{
  "ad_content": {
    "headline": "Premium Noise-Cancelling Headphones",
    "description": "Studio-quality audio with 40-hour battery life",
    "cta": "Shop Now",
    "image_url": "https://example.com/product/headphones.jpg",
    "landing_url": "https://example.com/shop/headphones"
  },
  "fcs_metadata": {
    "x-fcs-ad-lineage": {
      "seed_id": "ad-seed-91b4-42ea-b",
      "seed_source": "fcs://ads.contextual-ads.ai/seed/91b4",
      "campaign_id": "retail-q4-gift-guide",
      "creative_hash": "sha256:9ac4a1e6f3b2c7d8e5a4f1b9c2d3e4f5",
      "model_version": "gpt-4o-chat-2025-10",
      "signed_by": "ads.contextual-ads.ai",
      "timestamp": "2025-12-01T18:47:00Z",
      "lineage_chain": [
        "contextual-ads.ai:seed-generation:2025-12-01T18:45:00Z",
        "advertiser-x:campaign-approval:2025-12-01T18:46:00Z",
        "fcs-delivery:ad-serve:2025-12-01T18:47:00Z"
      ]
    },
    "x-fcs-bid-id": {
      "auction_id": "auction-2025-12-01-abc123",
      "slot_number": 2,
      "bid_cpm": 2.5,
      "winning_bid": true,
      "auction_timestamp": "2025-12-01T18:46:58Z"
    },
    "x-fcs-creative-source": {
      "generation_method": "ai-generated",
      "model": "gpt-4o-chat-2025-10",
      "training_attestation": "no-competitor-ip:verified",
      "human_review": true,
      "reviewer_id": "reviewer-alice-123"
    }
  },
  "trust_verification": {
    "verify_endpoint": "https://contextual-ads.ai/fcs/verify/ad-seed-91b4-42ea-b",
    "signature": "ed25519:a1b2c3d4e5f6...",
    "public_key_url": "https://contextual-ads.ai/.well-known/fcs-signing-keys.json"
  }
}