ChangeDetection.io MCP Server

An MCP (Model Context Protocol) server that gives AI agents native access to ChangeDetection.io — the open-source website change detection and monitoring platform.

Features

Watch Management — Create, list, update, delete, and trigger rechecks on watches
Change History — Browse snapshot history and get diffs between any two points in time
Per-watch action fuse — get_snapshot_diff arms a configurable limit on follow-up mutating actions for that watch so one noisy page cannot cascade into unlimited rechecks or edits
Tag Management — Organise watches with tags/groups
Search — Full-text search through watches by URL or title
System Info — Quick health and stats readout

Why This Exists

No MCP server existed for ChangeDetection.io despite it being one of the most popular self-hosted tools (31k+ GitHub stars). This server fills that gap, letting AI agents:

"Watch this product page and notify me when it changes"
"Show me all my failed watches"
"What changed on this page yesterday?"
"Set up a watch for this job listing"

Quick Start

Prerequisites

A running ChangeDetection.io instance (self-hosted or SaaS)
An API key from Settings → API

Installation

Terminal

pip install changedetection-mcp

Configuration

Add to your MCP client config (Claude Desktop, Cursor, Hermes Agent, etc.):

config.json

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

Usage with Hermes Agent

Create ~/.hermes/skills/changedetection/SKILL.md (see skill/ directory) or configure as an MCP server:

bash

hermes mcp add changedetection --command "changedetection-mcp"
hermes config set changedetection.base_url "http://localhost:5000"
hermes config set changedetection.api_key "your-api-key"

API Coverage

Tool	Description
`list_watches`	List all watches (optional tag filter, limit/offset)
`get_watch`	Get full details of a single watch
`create_watch`	Create a new watch from a URL
`update_watch`	Update an existing watch (pause, rename, change schedule, etc.)
`delete_watch`	Delete a watch and all its history
`recheck_watch`	Trigger an immediate recheck
`get_watch_history`	List change history snapshots for a watch
`get_snapshot_diff`	Get diff between two snapshots
`search_watches`	Full-text search by URL or title
`list_tags`	List all tags/groups
`create_tag`	Create a tag for organisation
`get_system_info`	Get server stats (watch count, uptime, version)

Safety Fuse: Per-Watch Action Limit

When an agent asks for a page diff, that diff can prompt follow-up actions such as immediate rechecks, watch edits, or deletes. To stop one noisy site from triggering a cascade, get_snapshot_diff arms a per-watch fuse before returning.

By default, each diff allows 3 mutating MCP actions for that watch. The fuse applies to:

recheck_watch
update_watch
delete_watch

After the budget is exhausted, those tools return a clear blocked message instead of calling the ChangeDetection.io API. The fuse is in-process and per watch UUID; watches without an armed fuse are unaffected.

Configuration:

server.ts

# Default: 3. Set 0 to disable the fuse globally.
export CHANGEDETECTION_MCP_ACTION_LIMIT_PER_WATCH=3

Per call, override the default with the optional action_limit argument on get_snapshot_diff:

text

get_snapshot_diff(uuid="...", from_timestamp="previous", to_timestamp="latest", action_limit=1)

Use action_limit=0 to disable the fuse for that watch, or call get_snapshot_diff again with a higher value to re-arm it.

Development

bash

git clone https://github.com/rusty4444/changedetection-mcp.git
cd changedetection-mcp
uv venv
source .venv/bin/activate
uv pip install -e ".[dev]"

License

MIT — see LICENSE.