{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Alternative Asset Listing",
  "description": "Listing for an alternative asset such as art, wine, watches, sports cards, sneakers, or other collectibles.",
  "type": "object",
  "properties": {
    "item_name": {
      "type": "string",
      "description": "Name or title of the item. Commonly found in: auction listing, marketplace listing."
    },
    "item_type": {
      "type": "string",
      "enum": ["art", "wine", "watch", "sports_card", "sneaker", "jewelry", "collectible", "real_assets", "other"],
      "description": "Category of the alternative asset. Commonly found in: auction category, marketplace category."
    },
    "artist_or_maker": {
      "type": "string",
      "description": "Artist, brand, or maker of the item. Commonly found in: listing details, auction catalog."
    },
    "title_or_model": {
      "type": "string",
      "description": "Title of artwork or model name/number. Commonly found in: listing title, auction catalog."
    },
    "year": {
      "type": "number",
      "description": "Year of creation or manufacture. Commonly found in: listing details, auction catalog."
    },
    "condition_grade": {
      "type": "string",
      "description": "Condition or grade of the item. Commonly found in: listing details, grading service report."
    },
    "authentication_status": {
      "type": "boolean",
      "description": "Whether the item has been authenticated. Commonly found in: listing details, authentication certificate."
    },
    "authentication_provider": {
      "type": "string",
      "description": "Name of the authentication or grading service. Commonly found in: listing details, authentication certificate."
    },
    "platform": {
      "type": "string",
      "description": "Name of the marketplace or auction platform. Commonly found in: platform name from URL, listing metadata."
    },
    "listing_type": {
      "type": "string",
      "enum": ["auction", "buy_now", "make_offer", "other"],
      "description": "Type of sale mechanism. Commonly found in: listing page, sale type indicator."
    },
    "estimate_low_usd": {
      "type": "number",
      "description": "Low end of auction house price estimate in USD. Commonly found in: auction catalog, estimate section."
    },
    "estimate_high_usd": {
      "type": "number",
      "description": "High end of auction house price estimate in USD. Commonly found in: auction catalog, estimate section."
    },
    "starting_bid_usd": {
      "type": "number",
      "description": "Starting bid for auction in USD. Commonly found in: auction listing."
    },
    "current_bid_usd": {
      "type": "number",
      "description": "Current highest bid in USD (for live auctions). Commonly found in: live auction page."
    },
    "buy_now_price_usd": {
      "type": "number",
      "description": "Fixed buy-now price in USD. Commonly found in: buy now listing."
    },
    "currency": {
      "type": "string",
      "description": "Currency code for the listed prices. Commonly found in: listing price display."
    },
    "auction_date": {
      "type": "string",
      "format": "date",
      "description": "Date of the auction. Commonly found in: auction listing, event calendar."
    },
    "sale_result_usd": {
      "type": "number",
      "description": "Final sale price in USD (post-auction). Commonly found in: auction results page."
    },
    "images": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "URLs of item images. Commonly found in: listing images."
    },
    "description": {
      "type": "string",
      "description": "Full description of the item. Commonly found in: listing description, auction catalog notes."
    },
    "page_title": {
      "type": "string",
      "description": "Title of the source page. Tabstack auto-fills this from page metadata when left empty."
    },
    "favicon": {
      "type": "string",
      "format": "uri",
      "description": "Favicon URL of the source page. Tabstack auto-fills this from page metadata when left empty."
    }
  },
  "required": ["item_name", "item_type", "platform", "listing_type"]
}