AdCP — Implementing Standard Format Support

This guide is for sales agents declaring the creative contracts their inventory accepts. In AdCP 3.2, author canonical Product.format_options[]. list_creative_formats, recursive creative-agent catalogs, and compound named format IDs are deprecated compatibility surfaces.

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Question	Authoritative surface
What does a publisher surface accept?	Publisher `adagents.json.formats[]`
What can this seller deliver for a product?	That product’s closed `format_options[]` set
Which creative agent can produce or validate it?	`get_adcp_capabilities.creative.supported_formats[]`

The seller declares deliverability; it does not nominate a creative producer. Buyers can use the AgenticAdvertising.org registry to find creative agents whose self-declared canonical envelope satisfies the product declaration. Zero registry matches is a valid result: it means no protocol-exposed build, validation, or preview service currently advertises that contract. The buyer may still supply an already-conforming finished manifest or use a seller-returned preview, but MUST NOT infer a renderer from the publisher or product format declaration.

Standard formats

For standard display, video, audio, and native shapes, use the canonical format_kind and narrow it with explicit parameters and slots. Do not create a new identifier merely because your product has a different price or placement name.

{
  "product_id": "daily_pulse_homepage_display",
  "name": "Daily Pulse homepage display",
  "format_options": [
    {
      "format_option_id": "homepage_image_300x250",
      "format_kind": "image",
      "params": {
        "width": 300,
        "height": 250,
        "slots": [
          { "asset_group_id": "image_main", "asset_type": "image", "required": true },
          { "asset_group_id": "landing_page_url", "asset_type": "url", "required": true }
        ]
      }
    }
  ]
}

format_options[] is a closed set. A package or creative selector outside it must be rejected. Price, floor, availability, and deal eligibility stay on the product or pricing option, not in format parameters.

Publisher-owned formats

When a product sells a publisher-catalog format, repeat its namespace and canonical declaration inline:

{
  "format_options": [
    {
      "publisher_domain": "shorts.streamhaus.example",
      "format_option_id": "vertical_video",
      "format_kind": "video_hosted",
      "params": {
        "width": 1080,
        "height": 1920,
        "duration_ms_range": [5000, 60000],
        "slots": [
          { "asset_group_id": "video_main", "asset_type": "video", "required": true }
        ]
      }
    }
  ]
}

Resolve the publisher’s /.well-known/adagents.json first. If the publisher has not adopted AdCP, use an explicitly identified AgenticAdvertising.org community mirror. Do not promote one sales agent’s product declaration into a publisher fact.

Custom formats

Use format_kind: "custom" only when the structural creative contract cannot be expressed by a canonical kind. Supply both format_shape and an immutable, digest-pinned format_schema.

{
  "format_option_id": "homepage_takeover",
  "format_kind": "custom",
  "format_shape": "multi_placement_takeover",
  "format_schema": {
    "uri": "https://formats.daily-pulse.example/homepage-takeover.schema.json",
    "digest": "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
  },
  "canonical_formats_only": true,
  "params": {}
}

Multi-placement coverage

Product-level options are the upper bound. Placement-level options may narrow that set but cannot broaden it. For every included delivery placement, the selected package format set must have a non-empty compatible intersection. Reject or refine a package that cannot cover all included placements; never silently drop inventory.

Finding a creative producer

Sales agents do not publish a recursive list of creative agents. A buyer can reverse-query the registry and then verify the selected agent directly:

GET /api/registry/agents?publisher_domain=shorts.streamhaus.example&format_option_id=vertical_video&creative_operation=build

The creative agent’s supported_formats[] entry supplies its local capability_id. That string is passed to build_creative.target_capability_id; it is never copied onto the product or returned manifest.

3.x compatibility

A 3.2 seller may project canonical declarations into deprecated format_ids[] for an older peer. When both fields are emitted, they must describe the same underlying contracts and canonical fields win. Do not independently author or extend the legacy catalog.

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FAQ

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Reference

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Implementing Standard Format Support

Choose the authority first

Standard formats

Publisher-owned formats

Custom formats

Multi-placement coverage

Finding a creative producer

3.x compatibility

​Choose the authority first

​Standard formats

​Publisher-owned formats

​Custom formats

​Multi-placement coverage

​Finding a creative producer

​3.x compatibility

​Related documentation

Choose the authority first

Standard formats

Publisher-owned formats

Custom formats

Multi-placement coverage

Finding a creative producer

3.x compatibility

Related documentation