What is a prompt? Definition and business implications

The prompt is the cornerstone of interaction with an LLM. Concretely, it is the text you type (or that your application sends in the background) to query the model. A minimal prompt can fit in one sentence; an elaborate prompt can include a role assigned to the model, a business context, examples (few-shot), a precise instruction, an expected output format, and negative constraints (“do not include X”). The quality of a prompt is measured against three criteria. Precision: no ambiguity about the expected output. Contextualisation: the model has the business elements it needs to answer. Structure: clean sections, clear hierarchy, instructions without contradiction. A bad prompt produces generic, off-topic responses, or confident hallucinations. A good prompt produces specific, actionable, reproducible responses. The same question, badly framed then well framed, can yield two radically different answers, with no change of model.