Fix CPM hallucination: pricing_type enum + quote validation

src/ad_seller/interfaces/api/main.py

@@ -140,6 +140,8 @@ class ProposalResponse(BaseModel):
     status: str
     counter_terms: Optional[dict[str, Any]] = None
     approval_id: Optional[str] = None
+    pricing_verified: bool = False
+    pricing_verification_reason: str = ""
     errors: list[str] = []
 
 
@@ -533,12 +535,24 @@ async def submit_proposal(
         products=setup_flow.state.products,
     )
 
+    # Verify pricing against quote history (Layer 4 — CPM hallucination defense)
+    from ...storage.factory import get_storage
+    from ...storage.quote_history import QuoteHistoryStore
+
+    storage = await get_storage()
+    quote_history = QuoteHistoryStore(storage)
+    verification = await quote_history.verify_pricing(
+        buyer_id=context.get_pricing_key(),
+        product_id=request.product_id,
+        proposed_cpm=request.price,
+    )
+    pricing_verified = verification.pricing_verified
+    pricing_verification_reason = verification.reason
+
     # If pending approval, create the approval request
     if result.get("pending_approval"):
         from ...events.approval import ApprovalGate
-        from ...storage.factory import get_storage
 
-        storage = await get_storage()
         gate = ApprovalGate(storage)
         approval_req = await gate.request_approval(
             flow_id=result["flow_id"],
@@ -549,6 +563,8 @@ async def submit_proposal(
                 "recommendation": result["recommendation"],
                 "evaluation": result.get("evaluation"),
                 "counter_terms": result.get("counter_terms"),
+                "pricing_verified": pricing_verified,
+                "pricing_verification_reason": pricing_verification_reason,
             },
             flow_state_snapshot=result.get("_flow_state_snapshot", {}),
             proposal_id=proposal_id,
@@ -559,6 +575,8 @@ async def submit_proposal(
             status="pending_approval",
             counter_terms=result.get("counter_terms"),
             approval_id=approval_req.approval_id,
+            pricing_verified=pricing_verified,
+            pricing_verification_reason=pricing_verification_reason,
             errors=result.get("errors", []),
         )
 
@@ -567,6 +585,8 @@ async def submit_proposal(
         recommendation=result["recommendation"],
         status=result["status"],
         counter_terms=result.get("counter_terms"),
+        pricing_verified=pricing_verified,
+        pricing_verification_reason=pricing_verification_reason,
         errors=result.get("errors", []),
     )
 
@@ -1939,6 +1959,18 @@ async def create_quote(
     storage = await get_storage()
     await storage.set_quote(quote_id, quote.model_dump(mode="json"), ttl=86400)
 
+    # Record in quote history for pricing verification (Layer 4)
+    from ...storage.quote_history import QuoteHistoryStore
+
+    quote_history = QuoteHistoryStore(storage)
+    await quote_history.record_quote(
+        quote_id=quote_id,
+        buyer_id=context.get_pricing_key(),
+        product_id=request.product_id,
+        quoted_cpm=final_cpm,
+        expires_at=expires_at,
+    )
+
     return quote.model_dump(mode="json")
 
 

src/ad_seller/models/__init__.py

@@ -27,6 +27,7 @@
     BuyerIdentity,
     IdentityLevel,
 )
+from .pricing_type import PricingType
 from .change_request import (
     ChangeRequest,
     ChangeRequestStatus,
@@ -170,6 +171,8 @@
 )
 
 __all__ = [
+    # Pricing type enum
+    "PricingType",
     # Core ad tech entities
     "Organization",
     "OrganizationRole",

src/ad_seller/models/core.py

@@ -18,6 +18,8 @@
 
 from pydantic import BaseModel, ConfigDict, Field
 
+from .pricing_type import PricingType
+
 # =============================================================================
 # Enums
 # =============================================================================
@@ -337,6 +339,7 @@ class Pricing(BaseModel):
 
     model_config = ConfigDict(populate_by_name=True)
 
+    pricing_type: PricingType = PricingType.FIXED
     pricing_model: Optional[PricingModel] = Field(default=None, alias="pricingmodel")
     price: Optional[float] = None
     currency: Optional[str] = None

src/ad_seller/models/flow_state.py

@@ -14,6 +14,7 @@
 from pydantic import BaseModel, Field
 
 from .core import DealType, PricingModel
+from .pricing_type import PricingType
 
 
 class ExecutionStatus(str, Enum):
@@ -44,8 +45,9 @@ class ProductDefinition(BaseModel):
     inventory_segment_ids: list[str] = Field(default_factory=list)
     supported_deal_types: list[DealType] = Field(default_factory=list)
     supported_pricing_models: list[PricingModel] = Field(default_factory=list)
-    base_cpm: float
-    floor_cpm: float
+    pricing_type: PricingType = PricingType.FIXED
+    base_cpm: Optional[float] = None
+    floor_cpm: Optional[float] = None
     audience_targeting: Optional[dict[str, Any]] = None
     content_targeting: Optional[dict[str, Any]] = None
     ad_product_targeting: Optional[dict[str, Any]] = None
@@ -113,6 +115,16 @@ class ProposalEvaluation(BaseModel):
         description="UCP embedding similarity score (0-1)",
     )
 
+    # Quote-based pricing verification (Layer 4 — CPM hallucination defense)
+    pricing_verified: bool = Field(
+        default=False,
+        description="Whether the proposed CPM matches a quote the seller issued",
+    )
+    pricing_verification_reason: str = Field(
+        default="",
+        description="Explanation of pricing verification result",
+    )
+
     # Overall recommendation
     recommendation: str  # accept, counter, reject
     counter_terms: Optional[dict[str, Any]] = None

src/ad_seller/models/media_kit.py

@@ -27,6 +27,7 @@
 from pydantic import BaseModel, Field
 
 from .core import PricingModel
+from .pricing_type import PricingType
 
 
 class PackageLayer(str, Enum):
@@ -88,8 +89,9 @@ class Package(BaseModel):
     geo_targets: list[str] = Field(default_factory=list)  # ["US", "US-NY", "US-CA"]
 
     # Pricing (blended from constituent products)
-    base_price: float
-    floor_price: float
+    pricing_type: PricingType = PricingType.FIXED
+    base_price: Optional[float] = None
+    floor_price: Optional[float] = None
     rate_type: PricingModel = PricingModel.CPM
     currency: str = "USD"  # ISO 4217
 

src/ad_seller/models/pricing_type.py

@@ -0,0 +1,26 @@
+# Author: Green Mountain Systems AI Inc.
+# Donated to IAB Tech Lab
+
+"""Pricing type enum for seller inventory pricing signals.
+
+Allows sellers to express whether a price is fixed, a floor for
+negotiation, or unavailable (rate on request). Buyer agents must
+respect these signals and never fabricate pricing when a seller
+has indicated on_request.
+"""
+
+from enum import Enum
+
+
+class PricingType(str, Enum):
+    """How pricing should be interpreted for a product or package.
+
+    - FIXED: Price is set by the seller, use as-is.
+    - FLOOR: Minimum price; negotiation expected above this level.
+    - ON_REQUEST: No price available; buyer must negotiate before
+      any pricing exists. Pricing fields should be None.
+    """
+
+    FIXED = "fixed"
+    FLOOR = "floor"
+    ON_REQUEST = "on_request"

src/ad_seller/models/quotes.py

@@ -15,6 +15,8 @@
 
 from pydantic import BaseModel, Field
 
+from .pricing_type import PricingType
+
 
 class QuoteStatus(str, Enum):
     """Status of a price quote."""
@@ -84,7 +86,8 @@ class QuoteProductInfo(BaseModel):
 class QuotePricing(BaseModel):
     """Pricing breakdown in a quote response."""
 
-    base_cpm: float
+    pricing_type: PricingType = PricingType.FIXED
+    base_cpm: Optional[float] = None
     tier_discount_pct: float = 0.0
     volume_discount_pct: float = 0.0
     final_cpm: float