Interface GetSignalsResponse

Session/conversation identifier for tracking related operations across multiple task invocations. Managed by the protocol layer to maintain conversational context. Distinct from context (per-request opaque echo, see below).

Unique identifier for tracking asynchronous operations. Present when a task requires extended processing time. Used to query task status and retrieve results when complete.

Human-readable summary of the task result. Provides natural language explanation of what happened, suitable for display to end users or for AI agent comprehension. Generated by the protocol layer based on the task response.

ISO 8601 timestamp when the response was generated. Useful for debugging, logging, cache validation, and tracking async operation progress.

Set to true when this response was returned from the idempotency cache rather than from a fresh execution. Set to false (or omitted) when the request was executed fresh. Buyers use this to distinguish cached replays from new executions — matters for billing reconciliation, audit logs, state-machine routing (cached state-tracking fields are historical snapshots, not current state — re-read via the resource's read endpoint), and any downstream system that assumes exactly-once event semantics. From 3.1 onward, replayed MAY appear on responses to any request that resolved via the idempotency cache, including read tools — universal idempotency_key (see security.mdx §Idempotency) means the cache holds read responses too.

Governance context token issued by the account's governance agent during check_governance. Buyers attach it to governed purchase requests (media buys, rights acquisitions, signal activations, creative services); sellers persist it and include it on all subsequent governance calls for that action's lifecycle. An account binds to one governance agent (see sync_governance); governance is phased across purchase / modification / delivery, not partitioned across specialist agents, so the envelope carries a single token for the full lifecycle.

Value format: governance agents MUST emit a compact JWS per the AdCP JWS profile (see Security — Signed Governance Context). Sellers MAY verify; sellers that do not verify MUST persist and forward the token unchanged. In 3.1 all sellers MUST verify. Non-JWS values from pre-3.0 governance agents are deprecated.

This is the primary correlation key for audit and reporting across the governance lifecycle.

Conceptual grouping for the task-specific response data defined by individual task response schemas (e.g., get-products-response.json, create-media-buy-response.json). payload is a documentary construct — it is NOT a required wire field, and its on-the-wire shape depends on transport (see Transport serialization below). Task response schemas declare body fields without wrapping them in a payload object; the wire representation places those body fields per transport convention. On MCP the body fields appear as siblings of envelope fields at the root of the tool response; on A2A they appear inside task.artifacts[0].parts[].DataPart; on REST they appear at the root of the JSON body.

Release-precision AdCP version (VERSION.RELEASE, e.g. "3.0", "3.1", "3.1-beta"). On a request: the buyer's release pin — the seller validates against its supported_versions and returns VERSION_UNSUPPORTED on cross-major mismatch, or downshifts to the highest supported release within the same major. On a response: the release the seller actually served — clients SHOULD validate the response against that release's schema, not against their pin. Patches are not negotiated; surface them as build_version on capabilities for operational visibility. When omitted, falls back to adcp_major_version (deprecated) or server default. Buyers SHOULD emit both adcp_version and adcp_major_version through 3.x to remain compatible with sellers that only read the legacy field. NORMALIZATION: SDKs that read full-semver values from bundle metadata (e.g. ComplianceIndex.published_version = "3.1.0-beta.1") MUST normalize to release-precision ("3.1-beta.1") before emitting on the wire — meta-field values are NOT valid wire values.

DEPRECATED in favor of adcp_version (release-precision string). Servers MUST continue to honor this field through 3.x. Removed in 4.0. Original semantics: the AdCP major version the buyer's payloads conform to. Sellers validate against their supported major_versions and return VERSION_UNSUPPORTED if unsupported. When omitted, the seller assumes its highest supported version.

Array of matching signals

Task-specific errors and warnings (e.g., signal discovery or pricing issues)

Declares what the agent could not finish within the caller's time_budget or due to internal limits. Each entry identifies a scope that is missing or partial. Absent when the response is fully complete.

Opaque token representing the version of the wholesale signals feed state used to compose this response. Agents that implement conditional-fetch (if_wholesale_feed_version) MUST return this on every wholesale-mode response so callers can cache and probe later. Callers MUST treat the value as opaque — no format, no ordering, no inspection. The token is scope-keyed: it describes a version for the cache_scope declared on this response, NOT a global agent version. A caller caches (cache_scope, wholesale_feed_version) pairs and presents the matching token on the next request. Scoping dimensions: (agent, discovery_mode, filters, destinations, countries) for cache_scope: 'public'; that tuple plus account_id for cache_scope: 'account'. pagination.cursor is NOT part of the scoping tuple. See specs/wholesale-feed-webhooks.md for the full cache layering model.

Opaque token representing the version of the pricing layer. When the agent supports independent pricing versioning, pricing_version changes when prices move but wholesale_feed_version changes only when structure/metadata moves. Same cache_scope keying as wholesale_feed_version. Agents not separating these MAY omit pricing_version and use wholesale_feed_version for both.

Declares whether the wholesale_feed_version and pricing_version on this response describe a universal layer or an account-specific overlay. REQUIRED on every 3.1+ response (the 3.1 schema enforces this — the safety property of the two-layer cache model depends on it). 'public': this response describes the agent's published rate card; the caller MAY dedupe under (agent, discovery_mode, filters, destinations, countries) without scoping by account. 'account': this response includes account-specific overrides; the caller MUST cache the version under that tuple plus account_id. When the request did NOT include account, the agent MUST return cache_scope: 'public'. When the request included account, the agent MUST return either 'public' (this account prices off the public rate card — caller dedupes) or 'account' (account-specific overrides exist — caller caches under the account key). Agents MAY return 'public' on an account-scoped request that previously had overrides — callers SHOULD interpret this as a downgrade. Without schema-required cache_scope, an agent silently omitting the field on an account-scoped response would cause callers to mis-key the cache and serve account-overlay payloads to other accounts — the canonical safety invariant of the entire cache layering model. Backward-compatibility note for 3.1 validators: SDKs validating strictly against the 3.1 schema MUST select the validator based on the server-declared adcp_version. For responses with adcp_version starting 3.0, the 3.1 cache_scope-required constraint MUST be relaxed — pre-3.1 agents correctly emit no cache_scope and remain conformant to their declared version. This is a tightening within 3.1, not a 3.0 break.

Present and true ONLY on wholesale-mode responses when the request carried if_wholesale_feed_version (and/or if_pricing_version) matching the agent's current version for the caller's cache_scope, in which case signals[] MUST be omitted; wholesale_feed_version (echoed), cache_scope (echoed), and pricing_version (echoed when used) MUST still be present. Callers receiving unchanged: true MUST NOT mutate their local wholesale signals mirror. One shape per state: agents MUST NOT emit unchanged: false — the absence of the field IS the signal that the response carries signals.

When true, this response contains simulated data from sandbox mode.