“Summarize this” is one of the most common requests people make of AI, and one of the most often disappointing. The usual result is a shorter version of everything, when what you needed was the three points that matter to you. The fix is in the request.
1. Say what the summary is for
A summary for a manager who must make a decision is different from one for a colleague taking over the work. Tell the model who will read it and what they need to do afterwards.
2. Ask for a structure
Name the sections you want. For a report: main findings, supporting numbers, recommendations. For a contract: parties, obligations, deadlines, payment terms, termination. For a long thread: decisions made, open questions, who is doing what.
3. Work through very long documents in parts
With very long material, summarize one section at a time and then ask for an overall summary of those summaries. Details survive better than when everything is compressed in a single pass.
4. Ask what is unclear or missing
A good follow-up question is: “What in this document is ambiguous, contradictory or left unanswered?” It often reveals more than the summary itself.
5. Check against the original
Compare every number, name, date and obligation in the summary with the source text. A summary is a guide to the document, not a replacement for it, especially where money or legal responsibility is involved.
A prompt you can reuse
“Summarize the document below for a department head who has five minutes. Give me: the three main conclusions, the figures that support them, any risks mentioned, and the decisions being asked of the reader. Use bullet points and quote the original wording for any figure.”