At every major inflection point in programmatic advertising, the industry goes through a familiar phase. A powerful new idea emerges, and then the debate over what it actually means follows.
Agentic advertising is firmly in that moment.
During a recent Innovators Unscripted live conversation, Brian Morrissey, founder of The Rebooting, sat down with Andrew Casale, president and CEO of Index Exchange, and Ant McDonagh, chief trading officer, North America at dentsu, for a candid conversation about what agentic advertising really is and where it’s already beginning to deliver impact.
Cutting through agentic confusion
Every wave of innovation begins with a period of definition setting. Agentic advertising is no different.
“There’s so much hype and there’s so much dialogue and there’s so much really cool innovation happening,” Andrew said, describing what he calls agentic confusion. “But there are also multiple solutions to our problems happening simultaneously. It’s almost too much for everyone to grok and keep on top of at once.”
To help cut through that confusion, he framed agentic advertising around two broad—and complementary—areas.
The first is workflow automation. This uses agents on both the buy and sell sides to automate tasks within the ad server that have historically required significant human time and effort. Industry efforts like the Ad Context Protocol (AdCP) are helping define how agents can communicate in these automated workflows.
The second is around sell-side decisioning, which brings AI-powered decisioning closer to the origin of the impression. This is where consumer context, data, and models can operate together more efficiently. The Agentic RTB Framework (ARTF), launched by the IAB Tech Lab, provides a standardized foundation for these types of agentic use cases.
“If we can move away from the model of ad tech operating at great distance to one where you have the impression, the consumer, the publisher, the data, the decisioning models—eventually agents—and then, to cap it off, really powerful GPUs very close to the impression, we can do things that we’d almost consider to be otherworldly.”
Andrew Casale, President and CEO
Index Exchange
What this looks like from the agency side
From an agency perspective, the promise of agentic systems is already tangible.
As Ant described, dentsu is a large-scale people and knowledge business, with tens of thousands of employees operating across markets and disciplines. Capturing, transferring, and applying that knowledge consistently is a real challenge—and one where agentic approaches are already delivering value through improved efficiency.
Over time, Ant predicts agentic systems will change how agencies are structured and how people spend their time.
“We’ll integrate very, very closely with agents. But we’ll assume supervisory roles. We’ll assume policymaking roles. We’ll assume model-making roles to ensure they’re delivering the way they should for our clients.”
Ant McDonagh, Chief Trading Officer, North America
dentsu
Outcomes at scale: what agentic advertising unlocks for the open internet
The conversation also addressed a reality the industry can’t ignore: Walled gardens already deliver outcome-based buying at scale.
As Ant noted, that advantage isn’t accidental. Walled gardens control the full stack, which includes technology, data, infrastructure, and compute. That level of control allows them to optimize quickly and deliver credible outcome-based solutions. For many marketers, those capabilities already work.
But that model has limits. It’s difficult for marketers to analyze holistic performance or understand how AI actually drove an outcome, which, in turn, limits their ability to apply consistent decisioning across channels.
“If we are only able to deliver an agentic solution within one garden and another garden and another garden, we’re not really solving the critical challenge that we’re being tasked with by our clients, which is: Grow my business holistically.”
Ant McDonagh, Chief Trading Officer, North America
dentsu
That’s where agentic advertising changes the equation for the open internet.
No independent publisher has the same combination of scale, data, and compute as the largest platforms—but collectively, the open internet does. Agentic approaches create a path to delivering similar outcome-driven capabilities without requiring every participant to independently rebuild the same infrastructure.
By enabling more shared, interoperable approaches, the open internet can efficiently deliver outcomes at scale while preserving transparency, flexibility, and choice.
“There are many benefits that we have already seen in some of the tests that we’ve run with sell-side decisioning that have shown us the ability to have a more transparent view across what is available in the ecosystem on the impression level…and to be able to provide a greater diversity of decisioning to our clients based on what’s important to them.”
Ant McDonagh, Chief Trading Officer, North America
dentsu
Standards as the catalyst
So what needs to happen next?
The answer is already emerging: shared standards, deeper collaboration across buy- and sell-side partners, and continued real-world testing.
“Scale is key for us in this space,” said Ant. “If we can only do this on a subset of the open internet, the cost benefit for us and our clients is not going to be there.”
Standards like AdCP and ARTF make it possible for innovation to scale without fragmenting the ecosystem. They allow companies to focus on solving specific problems well, while still operating within a shared framework that benefits the broader market.
“More partners leaning into the standards will help accelerate this…a growing number of buyers leaning in with their budgets, bringing their clients into it, will just continue to help this accelerate.”
Andrew Casale, President and CEO
Index Exchange
Agentic advertising is no longer theoretical. With shared standards and collective momentum, the open internet has a clear path to delivering outcomes at scale—while preserving transparency, choice, and long-term value for buyers and media owners alike.
Learn more about how you can activate intelligence on the sell side and drive stronger outcomes with sell-side decisioning and agentic AI solutions.
