product-price-monitor

Product Price Monitor

Monitor a concrete purchasable item and alert on a normalized all-in price or availability condition. Handle variants, taxes, fees, currencies, stock, cancellation terms, and duplicate alerts explicitly. Setup runs once in the foreground; the recurring check runs as a cronjob tick (the price-watch automation blueprint scaffolds this).

When to Use

• "Alert me when this laptop drops below $1,000."
• "Watch these flights for a fare under $500."
• "Tell me when this hotel has a refundable room."
• "Track ticket/listing availability."
• A cron tick fires for an existing price watch (steps 4-6).

Don't use for: one-off "what does this cost right now" lookups (use web_search/web_extract directly).

Procedure — Setup (foreground, once)

1. Define the exact item

Record source URL/provider, product/listing ID where available, variant, quantity, location, dates, travelers/guests, membership/login assumptions, condition, seller, and acceptable substitutes. Done when two variants cannot be confused.

2. Define the alert condition

Specify currency, all-in vs pre-tax price, maximum price, availability/stock rule, shipping, refundability, cabin/room/ticket class, cooldown, and notification destination. Done when synthetic examples have deterministic alert decisions.

3. Establish a live baseline, then schedule

Fetch a bounded live result with web_extract or browser_navigate and record retrieval time, source price, fees/taxes, availability, and terms. Do not schedule until one foreground fetch works. Write the watch contract (item, condition, baseline observation) to a state file under ~/.hermes/price-watches/<watch-slug>.json, then create the job:

cronjob(action="create",
        schedule="every 6h",
        prompt="Load the product-price-monitor skill and run the tick for the watch contract at ~/.hermes/price-watches/<watch-slug>.json.",
        deliver=<user's destination>)

Pick a cadence that respects rate limits and site terms. Done when the baseline matches the exact item contract and the job exists.