Price watcher

# Zero-LLM: pure diffing, free to run forever. Ships pointed at a
# scrape-friendly demo bookshop so it works out of the box — swap in the
# pricing page (and selector) you actually care about.
blueprint:
  id: price-watcher
  title: Price watcher
  description: >-
    Watches the prices on a page and alerts the moment any of them change.
    No LLM at all — pure change detection, free to run. Ships pointed at a
    demo bookshop; swap in the pricing page you care about.
config:
  synth:
    name: Price watcher
    goal: Alert me when a price on the page changes.
    schedule_seconds: 3600
  requires_credentials:
    - WEBHOOK_URL
  sources:
    - id: shop
      primitive: dom_scrape
      config:
        url: https://books.toscrape.com/
        selectors:
          prices: ".price_color"
  fast_path:
    primitive: fast_path_diff
    inputs:
      current: $sources.shop.prices
      previous: $state.last_prices
  actions:
    - if: $fast_path.triggered
      primitive: notify_webhook
      config:
        url: $secrets.WEBHOOK_URL
        body:
          alert: A price changed
          changes: $fast_path.diff
    - always: true
      primitive: write_state
      config:
        last_prices: $sources.shop.prices
        checked_at: $tick.started_at