Open-source MCP server gives agents page-change tracking with SHA-256 capture certificates
Einperegrin · reddit · 2026-09-24
The builder open-sourced @captureze/mcp (MIT, Node 20+), an 18-tool MCP server that goes beyond screenshots: scheduled monitoring, pixel diffs between captures, change percentages, and a 'Certificate of Capture' (SHA-256 + UTC timestamp + public verification URL), plus cookie-banner/CMP detection.
Key design lessons for MCP builders:
- Ad-hoc captures create sites paused so agents don't leave cron jobs behind
- Error text written as agent instructions ('needs Pro — report, don't retry') to stop blind retries
- Tool descriptions state the 10–60s capture time to prevent duplicate calls
- Images over 4.5MB return as URLs to protect the context window
- Stateless, multi-tenant HTTP transport with per-request bearer tokens
The server is free and MIT-licensed; it talks to the paid Captureze product with a 7-day no-card Pro trial.
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