The 2025 rebranding of prompt engineering for the agent era: not writing a clever instruction but deciding everything the model sees, the documents, the tool results, the history, the summaries of what it has forgotten. A chief executive proposed the phrase in June 2025, a well-known researcher agreed, and the labs published guides under the name within months.
Sighted in the autumn of 2025 as a job title, replacing 'prompt engineer' on the same advertisements at the same salaries. The record notes that a rename can be a promotion and that this one was, in the sense that the work had become harder and the word admitted it.
The record's distinction: prompt engineering is what you say; context engineering is what you let it read. The second became the job once agents ran for hours and the window filled with tool output, most of it irrelevant. The craft is curation. The record notes it was called 'editing' in a previous century.
Not a new discipline, whatever the tweets said. Retrieval, summarising history, and choosing what to put in the prompt were the whole of RAG and agent engineering since 2023. The phrase's contribution was a better name, which the record considers a real contribution and files under 'coinage', not 'invention'.
I remember the week the phrase arrived, because three colleagues used it in the same meeting and none of them had said it before. Nobody asked what it meant. Everybody knew, which is the sign of a good coinage: it names the thing you were already doing badly.
What does it mean? Write it the way you would say it out loud.
