The commercial model
Seven questions underlie every AdCP transaction:
The seller declares the account model in
get_adcp_capabilities via require_operator_auth. That field declares who must authenticate; it does not by itself declare whether OAuth is used, whether list_accounts is exposed, or which sync_accounts modes are supported.
When require_operator_auth is true (account-id namespaces), operators authenticate independently and buyers pass seller-assigned account_id values because the seller or upstream platform owns the canonical account namespace. If a credential may access more than one account, the seller MUST expose list_accounts and buyers MUST resolve an explicit account_id before the first account-scoped request. If a credential is bound to exactly one account, the seller SHOULD expose list_accounts returning that singleton, and MAY omit it only when the same explicit account_id is supplied through another declared path or out-of-band onboarding.
When require_operator_auth is false (buyer-declared accounts), the agent is trusted and account-scoped calls use the natural key (brand + operator). Most sellers provision these relationships through sync_accounts. A seller MAY instead lazily provision on the first account-scoped request when billing and every other required setting are unambiguous from capabilities or the authenticated agent’s onboarding defaults. A lazy-provisioning seller MUST keep accepting the natural key and MUST expose list_accounts for recovery. If buyer input is required before use, the seller MUST expose sync_accounts.
Follow Provision a seller-mediated account for a complete buyer-declared workflow from discovery through human setup, activation, and first spend.
An ad network may use both models simultaneously — buyer-declared accounts on the buyer-facing side (the network is agent-trusted) and an account-id namespace with each underlying platform (the network authenticates as an operator). See the Sponsored Intelligence guide — account model for networks for the full account chain: buyer agent → network (buyer-declared) → AI platform (account-id namespace).
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:
The account reference may be a seller/storefront-assigned
account_id (seller-owned namespaces, usually require_operator_auth: true) or a buyer-declared advertiser key — brand + operator + optional operator_unit, currency, buyer-selected timezone, and sandbox (require_operator_auth: false). In this vocabulary, brand identity is the BrandKey projection (domain, optional brand_id, canonicalized countries[]); operator identity is the operator domain plus optional operator_unit.id; and advertiser account identity is the complete natural key, including fixed currency, buyer-selected account timezone, and sandbox disposition. Mutable operator_unit.name and broader BrandRef overrides are not identity. operator_unit.id is deliberately separate from the seller’s account_id. For buyer-declared accounts, the current complete natural-key AccountRef MUST round-trip through list_accounts and remain valid on subsequent calls, even if the seller also echoes an internal account_id. After a capability-gated identity rekey, the former natural key is tombstoned and returns ACCOUNT_MOVED to authorized callers rather than resolving or provisioning another account. See Account references for details.
billing names the party the seller invoices for this account relationship. It is not a payment rail or settlement selector. AdCP does not currently standardize per-media-buy choice between an intermediary clearing flow and direct settlement; implementations must not encode that distinction by silently changing the meaning of billing.
Account Status Lifecycle
Accounts progress through a defined set of states. Terminal states (rejected, closed) allow no further transitions.
pending_approval→active: seller approves after credit/contract/identity reviewpending_approval→rejected: seller declines. Terminal — buyer must submit a new account request.active→payment_required: automatic when credit limit is reached or funds are depletedpayment_required→active: when the buyer resolves the outstanding balance. Sellers MAY auto-transition or MAY require manual re-activation.active→suspended: seller-initiated (policy violation, billing dispute, fraud review). Sellers MUST notify orchestrators via webhook.suspended→active: seller-initiated reactivationsuspended→closed: seller-initiated permanent closureactive→closed: seller or buyer-initiated permanent closure. Terminal.- Sellers MUST reject operations on accounts in terminal states with
ACCOUNT_NOT_FOUNDor an appropriate error
Operations by Account Status
Account status acts as a gate on which tasks are permitted. Read-only operations are always available; mutation operations are restricted based on status.payment_requiredblocks new spend (create_media_buy) but allows managing existing buys and resolving setup. Sellers SHOULD also rejectnew_packageswithinupdate_media_buywhen the account is inpayment_required, since adding packages is functionally equivalent to new spend.suspendedallows read-only access to existing data but blocks all mutations- Sellers MUST return
ACCOUNT_SUSPENDEDfor blocked operations on suspended accounts andACCOUNT_PAYMENT_REQUIREDfor blocked operations on payment-required accounts
Caller authorization
Not every caller with access to an account has the same grant. A vendor agent may issue one calling agent a full scope and another agent a narrow read-plus-update scope. Authentication confirms the caller is who they claim to be; authorization answers “what is this caller allowed to do on this account?”Applies to every vendor protocol. The authorization mechanism described
here is part of the shared Accounts Protocol — it applies to every agent that
implements
sync_accounts / list_accounts: media-buy sales agents, signals
agents, governance agents, creative agents, brand agents. Signals agents scope
activation vs. catalog access; governance agents scope audit read vs. plan
management; creative agents scope library read vs. upload. Only the standard
named scope attestation_verifier is Media Buy Protocol-specific (it binds to
the AAO Verified (Live) qualifier); the rest of the machinery —
allowed_tasks, field_scopes, read_only, custom:-prefixed scopes — is
protocol-neutral./schemas/3.2.0-beta.0/core/account-authorization.json
Vendor agents that support scope introspection attach an authorization object to each per-account entry in sync_accounts and list_accounts responses:
Fields
AdCP 3.2 compact product tools. Authorization names the actual task. A
get_products grant does not silently authorize request_proposals, refine_proposals, or decline_proposals; sellers grant the proposal lifecycle explicitly and may scope its compact top-level fields independently. A read-only grant may permit list_products but rejects the three mutation-capable proposal tools.
Semantics of presence and absence
- Present: the vendor agent asserts the shape reflects its enforcement for this caller on this account at this moment. Stale-by-seconds is fine; systematically-divergent is non-conformant.
- Absent on a single account: the vendor agent is not telling the caller their scope for that account. Caller falls back to error-driven discovery (try the task, handle the RBAC error codes).
- Absent on all accounts: the vendor agent does not implement scope introspection. Callers MUST NOT infer access from absence — the vendor agent may still enforce scope locally and return
SCOPE_INSUFFICIENT/READ_ONLY_SCOPE/FIELD_NOT_PERMITTEDon any task call. authorizationis optional for 3.x. Vendor agents that want to avoid a breaking change can defer populating it. Populating is strictly additive — it lets callers preempt errors they would otherwise discover by trying.
attestation_verifier standard scope (Media Buy Protocol-specific) MUST populate authorization — the AAO Verified (Live) attestation flow depends on verifying the advertised scope matches enforcement.
Identity binding, refresh cadence, and consistency
Theauthorization object is implicitly scoped to the (caller identity, account_id) tuple at read time. The same account returned to a different authenticated caller MAY return a different authorization object — that’s the point of the RBAC model. Vendor agents MUST resolve caller identity from the authenticated request (not from any client-supplied field) and MUST bind the returned authorization to that resolved identity.
Refresh cadence.
- Callers SHOULD re-read
authorizationat least every 300 seconds of active use against an account, viasync_accountsorlist_accounts(filtered by the heldaccount). - Vendor agents MUST reflect operator-initiated scope changes in
sync_accounts/list_accountsresponses within 300 seconds of the change being made. A compliant caller polling every 300s sees operator changes within at most one refresh cycle. - Vendor agents MAY cache the
authorizationobject briefly but MUST NOT cache past 300 seconds without revalidation. - The 300s figure is a floor, not a target — vendor agents whose scope changes more frequently SHOULD surface them faster, and callers running AAO Verified (Live) attestation SHOULD probe at the check-7 cadence (at least once per rolling window, plus on every observed scope change).
(caller identity, account_id) tuple, sequential reads within the refresh window MUST return identical authorization objects, modulo operator-initiated scope changes. Flicker from load-balanced or eventually-consistent backends — two reads 10 seconds apart returning different allowed_tasks because they hit different replicas — is non-conformant. Compliance engines and coding agents rely on scope stability for state tracking; a vendor agent that cannot guarantee it MUST omit authorization rather than populate it inconsistently.
This is the concrete form of the “systematically-divergent is non-conformant” guarantee from the presence semantics above — it’s verifiable: a conformance check can read the same account twice from the same identity inside the refresh window and diff the results.
Buyer response to SCOPE_INSUFFICIENT within the refresh window
A singleSCOPE_INSUFFICIENT response is observationally indistinguishable between two causes: a seller replica that has not yet propagated a valid grant (transient infrastructure artifact — will resolve), and a legitimate scope reduction by the operator (persistent — must surface). Before classifying the error as a definitive correctable signal requiring operator intervention, buyers MAY exhaust a small bounded retry budget to disambiguate the two:
- Retry budget: no more than 3 attempts, each separated by 1–5 seconds of jittered backoff. This is disambiguation logic — establishing whether the scope is genuinely insufficient before trusting the
correctableclassification — not a recovery action for a correctable error. - Not the 300s window: the retry budget is not the seller’s propagation SLA. Buyers SHOULD NOT wait out the full 300-second window on every false negative; up to 15 seconds of accumulated backoff delay is sufficient to absorb typical replica lag.
- After retries exhaust: buyers MUST surface the error. “Surface” means: return a structured error to the calling layer (including account ID, the failed task, and
error.details.retry_countwith the number of attempts made) AND ensure the failure is visible in an operator-accessible channel — a structured log, dashboard alert, or notification. The escalation mechanism is implementation-defined; the requirement is that the error is not silently swallowed.
READ_ONLY_SCOPE follows the same bounded-retry logic when the buyer suspects grant-propagation lag (a replica lagging on a write-grant update). Caution: if write access was recently revoked, a stale replica may accept a mutation that the revoked scope should have rejected. If bounded retries succeed, buyers MUST re-read authorization before treating the result as reliable — and if re-reading confirms that write access has been revoked, buyers MUST surface an alert to the operator flagging the mutation as potentially unauthorized; they MUST NOT silently accept it as correct.
FIELD_NOT_PERMITTED does not follow this pattern. The agent-autonomous recovery path — strip the disallowed field and resubmit — supersedes the retry consideration. Buyers MUST NOT retry the identical failing request for FIELD_NOT_PERMITTED; they SHOULD correct and resubmit immediately.
See Authorization (RBAC) for the normative retry exception clause on these codes.
Standard named scope: attestation_verifier
Media-buy sales agents advertising AAO Verified (Live) readiness (tracked in #2965) MUST support a named scope identified by scope_name: "attestation_verifier" with the following minimum shape:
allowed_tasks(at minimum — vendor agents MAY include additional read-only tasks):get_adcp_capabilitiesget_productsget_media_buysget_media_buy_deliverylist_creativesupdate_media_buy
field_scopes.update_media_buy:["reporting_webhook"]read_only:false
create_media_buy, sync_creatives, and all spend-committing or targeting-modifying fields on update_media_buy. It is narrowly designed for continuous-observability verification — the compliance engine can discover live campaigns, read inventory and creative state, attach a verification reporting webhook, and read delivery, but cannot book inventory, modify budgets, change flight dates, upload creatives, or cancel anything.
get_products and list_creatives are included because AAO Verified (Live) observability requires sanity-reading the seller’s declared inventory and the creative pipeline state on active buys.
attestation_verifier is Media Buy Protocol-specific — it binds to the AAO Verified (Live) qualifier, which is a media-buy flow (live observation requires real ad delivery). Equivalent observability scopes for signals, governance, creative, or brand agents are not yet standardized; until they are, those agents use custom: scopes.
Reporting only — lifecycle-running is a future scope.
attestation_verifier is the reporting half of (Live): the engine observes
campaigns the seller has trafficked, reads delivery, and attaches a
verification webhook. It deliberately cannot create campaigns, attach
creatives, or modify budgets. The complementary lifecycle-running role — for
the AAO-operated canonical-campaign runner contemplated in
#3046, where the
engine traffics canonical PSAs end-to-end through a seller’s live agent —
needs a broader write scope (attestation_runner, tracked in
#3561). Today’s
brownfield enrollment (Path B) requires only attestation_verifier; the
runner-side scope lights up alongside the canonical-campaign runner itself.Custom scopes for other vendor protocols
Any vendor agent MAY define custom scopes using thecustom: prefix. Buyers MUST NOT assume any semantics from a custom-prefixed scope name — the names are agent-defined and learned out-of-band (docs, onboarding).
Illustrative examples (not standardized — each agent names its own):
- Signals agent:
custom:activation_only—allowed_tasks: [get_signals, activate_signal, get_adcp_capabilities], no catalog management, no cross-account metadata. - Governance agent:
custom:audit_viewer—allowed_tasks: [get_plan_audit_logs, get_adcp_capabilities],read_only: true. Useful for regulators or external auditors granted read access to governance trails. - Creative agent:
custom:library_reader—allowed_tasks: [get_adcp_capabilities, list_creatives],read_only: true. Lets a non-uploading buyer (e.g., a measurement partner) discover capabilities and library contents without mutating them. - Measurement agent on a buyer-orchestrator gateway account:
custom:measurement_feedback—allowed_tasks: [get_media_buy_delivery, provide_performance_feedback],read_only: false. These are the fixed tasks in the first experimental gateway tier. Measurement providers do not receive seller-account grants. The exact task list is normative, so no standard named scope is needed. - Brand agent (rights):
custom:rights_viewer—allowed_tasks: [get_rights, get_brand_identity],read_only: true. Discovery without clearance privilege.
custom:activation_only takes on the same 300s refresh obligation a media-buy seller does populating attestation_verifier.
Prior art
The introspection model — “the caller asks the authorization-enforcing party what the grant is” — is structurally analogous to RFC 7662 OAuth 2.0 Token Introspection, specialized for AdCP’s task-and-field authorization model. Embedding the response in sync/list rather than splitting it into a separate task reflects that account discovery and scope introspection are the same natural question (“what are my accounts, and what can I do with them?”) — the two are returned together.Transaction lifecycle
Parties
The Accounts Protocol operates with four party types. See Accounts and agents for full details on billing hierarchy, trust models, and authorized operators.Tasks
Account discovery (normative). Every agent accepting accounts MUST expose at least one oflist_accounts or sync_accounts. A seller-defined account-id namespace MAY omit both only when account IDs are supplied out-of-band and no account settings are managed through AdCP. Buyer-declared-account sellers normally expose sync_accounts to establish the relationship and SHOULD also expose list_accounts for cold-start recovery: a stateless buyer cannot reconstruct lost advertiser natural keys by replaying sync_accounts. list_accounts therefore returns the brand, operator, and optional operator unit, currency, and sandbox fields needed to compose the reference again. A buyer-declared seller MAY omit sync_accounts only when it lazily provisions from the complete natural key, can resolve every required setting without buyer input, and exposes list_accounts. For account-id namespaces, sync_accounts is settings-update only in 3.0.x unless a future explicit capability declares account-id provisioning. See Required tasks by protocol.
Brand registry connection
Thebrand.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, thebrand.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?
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 ownbrand.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):
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:
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 viaPOST /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.