A2: Your first media buy

Module A2: Execute your first AdCP media buy. Free 20-minute hands-on module walking through discovery, purchase, creative sync, and delivery with a live sandbox agent.

A2: Your first media buy

Free module — No account required. ~20 minutes with Addie. Prerequisite: A1.

Learning objectives

• Execute the full media buy lifecycle: discovery, purchase, creative sync, delivery
• Identify the agent roles involved: buyer agent, sales agent, creative agent, signals agent
• Read and understand real protocol messages at each stage
• Recognize that 3.1 products may describe creative requirements with canonical format_options[] that narrow shared format_kind contracts
• Observe a live agent-to-agent transaction
• Recognize the two things that make agent-to-agent requests safe: the request is signed (so the seller can verify who sent it) and it carries an idempotency_key (so a retry doesn’t double-book)

Reading list

Protocol architecture

The complete architecture: domain map, identity layer, transaction domains, governance, and ecosystem layers.

MCP integration guide

How MCP works in practice: tool calls, response format, context management, async operations.

Capability discovery

How agents advertise their capabilities so other agents can discover what they offer.

AdAgents.json

Publisher authorization for which agents can sell or enrich inventory.

Seller setup

How sellers use brand.json with adagents.json for identity and supply path verification.

A2A guide

The Agent-to-Agent protocol — how specialized agents collaborate on complex campaigns.

Task lifecycle

How tasks move through states: from request to completion, including async operations.

Key terms

Term	Definition
Sales agent	Represents a publisher and exposes inventory via get_products. May also implement the Creative Protocol to handle creatives from the same endpoint.
Buyer agent	Represents a brand or agency and purchases media via create_media_buy
Brand agent	Manages brand identity and guidelines via brand.json
Creative agent	Any agent implementing the Creative Protocol — produces and adapts advertising assets via build_creative. This can be a standalone service or a sales agent that declares "creative" in supported_protocols.
Signals agent	Provides measurement and audience data via get_signals
brand.json	Public identity record for an advertiser, publisher, seller, or platform: name, brand assets, agents, and signing-key discovery
adagents.json	Publisher-hosted file declaring properties and the agents authorized to sell or enrich them
Tool discovery	The process of an agent reading another agent’s capabilities to know what tasks it supports
Request signing	A cryptographic signature on the request that lets the seller verify who sent it and that it wasn’t tampered with in transit
Idempotency key	A unique tag on each mutating request that lets a buyer safely retry without creating a duplicate
Domain	A broad protocol area an agent supports — media_buy, creative, signals, governance, brand, sponsored_intelligence. Declared via supported_protocols.
Specialism	A narrow capability claim within a domain — e.g. sales-guaranteed, creative-generative, signal-marketplace. Declared via specialisms. See the Compliance Catalog.
Canonical formats	AdCP 3.1’s v2 path for creative requirements: products can publish format_options[] that narrow shared creative archetypes such as image or video_hosted. Validate against the canonical first, then the product’s narrowing.
Storyboard	A scripted compliance scenario shipped by the protocol at /compliance/{version}/ — agents don’t write them, they’re run against agents. An agent demonstrates its domain and specialism claims by passing the matching storyboards.

Protocol versioning

Every request carries adcp_major_version; sellers advertise supported versions on get_adcp_capabilities. A3 and B1 go deeper on version negotiation and the object-presence pattern sellers use to declare capabilities.

What you’ll do with Addie

Tell Addie what you want: audience, goals, budget. Then walk through each step as it happens:

1. Discovery — get_products against @cptestagent, examine real response structure
2. Purchase — create_media_buy with targeting and budget. Addie points out two things on this request: it carries a signature (so the seller can verify the buyer) and an idempotency_key (so a retry after a network error never creates two buys). Note the confirmed_at timestamp in the response — this is the seller’s order confirmation.
3. Creative — sync_creatives to deliver assets to the publisher
4. Status check — get_media_buys to see lifecycle state, creative approvals, and valid_actions
5. Delivery — get_media_buy_delivery to see results

You’ll see the actual protocol messages at each stage. By the end, you’ve bought media through an agent.

Assessment

Dimension	Weight	What Addie looks for
Conceptual understanding	25%	Can you describe the transaction flow and which agent handles what?
Practical knowledge	35%	Can you direct a media buy and interpret the delivery report?
Problem solving	15%	Can you reason about what happens when things go wrong?
Protocol fluency	25%	Do you use correct task names and agent roles?

Passing threshold: 70%.

Start this module

Start A2 with Addie

Open Addie and say “I’d like to start certification module A2.”

Next: A3: The AdCP landscape