A2B: Testing your first agent call

Free module — No account required. ~20 minutes with Addie. Prerequisite: A2.

Learning objectives

Call the stateless MCP transport exposed by the AdCP test agent
Call get_products with a natural-language brief and read the product response
Place a media buy with create_media_buy and handle all three response shapes
Attach creatives with sync_creatives and check buy status via get_media_buys
Diagnose and resolve auth failures, schema mismatches, and async polling delays

Reading list

AdCP quickstart

End-to-end buyer workflow from setup to delivery.

Media buy lifecycle

Media buy status states — pending_creatives, pending_start, active, paused, completed — and what each means for the buyer.

Create media buy task

Full field reference, required fields, and all three response shapes.

Sync creatives task

How to attach assets to a buy, dry-run validation, and assignment patterns.

Error handling

Error codes, retry behavior, and how to read the errors[] array.

MCP integration guide

MCP transport and tool call formats.

Test agent

All curl examples below target the AdCP training agent:

https://test-agent.adcontextprotocol.org/sales/mcp

You’ll need an API key from your AgenticAdvertising.org dashboard. Replace <your-api-key> in every example.

What you’ll do with Addie

Walk through four calls in sequence. Addie demonstrates each call, shows the raw response, then guides you through reproducing it yourself.

Discover — get_products with a brief; read proposals
Buy — create_media_buy; handle all three response shapes
Attach creatives — sync_creatives; validate with dry-run first
Poll status — get_media_buys until valid_actions shows the buy is serving

The public test agent uses stateless HTTP transport: every request is a direct tools/call, with no initialize exchange or mcp-session-id header. Durable sandbox state is keyed by the authenticated caller and the account reference in each task, not by an MCP transport session. Use the same account object throughout the workflow.

Step-by-step curl reference

Use these as a quick reference while working through the module with Addie, or to reproduce any step independently.

Step 1 — Discover products

Call get_products with buying_mode: "brief" and a plain-English description of your campaign goals. The agent returns curated products[] and ready-to-execute proposals[].

curl -X POST https://test-agent.adcontextprotocol.org/sales/mcp \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <your-api-key>" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tools/call",
    "params": {
      "name": "get_products",
      "arguments": {
        "adcp_major_version": 3,
        "account": {
          "brand": { "domain": "nova-motors.com" },
          "operator": "pinnacle-media.com"
        },
        "buying_mode": "brief",
        "brief": "CTV campaign, adults 25-54 in the US, $50K budget, brand safety required"
      }
    },
    "id": 1
  }'

The result is in content[0].text as JSON. Look for proposals[0].proposal_id — you’ll pass it to create_media_buy.

Step 2 — Place a media buy

Pass the proposal_id from Step 1 and a total_budget. The idempotency_key lets you safely retry if the network drops — use a fresh UUID v4 per request.

curl -X POST https://test-agent.adcontextprotocol.org/sales/mcp \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <your-api-key>" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tools/call",
    "params": {
      "name": "create_media_buy",
      "arguments": {
        "adcp_major_version": 3,
        "idempotency_key": "mb-lab-20260428-001",
        "account": {
          "brand": { "domain": "nova-motors.com" },
          "operator": "pinnacle-media.com"
        },
        "proposal_id": "<proposal-id-from-step-2>",
        "total_budget": { "amount": 50000, "currency": "USD" }
      }
    },
    "id": 2
  }'

Three response shapes — you’ll see one of these:

Shape	What it means	Next step
`media_buy_id` + `media_buy_status: "pending_creatives"`	Buy confirmed; attach creatives	Go to Step 3
`media_buy_id` + `media_buy_status: "pending_start"`, `"active"`, or `"paused"`	Buy confirmed and ready	Creatives already attached or not required
`status: "submitted"` + `task_id`	Buy queued for async processing	Poll the AdCP task with `task_id` (see Async polling below)
`errors[]` present, no `media_buy_id`	Rejected — read `errors[0].code`	Fix the request and retry with a new `idempotency_key`

Step 3 — Attach creatives

A buy in pending_creatives state can’t serve until you call sync_creatives. Use dry_run: true first to validate your creative shapes without writing anything.

curl -X POST https://test-agent.adcontextprotocol.org/sales/mcp \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <your-api-key>" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tools/call",
    "params": {
      "name": "sync_creatives",
      "arguments": {
        "adcp_major_version": 3,
        "idempotency_key": "sc-lab-20260428-001",
        "account": {
          "brand": { "domain": "nova-motors.com" },
          "operator": "pinnacle-media.com"
        },
        "creatives": [
          {
            "creative_id": "nova-ctv-30s-v1",
            "format_id": {
              "agent_url": "https://test-agent.adcontextprotocol.org",
              "id": "ctv_1920x1080_30s"
            },
            "assets": [
              {
                "asset_id": "video_url",
                "url": "https://cdn.example.com/nova-ctv-30s.mp4"
              }
            ]
          }
        ],
        "dry_run": true
      }
    },
    "id": 3
  }'

Remove "dry_run": true to apply. The response includes creatives[].status — approved, pending_review, or rejected.

Step 4 — Check status

Poll get_media_buys with the media_buy_id from Step 2 to see lifecycle state and valid_actions.

curl -X POST https://test-agent.adcontextprotocol.org/sales/mcp \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <your-api-key>" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tools/call",
    "params": {
      "name": "get_media_buys",
      "arguments": {
        "adcp_major_version": 3,
        "account": {
          "brand": { "domain": "nova-motors.com" },
          "operator": "pinnacle-media.com"
        },
        "media_buy_ids": ["<media-buy-id-from-step-2>"]
      }
    },
    "id": 4
  }'

The media_buys[0].status field is one of pending_creatives, pending_start, active, paused, completed, rejected, or canceled. The valid_actions array tells you what the buyer can do next.

Async polling

When create_media_buy returns status: "submitted" and a task_id, the buy is queued. Poll until the task completes:

curl -X POST https://test-agent.adcontextprotocol.org/sales/mcp \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <your-api-key>" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tools/call",
    "params": {
      "name": "get_task_status",
      "arguments": { "task_id": "<task-id-from-create>", "include_result": true }
    },
    "id": 5
  }'

get_task_status is an AdCP application-layer polling alias exposed by the training agent’s /sales/mcp tenant. The legacy root /mcp alias does not expose it. Other sellers may instead expose the AdCP tasks/get surface; inspect their advertised tools rather than assuming the alias exists. Do not confuse either AdCP polling surface with transport-native MCP/A2A tasks/* methods, which use their own task wire shapes.

Poll every 2–5 seconds. When the AdCP task status is completed, the result field contains the full create_media_buy response with media_buy_id. See the Task lifecycle doc for all AdCP task status values.

Common errors

Symptom	Likely cause	Fix
HTTP 401 / `error: "invalid_token"`	Expired or wrong API key	Reissue the token from your dashboard; confirm the `Bearer` prefix
HTTP 401 / `error: "invalid_request"`	`Authorization` header missing	Add `-H "Authorization: Bearer <token>"` to every call
`errors[]` in body, no `media_buy_id`	Schema validation failure	Read `errors[0].field` and `errors[0].code`; fix the field and retry with a new `idempotency_key`
`status: "submitted"` stays indefinitely	Async task stalled	Check AdCP task status via `get_task_status` or legacy `tasks/get`; if `failed`, read the task error for the rejection reason
A later call cannot find the buy	The `account` reference differs from the create call	Reuse the exact same brand/operator account reference on later calls

Assessment

Dimension	Weight	What Addie looks for
Conceptual understanding	10%	Can you explain why the stateless transport relies on caller/account-scoped state rather than an MCP session ID?
Practical knowledge	40%	Can you trace through all four calls in order with correct task names and request shapes?
Problem solving	30%	Can you reason through what happens when each step fails or returns an unexpected response?
Error recovery	20%	Can you identify the correct fix for auth failures, schema errors, and async polling delays?

Passing threshold: 70%.

Start this module

Start A2B with Addie

Open Addie and say “I’d like to start certification module A2B.”

Next: A3: The AdCP landscape

Getting Started

Building with AdCP

Protocol

FAQ

Trust & Security

Reference

Certification

A2B: Testing your first agent call

A2B: Testing your first agent call

Learning objectives

Reading list

AdCP quickstart

Media buy lifecycle

Create media buy task

Sync creatives task

Error handling

MCP integration guide

Test agent

What you’ll do with Addie

Step-by-step curl reference

Step 1 — Discover products

Step 2 — Place a media buy

Step 3 — Attach creatives

Step 4 — Check status

Async polling

Common errors

Assessment

Start this module

Start A2B with Addie

​A2B: Testing your first agent call

​Learning objectives

​Reading list

AdCP quickstart

Media buy lifecycle

Create media buy task

Sync creatives task

Error handling

MCP integration guide

​Test agent

​What you’ll do with Addie

​Step-by-step curl reference

​Step 1 — Discover products

​Step 2 — Place a media buy

​Step 3 — Attach creatives

​Step 4 — Check status

​Async polling

​Common errors

​Assessment

​Start this module

Start A2B with Addie

A2B: Testing your first agent call

Learning objectives

Reading list

Test agent

What you’ll do with Addie

Step-by-step curl reference

Step 1 — Discover products

Step 2 — Place a media buy

Step 3 — Attach creatives

Step 4 — Check status

Async polling

Common errors

Assessment

Start this module