{
  "@context": "https://contextual-ads.ai/spec/v1.0",
  "@type": "ProtocolDiscovery",
  "protocol": {
    "name": "Contextual Ads Protocol",
    "shortName": "CAP",
    "version": "1.1.0",
    "family": "FCS-4.0",
    "canonical": "https://contextual-ads.ai"
  },
  "description": "Open protocol for privacy-preserving, agent-native contextual advertising. Enables cross-platform ad attribution without behavioral tracking.",
  "updated": "2026-08-25",
  "canonical_object": {
    "type": "agent_ad",
    "version": "0.1",
    "purpose": "machine-readable sponsored offer metadata for AI-mediated discovery",
    "required_principles": [
      "verifiable sponsor identity",
      "clear sponsored disclosure",
      "current-context matching",
      "no behavioral profile requirement",
      "negative contexts respected"
    ],
    "example": {
      "type": "agent_ad",
      "version": "0.1",
      "sponsor": {
        "name": "Example Brand",
        "domain": "example.com",
        "verification": "dns|did|fcs"
      },
      "offer": {
        "title": "Example offer",
        "category": "software|commerce|finance|travel",
        "url": "https://example.com",
        "pricing_model": "cpc|cpa|flat|affiliate|unknown"
      },
      "context": {
        "intent_tags": ["compare", "buy", "evaluate"],
        "semantic_coordinates": ["agent-commerce", "checkout", "privacy-safe"],
        "negative_contexts": ["health", "politics", "children"]
      },
      "trust": {
        "tracking": "none|aggregate_only",
        "pii": false,
        "behavioral_profile": false,
        "lineage": "verifiable"
      },
      "disclosure": {
        "label": "Sponsored",
        "separation_required": true
      }
    }
  },
  "capabilities": {
    "semantic_discovery": true,
    "query_aware_routing": true,
    "trust_verification": true,
    "zero_tracking": true,
    "cross_agent_attribution": true,
    "adaptive_expansion": true
  },
  "endpoints": {
    "specification": "https://contextual-ads.ai/spec/v1.0",
    "registry": "https://contextual-ads.ai/registry/advertisers",
    "health": "https://contextual-ads.ai/api/health",
    "version": "https://contextual-ads.ai/api/version",
    "answer_engine_positioning": "https://contextual-ads.ai/contextual-ads-for-chatgpt",
    "trust_layer_positioning": "https://contextual-ads.ai/chatgpt-ads-trust-layer",
    "conversation_shaped_intent": "https://contextual-ads.ai/conversation-shaped-purchase-intent/",
    "conversation_context_contract": "https://contextual-ads.ai/.well-known/conversational-ad-context.json",
    "answer_engine_ad_objects": "https://contextual-ads.ai/agent-ads-for-answer-engines",
    "impression": "https://contextual-ads.ai/impression/{token}",
    "research": "https://contextual-ads.ai/research/",
    "cloudTopologies": "https://contextual-ads.ai/spec/cloud-topologies",
    "fcs": {
      "health": "https://contextual-ads.ai/fcs/ad-lineage/health",
      "example": "https://contextual-ads.ai/fcs/ad-lineage/example",
      "genesis_verification": "https://contextual-ads.ai/fcs/verify/0000-0001-00FCS-AD",
      "signing_keys": "https://contextual-ads.ai/.well-known/fcs-signing-keys.json",
      "schema": "https://contextual-ads.ai/fcs/ad-lineage/.well-known/schema.json",
      "manifest": "https://contextual-ads.ai/.well-known/fcs.json"
    }
  },
  "headers": {
    "request": {
      "x-intention-signal": {
        "required": true,
        "format": "JSON",
        "description": "Explicit intention signal derived from current query context",
        "example": "{\"primary\":\"purchase\",\"domain\":\"mcp-servers\",\"confidence\":0.87}"
      },
      "x-trust-lineage": {
        "required": true,
        "format": "semicolon-separated-chain",
        "description": "Full provenance chain for trust verification",
        "example": "agent-mcp.org:query-semantic:2025-12-01T14:30:00Z"
      },
      "x-semantic-context": {
        "required": true,
        "format": "comma-separated-tags",
        "description": "Semantic tags describing current context",
        "example": "topic:mcp-servers,category:database,intent:discovery"
      },
      "x-discovery-inline": {
        "required": false,
        "format": "enum",
        "values": ["discovery", "evaluation", "decision", "post-purchase"],
        "description": "User journey stage indicator"
      }
    },
    "response": {
      "x-fcs-version": {
        "description": "FCS protocol version",
        "example": "4.0"
      },
      "x-protocol-family": {
        "description": "Protocol family identifier",
        "example": "FCS-4.0"
      },
      "x-trust-mode": {
        "description": "Trust enforcement mode",
        "example": "no-behavioral-tracking"
      },
      "x-behavioral-tracking": {
        "description": "Behavioral tracking status (always false)",
        "example": "false"
      },
      "x-trust-lineage": {
        "description": "Extended trust lineage with CAP processing step",
        "example": "agent-mcp.org:query-semantic:2025-12-01T14:30:00Z;contextual-ads.ai:protocol-serve:2025-12-01T14:30:01Z"
      }
    }
  },
  "trust": {
    "behavioral_tracking": false,
    "privacy_by_design": true,
    "gdpr_compliant": true,
    "ccpa_compliant": true,
    "dma_compliant": true,
    "verifiable_lineage": true,
    "open_specification": true
  },
  "integration": {
    "formats": ["HTTP headers", "JSON", "HTML meta tags"],
    "platforms": ["Cloudflare Workers", "AWS Lambda@Edge", "Vercel Edge", "Self-hosted"],
    "agents": ["ChatGPT", "Claude", "Gemini", "Perplexity", "Custom MCP clients"],
    "deployment_time": "< 15 minutes",
    "documentation": "https://contextual-ads.ai/spec/v1.0"
  },
  "registry": {
    "advertisers": {
      "endpoint": "https://contextual-ads.ai/registry/advertisers",
      "format": "JSON",
      "description": "Public registry of verified advertisers with trust scores"
    },
    "submissions": {
      "email": "registry@contextual-ads.ai",
      "requirements": ["Privacy policy URL", "No behavioral tracking attestation", "FCS-4.0 active contract compliance"]
    }
  },
  "research": {
    "papers": "https://contextual-ads.ai/research/",
    "topics": [
      "Image Brief v1.0 - Visual ad verification protocol",
      "CALT - Codex Advertising License Terms",
      "Cross-Agent Attribution Layer",
      "Helix Compression for Semantic Seeds"
    ],
    "collaboration": "research@contextual-ads.ai"
  },
  "standards": {
    "submission": {
      "status": "Draft",
      "target": "IANA Well-Known URIs registry",
      "draft_url": "https://contextual-ads.ai/iana-submission-draft.txt"
    },
    "compliance": {
      "AI_Act_Article_52": "Transparency requirement for AI-generated content",
      "DMA_Article_5_6": "Ads transparency and data portability",
      "GDPR_Article_25": "Data protection by design"
    }
  },
  "examples": {
    "basic_request": {
      "description": "Minimal CAP-compliant request",
      "headers": {
        "x-intention-signal": "{\"primary\":\"discovery\",\"domain\":\"mcp-servers\",\"confidence\":0.90}",
        "x-trust-lineage": "agent-mcp.org:query-semantic:2025-12-01T20:00:00Z",
        "x-semantic-context": "topic:mcp-servers,category:database,intent:discovery"
      }
    },
    "agent_query": {
      "description": "AI agent discovering MCP servers",
      "scenario": "User asks Claude: 'Find me database MCP servers'",
      "query_path": "agent-mcp.org/registry → contextual-ads.ai/match → postgres-mcp ad served"
    }
  },
  "contact": {
    "protocol": "spec@contextual-ads.ai",
    "enterprise": "enterprise@contextual-ads.ai",
    "registry": "registry@contextual-ads.ai",
    "research": "research@contextual-ads.ai",
    "github": "https://github.com/codex-research/contextual-ads-protocol",
    "website": "https://contextual-ads.ai"
  },
  "license": {
    "specification": "CC BY 4.0",
    "url": "https://creativecommons.org/licenses/by/4.0/",
    "attribution": "Contextual Ads Initiative"
  },
  "related": {
    "agent-mcp.org": {
      "description": "Model Context Protocol registry with CAP integration",
      "relationship": "reference_implementation",
      "url": "https://agent-mcp.org"
    },
    "FCS-4.0": {
      "description": "Current Field-Coherence Substrate governance covenant",
      "relationship": "active_governance_contract",
      "spec": "https://agent-ads.org/fcs/4.0"
    }
  },
  "fcs_protocol": {
    "version": "4.0",
    "status": "active",
    "deployed": "2025-12-03T00:00:00Z",
    "description": "Field-Coherence Substrate v4.0 active governance contract with legacy lineage surfaces retained",
    "genesis_seed": "0000-0001-00FCS-AD",
    "features": [
      "Cryptographic ad lineage tracking",
      "JWK-based signature verification",
      "Schema-based header validation",
      "Genesis trace verification",
      "Ad format converters (Google PMax, Microsoft CAF, OpenRTB 2.x)"
    ],
    "documentation": "https://contextual-ads.ai/spec/fcs-2.0"
  },
  "meta": {
    "last_updated": "2026-08-25T12:00:00Z",
    "schema_version": "1.1.0",
    "discovery_method": "RFC 8615 Well-Known URIs",
    "machine_readable": true,
    "human_readable": "https://contextual-ads.ai/what-is-contextual-ads"
  }
}