- Publisher properties — WHERE the ad runs (youtube.com, spotify.com)
- Collections / installments — WHAT CONTENT the ad runs in or around (a specific series and its installments)
- Placements — WHAT POSITION the ad appears in (pre-roll, mid-roll, host read)
Channel mapping
The collection/installment model maps to familiar concepts across media channels:
The
kind field on each collection indicates how to interpret it and its installments.
The collection object
A collection is a persistent content program that produces installments over time. Collections work like properties — publishers declare them in theiradagents.json, and products reference them via collections selectors with publisher_domain and collection_ids.
The installment object
An installment is a specific installment of a collection. Not all installments will be known in advance — a weekly podcast may only have next week’s installment scheduled, and some installments may be tentative (a playoff Game 7 depends on Game 6).Episode status lifecycle
Expected transitions:
scheduled or tentative → live → aired or published. A scheduled installment may become postponed (delayed) or cancelled. A postponed installment returns to scheduled when rescheduled. A tentative installment resolves to scheduled, cancelled, or postponed.
Inheritance from collections
Episodes inherit collection-level fields they do not override:content_rating: Episode value overrides collection baseline. When absent, the collection’s rating applies.special: Episode value overrides collection-level special. When absent, the collection’s special applies. A regular collection can have event-anchored installments (e.g., a daily news collection with an election night special).guest_talent: Additive to the collection’s recurringtalent— does not replace it.topics: Additive context for brand safety, not a replacement for the collection’sgenre.
Installment deadlines
Episodes can carry booking, cancellation, and material submission deadlines. These apply to any channel where inventory is tied to a scheduled unit — print issues, podcast installments, influencer posts, linear TV airings, DOOH rotations.
Deadlines MUST be chronologically ordered:
booking_deadline ≤ cancellation_deadline ≤ each material_deadlines[n].due_at (ascending by array index) ≤ the installment’s scheduled_at. Buyer agents SHOULD reject installments where deadlines violate this ordering.
Each material deadline has:
The two-stage pattern — draft then final — covers a wide range of channels:
Podcast with deadlines
Print issue with deadlines
Influencer post with deadlines
Deadline policy
High-frequency collections (daily newspapers, weekly podcasts) would generate large payloads if every installment carried explicit deadlines. Thedeadline_policy on a collection declares lead-time rules that agents use to compute deadlines from each installment’s scheduled_at.
Daily newspaper with policy
Instead of enumerating deadlines for every issue, the collection declares the rule once:scheduled_at: "2026-04-01"), an agent computes:
- Booking deadline: 4 business days before = March 26
- Cancellation deadline: 3 business days before = March 27
- Material due: 2 business days before = March 28
deadlines override the policy. A special edition with tighter turnaround declares its own deadlines; regular issues inherit from the policy.
Weekly podcast with policy
Policy vs explicit deadlines
When both are present, explicit installment
deadlines take precedence. An agent SHOULD NOT compute deadlines from the policy for installments that have their own.
Specials and limited series
Collections can carry optional annotations that signal their nature to buyer agents. These are composable — a collection can be both a special and a limited series (e.g., a 4-installment Olympics documentary).Specials
A special is content anchored to a real-world event or occasion. Thespecial object can appear on both collections and installments. On a collection, it means the entire collection is event-anchored. On an installment, it means that specific installment is event-anchored (and overrides the collection-level special when present, following the same inheritance pattern as content_rating).
special field is distinct from cadence. Cadence describes release frequency (event = one-time or occasional). The special object describes what real-world event anchors the content and when it happens — information a buyer agent needs to evaluate timing relevance and premium pricing.
Limited series
A limited series is a bounded content run with a defined arc. Unlike ongoing series, limited series have a planned end.limited_series field is distinct from season: a collection can have seasons without being limited (ongoing series have seasons too), and a limited series is a structural commitment that the collection has a planned end.
How products reference collections
Products reference collections viacollections — an array of {publisher_domain, collection_ids} selectors that point to collections declared in the publisher’s adagents.json. This is the same pattern as publisher_properties. Buyers resolve full collection objects from the publisher’s adagents.json. Episodes are listed per-product in the installments array, since different products may scope different installments of the same collection.
Run-of-collection (no specific installments)
A product can reference a collection without listing installments. This means “inventory across this collection, whatever installments air during the flight dates”:Specific installments
For premium or guaranteed buys, the seller scopes to specific installments:get_products response structure
Products reference collections viacollections selectors — the same pattern as publisher_properties. Each selector has a publisher_domain and collection_ids array pointing to collections declared in that publisher’s adagents.json. Buyers resolve full collection objects from adagents.json.
Canonical collection identity
A collection’s identity is{publisher_domain, collection_id} — scoped to the publisher that declares it in their adagents.json. This means any collection creator can serve as their own canonical registry.
Creator as canonical publisher
A creator like MrBeast declares collections inmrbeast.com/adagents.json. Any seller packaging that creator’s inventory — a YouTube sales house, a CTV distributor, the creator’s own team — references the same canonical source:
mrbeast.com + beast_games regardless of which seller or platform the inventory comes from. No cross-referencing of IMDb IDs or distribution identifiers needed — the creator’s domain is the registry.
When creators don’t publish adagents.json
Not every collection has a creator-owned domain. A streaming platform’s original series may only exist in that platform’sadagents.json. In that case, the platform is the canonical publisher and collections points to their domain. Distribution identifiers on the collection object handle cross-seller matching when the same collection appears on multiple platforms without a single canonical source.
Identity resolution priority
Buyer agents should resolve collection identity in this order:- Canonical publisher —
publisher_domain+collection_idfrom the creator’s ownadagents.json. Strongest signal. - Platform-independent identifiers —
imdb_id,gracenote_id,eidr_idfrom the collection’sdistributionarray. Reliable cross-reference when no canonical publisher exists. - Platform-specific identifiers — Spotify, Apple, YouTube IDs. Useful within a platform but not universal.
Discovery examples
CTV collection with installments
A streaming platform selling sponsorships against a known collection with upcoming installments:Related collections and derivative content
A streaming platform offering a main collection and its companion after-collection, plus highlight clips:derivative_of. The companion after-collection is linked via related_collections on the main collection — buyers targeting Nova Kitchen can discover the after-collection as an additional reach opportunity.
Podcast with distribution
A podcast network selling across multiple distribution platforms. The collection’sdistribution array in adagents.json captures the full distribution footprint; buyers use distribution identifiers for cross-seller matching:
Live event with tentative installments
A sports league selling sponsorships against a live event series. Live broadcasts useflexible_end because game duration is unpredictable, and unplanned_breaks because ad breaks follow game flow (timeouts, period breaks) rather than a fixed schedule. The tentative Game 5 depends on the series outcome — it only happens if neither team wins in four games.
cadence: "event" signals a non-recurring series, flexible_end tells buyers the broadcast length is approximate, and unplanned_breaks: true indicates ad breaks follow game flow rather than a predetermined schedule. The tentative Game 5 includes valid_until so buyer agents know when to re-query — if the series ends in four games, that installment will resolve to cancelled. Buyers should always check valid_until on tentative installments before committing budget.
Discovering collections
Buyers discover collections through the standardget_products workflow. Natural language briefs drive collection selection:
collections selectors. The buyer resolves full collection objects from each publisher’s adagents.json. There is no separate collection discovery endpoint — collections surface through product discovery and adagents.json crawling.
Brand safety
Collections provide a two-level brand safety model: a collection baseline and per-installment overrides.Collection baseline
A collection’s default brand safety profile comes from:content_rating— the collection’s declared rating system and valuegenre— content categories (ideally usinggenre_taxonomyfor machine-readable evaluation)talent— hosts and recurring cast, with optional brand.json references for deeper evaluation
Installment overrides
When installment details are available, they can shift the safety profile:- A
content_ratingthat differs from the collection baseline (this week is TV-14 instead of TV-PG) guest_talentthat changes the talent profile (a controversial guest)topicsthat add installment-specific content signals
What is not modeled
AdCP does not predict content safety for unknown future installments. A buyer who commits to “all April installments” buys based on the collection’s baseline profile, accepting variation. The seller’s content standards and the collection’s track record are the buyer’s basis for that decision.Distribution identifiers
Each collection’sdistribution array maps it to specific publisher platforms with platform-specific identifiers. This enables cross-seller matching: when two different sellers both offer products for the same collection, a buyer agent can match them via shared identifiers.
Cross-seller matching
Platform-independent identifiers are the most reliable for deduplication:
Shows SHOULD include at least one platform-independent identifier when available.
Platform-specific identifiers
apple_podcast_id, spotify_collection_id, rss_url, podcast_guid, amazon_music_id, iheart_id, podcast_index_id. Available video/CTV types: youtube_channel_id, youtube_playlist_id, amazon_title_id, roku_channel_id, pluto_channel_id, tubi_id, peacock_id, tiktok_id, twitch_channel. Other: domain, substack_id.
Ad inventory
Episodes declare break-based ad inventory in thead_inventory object:
For non-break ad formats like host reads, custom integrations, or sponsorships, use product placements instead. A podcast product might have a placement for “mid-roll host read (60s)” — that is a placement on the product, not part of
ad_inventory.
Relationship to LEAP
The installment model aligns with IAB Tech Lab’s LEAP Forecasting API for live streaming events:
LEAP targets SSP-to-DSP plumbing. AdCP operates at the agent-to-agent negotiation layer where buying decisions happen.
Collection targeting
Products with multiple collections default to bundles — the buyer gets all listed collections. Sellers can setcollection_targeting_allowed: true to let buyers target a subset, the same pattern as property_targeting_allowed for properties.
Multi-collection bundles
A single product can span multiple collections by listing multiple collection IDs incollections. When a product has multiple collections, each installment MUST include collection_id so the buyer agent knows which collection each installment belongs to.
Print publication with issues
A magazine publisher selling display ads across upcoming issues. Each issue is an installment with deadlines for booking, cancellation, and material delivery:deadlines object replaces what the German OBS system handles through separate message exchanges — booking, cancellation, and material delivery are all visible upfront.
See also
- Media products — the full product model
- Print ads — print-specific creative formats, physical dimensions, bleed, and DPI
- brand.json — talent identity and brand safety evaluation
- Product discovery — how buyers discover inventory via
get_products