The $0.004 Decision: When Prompt Engineering Beats Model Upgrades
Receipts are not glamorous. That is precisely why they are useful. A receipt-item categoriser is not a benchmark leaderboard, a launch demo, or a dramatic agentic workflow with a glowing dashboard. It is the kind of small, repetitive business decision that quietly determines whether an AI system becomes a product or remains an expensive toy. A bottle of iced coffee needs a category. A supermarket item needs to land in the right expense bucket. The output must be parseable. The cost must be low enough to repeat thousands or millions of times. Nobody wants a philosophical essay from the model. They want a JSON array. ...