mcp-page-monitor

A Model Context Protocol (MCP) server that watches web pages and fires alerts when their content changes. Designed to be dropped into any MCP client (Claude Desktop, WorkBuddy, custom agents) so an AI assistant can "keep an eye on" pages without polling them itself.

┌────────────┐   add_target / check_target   ┌──────────────────┐
│  MCP Client │ ───────────────────────────▶ │  page-monitor    │
│ (assistant) │ ◀─────────────────────────── │  (FastMCP)       │
└────────────┘      change status / alert    └────────┬─────────┘
                                                      │
                              ┌───────────────────────┼───────────────────────┐
                              ▼                       ▼                       ▼
                        ┌──────────┐          ┌──────────────┐        ┌────────────┐
                        │ fetcher  │          │  differ      │        │ alert sink │
                        │(requests)│ ───────▶ │(hash + LCS)  │ ─────▶ │(console/..)│
                        └──────────┘          └──────────────┘        └────────────┘

Why this exists

LLMs are bad at polling — they can't sit and wait. But they're great at reacting to a change notification. mcp-page-monitor bridges that gap: register URLs once, and the server tells the assistant what changed in plain text whenever a page moves.

Features

Feature	Notes
Multi-target watching	Register many URLs, each with its own sensitivity
Robust diffing	SHA-256 hashing + difflib LCS; whitespace/case-insensitive
Adjustable sensitivity	threshold (default 0.98) suppresses cosmetic noise
Pluggable alerts	ConsoleAlertSink built in; subclass AlertSink for Slack/email/webhook
Network-free core	Diff/monitor/alert logic is 100% testable without internet

Install

pip install -r requirements.txt

Use as an MCP server

python -m mcp_page_monitor.server

Then in your MCP client config point to the module. Tools exposed:

• add_target(url, name?, threshold?) — start watching a page
• check_target(url) — fetch, diff vs baseline, return change status

Use the engine directly

from mcp_page_monitor.monitor import PageMonitor
from mcp_page_monitor.alerts import ConsoleAlertSink
from mcp_page_monitor.fetching import fetch_url

mon = PageMonitor(fetcher=fetch_url, alert_sink=ConsoleAlertSink())
mon.add("https://example.com", threshold=0.95)
mon.check("https://example.com")   # baseline
mon.check("https://example.com")   # alerts if content shifted

Architecture in one line

fetch ➜ normalize ➜ hash+diff ➜ (changed?) ➜ alert

The diff math (identities verified by tests):

• identical pages ⇒ similarity == 1.0, changed == False
• one line changed in 100 ⇒ similarity ≈ 0.99, changed == True under strict threshold
• first observation is always a baseline and never alerts

Project layout

mcp-page-monitor/
├── mcp_page_monitor/
│   ├── __init__.py
│   ├── differ.py      # hashing + diff (no deps)
│   ├── monitor.py     # polling engine (fetcher injected)
│   ├── alerts.py      # alert sinks
│   ├── fetching.py    # requests-based fetcher (prod only)
│   └── server.py      # MCP/FastMCP adapter (lazy import of mcp)
├── tests/
│   └── test_monitor.py
├── conftest.py
├── requirements.txt
├── README.md
├── LICENSE
└── .gitignore

License

MIT © wzx11223344