> ## Documentation Index > Fetch the complete documentation index at: https://docs.interchange.io/llms.txt > Use this file to discover all available pages before exploring further. # Create advertiser creative master > Create a creative manifest under an advertiser, before any campaign exists `POST /api/v2/buyer/advertisers/{advertiserId}/creatives/create` Creates a creative manifest scoped to an **advertiser** instead of a campaign. Use it to stage creative you already have before a campaign exists, or to build a reusable master you assign to several campaigns later. The manifest is stored with `campaign_id` unset and `advertiser_id` set, and it appears in [the advertiser-scoped creative listing](/v2/object-guides/creative#advertiser-scoped-creative-listing). Everything else about a manifest is the same as the campaign-scoped [Create creative manifest](/v2/buyer/creatives/tasks/create-creative-manifest): same `metadata` body, same asset handling, same tracking macros, same 50 MB per-file and 20-file-per-request limits. An advertiser-level master does not deliver on its own. It reaches a media buy only after it is assigned to a campaign — see [Advertiser library: assign and unassign](/v2/object-guides/creative#advertiser-library-assign-and-unassign). ## What differs from the campaign-scoped create | | Campaign-scoped | Advertiser-scoped | | ------------------- | ----------------------------------------------------- | ---------------------------------------------------------------------------- | | Path | `/campaigns/{campaignId}/creatives/create` | `/advertisers/{advertiserId}/creatives/create` | | Scope proof | The campaign must belong to the authenticated account | The advertiser must belong to the authenticated account | | `format_option_ref` | Accepts `scope: "product"` and `scope: "publisher"` | `scope: "product"` is rejected — resolving a product option needs a campaign | | Name uniqueness | Deduplicated on `(campaign_id, name)` | Deduplicated on `(advertiser_id, name)` among non-archived manifests | | Delivery | Propagates to media buys when the campaign executes | Inert until assigned to a campaign | ## Request ```bash curl theme={null} curl -X POST https://api.interchange.io/api/v2/buyer/advertisers/10632/creatives/create \ -H "Authorization: Bearer $SCOPE3_API_KEY" \ -H "Content-Type: multipart/form-data" \ -F 'metadata={ "name": "Evergreen hero banner", "message": "Always-on brand banner", "format_kind": "image", "linked_assets": [ { "url": "https://cdn.acme.com/hero-728x90.png", "asset_type": "IMAGE" } ], "url_assets": [ { "asset_id": "click_url", "url": "https://acme.com/promo" } ] };type=application/json' ``` ## Parameters `advertiserId` is a path parameter. The `metadata` JSON part carries the same fields as the campaign-scoped create: | Field | Type | Required | Notes | | ---------------------- | ------ | ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `name` | string | No | Manifest name (max 255). Auto-generated if omitted. Also the dedupe key within this advertiser | | `message` | string | No | Creative brief / direction text (max 5000) | | `format_kind` | string | Conditional | AdCP 3.1 canonical kind (e.g. `image`, `video_hosted`). Inferred from the one renderable primary asset when omitted; **required** when the create has no such asset — a brief-only, click-URL-only, or `TEXT`-only manifest | | `format_id` | object | No | `{ agent_url, id, width?, height?, duration_ms? }` — legacy ADCP format reference | | `format_option_ref` | object | No | Only `{ scope: "publisher", publisher_domain, format_option_id }` is accepted without a campaign | | `template_id` | string | No | Creative template or vendor tag | | `linked_assets` | array | No | Already-hosted or inline assets (max 50): `{ url` or `data_url, asset_type, content_type?, label?, make_primary? }` | | `url_assets` | array | No | Slot-assigned URL assets (max 50): `{ asset_id, url, url_type? }`. Use `asset_id: "click_url"` for the click destination | | `url_asset` | object | No | Single URL asset: `{ url, url_type }` | | `text_assets` | array | No | Slot-assigned text assets: `{ asset_id, content }` | | `webhook_asset` | object | No | Webhook-backed asset configuration | | `assets` | array | No | Per-uploaded-file metadata: `{ filename, asset_type?, label?, slot_asset_id? }` | | `cards` | array | No | Carousel cards for `image_carousel` (2–10) | | `industry_identifiers` | array | No | Industry identifiers per the AdCP spec: `[{ type, value }]`, where `type` is `ad_id`, `isci`, `clearcast_clock`, or `idcrea` | | `frequencyCaps` | array | No | Buyer-defined caps: `{ max_impressions, window: { interval, unit } }` | A create must satisfy two independent requirements, and a request that misses either is rejected with `400 VALIDATION_ERROR`: * **Content** — at least one file, `linked_assets` entry, `url_asset`/`url_assets` entry, `text_assets` entry, `cards` entry, `webhook_asset`, or a `message`. A request carrying only a `name` has none. * **Format identity** — a canonical `format_kind`, either supplied directly or inferred from exactly one renderable primary asset (`IMAGE`, `VIDEO`, `AUDIO`, `HTML`, `VAST`). A brief, a click-through URL, and a `TEXT` asset carry no identity, so a create built only from those must supply `format_kind`. `brandAgentId` is accepted in the body for wire compatibility and ignored on this route — the path `advertiserId` is authoritative. Form parts: `files=@` (one per uploaded asset). Limits: 50 MB per file, 20 files per request. ## Response Returns `201` with the same `CreativeManifestResponse` the campaign-scoped create returns, except `campaign_id` is absent and `advertiser_id` is set: ```json theme={null} { "creative_id": "cm_abcdef", "advertiser_id": "10632", "name": "Evergreen hero banner", "format_kind": "image", "assets": [ { "asset_id": "asset_001", "name": "hero-728x90", "original_filename": "hero-728x90.png", "asset_type": "IMAGE", "content_type": "image/png", "file_size": 18244, "public_url": "https://cdn.acme.com/hero-728x90.png", "asset_source": "CREATIVE_SOURCE", "created_at": "2026-09-01T10:00:00Z" } ], "created_at": "2026-09-01T10:00:00Z", "updated_at": "2026-09-01T10:00:00Z" } ``` When a non-archived manifest with the same `(advertiser_id, name)` already exists, that manifest is returned with `already_exists: true` and `ignored_files` set. **The assets sent with that request are not attached to it** — create under a different name, or use [Update creative manifest](/v2/buyer/creatives/tasks/update-creative-manifest) to add assets to the existing one. ## Errors * `400 VALIDATION_ERROR` — no content supplied (name only), no resolvable `format_kind`, a `files` part with no matching `assets[].filename`, more than one `make_primary` asset, a file over 50 MB, an unsupported MIME type, or a non-numeric `advertiserId`. * `400 VALIDATION_ERROR` — a product-scoped `format_option_ref`, which cannot be resolved without a campaign. * `404 NOT_FOUND` — `advertiserId` does not exist **or does not belong to the authenticated account**. The two cases are deliberately indistinguishable so the response never confirms that an advertiser exists in another account. * `409 CONFLICT` — the name is held by a creative that is still being written (`details.reason: name_creation_in_progress`) or was left incomplete by an earlier attempt (`name_creation_abandoned`). Branch on `details.reason`, not the message. See [Errors](/v2/reference/errors) for the full error contract. ## From an agent The `save_creative` MCP tool reaches this operation: omit `creativeId`, supply `advertiserId` (with no `campaignId`), a `name`, content (`message`, `assets`, `sourceAssetRef`, or `clickUrl`), and identity (`formatKind`, unless an asset or private JPEG/PNG source implies it). Supplying `campaignId` instead creates the Creative under that campaign's advertiser and then attaches it to the campaign. The tool enforces both requirements before dispatching, so a brief-only call fails with a named field rather than a generic service error. `save_creative` sends assets as hosted URLs or inline base64 data URLs; it has no multipart `files` equivalent. A finalized private JPEG/PNG upload is the exception: pass its opaque `scope3-asset://v1/...` reference as `sourceAssetRef`, and Interchange re-verifies and copies the bytes into the governed Creative store. The manifest keeps only the durable asset and a one-way source fingerprint, never the private reference, object path, or a signed URL. Retrying the same source and name returns the same Creative and completes an interrupted campaign attachment. Package and media-buy attachment remain separate workflows. For ordinary `assets`, if the manifest comes back with fewer assets than the call requested, the tool says so in its response text and sets `assetAttachWarning`, `assetsRequested`, and `assetsAttached` — the creative was saved, but the missing media is not on it. Re-send it as a hosted `url` rather than assuming the creative is complete. ## Related The campaign-scoped create Manifest fields, the advertiser library, assign and unassign