{"name":"unit_price_compare","title":"Unit Price Comparator","category":"math","description":"Compare 2+ products' price-per-unit across mass/volume/count, converting units within the same dimension, and flag the best value.","price_usd":0.001,"input_schema":{"type":"object","properties":{"items":{"type":"array","description":"Array of 2+ {name, price, quantity, unit} objects"}},"additionalProperties":false,"required":["items"]}}