Monitor web pages for changes, price drops, stock availability, and custom conditions. Use when a user asks to watch/track/monitor a URL, get notified about price changes, check if something is back in stock, or track any website for updates. Also handles listing, removing, checking, and reporting on existing monitors. v3 adds change summaries, visual diffs, price comparison, templates, JS rendering, and webhooks.

监控网页的变化、价格下跌、库存状态和自定义条件。当用户要求监视跟踪某个URL、获取价格变动通知、检查商品是否重新有货或跟踪任何网站更新时使用。还支持管理现有监控任务，包括添加、删除、查看和报告。v3版本新增变更摘要、视觉对比、价格比较、模板、JavaScript渲染和Webhook功能