{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://adcontextprotocol.org/schemas/3.2.0-beta.0/core/placement-selection.json",
  "title": "Placement Selection",
  "description": "Complete purchased placement set within a product. This is inventory targeting, not creative routing: creative_assignments[].placement_refs route a creative only within this purchased set. Requests use mode selected to name the complete required set or mode default to accept the product/seller default. Across discovery, create, and update, a selected set is satisfied inherently when it exactly equals a fixed product's complete included placement set; this exact restatement does not require overlay_support.placement_selection, while partial selection does. Included placements are never independently selectable. Products with any fixed mode:included placement cannot advertise selectable placement overlay support because the fixed placement would make a partial buyer-selected set incomplete; sellers expose separately selectable inventory when needed. Successful package readback MUST echo the committed selected set. Sellers reject unknown, duplicate, cross-publisher, incompatible, or partially applicable refs rather than silently changing the selection.",
  "type": "object",
  "discriminator": {
    "propertyName": "mode"
  },
  "oneOf": [
    {
      "title": "Selected placements",
      "type": "object",
      "properties": {
        "mode": {
          "type": "string",
          "const": "selected"
        },
        "placement_refs": {
          "type": "array",
          "description": "Complete required placement set. A reference normally identifies a mode targetable placement. It MAY identify a mode included placement only when the set exactly equals the product's complete fixed included set, which is an inherent match rather than independent selection. publisher_domain is required in this targeting context even though legacy creative-routing refs may omit it.",
          "items": {
            "allOf": [
              {
                "$ref": "https://adcontextprotocol.org/schemas/3.2.0-beta.0/core/placement-ref.json"
              },
              {
                "required": [
                  "publisher_domain"
                ]
              }
            ]
          },
          "minItems": 1,
          "uniqueItems": true
        },
        "ext": {
          "$ref": "https://adcontextprotocol.org/schemas/3.2.0-beta.0/core/ext.json"
        }
      },
      "required": [
        "mode",
        "placement_refs"
      ],
      "additionalProperties": false
    },
    {
      "title": "Product default placements",
      "type": "object",
      "properties": {
        "mode": {
          "type": "string",
          "const": "default"
        },
        "ext": {
          "$ref": "https://adcontextprotocol.org/schemas/3.2.0-beta.0/core/ext.json"
        }
      },
      "required": [
        "mode"
      ],
      "additionalProperties": false
    }
  ]
}