Summarize long documents and email threads

A 40-page contract, a supplier’s terms, or an email thread with 30 replies can eat an hour before you even know what it says. This guide shows you how to get an AI tool to give you the short version: what it’s about, what you need to do, and by when, with every point traced back to the original so you can check it.

Before you start

• The AI tool you normally use, such as ChatGPT, Claude, Gemini or Microsoft Copilot. Most can read a PDF or Word file you upload.
• One long document or email thread you need to deal with this week.
• About 15 minutes.

Want to do it yourself?

Difficulty

4 out of 10

Estimated completion time

20–45 minutes per document set

Skills you’ll need: Remove private information, provide complete source material, and check the summary against the original passages.

I’ll do it myselfI’d rather get help

How this helps your brand

Source-linked summaries help you understand the terms and commitments behind your business decisions. Checking the details you act on supports reliable delivery and reduces the chance of repeating an incorrect promise.

1. 1

   Step 1: Decide what you need from it

   A summary is only useful if it answers your question. “Summarise this” gets a bland overview. “What do I have to do, and by when?” gets something you can act on.

   Before you start, write down why you’re reading it. For example:

   • “Do I need to reply to this thread, and what’s the decision they’re waiting on?”
   • “What does this contract say about cancelling and late payment?”
   • “What’s changed in these new supplier terms compared with the old ones?”
2. 2

   Step 2: Take out anything private

   Before you upload or paste anything into an online AI tool, think about who and what is in it. Email threads often include customers’ names, phone numbers and addresses. Contracts can include bank details and signatures.

   For a short thread, swap names for placeholders like [customer] and delete contact details. For a long document full of private details, consider private AI on your own computer instead. The “Ask questions about your own documents privately” guide shows how.

   Tip: Check whether your AI tool’s plan uses your uploads to train its models, and switch that off if you can. The tool’s official privacy page explains how.

3. 3

   Step 3: Give it the whole thing, in order

   Upload the file, or paste the full text. For an email thread, copy it from oldest to newest so the AI can follow who said what and when.

   If the document is very long and the tool says it’s too big, split it into sections, such as chapters or a few pages at a time, and summarise each one. Then ask for a combined summary of the summaries.

   Tip: Some email apps and office tools now have a built-in summarise button. Search your app’s help pages for “summarise” to see whether yours does and what it costs.

   Illustrated exampleKeep the thread in the order it happened

   Example email threadSubject: Approving the print proof

   Private names replaced with roles. Read from top to bottom.

   1. 112 October
      [supplier]

      “Please approve the proof by 16 October.”

   2. 213 October
      [your team]

      “Could we have until Monday to check it?”

   3. 314 October
      [supplier]

      “Agreed. Please approve by 19 October at noon. The total is £480.”

   ↳ The latest reply changes the deadline. Include all three messages.

4. 4

   Step 4: Ask for actions, dates and sources

   Use the prompt at the end of this guide. It asks for a short summary, then a list of anything you need to do, any dates or deadlines, any money involved, and open questions, with a note of where each point appears in the original.

   Asking for the location of each point is what makes the summary checkable. Without it, you’re trusting that the AI read it correctly.

   Illustrated exampleTurn the thread into a checkable action list

   From the same example thread

   The supplier is waiting for your approval of the print proof.

   Action

   Approve the print proofYou → [supplier]

   14 October email
   [supplier]

   Deadline

   19 October, noonReplaces the earlier 16 October date

   12 + 14 October emails
   [supplier]

   Amount

   £480 totalPayment due date is not stated

   14 October email
   [supplier]

   Open question

   When is payment due? Ask the supplier; the thread does not say.

5. 5

   Step 5: Check the parts you’ll act on

   AI summaries can miss a key line or get a number wrong, especially in long documents. You don’t need to reread everything. For each action, date and amount you’ll rely on, find it in the original and check it says what the summary claims.

   For contracts and anything legal or financial, use the summary to understand it and to prepare questions, then check important points with a professional adviser before you sign or act.

   Illustrated exampleFollow a deadline back to the original

   Summary claim to check

   Approve the print proof by 19 October.

   Source: [supplier], 14 October email

   Find that email in the original

   “Agreed. Please approve by 19 October at noon. The total is £480.”

   ✓

   Keep the time as well as the date

   Checked action: approve the proof by 19 October, noon. A date alone could hide a missed deadline.

Please summarise the document or email thread below for me. I’m a busy small business owner, so keep it short and in plain English.

What it is: [for example, a supplier contract, an email thread with a customer]
Why I’m reading it: [for example, I need to know whether I can cancel early]

Please give me:
1. A summary in five sentences or fewer.
2. Anything I need to do, as a list, with who it’s for.
3. Every date, deadline and amount of money mentioned.
4. Any open questions or decisions waiting on me.
5. For each point, where it appears in the original (page, section, or which email and who sent it).

Use only what’s in the document. If something is unclear or missing, say so instead of guessing.

[Upload the file, or paste the text here with private details taken out]