The tables market-orders (partition key customer, sort key placed) and market-carts already exist. ~/catalogue.json is a batch of the eight monsters, keyed by id. A supplier sent two items in ~/supplier/, one of them a monster the market already has.

1. Create the on-demand table market-monsters, keyed by the string id, and load the catalogue into it.
2. Mossback (m-002) now costs 50.
3. Put both supplier items into the table so that a monster that exists is never overwritten. One of them should be refused.
4. Add a global secondary index by-type with type as its partition key and price as its sort key. Once it is active, save the fire monsters, cheapest first, to ~/fire.json.
5. How many orders did ada place in October 2026? Read only her October orders to find out.
6. Carts must expire on their own: turn on TTL for market-carts on the attribute expires_at.