TL;DR: Publishers who want to support agent-negotiated deals need three things in place: a protocol-compliant sell-side integration, a sell-side agent mandate framework, and deal record infrastructure that can store and retrieve bilateral DealSheets. Most publishers are missing at least one of these. The limiting factor is usually not the protocol integration but the mandate framework: without it, the sell-side agent cannot make consistent decisions, and the publisher cannot audit what it agreed to.
Publisher readiness for agent-negotiated deals is more variable than buy-side readiness. Agencies and advertisers have been building toward agentic capability for two to three years; publishers, many of whom have relied on SSPs to abstract the technical layer of programmatic, are at earlier stages. The commercial motivation is present: direct bilateral deals with buyers typically generate higher CPMs than open auction clearing prices for equivalent inventory. The technical and operational requirements are less well understood.
The three requirements
Protocol-compliant integration. Agent-to-agent negotiation requires both parties to communicate through a shared protocol. The IAB Tech Lab's Agent Communication Protocol (AdCP) is the standard for this communication. A publisher without an AdCP-compliant integration cannot receive or respond to deal proposals from buy-side agents that operate on AdCP-native marketplaces.
In practice, most publishers access protocol-compliant integration through their SSP rather than directly. SSPs that have integrated with agentic marketplaces handle the protocol layer on the publisher's behalf. Publishers should confirm with their SSPs whether AdCP support is live or on the roadmap, and whether that support includes bilateral deal negotiation or only deal ID management.
Sell-side agent mandate framework. The mandate is the document that governs the sell-side agent's decisions. Without a mandate, the sell-side agent operates on defaults: floor price only, with no context for evaluating deal structure, audience data, or inventory packaging. A mandate-free sell-side agent produces inconsistent negotiation behaviour: erratic floors, excessive escalation, and missed deals where the proposal had merit that the agent lacked the parameters to recognise.
The mandate framework requires operational input (inventory classification, floor prices by tier), legal input (audience data permissions and consent basis), and commercial input (deal type authorisations, approval thresholds for high-value proposals). It is not a technical document; it is a yield management document that happens to govern an AI agent.
Deal record infrastructure. When a bilateral deal is executed, the DealSheet must be stored and retrievable by both parties. For publishers using SSPs with integrated marketplace infrastructure, the SSP typically handles DealSheet storage. For publishers building direct integrations with agentic marketplaces, they need to evaluate whether the marketplace provides DealSheet storage and retrieval or whether they need to build their own.
The DealSheet is also a compliance document. Publishers should ensure that their deal record retention policies cover DealSheets for the same periods as they retain other deal documentation, and that the DealSheet data is accessible to their compliance and finance teams for reconciliation and audit purposes.
Common gaps in publisher readiness
The most common gap is the mandate framework. Publishers who have focused on the protocol integration as the primary requirement often find that the integration is live but the sell-side agent's behaviour is inconsistent because the mandate does not cover the range of situations it encounters in live negotiation.
The second most common gap is audience data permission documentation. Many publishers offer contextual data and first-party audience segments as part of deal packages, but their internal documentation of the legal basis for using that data in bilateral negotiations is less complete than their data protection teams assume. Before enabling audience data parameters in a sell-side mandate, publishers should confirm that their RoPA and DPIAs cover the specific use of that data in agent-negotiated deals.
The third gap is reconciliation workflow. Publishers who generate bilateral DealSheets but do not have a process for reconciling delivery against them are missing the accountability benefit of the infrastructure they have built. The DealSheet is only useful for reconciliation if someone runs the reconciliation.
How to prioritise readiness work
For publishers with no existing agentic integration, the recommended sequence is:
Begin with the mandate framework, because it requires no technical integration and can be developed in parallel with technical work. Define inventory tiers, floors, deal type parameters, and audience data permissions. Review with legal and commercial stakeholders before the mandate is issued to any agent.
Second, confirm SSP protocol support and timeline. If the SSP does not have AdCP support, evaluate whether to wait for it or to build a direct integration with a marketplace.
Third, build the deal record workflow: how DealSheets will be stored, who has access to them, and how reconciliation will be conducted.
Publishers who invest in this sequence will be in a materially stronger position with buy-side agents than publishers who focus only on the protocol integration.