Summarise Long Documents Without Losing the Thread
What it is
Summarising a long document by having Claude condense it in sections and then reconcile those into one coherent brief — while explicitly tracking the argument that runs through it.
Why it works
Claude reads long context well, but a naive 'summarise this' can flatten a document into disconnected bullet points and lose the actual argument. Summarising in parts and then merging keeps both the detail and the through-line.
When to use it
Long reports, papers, transcripts, and books where a one-shot summary risks dropping either nuance or the overall thread.
When not to use it
Short documents that fit comfortably in a single read — the extra structure is wasted there.
Prompt
Summarise this long document faithfully.
1. First, in one line, state the document's central argument or purpose.
2. Then summarise each major section in 2-3 sentences.
3. Finally, give a merged brief that keeps the through-line from step 1.
Flag anything where sections contradict each other.
<document>Example
On a 60-page strategy doc, Claude names the core thesis, condenses each part, and surfaces that section 4 quietly contradicts the headline goal — the single most useful thing in the summary.
Advanced version
Ask Claude to produce the summary and a list of the three claims most worth verifying against the source, so you know where to spot-check rather than trusting the whole thing.
Common mistakes
- Accepting a bag of bullet points that lost the argument connecting them.
- Assuming Claude ingested the entire document — confirm coverage on very long inputs.
- Never spot-checking, so a confident-but-wrong line rides along unnoticed.