AI email previews: What happens to your offer when AI summarizes it?

You may have checked every date in your email and still find that its AI summary gives readers the wrong deadline. In email consultant Jeanne Jennings’ published review of Gemini summaries, the end of the early-bird discount became the registration deadline. A subscriber could read that and assume they had less time to book than they actually did.

A summary may keep the price but omit a condition that would change what the customer will pay. We’ll look at examples from published reviews and discuss what to check in your own emails, from the wording of a discount to details placed inside an image. These examples can help you decide what needs a closer look before you send a campaign.

Key takeaways

1. Read the price together with its conditions. Customers need to know whether an amount covers one month or requires payment for a full year.
2. Check which messages the summary covers. The preview in the inbox may describe one email, while a conversation summary may include replies as well.
3. Put the conditions where the customer reads the offer, and include them in the email text even if they also appear in a banner. Then check the summary again to see whether it includes those details.
4. Keep a copy of the email that arrived, along with its summary so that you can refer to both later. Another recipient’s email app may summarize the same message differently.

What counts as an AI email preview?

Here, “AI email preview” means a summary generated by the recipient’s email app. You still write the preheader, but you do not write this summary. The app chooses what to include from the message or conversation and puts it into its own words.

Before comparing a summary with your email, check where you’re reading it. In the inbox, it gives the recipient a quick idea of the message, perhaps enough that they won’t open it. Open a conversation with several replies, though, and the summary may cover that exchange too. You’re then reviewing an account of the conversation, rather than just the email you sent.

 

The links for Apple Mail, Gmail conversation summaries, and Copilot in Outlook explain how to use each feature and who has access to it. Check the one you plan to use before sending your test.

(Source: Google Workspace)

Google’s Promotions annotations let you supply images and offer details for display in the inbox. They use structured markup, so you decide what information to provide. The Gemini summary is written separately; adding annotations does not let you choose its wording.

Things that might go wrong

What could go wrong with an offer, a date, or an instruction? The published reviews below give us some examples. We’ve also included sample promotions to explain what to look for, clearly marked so you can tell them apart from the reported results.

1. Does the summary keep the conditions of the offer?

One published BuzzStream comparison concerned advice about a car battery. The email said to keep it as charged as possible. In Gemini’s summary, that became 40% to 80%. Those numbers sound quite precise, but they weren’t in the advice the reader was supposed to receive.

Even a small change in a promotion can affect what someone expects to pay. Compare the offers below with the wording beside them. These are examples we’ve written to show the problem, not summaries captured from an email app.

 

Different wording is usually fine. “Members get free delivery” says the same thing as “Free delivery for members.” The harder question is whether a missing detail matters. You might leave a jacket’s color out of a general promotion, for instance. But if only that color is on sale, the customer needs to know.

Read a multi-product offer item by item. If the jackets are on sale and the shoes are full price, a summary saying “Discounts on jackets and shoes” is wrong about the shoes. The jacket discount may be described perfectly.

2. Does the summary explain what each deadline is for?

The first deadline in an event email is not necessarily the last chance to book. People may still be able to register after the early-bird price period ends, even if the event is later. All three dates can be correct in a summary and still be attached to the wrong thing.

Jennings’ newsletter review is a useful example. Her original newsletter offered 40% off a workshop until April 10, 2026; the workshop was on May 11 and 12. Gemini treated early-bird dates as the last dates to register. Jennings got a more useful answer when she asked for a longer summary. She changed the request, though, not the email copy.

Consider someone returning to this sample invitation on November 9. “Book by November 8 to save” tells them they have missed a saving, but leaves them to work out what booking costs now. 

You could spell out the two prices this way:

Before: Book by November 8 to save. Registration stays open until November 20.

After: Register by November 8 for the early-bird price. After that, you can book at the standard price until registration closes on November 20.

The extra explanation is for anyone booking after November 8: they can still attend, but they will pay the standard price. This is a suggested copy edit. We have not tested the summary it would produce.

When you read the summary, look for the booking deadline first. November 8 would be wrong here and could put someone off registering. November 20 is correct. If that date appears without the early-bird offer, the customer knows they can still book, but may miss the chance to save.

3. Does placing a condition beside the offer make a difference?

A condition in the footer is easy for a reader to miss. Moving it beside the offer makes the connection clearer in the email. Whether the summary picks it up is something you can check.

BuzzStream and Aira looked at this in their study of 628 summaries from 13 digital PR campaigns sent in March and April 2026. Information from the first half of the pitches appeared more often in summaries. That is worth investigating in your own emails, with one qualification: their pitches went to journalists, so the findings may not carry over to a retail offer.

Start with the line that gives the discount. If it says “20% off,” put “For orders over $100” right there, before the product descriptions. A customer can then read the entire offer without having to search for the terms.

The customer must spend over $100 to receive this discount. That is what the summary needs to explain. Mentioning $100 as a price or an amount saved would give them a different offer.

These findings do not tell us how many opening characters every app will read.

4. What happens to an offer shown inside an image?

In BuzzStream’s analysis of graphics and attachments, the summaries largely omitted information from the graphics. Copilot often said there was an attachment without telling the reader what it contained. For an email built around a promotional banner, that could leave out the offer itself. The findings apply to the examples in that study, so check what happens with your own email.

“Sale now on” could describe almost any promotion. Your banner is much more specific: 20% off, provided the order is over $100. Give that information in the body copy as well. Any deadline or eligibility rule shown in the banner belongs there too, as visible HTML text.

Visible text also gives the reader more options. As the W3C guidance on images of text explains, people can resize real text and adjust its appearance more easily than words inside a picture. If you do need an image of text, its text alternative should include the same words.

Keep the alt text for people who cannot see the image. Just don’t assume the summary will use it; the examples discussed above don’t show that every app does.

In Stripo, turn off images in the preview and read what remains. Can you still find the offer and its terms? That checks the email without pictures. Reading the actual summary in the receiving app tells you whether those terms were included in the summary as well.

5. Can the reader tell what to do next?

They should be able to understand any action that is still required, even if the summary uses different words from your button. A payment reminder makes this distinction particularly clear.

The store is still waiting for payment. That detail is missing from “Your order is confirmed,” so the customer may not realize they need to pay. “Your order is ready to ship” could also make them expect a delivery, even though the email says nothing about the order being ready.

The email can explain what the payment is for: “Complete payment so we can prepare your order.” Follow it with a “Complete payment” button. The customer then knows both why the order is waiting and how to continue.

Use bullets when they make instructions easier for a person to follow. In BuzzStream’s formatting comparisons, bullet content did appear in summaries, but where it sat in the email may have mattered too. Turning a sentence into a bullet is therefore something to try, not a way to guarantee its inclusion.

Jennings’ review of an event invitation found that the summaries included the event details but did little to encourage registration. The facts could be correct while the invitation lost some of its purpose. The review did not measure a drop in registrations.

How much this matters depends on the email. Someone reading a newsletter can choose from several articles. Someone receiving a payment reminder needs to know there is a balance to pay.

6. Will another recipient see the same summary?

BuzzStream’s recipient comparison produced Copilot summaries of 290 and 87 words for the same template. That is a substantial difference in length. To decide which was more useful, you would still have to read what each version included.

A reply can also change what a summary says. Google’s Gemini summary cards incorporate replies as the conversation continues. In Outlook, citations in a thread summary can take you to the message behind a detail. Check those messages before treating something absent from your original email as an error.

(Source: Microsoft)

The two summaries do not have to use the same words. “Annual billing applies” and “Billed once a year” convey the same information to the reader. In your notes, record the app and version, device, summary feature, account language, settings, and date. These details allow a colleague to see the conditions under which you obtained the result.

No summary may appear at all. Check whether the feature is available and enabled in the account before changing the copy. Google’s AI Inbox, for instance, draws on Primary and excludes Promotions and Social. This applies to AI Inbox, not to all summary features in Gmail.

An unchanged summary may be a saved copy of the first result. Unless you know the app generated it again, reopening the email gives you nothing new to count. Keep voice and chat answers in separate notes, with the request you used, as they may draw on other emails.

How to check an AI summary before sending

Use the approved brief as your reference. The summary can shorten the message, but someone relying on it should still understand the terms. Here is a way to review it using a sample jacket promotion.

1. Write down the facts that must remain clear

For our example, the brief says: 20% off selected jackets, on orders over $100, until November 8. Those are the details to look for in the summary. With your own promotion, add any other requirements from the brief, such as entering a code at checkout.

2. Prepare the email and send a test

Stripo’s preview and test-send options let you review the desktop and mobile layouts and send a copy to your test accounts. Use the accounts that support the summary feature.

Inbox preview lets you review the subject and preheader before sending. You can check the AI summary once the test arrives in the receiving app.

If your sending platform adds personalized content after export, use it to send a test as well. A condition added for one recipient belongs in the comparison, even though it wasn’t in the draft you reviewed in Stripo.

3. Keep a copy of the summary to refer to later

Keep the delivered email, along with a screenshot of the summary, including the subject and preheader, in your record. The offer can go in the same screenshot if it fits; otherwise, you have the saved email to refer to. Add how the summary was obtained: automatically, by clicking a button, or by typing a request. Keep that request with the result.

A summary made from copy-pasting into a chat is not a Gmail or Apple Mail result. If you use one for comparison, label it as a simulation. A summary-testing service may also produce a simulation, so ask where its results come from. Use suitable test data in any screenshots you plan to share.

4. Compare meaning against the fact list

Compare the terms in your brief with what the summary tells the reader. A missing condition and an invented claim need different corrections. You can record them using these labels:

 

If your colleagues disagree about an omission, ask them what they think the offer allows them to buy. A different expectation is a reason to look at the missing detail again.

5. Change one element and compare again

You won’t learn much from the next summary if you change several things in the email at once. When the minimum spend is missing, try moving “For orders over $100” beside the discount and sending the email again. Leave the wording and everything else alone for now. 

Then compare the two summaries to see whether the spending requirement has appeared. One comparison won’t prove why the result changed, but it gives you something to work from.

Read beyond the condition you were trying to fix. The summary may now include the minimum spend and still give the wrong deadline. Keep the earlier result for comparison, and try the revised email in other available apps before changing more templates.

You will still need to open the links and check the design on desktop and mobile. A summary can describe the offer correctly while the button takes the customer to the wrong page. Complete your usual accessibility review too.

Moving the spending requirement closer to the discount

We used a short-jacket promotion to check whether changing the offer conditions would affect the summary in Gmail and Apple Mail. Both versions had the subject “Your jacket offer” and offered 20% off selected jackets on orders over $100 until November 8.

In the first email, the conditions came after the button:

The summary in both apps read: “Get 20% off selected jackets until November 8.” It included the discount, the eligible products, and the deadline. There was nothing about how much the customer needed to spend.

We then moved the conditions directly below the heading:

After sending the revised email, we checked its summary in both apps again. This time, each included the spending requirement: “Get 20% off selected jackets on orders over $100 until November 8.”

The customer needed to spend over $100 in both versions. Moving that condition into the summaries we received did not remove any of the other offer details. This gives us a useful example to refer to when a summary misses a restriction. It does not establish that the same edit will work for every email or account.

Wrapping up

For the next campaign, choose an offer you know well and read what the email app says about it. You may find that it is accurate already. If a condition is missing or a date has changed meaning, use that specific detail for your first edit.

Save the attempts that made no difference, as well as those that helped. They give your team examples to refer to when another email has the same problem. Any effect on clicks, sales, or delivery would need to be measured separately.