AdCP — Accounts Protocol

The Accounts Protocol defines the commercial layer beneath all AdCP vendor protocols. Every transaction — a media buy, a data signal, a content standards check — happens between parties that have a commercial relationship. The Accounts Protocol establishes that relationship and provides consumption reporting so vendors can track how their services were used.

The commercial model

Six questions underlie every AdCP transaction:

Question	Answered by	Mechanism
Who is the advertiser?	Brand registry	`brand.domain` resolves to `brand.json`
Who operates on the brand’s behalf?	Brand registry	`authorized_operators` in `brand.json` declares who can buy on the brand’s behalf
How does the operator authenticate?	Seller capabilities	`require_operator_auth` determines the account model: `true` means explicit accounts (operator credentials required, discover via `list_accounts`), `false` means implicit accounts (agent trusted, declare via `sync_accounts`)
Who gets billed?	Buyer declaration	Buyer passes `billing` in `sync_accounts` — `operator` or `agent`. Seller accepts or rejects.
What was consumed?	Usage reporting	`report_usage` informs vendor agents how their services were used after delivery

The seller declares the account model in get_adcp_capabilities via require_operator_auth. When true (explicit accounts), operators authenticate independently and the buyer discovers accounts via list_accounts. When false (implicit accounts), the agent is trusted and the buyer declares brand/operator pairs via sync_accounts to provision accounts. An ad network may use both models simultaneously — implicit accounts on the buyer-facing side (the network is agent-trusted) and explicit accounts with each underlying platform (the network authenticates as an operator). See the AI media guide — account model for networks for the full account chain: buyer agent → network (implicit) → AI platform (explicit). After delivery, the orchestrator calls report_usage to inform vendor agents (signals, governance, creative) how their services were consumed. This is not settlement — it’s consumption reporting so the vendor can track earned revenue and verify billing.

Scope

The Accounts Protocol applies across all vendor protocols. An orchestrator establishes an account once per brand/operator pair per vendor agent and reuses the same account reference across all interactions with that agent:

Vendor Protocol	Account reference used for
Media Buy	Rate cards, invoicing, campaign attribution
Signals	Per-account pricing options, activation, usage reporting
Governance	Content standards billing
Creative	Creative service billing

The account reference may be a seller-assigned account_id (explicit accounts, require_operator_auth: true) or a natural key — brand + operator (implicit accounts, require_operator_auth: false). For sandbox, the path depends on the account model: explicit accounts discover pre-existing test accounts via list_accounts, while implicit accounts declare sandbox via sync_accounts with sandbox: true. See Account references for details.

Transaction lifecycle

1. Discover seller capabilities
   get_adcp_capabilities → require_operator_auth, supported_billing

2. Resolve brand identity
   Fetch brand.domain/.well-known/brand.json → canonical brand (domain, brand_id)

3. Verify operator identity
   Check authorized_operators in brand.json → confirm operator is permitted to buy for this brand

4. Authenticate (if required)
   When require_operator_auth is true → obtain operator credential via authorization_endpoint or out-of-band

5. Establish account reference
   Explicit (require_operator_auth: true):
     list_accounts() → find existing account_id for this brand/operator
   Implicit (require_operator_auth: false):
     sync_accounts({ accounts: [{ brand, operator, billing }] }) → status, billing terms

6. Execute
   Protocol tasks use the account reference to apply correct rates and terms
   Examples: get_products(account: {...}), create_media_buy(account: {...})

7. Report usage
   report_usage(usage: [{ account: {...}, operator_id, kind, vendor_cost, ... }])
   Informs vendor agents how their services were consumed after delivery

Principals

The Accounts Protocol operates with four principal types. See Accounts and agents for full details on billing hierarchy, trust models, and authorized operators.

Principal	Role	Identified by
Brand	Whose products are advertised	`brand.domain` + optional `brand.brand_id` via brand.json
Operator	Who drives the buys	Domain (e.g., `pinnacle-media.com`)
Agent	What software places the buys	Authenticated session
Vendor agent	The seller’s AdCP agent	`agent_url`

Tasks

Task	Purpose
`sync_accounts`	Declare brand/operator pairs and billing; provision accounts (implicit accounts, `require_operator_auth: false`)
`list_accounts`	Discover existing accounts (explicit accounts, `require_operator_auth: true`); poll status on pending accounts
`get_account_financials`	Query spend, credit, and invoice status for operator-billed accounts
`report_usage`	Inform vendor agents how their services were consumed after delivery

Brand registry connection

The brand.domain in account references is not an arbitrary identifier — it is the brand’s domain, resolvable to a brand.json file that declares the brand’s canonical identity, sub-brands, authorized operators, and properties. Vendor agents can verify buyer claims against the brand registry: if an orchestrator claims to represent acme-corp.com, the vendor can fetch acme-corp.com/.well-known/brand.json to confirm authorized operators and brand hierarchy. This makes the Accounts Protocol tamper-resistant — account relationships are grounded in publicly verifiable brand identity. See the Brand Protocol for how brand identity resolution works.

Counterparty verification

Every commercial relationship in advertising depends on knowing who you’re actually doing business with. The Accounts Protocol addresses this at the protocol level through the brand registry. When an orchestrator references an account, the brand.domain identifies the advertiser. Vendor agents can fetch brand.domain/.well-known/brand.json to verify:

Brand identity: Is this brand who they claim to be?
Operator authorization: Is the operator listed in the request actually authorized to buy on this brand’s behalf?
Brand hierarchy: Which sub-brands does this house portfolio include?

This verification is grounded in publicly accessible DNS-hosted identity — not in what the buyer agent asserts, but in what the brand itself has declared. The pending_approval account state is where human review occurs: credit checks, legal agreements, and identity verification. Vendor agents that require these steps return a setup.url for the human to complete the process before the account becomes active.

Brand registry and the contribute-back pattern

The AgenticAdvertising.org brand registry provides a community-maintained layer of brand identity for brands that haven’t yet published their own brand.json. Buyer agents resolving brands before account setup can contribute data back to the registry as a byproduct of normal workflows — improving identity coverage for the ecosystem without extra effort. The recommended pattern for buyer agents uses three building blocks (see #1166):

Tool	Purpose
`resolve_brand`	Check registry and fetch brand.json — returns canonical identity if available
`research_brand`	Enrich via Brandfetch and auto-save to registry as `enriched`
`save_brand`	Manually contribute a brand to the registry as `community`

async function ensureBrand(domain) {
  // 1. Check registry (brand.json or previously resolved)
  const resolved = await resolveBrand(domain);

  if (resolved.errors) {
    // Resolution failed — brand unknown, proceed to enrich
  } else if (resolved.source === 'brand_json' || resolved.source === 'enriched') {
    // Authoritative or enriched data available — confirm with user, then use
    return await confirmWithUser(resolved);
  }
  // source === 'community': registry has a placeholder, but enrich for richer data

  // 2. Enrich via Brandfetch — auto-saves to registry as 'enriched'
  const enriched = await researchBrand(domain);
  if (enriched.errors) {
    // Enrichment unavailable — fall back to community entry or prompt user to correct
    return resolved ? await confirmWithUser(resolved) : null;
  }

  // 3. Confirm with user before using enriched data
  // Enrichment is third-party — user confirmation catches errors and improves registry quality
  return await confirmWithUser(enriched);
}

confirmWithUser is a placeholder for whatever confirmation mechanism fits your UX — an explicit prompt, a review step in a workflow UI, or a low-confidence flag that triggers human review. The confirmation step is what makes the improvement loop work: enrichment data comes from third parties and isn’t guaranteed to be correct. User verification before the data is used in a live campaign is what keeps the registry accurate over time.

Source authority

The registry tracks where brand data came from. Sources in descending authority:

Source	Meaning	Can be overwritten?
`brand_json`	Brand self-declared via `/.well-known/brand.json`	No — returns 409
`enriched`	Third-party enrichment (Brandfetch)	Only by higher authority
`community`	Manually contributed by a registry member	Yes

When an agent calls save_brand or research_brand, the registry applies merge logic: existing fields from a higher-authority source are preserved, and only missing fields are filled in. This respects what brands have declared while filling gaps. research_brand skips re-enrichment if the registry already has recent enriched data for the domain, avoiding redundant API calls. The full edit history for any brand — who contributed, when, and with what summary — is queryable via GET /api/brands/history.

Property contribute-back

The same pattern applies to publisher properties. When a buyer agent discovers a new publisher through a sales agent interaction, it can contribute that property back to the registry via POST /api/properties/save. This improves property coverage for the ecosystem the same way brand contribute-back improves brand coverage. See Registry API — save property for details.

Usage reporting

Vendor agents (signals, governance, creative) are not direct participants in campaign execution — the orchestrator uses their services as inputs to a media buy. After delivery, report_usage tells these vendors what was consumed so they can track earned revenue and verify billing. report_usage is buyer-reported: the orchestrator computes and reports consumption. Each record carries its own account, operator_id, and kind ("signal", "content_standards", "creative"). The vendor agent uses the reported pricing_option_id to verify the correct rate was applied. Partial acceptance is valid — a single request can span multiple accounts, operators, and campaigns. The response confirms how many records were accepted and which (if any) failed validation.

Getting Started

Building with AdCP

Protocol

FAQ

Trust & Security

Reference

Certification

Accounts Protocol

The commercial model

Scope

Transaction lifecycle

Principals

Tasks

Brand registry connection

Counterparty verification

Brand registry and the contribute-back pattern

Source authority

Property contribute-back

Usage reporting

​The commercial model

​Scope

​Transaction lifecycle

​Principals

​Tasks

​Brand registry connection

​Counterparty verification

​Brand registry and the contribute-back pattern

​Source authority

​Property contribute-back

​Usage reporting

The commercial model

Scope

Transaction lifecycle

Principals

Tasks

Brand registry connection

Counterparty verification

Brand registry and the contribute-back pattern

Source authority

Property contribute-back

Usage reporting