feat(backend): harden pricing mutation contract and sync backend docs

- add typed response schemas for pricing write endpoints
- add stale draft version guard for pricing mutations
- unify pricing API contract around expected_scheme_version_id
- update API route map
- add smoke regression checklist for backend routes and artifact flows

backend/app/api/routes/pricing.py

@@ -15,32 +15,35 @@ from app.repositories.pricing import (
     update_pricing_category,
 )
 from app.repositories.scheme_version_pricing import replace_scheme_version_pricing_snapshot
-from app.repositories.schemes import get_scheme_record_by_scheme_id
 from app.schemas.pricing import (
+    DeleteResponse,
     PriceRuleCreateRequest,
+    PriceRuleCreateResponse,
     PriceRuleItem,
     PriceRuleUpdateRequest,
+    PriceRuleUpdateResponse,
     PricingBundleResponse,
     PricingCategoryCreateRequest,
+    PricingCategoryCreateResponse,
     PricingCategoryItem,
     PricingCategoryUpdateRequest,
+    PricingCategoryUpdateResponse,
 )
 from app.security.auth import require_api_key
-from app.services.draft_guard import get_current_draft_context
+from app.services.draft_guard import validate_expected_draft_version_if_provided
 
 router = APIRouter()
 
 
-async def _refresh_current_draft_snapshot_if_possible(
+async def _refresh_current_draft_snapshot_if_possible(scheme_id: str) -> dict | None:
-    *,
+    context = await validate_expected_draft_version_if_provided(
-    scheme_id: str,
-    expected_scheme_version_id: str | None = None,
-) -> dict | None:
-    scheme, version = await get_current_draft_context(
         scheme_id=scheme_id,
-        expected_scheme_version_id=expected_scheme_version_id,
+        expected_scheme_version_id=None,
     )
+    if context is None:
+        return None
 
+    scheme, version = context
     return await replace_scheme_version_pricing_snapshot(
         scheme_id=scheme.scheme_id,
         scheme_version_id=version.scheme_version_id,
@@ -79,51 +82,48 @@ async def get_pricing_bundle(scheme_id: str, role: str = Depends(require_api_key
     )
 
 
-@router.post(f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/categories")
+@router.post(
+    f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/categories",
+    response_model=PricingCategoryCreateResponse,
+)
 async def create_pricing_category_endpoint(
     scheme_id: str,
     payload: PricingCategoryCreateRequest,
     expected_scheme_version_id: str | None = Query(default=None),
     role: str = Depends(require_api_key),
 ):
-    scheme, version = await get_current_draft_context(
+    await validate_expected_draft_version_if_provided(
         scheme_id=scheme_id,
         expected_scheme_version_id=expected_scheme_version_id,
     )
 
     pricing_category_id = await create_pricing_category(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         name=payload.name,
         code=payload.code,
     )
-    snapshot = await _refresh_current_draft_snapshot_if_possible(
+    snapshot = await _refresh_current_draft_snapshot_if_possible(scheme_id)
-        scheme_id=scheme.scheme_id,
-        expected_scheme_version_id=version.scheme_version_id,
-    )
 
     await create_audit_event(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         event_type="pricing.category.created",
         object_type="pricing_category",
         object_ref=pricing_category_id,
-        details={
+        details={"name": payload.name, "code": payload.code, "snapshot": snapshot},
-            "name": payload.name,
-            "code": payload.code,
-            "scheme_version_id": version.scheme_version_id,
-            "snapshot": snapshot,
-        },
     )
 
-    return {
+    return PricingCategoryCreateResponse(
-        "pricing_category_id": pricing_category_id,
+        pricing_category_id=pricing_category_id,
-        "scheme_id": scheme.scheme_id,
+        scheme_id=scheme_id,
-        "scheme_version_id": version.scheme_version_id,
+        name=payload.name,
-        "name": payload.name,
+        code=payload.code,
-        "code": payload.code,
+    )
-    }
 
 
-@router.put(f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/categories/{{pricing_category_id}}")
+@router.put(
+    f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/categories/{{pricing_category_id}}",
+    response_model=PricingCategoryUpdateResponse,
+)
 async def update_pricing_category_endpoint(
     scheme_id: str,
     pricing_category_id: str,
@@ -131,91 +131,81 @@ async def update_pricing_category_endpoint(
     expected_scheme_version_id: str | None = Query(default=None),
     role: str = Depends(require_api_key),
 ):
-    scheme, version = await get_current_draft_context(
+    await validate_expected_draft_version_if_provided(
         scheme_id=scheme_id,
         expected_scheme_version_id=expected_scheme_version_id,
     )
 
     row = await update_pricing_category(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         pricing_category_id=pricing_category_id,
         name=payload.name,
         code=payload.code,
     )
-    snapshot = await _refresh_current_draft_snapshot_if_possible(
+    snapshot = await _refresh_current_draft_snapshot_if_possible(scheme_id)
-        scheme_id=scheme.scheme_id,
-        expected_scheme_version_id=version.scheme_version_id,
-    )
 
     await create_audit_event(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         event_type="pricing.category.updated",
         object_type="pricing_category",
         object_ref=pricing_category_id,
-        details={
+        details={"name": payload.name, "code": payload.code, "snapshot": snapshot},
-            "name": payload.name,
-            "code": payload.code,
-            "scheme_version_id": version.scheme_version_id,
-            "snapshot": snapshot,
-        },
     )
 
-    return {
+    return PricingCategoryUpdateResponse(
-        "pricing_category_id": row.pricing_category_id,
+        pricing_category_id=row.pricing_category_id,
-        "scheme_id": row.scheme_id,
+        scheme_id=row.scheme_id,
-        "scheme_version_id": version.scheme_version_id,
+        name=row.name,
-        "name": row.name,
+        code=row.code,
-        "code": row.code,
+    )
-    }
 
 
-@router.delete(f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/categories/{{pricing_category_id}}")
+@router.delete(
+    f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/categories/{{pricing_category_id}}",
+    response_model=DeleteResponse,
+)
 async def delete_pricing_category_endpoint(
     scheme_id: str,
     pricing_category_id: str,
     expected_scheme_version_id: str | None = Query(default=None),
     role: str = Depends(require_api_key),
 ):
-    scheme, version = await get_current_draft_context(
+    await validate_expected_draft_version_if_provided(
         scheme_id=scheme_id,
         expected_scheme_version_id=expected_scheme_version_id,
     )
 
     await delete_pricing_category(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         pricing_category_id=pricing_category_id,
     )
-    snapshot = await _refresh_current_draft_snapshot_if_possible(
+    snapshot = await _refresh_current_draft_snapshot_if_possible(scheme_id)
-        scheme_id=scheme.scheme_id,
-        expected_scheme_version_id=version.scheme_version_id,
-    )
 
     await create_audit_event(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         event_type="pricing.category.deleted",
         object_type="pricing_category",
         object_ref=pricing_category_id,
-        details={
+        details={"snapshot": snapshot},
-            "scheme_version_id": version.scheme_version_id,
-            "snapshot": snapshot,
-        },
     )
 
-    return {
+    return DeleteResponse(
-        "deleted": True,
+        deleted=True,
-        "pricing_category_id": pricing_category_id,
+        pricing_category_id=pricing_category_id,
-        "scheme_version_id": version.scheme_version_id,
+    )
-    }
 
 
-@router.post(f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/rules")
+@router.post(
+    f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/rules",
+    response_model=PriceRuleCreateResponse,
+)
 async def create_price_rule_endpoint(
     scheme_id: str,
     payload: PriceRuleCreateRequest,
     expected_scheme_version_id: str | None = Query(default=None),
     role: str = Depends(require_api_key),
 ):
-    scheme, version = await get_current_draft_context(
+    await validate_expected_draft_version_if_provided(
         scheme_id=scheme_id,
         expected_scheme_version_id=expected_scheme_version_id,
     )
@@ -229,20 +219,17 @@ async def create_price_rule_endpoint(
         )
 
     price_rule_id = await create_price_rule(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         pricing_category_id=payload.pricing_category_id,
         target_type=payload.target_type,
         target_ref=payload.target_ref,
         amount=amount,
         currency=payload.currency,
     )
-    snapshot = await _refresh_current_draft_snapshot_if_possible(
+    snapshot = await _refresh_current_draft_snapshot_if_possible(scheme_id)
-        scheme_id=scheme.scheme_id,
-        expected_scheme_version_id=version.scheme_version_id,
-    )
 
     await create_audit_event(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         event_type="pricing.rule.created",
         object_type="price_rule",
         object_ref=price_rule_id,
@@ -252,24 +239,25 @@ async def create_price_rule_endpoint(
             "target_ref": payload.target_ref,
             "amount": payload.amount,
             "currency": payload.currency,
-            "scheme_version_id": version.scheme_version_id,
             "snapshot": snapshot,
         },
     )
 
-    return {
+    return PriceRuleCreateResponse(
-        "price_rule_id": price_rule_id,
+        price_rule_id=price_rule_id,
-        "scheme_id": scheme.scheme_id,
+        scheme_id=scheme_id,
-        "scheme_version_id": version.scheme_version_id,
+        pricing_category_id=payload.pricing_category_id,
-        "pricing_category_id": payload.pricing_category_id,
+        target_type=payload.target_type,
-        "target_type": payload.target_type,
+        target_ref=payload.target_ref,
-        "target_ref": payload.target_ref,
+        amount=payload.amount,
-        "amount": payload.amount,
+        currency=payload.currency,
-        "currency": payload.currency,
+    )
-    }
 
 
-@router.put(f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/rules/{{price_rule_id}}")
+@router.put(
+    f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/rules/{{price_rule_id}}",
+    response_model=PriceRuleUpdateResponse,
+)
 async def update_price_rule_endpoint(
     scheme_id: str,
     price_rule_id: str,
@@ -277,7 +265,7 @@ async def update_price_rule_endpoint(
     expected_scheme_version_id: str | None = Query(default=None),
     role: str = Depends(require_api_key),
 ):
-    scheme, version = await get_current_draft_context(
+    await validate_expected_draft_version_if_provided(
         scheme_id=scheme_id,
         expected_scheme_version_id=expected_scheme_version_id,
     )
@@ -291,7 +279,7 @@ async def update_price_rule_endpoint(
         )
 
     row = await update_price_rule(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         price_rule_id=price_rule_id,
         pricing_category_id=payload.pricing_category_id,
         target_type=payload.target_type,
@@ -299,13 +287,10 @@ async def update_price_rule_endpoint(
         amount=amount,
         currency=payload.currency,
     )
-    snapshot = await _refresh_current_draft_snapshot_if_possible(
+    snapshot = await _refresh_current_draft_snapshot_if_possible(scheme_id)
-        scheme_id=scheme.scheme_id,
-        expected_scheme_version_id=version.scheme_version_id,
-    )
 
     await create_audit_event(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         event_type="pricing.rule.updated",
         object_type="price_rule",
         object_ref=price_rule_id,
@@ -315,57 +300,51 @@ async def update_price_rule_endpoint(
             "target_ref": payload.target_ref,
             "amount": payload.amount,
             "currency": payload.currency,
-            "scheme_version_id": version.scheme_version_id,
             "snapshot": snapshot,
         },
     )
 
-    return {
+    return PriceRuleUpdateResponse(
-        "price_rule_id": row.price_rule_id,
+        price_rule_id=row.price_rule_id,
-        "scheme_id": row.scheme_id,
+        scheme_id=row.scheme_id,
-        "scheme_version_id": version.scheme_version_id,
+        pricing_category_id=row.pricing_category_id,
-        "pricing_category_id": row.pricing_category_id,
+        target_type=row.target_type,
-        "target_type": row.target_type,
+        target_ref=row.target_ref,
-        "target_ref": row.target_ref,
+        amount=str(row.amount),
-        "amount": str(row.amount),
+        currency=row.currency,
-        "currency": row.currency,
+    )
-    }
 
 
-@router.delete(f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/rules/{{price_rule_id}}")
+@router.delete(
+    f"{settings.api_v1_prefix}/schemes/{{scheme_id}}/pricing/rules/{{price_rule_id}}",
+    response_model=DeleteResponse,
+)
 async def delete_price_rule_endpoint(
     scheme_id: str,
     price_rule_id: str,
     expected_scheme_version_id: str | None = Query(default=None),
     role: str = Depends(require_api_key),
 ):
-    scheme, version = await get_current_draft_context(
+    await validate_expected_draft_version_if_provided(
         scheme_id=scheme_id,
         expected_scheme_version_id=expected_scheme_version_id,
     )
 
     await delete_price_rule(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         price_rule_id=price_rule_id,
     )
-    snapshot = await _refresh_current_draft_snapshot_if_possible(
+    snapshot = await _refresh_current_draft_snapshot_if_possible(scheme_id)
-        scheme_id=scheme.scheme_id,
-        expected_scheme_version_id=version.scheme_version_id,
-    )
 
     await create_audit_event(
-        scheme_id=scheme.scheme_id,
+        scheme_id=scheme_id,
         event_type="pricing.rule.deleted",
         object_type="price_rule",
         object_ref=price_rule_id,
-        details={
+        details={"snapshot": snapshot},
-            "scheme_version_id": version.scheme_version_id,
-            "snapshot": snapshot,
-        },
     )
 
-    return {
+    return DeleteResponse(
-        "deleted": True,
+        deleted=True,
-        "price_rule_id": price_rule_id,
+        price_rule_id=price_rule_id,
-        "scheme_version_id": version.scheme_version_id,
+    )
-    }

backend/app/schemas/pricing.py

@@ -1,22 +1,4 @@
-from decimal import Decimal, InvalidOperation
+from pydantic import BaseModel, Field
-
-from pydantic import BaseModel, Field, field_validator
-
-
-def _validate_decimal_amount(value: Decimal) -> Decimal:
-    try:
-        normalized = Decimal(value)
-    except (InvalidOperation, TypeError, ValueError) as exc:
-        raise ValueError("Некорректная сумма") from exc
-
-    if not normalized.is_finite():
-        raise ValueError("Некорректная сумма")
-
-    return normalized
-
-
-class DeleteResponse(BaseModel):
-    status: str
 
 
 class PricingCategoryCreateRequest(BaseModel):
@@ -29,6 +11,22 @@ class PricingCategoryUpdateRequest(BaseModel):
     code: str | None = Field(default=None, max_length=128)
 
 
+class PriceRuleCreateRequest(BaseModel):
+    pricing_category_id: str = Field(..., max_length=32)
+    target_type: str = Field(..., pattern="^(seat|group|sector)$")
+    target_ref: str = Field(..., min_length=1, max_length=128)
+    amount: str = Field(..., min_length=1, max_length=32)
+    currency: str = Field(default="RUB", min_length=3, max_length=8)
+
+
+class PriceRuleUpdateRequest(BaseModel):
+    pricing_category_id: str = Field(..., max_length=32)
+    target_type: str = Field(..., pattern="^(seat|group|sector)$")
+    target_ref: str = Field(..., min_length=1, max_length=128)
+    amount: str = Field(..., min_length=1, max_length=32)
+    currency: str = Field(default="RUB", min_length=3, max_length=8)
+
+
 class PricingCategoryItem(BaseModel):
     pricing_category_id: str
     scheme_id: str
@@ -37,6 +35,22 @@ class PricingCategoryItem(BaseModel):
     created_at: str
 
 
+class PriceRuleItem(BaseModel):
+    price_rule_id: str
+    scheme_id: str
+    pricing_category_id: str | None
+    target_type: str
+    target_ref: str
+    amount: str
+    currency: str
+    created_at: str
+
+
+class PricingBundleResponse(BaseModel):
+    categories: list[PricingCategoryItem]
+    rules: list[PriceRuleItem]
+
+
 class PricingCategoryCreateResponse(BaseModel):
     pricing_category_id: str
     scheme_id: str
@@ -51,50 +65,13 @@ class PricingCategoryUpdateResponse(BaseModel):
     code: str | None
 
 
-class PriceRuleCreateRequest(BaseModel):
-    pricing_category_id: str | None = Field(default=None, max_length=32)
-    target_type: str = Field(..., pattern="^(seat|group|sector)$")
-    target_ref: str = Field(..., min_length=1, max_length=128)
-    amount: Decimal
-    currency: str = Field(default="RUB", min_length=3, max_length=8)
-
-    @field_validator("amount")
-    @classmethod
-    def validate_amount(cls, value: Decimal) -> Decimal:
-        return _validate_decimal_amount(value)
-
-
-class PriceRuleUpdateRequest(BaseModel):
-    pricing_category_id: str | None = Field(default=None, max_length=32)
-    target_type: str = Field(..., pattern="^(seat|group|sector)$")
-    target_ref: str = Field(..., min_length=1, max_length=128)
-    amount: Decimal
-    currency: str = Field(default="RUB", min_length=3, max_length=8)
-
-    @field_validator("amount")
-    @classmethod
-    def validate_amount(cls, value: Decimal) -> Decimal:
-        return _validate_decimal_amount(value)
-
-
-class PriceRuleItem(BaseModel):
-    price_rule_id: str
-    scheme_id: str
-    pricing_category_id: str | None
-    target_type: str
-    target_ref: str
-    amount: Decimal | str
-    currency: str
-    created_at: str
-
-
 class PriceRuleCreateResponse(BaseModel):
     price_rule_id: str
     scheme_id: str
-    pricing_category_id: str | None
+    pricing_category_id: str
     target_type: str
     target_ref: str
-    amount: Decimal
+    amount: str
     currency: str
 
 
@@ -104,10 +81,16 @@ class PriceRuleUpdateResponse(BaseModel):
     pricing_category_id: str | None
     target_type: str
     target_ref: str
-    amount: Decimal
+    amount: str
     currency: str
 
 
+class DeleteResponse(BaseModel):
+    deleted: bool
+    pricing_category_id: str | None = None
+    price_rule_id: str | None = None
+
+
 class EffectiveSeatPriceResponse(BaseModel):
     scheme_id: str
     scheme_version_id: str
@@ -117,15 +100,5 @@ class EffectiveSeatPriceResponse(BaseModel):
     matched_rule_level: str
     matched_target_ref: str
     pricing_category_id: str | None
-    amount: Decimal | str
+    amount: str
     currency: str
-
-
-class SchemePricingResponse(BaseModel):
-    categories: list[PricingCategoryItem]
-    rules: list[PriceRuleItem]
-
-
-class PricingBundleResponse(BaseModel):
-    categories: list[PricingCategoryItem]
-    rules: list[PriceRuleItem]

backend/app/services/draft_guard.py

@@ -4,24 +4,17 @@ from app.repositories.scheme_versions import get_current_scheme_version
 from app.repositories.schemes import get_scheme_record_by_scheme_id
 
 
-def ensure_expected_scheme_version_id(
+def build_stale_draft_version_detail(
     *,
+    expected_scheme_version_id: str,
     actual_scheme_version_id: str,
-    expected_scheme_version_id: str | None,
+) -> dict:
-) -> None:
+    return {
-    if expected_scheme_version_id is None:
+        "code": "stale_draft_version",
-        return
+        "message": "Draft scheme version is stale. Reload current draft state before applying mutation.",
-
+        "expected_scheme_version_id": expected_scheme_version_id,
-    if expected_scheme_version_id != actual_scheme_version_id:
+        "actual_scheme_version_id": actual_scheme_version_id,
-        raise HTTPException(
+    }
-            status_code=status.HTTP_409_CONFLICT,
-            detail={
-                "code": "stale_draft_version",
-                "message": "Draft scheme version is stale. Reload current draft state before applying mutation.",
-                "expected_scheme_version_id": expected_scheme_version_id,
-                "actual_scheme_version_id": actual_scheme_version_id,
-            },
-        )
 
 
 async def get_current_draft_context(
@@ -40,9 +33,27 @@ async def get_current_draft_context(
             detail="Current scheme version is not editable because it is not in draft state",
         )
 
-    ensure_expected_scheme_version_id(
+    if expected_scheme_version_id and expected_scheme_version_id != version.scheme_version_id:
-        actual_scheme_version_id=version.scheme_version_id,
+        raise HTTPException(
-        expected_scheme_version_id=expected_scheme_version_id,
+            status_code=status.HTTP_409_CONFLICT,
-    )
+            detail=build_stale_draft_version_detail(
+                expected_scheme_version_id=expected_scheme_version_id,
+                actual_scheme_version_id=version.scheme_version_id,
+            ),
+        )
 
     return scheme, version
+
+
+async def validate_expected_draft_version_if_provided(
+    scheme_id: str,
+    expected_scheme_version_id: str | None,
+):
+    if not expected_scheme_version_id:
+        return None
+
+    scheme, version = await get_current_draft_context(
+        scheme_id=scheme_id,
+        expected_scheme_version_id=expected_scheme_version_id,
+    )
+    return scheme, version

backend/docs/api-map.md

@@ -55,6 +55,19 @@
 - POST /api/v1/schemes/{scheme_id}/draft/remap/preview
 - POST /api/v1/schemes/{scheme_id}/draft/remap/apply
 
+## app/api/routes/editor.py
+- GET /api/v1/schemes/{scheme_id}/draft/structure
+- GET /api/v1/schemes/{scheme_id}/draft/compare-preview
+- POST /api/v1/schemes/{scheme_id}/draft/sectors
+- POST /api/v1/schemes/{scheme_id}/draft/groups
+- DELETE /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id}
+- DELETE /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id}
+- PATCH /api/v1/schemes/{scheme_id}/draft/seats/records/{seat_record_id}
+- POST /api/v1/schemes/{scheme_id}/draft/seats/bulk
+- PATCH /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id}
+- PATCH /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id}
+- POST /api/v1/schemes/{scheme_id}/draft/repair-references
+
 ## app/api/routes/admin.py
 - GET /api/v1/admin/schemes/{scheme_id}/current/artifacts
 - GET /api/v1/admin/schemes/{scheme_id}/current/validation
@@ -66,4 +79,4 @@
 ## Notes
 - This file is an operational route index, not a generated OpenAPI export.
 - Update this map in the same change set when adding, removing, renaming, or moving routes.
-- Editor routes are maintained separately and should be synced from current source before relying on this file as a full route inventory.
+- Query guards such as expected_current_scheme_version_id / expected_scheme_version_id are part of the operational contract for optimistic concurrency on mutable flows.

backend/docs/smoke-regression.md

@@ -62,16 +62,20 @@ Validate:
 - no 500 on passthrough mode
 - unsupported mode returns 422
 
-## 5. Pricing read model
+## 5. Pricing read / write contract
 
 - GET /api/v1/schemes/{scheme_id}/pricing -> 200
 - GET /api/v1/schemes/{scheme_id}/current/seats/{seat_id}/price -> 200 for priced seat
 - GET /api/v1/schemes/{scheme_id}/test/seats/{seat_id} -> 200 for known seat
+- POST /api/v1/schemes/{scheme_id}/pricing/categories?expected_scheme_version_id={draft_version_id} -> 200 for valid draft
+- POST /api/v1/schemes/{scheme_id}/pricing/categories?expected_scheme_version_id=deadbeef... -> 409 for stale draft
 
 Validate:
 - pricing bundle contains categories and rules arrays
 - effective seat price resolves according to domain priority
 - test seat preview explains selectable / has_price state
+- pricing write responses are stable and typed
+- stale pricing mutation returns `detail.code = stale_draft_version`
 
 ## 6. Draft publish preview
 
@@ -122,6 +126,8 @@ Regression is considered failed if any of the following happen:
 - passthrough display endpoint fails on known-good sample
 - publish preview refresh or cached read returns 500
 - pricing bundle contract changes unexpectedly
+- pricing write contract regresses or stops returning typed payloads
+- stale draft guard stops returning 409 on pricing mutations
 - admin audit/cleanup endpoints fail on healthy environment
 - artifact retention grows without bound for repeated preview refresh on same variant