skill

ChangeDetection.io — MCP Server & Hermes Skill

Overview

ChangeDetection.io is a self-hosted or SaaS tool for monitoring web pages for changes — price drops, restock alerts, content updates, defacement monitoring. It's one of the most popular self-hosted tools (31k+ GitHub stars).

This skill pairs the changedetection-mcp MCP server with Hermes-native features (cron scheduling, multi-platform delivery) to create a powerful watch-and-notify loop.

When to Use

• User asks to "watch this page" or "monitor this URL for changes"
• User needs to be notified about price drops, restocks, or content updates
• User wants to check what changed on a page overnight
• User wants to set up recurring checks with delivery to Telegram/Discord/email

Don't use for: One-off checks (use web_extract or browser_navigate instead). This is for ongoing monitoring.

Prerequisites

1. ChangeDetection.io instance — self-hosted at http://localhost:5000 (or any URL) or use the SaaS plan at https://changedetection.io
2. API key — found in Settings → API tab in the ChangeDetection.io dashboard
3. changedetection-mcp installed — pip install changedetection-mcp (or run from source)

Setup

Option A: MCP Server (any MCP client)

Add to your MCP configuration:

{
  "mcpServers": {
    "changedetection": {
      "command": "changedetection-mcp",
      "env": {
        "CHANGEDETECTION_BASE_URL": "http://localhost:5000",
        "CHANGEDETECTION_API_KEY": "your-api-key"
      }
    }
  }
}

Option B: Hermes Config (recommended for Hermes users)

# Install the MCP server
pip install changedetection-mcp

# Add as an MCP server to Hermes
hermes mcp add changedetection --command "changedetection-mcp"

Then set env vars in ~/.hermes/.env:

CHANGEDETECTION_BASE_URL=http://localhost:5000
CHANGEDETECTION_API_KEY=your-api-key

Usage Examples

Create a watch

Can you watch https://example.com/product-page for price changes? Check hourly.