Optionaladcp_version?: stringRelease-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.
Optionaladcp_major_version?: numberDEPRECATED 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.
Optionaldiscovery_mode?: "brief" | "wholesale"Declares caller intent for this request. 'brief' (default): semantic discovery — signal_spec, signal_refs, or legacy signal_ids is required and the agent performs inference/RAG. 'wholesale': raw wholesale signals feed enumeration — signal_spec, signal_refs, and signal_ids MUST NOT be provided and the agent returns its full priced signals feed, paginated, scoped by filters/account/destinations/countries when present. Sellers receiving requests from pre-v3.1 clients without discovery_mode MUST default to 'brief'. Timing semantics: 'wholesale' is a wholesale signals feed read — agents SHOULD respond synchronously and MUST NOT route a 'wholesale' request through the async/Submitted arm; partial completion is signalled via the response's incomplete[] field, not via a task-handoff envelope. Agents that do not implement wholesale enumeration MAY return INVALID_REQUEST for wholesale calls; callers SHOULD probe via get_adcp_capabilities (signals.discovery_modes) first.
Optionalaccount?: AccountReferenceOptionalsignal_spec?: stringNatural language description of the desired signals. When used alone, enables semantic discovery. When combined with signal_refs, provides context for the agent but signal_ref matches are returned first. MUST NOT be provided when discovery_mode is 'wholesale'.
Optionalsignal_refs?: SignalRef[]Specific signals to look up by reference. Returns exact matches for the requested SignalRef values. When combined with signal_spec, these signals anchor the starting set and signal_spec guides adjustments. MUST NOT be provided when discovery_mode is 'wholesale'.
Optionalsignal_ids?: SignalID[]Optionaldestinations?: Destination[]Filter signals to those activatable on specific agents/platforms. When omitted, returns all signals available on the current agent. If the authenticated caller matches one of these destinations, activation keys will be included in the response.
Optionalcountries?: string[]Countries where signals will be used (ISO 3166-1 alpha-2 codes). When omitted, no geographic filter is applied.
Optionalfilters?: SignalFiltersOptionalfields?: (Specific signal fields to include in the response, aligned with get_products.fields. Required identity and activation fields such as signal_ref or signal_id, signal_agent_segment_id, name, description, signal_type, coverage_percentage, and deployments are always included when required by the response schema. Use for progressive disclosure of rich signal-definition metadata: request fields such as taxonomy, data_sources, methodology, segmentation_criteria, criteria_url, refresh_cadence, lookback_window, onboarder, modeling, audience_expansion, device_expansion, countries, consent_basis, restricted_attributes, policy_categories, art9_basis, data_subject_rights, and last_updated when the buyer needs them inline. Omit for the agent's default discovery projection. Agents SHOULD honor requested fields for exact lookup, refinement, small custom-signal result sets, and private/source-native signals when available. fields is a projection request, not an entitlement grant; agents MAY redact requested definition fields unless the caller is authorized for the underlying lineage, methodology, and rights-routing metadata. When consent_basis or art9_basis is projected for another provider's signal, the value remains provider-declared signal-definition posture; sellers and federating agents MUST NOT substitute their own processing basis. For broad discovery and wholesale pages, agents MAY return compact pointers instead of inlining large resources, especially when provider-published definitions can be resolved from signal_ref, taxonomy.ref, criteria_url, disclosure_url, and validators such as resolved URL plus catalog_etag, HTTP ETag/Last-Modified, or taxonomy.etag.
Optionalmax_results?: numberDEPRECATED: Use pagination.max_results instead. When both fields are present, agents MUST honor pagination.max_results. When only this field is present without a pagination envelope, agents SHOULD treat it as the page size subject to a maximum of 100 results. This field will be removed in AdCP 4.0.
Optionalpagination?: PaginationRequestOptionalpush_notification_config?: PushNotificationConfigOptionalif_wholesale_feed_version?: stringOpaque wholesale_feed_version token returned by a prior wholesale-mode get_signals response from this agent. Only valid when discovery_mode is wholesale. When provided, the agent compares against its current wholesale signals feed version for the caller's cache_scope and MAY return an unchanged: true response (with signals omitted) if nothing has changed. The token is scope-keyed: callers cache (cache_scope, wholesale_feed_version) pairs. 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 sync pattern.
Optionalif_pricing_version?: stringOpaque pricing_version token from a prior get_signals response. MUST only be sent together with if_wholesale_feed_version — pricing version has no structural baseline to compare against on its own. Evaluation order: (1) if_wholesale_feed_version mismatch → agent returns the full payload; (2) if_wholesale_feed_version matches but if_pricing_version mismatches → agent returns the full payload so the caller sees updated pricing_options; (3) both match → agent MAY return unchanged: true. Agents that don't track pricing separately ignore this and fall back to if_wholesale_feed_version semantics.
Optionalcontext?: ContextObjectOptionalext?: ExtensionObject
Request parameters for discovering and refining signals. Use signal_spec for natural language discovery, signal_refs for exact lookups, both together to refine previous results, or discovery_mode: 'wholesale' to enumerate the agent's full priced signals feed (symmetric with get_products buying_mode: 'wholesale'). The legacy signal_ids field is deprecated.