: { videoUri, description }
- wiki-explorer-server: { page, links, error }

* prettier:fix

* revert: remove unrelated workflow, version, and arch changes

* chore: update package-lock.json

* refactor(basic-server-vanillajs): address PR review comments

- Simplify server.ts to return plain time string in text content (not JSON),
  matching the quickstart guide pattern
- Add defensive coding in mcp-app.ts with optional chaining and fallback
  to handle potential type mismatches gracefully

* refactor: restore rich text formatting for LLM-readable content

Restore the human-readable text formatting functions that were removed,
providing meaningful summaries in the text content while keeping
structuredContent for programmatic UI consumption:

- budget-allocator-server: formatBudgetSummary with config overview
- cohort-heatmap-server: formatCohortSummary with retention stats
- scenario-modeler-server: formatScenarioSummary with financial metrics
2026-01-12 14:25:16 +00:00
..
src feat: use structuredContent with outputSchema in example servers (#220) 2026-01-12 14:25:16 +00:00
mcp-app.html Add color-scheme meta tag to all example apps 2025-12-15 11:42:18 -08:00
package.json chore: release 0.3.1 (#224) 2026-01-09 18:22:27 +00:00
README.md docs: add tool visibility and restructure _meta.ui (#131) 2025-12-16 21:47:40 +00:00
server-utils.ts fix: add error handling for server startup failures (#236) 2026-01-11 16:52:55 +00:00
server.ts feat: use structuredContent with outputSchema in example servers (#220) 2026-01-12 14:25:16 +00:00
tsconfig.json Add system-monitor-server example 2025-12-04 14:32:41 -06:00
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