{
  "schemaVersion": "1.0",
  "edition": "2026-09-13",
  "experimentId": "feed-portability-2026-09-13",
  "exampleOnly": true,
  "scope": "Controlled local portability demonstration. Twelve deliberately authored synthetic records: two controls and ten edge cases. No merchant feed, vendor upload, live page request, or model inference.",
  "target": "An editorial review subset inspired by OpenAI Stable native discovery, with additional identity and evidence checks. Not a complete provider validator.",
  "methods": [
    "copy",
    "mapped"
  ],
  "denominator": "12 records per method; 2 controls and 10 failure cases. Do not infer real-world rates.",
  "oracle": "Expected mapped decisions were recorded in this fixture file before the experiment was executed. The same author designed the fixtures and checks; this is not an independent or blind evaluation.",
  "sources": [
    {
      "id": "openai",
      "title": "OpenAI: Stable product file-upload specification",
      "url": "https://developers.openai.com/commerce/specs/file-upload/products",
      "note": "Native discovery fields and the distinct Google-compatible path. This edition is a selected comparison, not the complete upload contract.",
      "checked": "2026-09-13"
    },
    {
      "id": "google-group",
      "title": "Google Merchant Center: Item group ID",
      "url": "https://support.google.com/merchants/answer/6324507?hl=en",
      "note": "Variant groups, identifying attributes, and matching landing-page values.",
      "checked": "2026-09-13"
    },
    {
      "id": "google-price",
      "title": "Google Merchant Center: Price",
      "url": "https://support.google.com/merchants/answer/6324371?hl=en",
      "note": "Amount and currency, plus agreement with landing page and checkout.",
      "checked": "2026-09-13"
    },
    {
      "id": "google-dimensions",
      "title": "Google Merchant Center: Product dimensions and weight",
      "url": "https://support.google.com/merchants/answer/11018531?hl=en",
      "note": "Product measures, accepted units, and agreement between repeated measurements. Packaging has a different meaning.",
      "checked": "2026-09-13"
    }
  ],
  "cases": [
    {
      "id": "C01",
      "label": "Native nonvariant control",
      "control": true,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD"
      },
      "evidence": {},
      "expectedAfterMapping": "clear",
      "reason": "The selected local checks find no issue."
    },
    {
      "id": "C02",
      "label": "Native variant control",
      "control": true,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD",
        "group_id": "DEMO-MUG",
        "listing_has_variations": true,
        "variant_dict": {
          "color": "Blue"
        },
        "color": "Blue"
      },
      "evidence": {},
      "expectedAfterMapping": "clear",
      "reason": "The selected local checks find no issue in the declared variant."
    },
    {
      "id": "F01",
      "label": "Destination field names",
      "control": false,
      "exampleOnly": true,
      "input": {
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "availability": "in_stock",
        "price": "18.00 USD",
        "id": "DEMO-MUG-BLUE",
        "link": "https://example.com/mug?color=blue",
        "image_link": "https://example.com/images/mug-blue.jpg"
      },
      "evidence": {},
      "expectedAfterMapping": "clear",
      "reason": "Map source keys to the selected native representation."
    },
    {
      "id": "F02",
      "label": "Preorder spelling",
      "control": false,
      "exampleOnly": true,
      "input": {
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "availability": "preorder",
        "price": "18.00 USD",
        "id": "DEMO-MUG-BLUE",
        "link": "https://example.com/mug?color=blue",
        "image_link": "https://example.com/images/mug-blue.jpg"
      },
      "evidence": {},
      "expectedAfterMapping": "clear",
      "reason": "Translate the explicit Google stock value to native pre_order."
    },
    {
      "id": "F03",
      "label": "Variant representation",
      "control": false,
      "exampleOnly": true,
      "input": {
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "availability": "in_stock",
        "price": "18.00 USD",
        "id": "DEMO-MUG-BLUE",
        "link": "https://example.com/mug?color=blue",
        "image_link": "https://example.com/images/mug-blue.jpg",
        "item_group_id": "DEMO-MUG",
        "variant_option": "color:Blue",
        "color": "Blue"
      },
      "evidence": {},
      "expectedAfterMapping": "clear",
      "reason": "Preserve the parent and selected options while constructing native grouping fields."
    },
    {
      "id": "F04",
      "label": "Mixed explicit product units",
      "control": false,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD",
        "product_length": "30 in",
        "product_width": "50.8 cm"
      },
      "evidence": {
        "dimensionBasis": "product"
      },
      "expectedAfterMapping": "clear",
      "reason": "Convert two evidenced product axes to one unit."
    },
    {
      "id": "F05",
      "label": "Missing seller identity",
      "control": false,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD"
      },
      "evidence": {},
      "expectedAfterMapping": "hold",
      "reason": "A required seller identity cannot be derived from the product brand."
    },
    {
      "id": "F06",
      "label": "Numeric item identifier",
      "control": false,
      "exampleOnly": true,
      "input": {
        "item_id": 12345,
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD"
      },
      "evidence": {},
      "expectedAfterMapping": "hold",
      "reason": "The local profile refuses numeric IDs because prior string information may be lost."
    },
    {
      "id": "F07",
      "label": "Parent reused as item ID",
      "control": false,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD",
        "group_id": "DEMO-MUG-BLUE",
        "listing_has_variations": true,
        "variant_dict": {
          "color": "Blue"
        },
        "color": "Blue"
      },
      "evidence": {},
      "expectedAfterMapping": "hold",
      "reason": "The parent and selected item must remain distinct."
    },
    {
      "id": "F08",
      "label": "Conflicting selected color",
      "control": false,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD",
        "group_id": "DEMO-MUG",
        "listing_has_variations": true,
        "variant_dict": {
          "color": "White"
        },
        "color": "Blue"
      },
      "evidence": {},
      "expectedAfterMapping": "hold",
      "reason": "A mapping must not silently choose between contradictory selected colors."
    },
    {
      "id": "F09",
      "label": "Price disagrees with page",
      "control": false,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD"
      },
      "evidence": {
        "pagePrice": "19.00 USD"
      },
      "expectedAfterMapping": "hold",
      "reason": "The supplied fictional page evidence disagrees with the offer price."
    },
    {
      "id": "F10",
      "label": "Package dimensions relabeled",
      "control": false,
      "exampleOnly": true,
      "input": {
        "item_id": "DEMO-MUG-BLUE",
        "title": "Demo ceramic mug — blue",
        "description": "Synthetic blue ceramic mug for a local feed experiment.",
        "url": "https://example.com/mug?color=blue",
        "brand": "Example Workshop",
        "seller_name": "Example Retailer",
        "image_url": "https://example.com/images/mug-blue.jpg",
        "availability": "in_stock",
        "price": "18.00 USD",
        "dimensions": {
          "length": "12",
          "width": "10",
          "unit": "cm"
        }
      },
      "evidence": {
        "dimensionBasis": "shipping_package"
      },
      "expectedAfterMapping": "hold",
      "reason": "Package measurements do not establish the item dimensions."
    }
  ]
}