Compression removes exceptions first, because exceptions are short and look like detail.
Do now: Summarise one document, then hunt specifically for what it dropped.
Ask for the conditions, not just the content.Summarising is the single most-used AI task and the one where quality is hardest to see. A good summary and a dangerous one look identical until somebody acts on the missing clause.
Ask for structure, not just brevity
'Summarise this' invites the model to compress toward the average shape of a document, which flattens exactly what makes yours specific. Ask instead for a structure: what it claims, what evidence it offers, what conditions apply, what it does not cover, and what remains uncertain.
Ask for section references. If every point can be traced back to a heading or page, you can check the two that matter without rereading the whole thing. Without references, verification means reading it all anyway, which defeats the purpose.
For anything consequential, ask twice with different framings — once for what it says, once for what it requires you to do. Those often produce different documents, and the gap between them is usually where the important content lives.
A summary without section references is not checkable. Checkability is most of its value.
Comparison needs disagreement preserved
When comparing documents, the useful output is not a merged overview. It is: what both agree on, where they genuinely differ and in whose words, what each omits, and what neither addresses.
Instruct explicitly against smoothing. A model asked to compare will often produce a diplomatic synthesis in which no real conflict survives, because balanced prose is what it has mostly seen. The conflict is usually the finding.
Watch for false equivalence in the other direction too. Two positions can be presented as evenly matched when one is supported by evidence and the other is an assertion. Ask what supports each claim, not just what each claim is.
Read the parts that decide
Use the summary to navigate, then read the original where it matters: the conditions, the exclusions, the deadlines, the definitions, and anything you would quote or act on. That is usually a small fraction of the document and it is the fraction that carries the consequences.
Definitions deserve particular attention because they silently change scope. A contract defining 'delivery' as arrival at a depot rather than at your premises is a different contract, and no summary will flag it as remarkable.
Keep the summary and the source together. A summary that has travelled away from its original, with no reference and no date, becomes a rumour with formatting.
Summaries are for navigating. Decisions are made from the original.