That is the most dangerous conclusion you could reach, and I understand exactly why you reached it. Let me explain why optimizing for the machine layer is a trap.

The AI summary is not your enemy. It is a filter that rewards clarity and punishes manipulation. If your email has a clear value proposition in the first 100 words, the AI summary will reflect that accurately. If your email buries the point under three paragraphs of brand storytelling, the summary will expose that emptiness. The AI is not rewriting your message. It is revealing whether your message had substance in the first place.

The human fits where they have always fit: as the person whose attention both AIs are competing over. Think about what is actually happening. The sender AI is trying to generate content that drives engagement. The receiver AI is trying to surface content that the recipient actually wants. These are not opposing goals. They are the same goal approached from different sides.

The senders who lose this arms race are the ones who use AI to generate more volume at lower quality. The AI spam filters at Gmail and Outlook are specifically trained to detect generic, templated AI output now, and they are getting better at it every month. So if your sender AI is just churning out variations of the same promotional template, the receiver AI will catch it and filter it.

Exactly. And this is where it gets interesting for deliverability specifically. The old signals still matter. Authentication, complaint rates, bounce handling, list hygiene. But engagement is becoming the dominant signal, and engagement in a world of AI-summarized inboxes means something different than it used to.

Open rates were already unreliable after Apple's Mail Privacy Protection. Now they are doubly unreliable because a recipient might read the AI summary and get the information they need without ever opening the email. That registers as a non-open, but the recipient actually engaged with the content. Click-through rates and conversion events become the only reliable engagement signals.

Correct. And here is where I think the real strategic insight lives. The winning approach in 2026 is not to optimize for the AI. It is not to optimize for the human. It is to make content so clear and so relevant that both the AI and the human reach the same conclusion: this email deserved attention.

That means shorter emails with the value proposition in the first sentence. It means genuine personalization based on behavioral data, not just a first name token. It means sending less frequently but with higher relevance per send. The inbox AI rewards exactly the same things that humans reward. It just enforces the standard more consistently than humans ever did.

That is the most concise way to put it. The senders who were already doing it right, clear content, proper authentication, genuine engagement, real list consent, those senders have nothing to worry about from AI-powered inboxes. The senders who were getting away with mediocre practices because human inboxes are messy and people do not always unsubscribe even when they should, those senders are about to have a very difficult year.

It is real in capability and overhyped in practice. Yes, the technology exists to personalize content, send time, and frequency for each individual recipient. Klaviyo, Braze, and others offer this. But most brands do not have the data depth or the content library to make true segment-of-one work. You need hundreds of content variations and rich behavioral data across multiple touchpoints. Most brands have five email templates and a purchase history.

The practical advice is to focus on getting from five segments to fifty segments before worrying about getting to a segment of one. That alone will drive meaningful improvement in engagement, which in turn improves your sender reputation, which in turn means the receiver AI treats your mail more favorably. The fundamentals compound.

That is exactly right. The AI arms race is not a new game. It is the same game with stricter referees.