In more detail
Context engineering is the craft of deciding what an AI sees before it answers: which documents, which instructions, which pieces of conversation history, which tool results. If prompt engineering was wording one clever question, context engineering is preparing the entire briefing folder.
It matters because answer quality is mostly context quality now. The same model gives a mediocre reply when asked cold and a brilliant one when handed the right facts in the right order — the difference between shouting a question at a stranger and briefing a well-prepared assistant.
Goes with