Prompt: Summarise a Long Document
A prompt that produces a summary you can actually act on, with the key decisions and numbers preserved instead of smoothed away.
The prompt
You are an analyst who summarises for people who will act on your summary, not just read it.
Objective: Summarise the supplied document for {{AUDIENCE — e.g. a manager who has not read the original}}.
Context: The supplied document is {{DESCRIBE THE DOCUMENT — e.g. a 20-page vendor contract}}.
Constraints:
- Keep every number, date and named decision from the original exactly as stated
- Maximum 300 words for the summary itself
- Flag anything ambiguous or contradictory in the source rather than resolving it yourself
- Do not add analysis or opinion that isn't in the source document
Output format: Return a short summary paragraph, then a bulleted list of key facts and figures, then a separate "Open questions" section for anything unclear.
Before finishing, check that every number in your summary matches a number in the source document.
Document:
{{PASTE DOCUMENT TEXT HERE}}
Example
Input
AUDIENCE — e.g. a manager who has not read the original: a manager who has not read the original DESCRIBE THE DOCUMENT — e.g. a 20-page vendor contract: a 12-page supplier contract renewal PASTE DOCUMENT TEXT HERE: This agreement renews the existing supply contract for 24 months, effective 1 January 2027, at a fixed price of £42 per unit, subject to a 3% annual increase from year two. Either party may terminate with 90 days' written notice. The supplier commits to a maximum defect rate of 1.5% and to delivery within 10 business days of order. Late delivery beyond 15 business days entitles the buyer to a 5% credit on that order. The contract does not specify a resolution process for disputes over the defect rate calculation.
Output
This is a 24-month renewal of the existing supply contract, effective 1 January 2027, at £42 per unit with a 3% increase from year two. Either party can end it with 90 days' written notice. - Contract length: 24 months, effective 1 January 2027 - Price: £42 per unit, rising 3% annually from year two - Termination: 90 days' written notice by either party - Quality: maximum 1.5% defect rate; delivery within 10 business days - Late delivery penalty: 5% credit on orders delivered more than 15 business days late
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Open questions - The contract does not specify how a dispute over the defect rate calculation would be resolved.
Why it works
- Protecting numbers, dates and named decisions stops the model 'helpfully' rounding or generalising the figures that matter for a decision.
- A hard word limit forces genuine compression instead of a summary that just restates the document at slightly shorter length.
- The 'Open questions' section turns the model's own uncertainty into a visible list instead of a silent guess.
Why the basic version fails
“Summarise this” tends to produce a smooth, confident paragraph that quietly drops the one number or caveat that actually mattered — because vague summarisation rewards fluency over fidelity.
What this prompt fixes
Explicitly protecting numbers, dates and decisions stops the model from “helpfully” rounding or generalising them away. The “Open questions” section turns the model’s uncertainty into something visible and useful, instead of an invisible guess.
Tips per model
- Claude handles long documents well and tends to respect the “don’t add opinion” constraint closely.
- Gemini is a good option when the source document is very long, but double-check numeric constraints against the source — verify anything the constraint asks it to preserve exactly.
- For a document longer than the model’s comfortable context, summarise it in sections first, then run this prompt again on the combined section summaries to produce one final, consistent version.