How to summarize a long document without losing what matters

Where do you start when summarizing a long document?

With the question, not with page one. A summary is not a shorter version of the document: it is the answer to what someone needs to know. The same contract is summarized differently for the person deciding whether to sign it, the person who has to make the payments, and the person who only needs to know when it expires.

Before you read, write one line stating which decision the summary will support and who will read it. For example:

• Should I sign this, and what am I committing to?
• What does this report conclude, and on what basis?
• What do I have to do, by when, and what does it cost?
• What changed compared with the previous version?

That line is your filter. Anything that does not help answer it can be left out without regret.

How do you summarize a long document or PDF by hand, step by step?

In two passes: a quick one to understand the structure and a targeted one to mark the facts. Reading straight through once is the slowest approach and the one that misses the most.

1. Skim the structure. Read the table of contents, headings, introduction and conclusions. Note in a few words what each section covers.
2. Find the sections that answer your question. In a contract these are usually scope, price, term, obligations, termination and penalties. In a report, method, results and limitations.
3. Mark the hard facts. Dates, amounts, percentages, deadlines, names of the parties and who is responsible.
4. Mark the obligations. Who must do what, for whom, and by when.
5. Mark conditions and exceptions. Look for phrases such as unless, provided that, except where, subject to, up to a maximum of.
6. Check the appendices and footnotes. Price tables, definitions and exceptions tend to live there.
7. Group what you marked by topic, not by the order it appears in.
8. Write the gist last. Only once you have the facts can you say in four or five lines what the document is about and what it implies.

Keep the document's own wording for critical details. If the text says "thirty business days", do not write "a month": they are not the same.

What should a summary of a contract or report always include?

The items that, if missing, would lead the reader to a bad decision. They vary with the type of document.

A good summary keeps what the document says apart from what you make of it. If you add an opinion or a doubt, label it as one.

What are the risks of summarizing a document with AI?

There are three, and none is obvious at a glance, because the output always reads as fluent and confident.

• Dropping exceptions and conditions. The summary says the contract renews every year and leaves out that you must give advance notice to stop it.
• Inventing details. A date, amount or name that is not in the text can appear, or a real fact can be assigned to the wrong party.
• Flattening nuance. "May" becomes "must", an estimate is presented as a result, and a hedged conclusion turns into a flat statement.

The risk grows with length. In very long documents, material in the appendices or near the end gets less attention, and some tools process only part of the file.

How do you check an AI summary?

By comparing it with the source at the points where a mistake would be expensive. You do not have to reread everything.

1. Verify every number and every date in the summary by finding it in the document.
2. Confirm each obligation is assigned to the right party.
3. Read the termination, penalty and renewal clauses yourself.
4. Search the source for the words that signal exceptions and see whether the summary reflects them.
5. Ask what is not in the summary: appendices, definitions, footnotes, limitations.
6. Confirm the whole document was processed, not just the first part.

If an earlier version of the document exists, it is also worth using a tool to compare the documents and see what changed, rather than relying on two summaries produced separately.

When should you not rely on a summary?

When the decision has consequences that are hard to reverse. Before signing a contract, accepting a condition, answering a legal notice or deciding something about your health, a summary tells you where to look; it does not excuse you from looking.

In those cases read the full text of the critical sections, and if something is unclear, ask a professional. A summary, whether written by hand or produced by a tool, is not legal or medical advice.

What about privacy when you upload a document to summarize it?

It depends on the service, and you should find out before uploading anything. Contracts, medical reports and employment records contain other people's data that is not yours to expose. Check whether the service stores files, for how long, and who can see them.

If the document holds personal data the summary does not need, you can remove it first with the anonymize document tool.

What our tool does

The summarize document tool returns three things: a short summary, the key points, and the important details in the text, such as dates, amounts, deadlines, parties and obligations. It accepts PDF, Word and text files, as well as scanned PDFs and photos of documents, which it reads with text recognition.

It has two limits worth knowing. Very long documents are processed only up to a certain size, and when that happens the tool says so. And the result is a reading aid: check it against the source as you would any other summary. Uploaded files are deleted when processing ends.

What should you check before using a summary, and which mistakes should you avoid?

1. The summary answers the question you set at the start.
2. Every figure and date matches the source.
3. Conditions and exceptions sit next to the rule they modify.
4. It is clear who must do what, and by when.
5. What the document leaves unresolved is stated.
6. The whole document was processed, appendices included.

• Summarizing without a question. You end up with an expanded table of contents that supports no decision.
• Writing the gist first. You then bend the facts to fit an idea you already had.
• Rounding deadlines and amounts. The exact details are the useful part.
• Skipping the appendices. They often hold what matters most.
• Forwarding an automatic summary unchecked. The recipient assumes someone verified it.
• Signing on the strength of the summary. What binds you is the full text.