> ## Documentation Index
> Fetch the complete documentation index at: https://docs.adcontextprotocol.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Sponsored Placement adapter contracts

> Four runtime contract families that ship under the single sponsored_placement canonical — Amazon SP, Criteo/CitrusAd, Pinterest/Snap Collection, generative-per-SKU.

The `sponsored_placement` canonical covers retail-media catalog-driven creative — Amazon SP, Criteo SP, CitrusAd SP, Pinterest Collection, generative-per-SKU. The schema captures the binary axes (`composition_model`, `fanout_mode`, `item_production_model`) but the runtime contract — fan-out semantics, catalog-asset wiring, per-adopter tracking — differs enough between adopter families that a manifest validating against `sponsored_placement` tells the buyer little about whether it will actually serve on a given retail-media network.

This page documents the four contract families, their current experimental readiness, and the adopter-specific quirks that don't live in the schema. The canonical stays `experimental: true` past 3.1 GA until at least two retail-media networks ship `format_schema` evidence (see [`canonical-formats.mdx` §`experimental` — one field, both axes](/docs/creative/canonical-formats#experimental--one-field-both-axes)).

## The four contract families

| Family                                         | `composition_model`         | `fanout_mode`            | `item_production_model`          | Nondeterminism flag                | Adopters                                                           |
| ---------------------------------------------- | --------------------------- | ------------------------ | -------------------------------- | ---------------------------------- | ------------------------------------------------------------------ |
| **Retail-media deterministic, buyer-uploaded** | `deterministic`             | `per_item`               | `buyer_uploaded`                 | Not set                            | Amazon SP                                                          |
| **Retail-media network-composed**              | `deterministic`             | `per_item`               | `seller_pre_rendered_from_brief` | Not set                            | Criteo SP, CitrusAd SP                                             |
| **Collection-layout per impression**           | `deterministic` (debatable) | `multi_item_in_creative` | `buyer_uploaded`                 | Not set                            | Pinterest Collection, Snap Collection                              |
| **Generative-per-SKU**                         | `deterministic`             | `per_item`               | `agent_synthesized`              | `synthesis_nondeterministic: true` | Vendor-specific (Pencil, Persado, vertical retail-media platforms) |

### 1. Retail-media deterministic, buyer-uploaded (Amazon SP)

The buyer uploads the catalog assets (product image, headline, description) via `sync_creatives`. The retail-media network ingests the catalog row + assets and serves them deterministically against query/category triggers — no fan-out at render time. The buyer can predict per-impression rendering.

* **Catalog-asset contract:** buyer supplies one creative per catalog item; the `source_catalog` slot points at the buyer's product feed; per-item assets are required.
* **Tracking:** Amazon ASIN + standard retail-media event vocabulary. Per-item attribution maps to the catalog row's identifier.
* **Adopter quirks:** Amazon's category-trigger system means the same uploaded creative may serve under different category contexts — buyers MUST treat impression-level category as untrusted-by-creative-shape; rely on Amazon's reporting for category attribution.
* **Experimental readiness:** predictable enough for sandbox and controlled-adopter use. Most predictable family; `format_schema` evidence from Amazon would support promotion toward non-experimental.

### 2. Retail-media network-composed (Criteo SP, CitrusAd SP)

The buyer supplies a brief + brand assets (logo, brand colors); the retail-media network composes the placement against its own catalog + design templates. The buyer cannot predict per-impression rendering at the asset-bundle level, only at the brand-direction level.

* **Catalog-asset contract:** buyer supplies brief + brand assets; the `source_catalog` is the *seller's* catalog (the retail-media network's product index), not the buyer's. The buyer's product references are matched to seller-catalog rows via SKU / GTIN / category.
* **Tracking:** retail-media network's own event vocabulary; buyer attribution maps through the network's reporting API, not direct creative events.
* **Adopter quirks:** Criteo's composition logic varies by retailer integration — the same buyer brief produces different placements on Walmart vs. Target vs. Best Buy via Criteo. Buyers MUST treat per-retailer rendering as opaque and rely on Criteo's aggregated reporting.
* **Experimental readiness:** suitable for controlled-adopter use. The composition opacity is the gap to non-experimental promotion — `format_schema` evidence would need to document the per-retailer variability.

### 3. Collection-layout per impression (Pinterest Collection, Snap Collection)

The buyer supplies a hero image + a collection of catalog items; the surface picks the collection layout per impression (grid, carousel, cover + reveal). `composition_model: deterministic` is technically true at the asset level but loose at the layout level.

* **Catalog-asset contract:** buyer supplies one creative with a hero asset slot + an items array (each item: image + caption + URL). The `source_catalog` slot is the buyer's curated item collection, not a full product feed.
* **Tracking:** Pinterest's collection-item events (`collection_item_click`, `collection_close_up`) plus standard impression/click. Per-item attribution available; layout-variant attribution is not exposed.
* **Adopter quirks:** Snap Collection's "cover + reveal" layout requires a specific aspect ratio and asset count combination — schema doesn't enforce; buyers SHOULD pre-validate before sync.
* **Experimental readiness:** suitable for controlled-adopter use. The "deterministic" claim survives at the asset level but layout variability blocks non-experimental promotion without per-surface conformance evidence.

### 4. Generative-per-SKU (vendor-specific)

The buyer supplies a brief + catalog reference; the seller's generative pipeline produces a unique creative per SKU. 1 brief × N catalog items → N rendered creatives. `composition_model` remains `deterministic` because each rendered item is produced before delivery and then served as produced; the generative mechanism is captured by `item_production_model: "agent_synthesized"`.

* **Catalog-asset contract:** buyer supplies the brief + a catalog scope (SKUs, categories, or full feed); the seller produces creatives via `build_creative` with `item_production_model: agent_synthesized` and `fanout_mode: per_item`. The `source_catalog` slot is the buyer's product feed; assets are seller-generated.
* **Nondeterminism:** products in this family SHOULD declare `synthesis_nondeterministic: true` when generation cannot guarantee in-spec output before the QA loop completes.
* **Tracking:** generative-output ID + buyer's catalog-item key (SKU/GTIN). Buyers SHOULD treat each generated creative as a distinct rendered output with its own performance signal, not as a copy of the brief.
* **Adopter quirks:** generative seeds and prompts are typically not exposed back to the buyer; buyers cannot reproduce a specific generation. Plan for re-generation cycles rather than asset-edit cycles.
* **Experimental readiness:** leave `experimental: true` until generative-quality evidence is documented per-adopter. Controlled use is possible, but the composition is opaque to the buyer and needs per-vendor framing.

## Experimental-readiness matrix

| Family                                     | Controlled-adopter use | Default production routing             | Promotion evidence                                                      |
| ------------------------------------------ | ---------------------- | -------------------------------------- | ----------------------------------------------------------------------- |
| Retail-media deterministic, buyer-uploaded | Ready                  | Keep experimental until evidence lands | Amazon `format_schema` evidence                                         |
| Retail-media network-composed              | Ready                  | Keep experimental until evidence lands | Per-retailer variability documentation                                  |
| Collection-layout per impression           | Ready                  | Keep experimental until evidence lands | Per-surface conformance evidence                                        |
| Generative-per-SKU                         | Vendor-specific only   | Keep experimental                      | Generative-quality evidence; may not promote without per-vendor framing |

`experimental` lives on both the canonical and the product declaration. See [`canonical-formats.mdx` §`experimental` — one field, both axes](/docs/creative/canonical-formats#experimental--one-field-both-axes) for the field-level contract.

## What this page is not

* **Not a normative spec extension.** The four families share the existing `sponsored_placement` schema; this doc names the variability sellers and buyers will encounter against the canonical, but adds no required fields.
* **Not a promotion gate.** The canonical's promotion to non-experimental is gated on `format_schema` evidence across at least two adopters, per [canonical-formats.mdx](/docs/creative/canonical-formats). This page documents what `format_schema` evidence will need to cover for each family.
* **Not exhaustive.** Adopters whose runtime contract doesn't fit one of the four families above SHOULD file an issue against the canonical-formats track so the matrix can be extended.

## Refs

* [#3307](https://github.com/adcontextprotocol/adcp/pull/3307) — original `sponsored_placement` canonical
* [#4592](https://github.com/adcontextprotocol/adcp/issues/4592) — this doc
* [`canonical-formats.mdx`](/docs/creative/canonical-formats) — overall canonical-formats vocabulary