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
pip install changedetection-mcp
Configuration
Add to your MCP client config (Claude Desktop, Cursor, Hermes Agent, etc.):
{
"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:
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_watchupdate_watchdelete_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:
export CHANGEDETECTION_MCP_ACTION_LIMIT_PER_WATCH=3
Per call, override the default with the optional action_limit argument on get_snapshot_diff:
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
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.