Editorial: the agent layer. Three possible owners.
This week Google rebuilt Search around Gemini 3.5 Flash. AI Mode has 1 billion users. OpenAI runs its own ads manager. Anthropic and Perplexity arrive rented by Meta, TikTok and Walmart. The agent layer has three possible owners.
Mariano De Vitto · May 2026
This week Google rebuilt Search around Gemini 3.5 Flash, OpenAI ran a full quarter with its own ads manager, and Meta added Perplexity as its third certified model. Read together, those aren't three separate news items. They're the opening of the fight over who owns the agent layer: the one that talks to the consumer and the one that talks to the advertiser.
The agent layer is the place where someone asks and someone answers. If a person looks for a product, they ask an agent which one fits. If a brand wants to buy inventory, it tells an agent to set up the campaign. Twelve months ago, the first happened on Google, Amazon or TikTok, and the second happened in a visual console. Now, the same agent can handle both questions. Whoever owns that agent collects a toll twice: on product discovery and on media operation. That's the structural fight of the next year, not the release of a new model.
The three contenders
Three possible owners, three different business models. One, **Google**. Ask Advisor sits across Google Ads, Analytics, Merchant Center and Marketing Platform. AI Mode has 1 billion users. AI Overviews has 2.5 billion. Vertical integration is total: the brand pays for media, pays for the agent that operates the media, and competes to show up inside the answer that same agent returns to the consumer. Two, **OpenAI**. The ChatGPT ads manager runs CPC, measurement partners and self-serve. The surface is new, the operation feels like Google AdWords circa 2003. Three, **open ecosystem**. Claude and Perplexity arrive rented, not bought, by Meta, TikTok, Walmart and Snapchat. The brand picks the model, the platform charges for inventory.
Why it's worth taking a side
The editorial thesis: bet on the open ecosystem for the team's operation, and plan assuming Google will dominate consumer search for at least twelve months. Both at once. Why. Internal operations call for multi-model (Claude for long workflows, Perplexity for research, GPT for fast editing) because none wins every benchmark. Consumer-facing presence calls for Google because that's where the scale is. A single bet is a broken bet. The team that puts all the content into one agent layer for 2027 will hit trouble with the diversification the brand will demand when regulation or a pricing change squeezes the model.
Three critical responsibilities
Three operational rules for the next quarter. One, the **40% rule**. No single agent should operate more than 40% of the brand's media spend, or 40% of content generation. Crossing that line is platform risk. Two, the **log rule**. Every agent operating spend must produce an auditable log the human team can explain to the client or the board in a week, without vendor assistance. If the vendor doesn't expose the log, the contract doesn't get signed. Three, the **protocol rule**. Avoid closed proprietary protocols (Google's UCP is this month's example) until there are open reference implementations. Today's convenience is tomorrow's lock-in.
What changes for the team
There's a new job that appears and it's called agent governance. It is not the same as data governance. It is: who decides which agent can take which action, under what cap, on what inventory, with what log. Today that role doesn't exist in most marketing teams because the decision gets taken by the vendor by default. That changes when there are three vendors at the table. The new function asks for someone with a mixed profile, half senior media planner and half platform architect, who can sign contracts with clauses that protect the client, not the agency. That hire is the most important of the semester. More than any creative hire.
The signal: The agent layer is won by whoever controls it. There are three candidates. The team that gets this hedges with multi-agent for operation and with presence in Google for discovery. The team that bets on one wins this week's speed and loses optionality when the model changes its terms. It's not a technical decision. It's strategic.
The Signal Brief · Mariano De Vitto — Head of Marketing, Barcelona