Agencies use AI in programmatic buying to plan, buy and report across many clients at once: drafting plans from briefs, optimising bids inside demand-side platforms, pacing budgets, versioning creative and, increasingly, letting AI agents find inventory and negotiate deal terms within limits a person has set. What an agency needs from an agentic platform differs from what a brand buying direct needs. An agency needs to keep many clients' mandates, approvals and records apart. A brand needs a short path from its own mandate to the deal, without depending on an intermediary to show it what was agreed.

TL;DR. Agencies apply AI to planning, bid optimisation, pacing, creative versioning, reporting and, more recently, agent-led deal negotiation. An agency's main platform requirement is separation: one mandate, one approval chain and one deal record per client. A brand-direct buyer's main requirement is ownership: the brand writes the mandate, approves the spend and holds the record itself. Both need buy-side agents that stop at their limits and deal terms that the seller holds in the same form.

How do agencies use AI for programmatic buying?

Agencies use AI at five points in the buying cycle. In planning, models turn a client brief into audience and inventory options and scenario budgets. In execution, bidding algorithms inside DSPs price impressions against the campaign goal. In pacing, automated rules move budget between line items as delivery runs ahead or behind. In creative, generative tools produce variants for different formats and audiences. In reporting, AI combines delivery data from several platforms into one client view.

The newer use is the AI agent: software that works from a mandate, makes decisions inside it, hands decisions outside it back to a person, and leaves a record. For an agency, an agent can send one brief to many sellers, compare the proposals, negotiate within each client's limits and place deals across the deal types a trading desk already runs. According to IAB Tech Lab, its AAMP framework's support for the Deals API covers programmatic guaranteed, preferred deals, private marketplaces, the open marketplace and linear GRPs.

Why do agencies and brands need different things from an agentic platform?

The difference comes from how many principals each one serves. An agency acts for many clients from one trading desk, often on the same day. A brand buying direct acts for itself. Every control an agency needs is a control that keeps client A's authority, spend and data from touching client B's. Every control a brand needs is a control that keeps the brand in charge of its own spend without an intermediary in the middle.

What does an agency need from an agentic platform?

An agency needs five things, each testable before a pilot.

A mandate per client. Each client's price ceilings, brand safety rules, excluded categories and frequency caps should sit in its own mandate, so an agent negotiating for one client cannot apply another client's terms.

Two-level approvals. Some commitments need the agency's sign-off, others the client's. The platform should route a decision to the right person by threshold and by client, not to one shared inbox.

Authority that can be checked. A seller should be able to confirm that the agency's agent is authorised to buy for the client it names. Without that check, any agent could claim to represent any brand.

Records attributable to a client. Each agreed deal should be recorded against the client it was made for, in a form the agency can share with that client without editing.

Reporting that matches the record. Delivery reports should reconcile to each client's agreed terms, so the agency can show what was agreed and whether it ran without rebuilding the answer from logs.

What does a brand-direct buyer need from an agentic platform?

A brand buying direct needs fewer layers but more ownership.

A mandate the brand writes. Marketing and finance owners set the limits directly rather than through an agency brief that is then translated.

Approvals inside the brand. Thresholds route to named people in the brand's own team, so the platform has to suit a small in-house group rather than a trading desk.

Direct access to sellers' agents. The brand's buy-side agent needs sellers whose agents can respond to it. IAB Tech Lab's OpenProposal specification, part of AAMP, standardises how publishers describe products and packages in RFP responses, which lowers the work of comparing offers for a team without specialist traders.

A record the brand holds itself. The brand should hold the agreed terms directly, not receive them second hand. This is the point brands have historically struggled with. The ISBA/PwC programmatic supply chain study of May 2020 found that only 12% of impressions could be matched end to end, a measure of how hard it has been for advertisers to trace their own spend.

What does this look like in practice?

Consider two hypothetical buyers with the same goal: a quarter of display and video across a dozen premium publishers.

A hypothetical agency running this for three clients writes three mandates. Client one allows news environments; client two excludes them. Client three requires sign-off from its own marketing director on any deal above £15,000. One buy-side agent sends the briefs, but each negotiation runs under its own client's mandate, approvals route to different people, and each deal record carries the client's name. The agency's value lies in keeping the three apart and showing each client its own terms.

A hypothetical brand running a £120,000 quarter direct writes one mandate and names two approvers, its head of digital and a finance lead. The brand's value lies in seeing every agreed term itself, on the day of agreement, without waiting for a monthly report.

How can a buyer judge whether a platform suits it?

Four signals help either kind of buyer judge fit, each observable before a contract is signed.

The first is mandate structure: whether the platform supports one mandate or many, and whether they are isolated from each other. The second is approval routing: whether thresholds can route to different people for different clients or budgets. The third is agent authority: whether connecting agents are checked as authorised by the party they claim to represent, and whether those agents appear in a public directory such as the IAB Tech Lab Agent Registry. The fourth is the record: whether each agreed deal produces terms that buyer and seller both hold.

An agency should weight the first two most heavily. A brand should weight the last two.

Where does a neutral marketplace fit for both?

Agencies and brands differ in how many principals sit behind the agent, but both depend on an agreed record that the seller holds too. Alkimi, a neutral agentic advertising marketplace working within IAB Tech Lab's AAMP framework, is built for that step whichever kind of buyer is connecting: it verifies that each connecting agent is authorised by the buyer or publisher it represents, and writes agreed terms to a timestamped DealSheet that either side can retrieve independently.

Frequently asked questions

How do agencies use AI for programmatic buying?

Agencies use AI for planning from briefs, bid optimisation inside DSPs, budget pacing, creative versioning and cross-platform reporting. AI agents add the ability to find inventory and negotiate deal terms within each client's mandate.

Do brands need an agency to use agentic advertising?

No. A brand can run a buy-side agent directly if it writes its own mandate, names its own approvers and can reach sellers whose agents respond to it. An agency adds scale, trading expertise and publisher relationships.

What is the biggest platform requirement for an agency?

Separation between clients: one mandate, one approval chain and one deal record per client, so no agent can apply one client's terms or budget to another.

What is the biggest platform requirement for a brand buying direct?

Ownership: the brand writes the mandate, approves spend above its thresholds and holds the agreed deal terms itself rather than receiving them second hand.

Agentic Advertising for Agencies vs Brand-Direct Buyers: What Does Each Need From a Platform?