diff --git a/api/src/pcapi/routes/public/collective/endpoints/categories.py b/api/src/pcapi/routes/public/collective/endpoints/categories.py
index ef3a4d628bd..179e79e50bb 100644
--- a/api/src/pcapi/routes/public/collective/endpoints/categories.py
+++ b/api/src/pcapi/routes/public/collective/endpoints/categories.py
@@ -1,11 +1,9 @@
 from collections import defaultdict
-from typing import cast
 
 from pcapi.core.categories import categories
 from pcapi.core.categories import subcategories_v2
 from pcapi.routes.public import blueprints
 from pcapi.routes.public.collective.serialization import offers as offers_serialization
-from pcapi.routes.serialization import BaseModel
 from pcapi.serialization.decorator import spectree_serialize
 from pcapi.serialization.spec_tree import ExtendResponse as SpectreeResponse
 from pcapi.validation.routes.users_authentifications import api_key_required
@@ -16,18 +14,14 @@
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            {
-                "HTTP_200": (
-                    offers_serialization.CollectiveOffersListCategoriesResponseModel,
-                    "La liste des catégories éligibles existantes.",
-                ),
-                "HTTP_401": (
-                    cast(BaseModel, offers_serialization.AuthErrorResponseModel),
-                    "Authentification nécessaire",
-                ),
-            }
-        )
+        HTTP_200=(
+            offers_serialization.CollectiveOffersListCategoriesResponseModel,
+            "La liste des catégories éligibles existantes.",
+        ),
+        HTTP_401=(
+            offers_serialization.AuthErrorResponseModel,
+            "Authentification nécessaire",
+        ),
     ),
 )
 @api_key_required
@@ -48,18 +42,14 @@ def list_categories() -> offers_serialization.CollectiveOffersListCategoriesResp
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            {
-                "HTTP_200": (
-                    offers_serialization.CollectiveOffersListSubCategoriesResponseModel,
-                    "La liste des sous-catégories éligibles existantes.",
-                ),
-                "HTTP_401": (
-                    cast(BaseModel, offers_serialization.AuthErrorResponseModel),
-                    "Authentification nécessaire",
-                ),
-            }
-        )
+        HTTP_200=(
+            offers_serialization.CollectiveOffersListSubCategoriesResponseModel,
+            "La liste des sous-catégories éligibles existantes.",
+        ),
+        HTTP_401=(
+            offers_serialization.AuthErrorResponseModel,
+            "Authentification nécessaire",
+        ),
     ),
 )
 @api_key_required
diff --git a/api/src/pcapi/routes/public/collective/endpoints/domains.py b/api/src/pcapi/routes/public/collective/endpoints/domains.py
index e28acf2c853..a17f18a6cfb 100644
--- a/api/src/pcapi/routes/public/collective/endpoints/domains.py
+++ b/api/src/pcapi/routes/public/collective/endpoints/domains.py
@@ -1,10 +1,7 @@
-from typing import cast
-
 from pcapi.core.educational import repository as educational_repository
 from pcapi.routes.public import blueprints
 from pcapi.routes.public.collective.serialization import domains as domains_serialization
 from pcapi.routes.public.collective.serialization import offers as offers_serialization
-from pcapi.routes.serialization import BaseModel
 from pcapi.serialization.decorator import spectree_serialize
 from pcapi.serialization.spec_tree import ExtendResponse as SpectreeResponse
 from pcapi.utils.cache import cached_view
@@ -16,18 +13,14 @@
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            {
-                "HTTP_200": (
-                    domains_serialization.CollectiveOffersListDomainsResponseModel,
-                    "La liste des domaines d'éducation.",
-                ),
-                "HTTP_401": (
-                    cast(BaseModel, offers_serialization.AuthErrorResponseModel),
-                    "Authentification nécessaire",
-                ),
-            }
-        )
+        HTTP_200=(
+            domains_serialization.CollectiveOffersListDomainsResponseModel,
+            "La liste des domaines d'éducation.",
+        ),
+        HTTP_401=(
+            offers_serialization.AuthErrorResponseModel,
+            "Authentification nécessaire",
+        ),
     ),
 )
 @api_key_required
diff --git a/api/src/pcapi/routes/public/collective/endpoints/educational_institutions.py b/api/src/pcapi/routes/public/collective/endpoints/educational_institutions.py
index 14632ed7881..4fb36e76401 100644
--- a/api/src/pcapi/routes/public/collective/endpoints/educational_institutions.py
+++ b/api/src/pcapi/routes/public/collective/endpoints/educational_institutions.py
@@ -1,10 +1,7 @@
-from typing import cast
-
 from pcapi.core.educational.api.institution import search_educational_institution
 from pcapi.routes.public import blueprints
 from pcapi.routes.public.collective.serialization import institutions as institutions_serialization
 from pcapi.routes.public.collective.serialization import offers as offers_serialization
-from pcapi.routes.serialization import BaseModel
 from pcapi.serialization.decorator import spectree_serialize
 from pcapi.serialization.spec_tree import ExtendResponse as SpectreeResponse
 from pcapi.validation.routes.users_authentifications import api_key_required
@@ -15,22 +12,18 @@
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            {
-                "HTTP_200": (
-                    institutions_serialization.CollectiveOffersListEducationalInstitutionResponseModel,
-                    "La liste des établissement scolaires éligibles.",
-                ),
-                "HTTP_400": (
-                    cast(BaseModel, offers_serialization.ErrorResponseModel),
-                    "Requête malformée",
-                ),
-                "HTTP_401": (
-                    cast(BaseModel, offers_serialization.AuthErrorResponseModel),
-                    "Authentification nécessaire",
-                ),
-            }
-        )
+        HTTP_200=(
+            institutions_serialization.CollectiveOffersListEducationalInstitutionResponseModel,
+            "La liste des établissement scolaires éligibles.",
+        ),
+        HTTP_400=(
+            offers_serialization.ErrorResponseModel,
+            "Requête malformée",
+        ),
+        HTTP_401=(
+            offers_serialization.AuthErrorResponseModel,
+            "Authentification nécessaire",
+        ),
     ),
 )
 @api_key_required
diff --git a/api/src/pcapi/routes/public/collective/endpoints/offers.py b/api/src/pcapi/routes/public/collective/endpoints/offers.py
index 16f3593461c..a3bcda385e5 100644
--- a/api/src/pcapi/routes/public/collective/endpoints/offers.py
+++ b/api/src/pcapi/routes/public/collective/endpoints/offers.py
@@ -35,15 +35,11 @@
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            BASE_CODE_DESCRIPTIONS
-            | {
-                "HTTP_200": (
-                    offers_serialization.CollectiveOffersListResponseModel,
-                    "L'offre collective existe",
-                ),
-            }
-        )
+        **(BASE_CODE_DESCRIPTIONS),
+        HTTP_200=(
+            offers_serialization.CollectiveOffersListResponseModel,
+            "L'offre collective existe",
+        ),
     ),
 )
 @api_key_required
@@ -76,15 +72,11 @@ def get_collective_offers_public(
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            BASE_CODE_DESCRIPTIONS
-            | {
-                "HTTP_200": (
-                    offers_serialization.GetPublicCollectiveOfferResponseModel,
-                    "L'offre collective existe",
-                ),
-            }
-        )
+        **(BASE_CODE_DESCRIPTIONS),
+        HTTP_200=(
+            offers_serialization.GetPublicCollectiveOfferResponseModel,
+            "L'offre collective existe",
+        ),
     ),
 )
 @api_key_required
diff --git a/api/src/pcapi/routes/public/collective/endpoints/students_levels.py b/api/src/pcapi/routes/public/collective/endpoints/students_levels.py
index 14a81cd8d92..e5c9c043e69 100644
--- a/api/src/pcapi/routes/public/collective/endpoints/students_levels.py
+++ b/api/src/pcapi/routes/public/collective/endpoints/students_levels.py
@@ -1,10 +1,7 @@
-from typing import cast
-
 from pcapi.core.educational import models as educational_models
 from pcapi.routes.public import blueprints
 from pcapi.routes.public.collective.serialization import offers as offers_serialization
 from pcapi.routes.public.collective.serialization import students_levels as students_levels_serialization
-from pcapi.routes.serialization import BaseModel
 from pcapi.serialization.decorator import spectree_serialize
 from pcapi.serialization.spec_tree import ExtendResponse as SpectreeResponse
 from pcapi.validation.routes.users_authentifications import api_key_required
@@ -15,18 +12,14 @@
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            {
-                "HTTP_200": (
-                    students_levels_serialization.CollectiveOffersListStudentLevelsResponseModel,
-                    "La liste des domaines d'éducation.",
-                ),
-                "HTTP_401": (
-                    cast(BaseModel, offers_serialization.AuthErrorResponseModel),
-                    "Authentification nécessaire",
-                ),
-            }
-        )
+        HTTP_200=(
+            students_levels_serialization.CollectiveOffersListStudentLevelsResponseModel,
+            "La liste des domaines d'éducation.",
+        ),
+        HTTP_401=(
+            offers_serialization.AuthErrorResponseModel,
+            "Authentification nécessaire",
+        ),
     ),
 )
 @api_key_required
diff --git a/api/src/pcapi/routes/public/collective/endpoints/venues.py b/api/src/pcapi/routes/public/collective/endpoints/venues.py
index 1dabf99c8bb..939b18281eb 100644
--- a/api/src/pcapi/routes/public/collective/endpoints/venues.py
+++ b/api/src/pcapi/routes/public/collective/endpoints/venues.py
@@ -1,12 +1,9 @@
-from typing import cast
-
 from pcapi.core.offerers import repository as offerers_repository
 from pcapi.core.providers import repository as providers_repository
 from pcapi.models.feature import FeatureToggle
 from pcapi.routes.public import blueprints
 from pcapi.routes.public.collective.serialization import offers as offers_serialization
 from pcapi.routes.public.collective.serialization import venues as venues_serialization
-from pcapi.routes.serialization import BaseModel
 from pcapi.serialization.decorator import spectree_serialize
 from pcapi.serialization.spec_tree import ExtendResponse as SpectreeResponse
 from pcapi.validation.routes.users_authentifications import api_key_required
@@ -18,18 +15,14 @@
     api=blueprints.v2_prefixed_public_api_schema,
     tags=["API offres collectives"],
     resp=SpectreeResponse(
-        **(
-            {
-                "HTTP_200": (
-                    venues_serialization.CollectiveOffersListVenuesResponseModel,
-                    "La liste des lieux ou vous pouvez créer une offre.",
-                ),
-                "HTTP_401": (
-                    cast(BaseModel, offers_serialization.AuthErrorResponseModel),
-                    "Authentification nécessaire",
-                ),
-            }
-        )
+        HTTP_200=(
+            venues_serialization.CollectiveOffersListVenuesResponseModel,
+            "La liste des lieux ou vous pouvez créer une offre.",
+        ),
+        HTTP_401=(
+            offers_serialization.AuthErrorResponseModel,
+            "Authentification nécessaire",
+        ),
     ),
 )
 @api_key_required
diff --git a/api/src/pcapi/serialization/decorator.py b/api/src/pcapi/serialization/decorator.py
index 2a06cae2f39..68dff27f118 100644
--- a/api/src/pcapi/serialization/decorator.py
+++ b/api/src/pcapi/serialization/decorator.py
@@ -9,13 +9,13 @@
 from flask import Response
 from flask import make_response
 from flask import request
+import spectree
 from werkzeug.exceptions import BadRequest
 
 from pcapi.models.api_errors import ApiErrors
 from pcapi.routes.apis import api as default_api
 from pcapi.routes.serialization import BaseModel
 from pcapi.serialization.spec_tree import ExtendResponse as SpectreeResponse
-from pcapi.serialization.spec_tree import ExtendedSpecTree
 
 
 logger = logging.getLogger(__name__)
@@ -71,7 +71,7 @@ def spectree_serialize(
     on_success_status: int = 200,
     on_empty_status: int | None = None,
     on_error_statuses: list[int] | None = None,
-    api: ExtendedSpecTree = default_api,
+    api: spectree.SpecTree = default_api,
     json_format: bool = True,
     response_headers: dict[str, str] | None = None,
     resp: SpectreeResponse | None = None,