AAMP 3.0 and OpenProposal: Getting Your Inventory Ready for Agent-Written RFPs

Most of the conversation about AI agents in advertising has focused on buying: agents that plan campaigns, pick inventory and optimize spend. Last week IAB Tech Lab addressed a part of the process that has stayed stubbornly manual on both sides, the request for proposal. On September 22 it introduced AAMP 3.0 with a new specification called OpenProposal, and it is taking public comment until October 22.

For publishers that sell directly, and B2B, niche and specialist publishers in particular, this is worth understanding now.

Where this fits

IAB Tech Lab unveiled its agentic roadmap on January 6, 2026, laying out how it planned to extend existing standards into agent-driven buying and selling rather than replace them. In February it gave the program a name: AAMP, short for Agentic Advertising Management Protocols. AAMP 3.0 is the next step, and it targets the part of the workflow before any impression is bought: briefs, proposals and commitments.

What OpenProposal does

According to IAB Tech Lab, OpenProposal gives buyer and seller agents a common way to exchange proposals and evaluate opportunities before a transaction moves to execution. In practice:

• Sellers can publish catalogs of their advertising products and packages, and respond to buyer briefs in a standardized, agent-readable format.
• Buying agents can discover and browse public packages, evaluate and rank proposals against a declared brief and compare opportunities across many publishers.
• Continuity with existing standards. OpenProposal connects to AdCOM, OpenDirect and the Deals API, so an opportunity can move from planning through negotiation, execution and reporting on familiar rails. Tech Lab says existing programmatic implementations can continue without changes.

One early supporter, PMG's Mike Treon, described a notable feature: proposals can carry reasoning. "A seller can tell us not just cost, but why they believe it fits."

Why the RFP is the right target

For many publishers, the RFP process is where direct revenue is won or lost, and it is expensive. A buyer sends a brief; a sales team interprets it, assembles a package, prices it and writes a response; the buyer compares responses that arrive in different formats with different assumptions. Much of that work is translation between formats, not judgment.

If agents on both sides can read and write proposals in a common structure, the translation cost falls. That matters most for publishers whose inventory is valuable but whose sales teams are small, which describes a large share of B2B, trade, local and specialist publishers.

What changes for sellers

The shift to agent-readable proposals raises the value of things publishers often keep informal:

• A clear product catalog. If your packages live in a sales deck and people's heads, an agent cannot find them. Defined products, with audiences, placements, formats, pricing ranges and availability, become discoverable.
• Honest descriptions. Agents will compare claims across publishers. Vague or inflated descriptions are easier to spot when every proposal is in the same structure.
• Clean deal plumbing. A proposal that cannot be executed cleanly as a deal, with correct deal IDs, targeting and delivery, loses to one that can.
• Reasoning, not just rates. If proposals can explain why inventory fits a brief, publishers with real audience knowledge have a new way to show it.

The open questions

OpenProposal is in public comment, not in production across the industry. Several questions will shape how useful it becomes: how many buying platforms and agencies adopt it, how sellers control what they expose publicly versus privately, how pricing and negotiation work when agents represent both sides and how it coexists with other agent protocols, including the Ad Context Protocol (AdCP) launched by a separate industry group in 2025. Prebid's new chairman, OpenX CTO Joel Meyer, told AdExchanger in August that Prebid intends to stay protocol-agnostic across the competing agentic standards, which suggests more than one approach will be in use for some time.

There is also a practical question about control. A publisher that exposes a public catalog of packages is, in effect, publishing a rate card to every agent that looks. Many publishers will want some products public and others visible only to specific buyers, and how well the specification supports that split will matter to adoption.

What publishers can do now

1. Read the specification and comment. Publishers are underrepresented in standards discussions. If agent-written RFPs will shape how you are bought, say what you need before October 22.
2. Write down your product catalog. Even without any agent involved, a clear, structured list of what you sell improves every RFP response your team writes today.
3. Audit your deal setup. Check that private marketplace and programmatic guaranteed deals are configured consistently and deliver reliably. Agentic demand will flow through the same pipes.
4. Tighten audience descriptions. Document who your audience is, how you know it and what data supports it, in plain terms a buyer or an agent can verify.
5. Ask your partners. Ask your SSPs and ad server how they plan to support AAMP and OpenProposal, and on what timeline.

The bottom line

Agentic buying will not replace the open auction soon, and it will not replace good sales teams. What it can do is lower the cost of the most tedious part of direct sales and make well-described inventory easier to find. B2B and specialist publishers, who often have exactly the audiences agents are asked to find but lack the sales headcount of big media groups, stand to gain most, provided their products are clearly defined and their deal plumbing works. That plumbing, from deal setup to delivery, is familiar ground for HBDR's ad ops team.