Price Watcher

Monitor product URLs to track and alert on significant price changes using a local watchlist without requiring API keys.

Monitor product URLs for price changes via a local watchlist. No API keys required.

Skill Location

~/.openclaw/workspace/skills/price-watcher/

All scripts use SKILL_DIR (parent of scripts/) to resolve watchlist.json.

Core Workflow

Add a product to watch

# Auto-fetch current price from page
python3 scripts/add_product.py "https://www.amazon.com/dp/BXXX"

# Explicit price + name (use when auto-fetch fails)
python3 scripts/add_product.py "https://..." 49.99 "Product Name"

Check all prices

python3 scripts/check_prices.py

Outputs JSON to stdout. Updates watchlist.json with new prices and timestamps.

Filter significant changes

python3 scripts/check_prices.py | python3 scripts/compare.py
python3 scripts/check_prices.py | python3 scripts/compare.py --threshold 10

Default threshold: 5%. Always surfaces fetch errors and no-price results.

Format as markdown alert

python3 scripts/check_prices.py | python3 scripts/compare.py | python3 scripts/format_alert.py

Produces a markdown report with 📉 drops, 📈 increases, and ⚠️ errors.

Watchlist Format

watchlist.json (in skill root) stores an array of objects:

{
  "url": "https://...",
  "name": "Product Name",
  "baseline_price": 49.99,
  "last_price": 44.99,
  "last_checked": "2024-03-15T14:00:00+00:00",
  "price_history": [{"price": 49.99, "date": "..."}]
}

See assets/watchlist.example.json for a full example.

Scheduling

For cron setup, threshold tuning, and anti-bot notes, see references/setup-guide.md.

Error Handling

• fetch_error: Page couldn't be retrieved (503, timeout, network issue)
• no_price: Page loaded but no price found — check if site layout changed
• Both statuses surface in compare.py output and format_alert.py regardless of threshold
• add_product.py exits with an error if price can't be extracted and none was provided manually