diff --git a/components/renku_data_services/crc/api.spec.yaml b/components/renku_data_services/crc/api.spec.yaml
index 7c5bb2517..5c573fb3f 100644
--- a/components/renku_data_services/crc/api.spec.yaml
+++ b/components/renku_data_services/crc/api.spec.yaml
@@ -996,7 +996,17 @@ components:
           $ref: "#/components/schemas/StorageClassName"
         service_account_name:
           $ref: "#/components/schemas/K8sResourceName"
-      required: [ "name", "config_name", "session_protocol", "session_host", "session_port", "session_path", "session_ingress_annotations", "session_tls_secret_name" ]
+      required:
+        [
+          "name",
+          "config_name",
+          "session_protocol",
+          "session_host",
+          "session_port",
+          "session_path",
+          "session_ingress_annotations",
+          "session_tls_secret_name",
+        ]
     ClusterPatch:
       type: object
       additionalProperties: false
@@ -1051,7 +1061,18 @@ components:
           $ref: "#/components/schemas/StorageClassName"
         service_account_name:
           type: string
-      required: [ "name", "config_name", "session_protocol", "session_host", "session_port", "session_path", "session_ingress_annotations", "session_tls_secret_name", "id" ]
+      required:
+        [
+          "name",
+          "config_name",
+          "session_protocol",
+          "session_host",
+          "session_port",
+          "session_path",
+          "session_ingress_annotations",
+          "session_tls_secret_name",
+          "id",
+        ]
     ClustersWithId:
       type: array
       items:
@@ -1078,7 +1099,16 @@ components:
           $ref: "#/components/schemas/K8sLabelList"
         node_affinities:
           $ref: "#/components/schemas/NodeAffinityList"
-      required: ["cpu", "memory", "gpu", "max_storage", "name", "default", "default_storage"]
+      required:
+        [
+          "cpu",
+          "memory",
+          "gpu",
+          "max_storage",
+          "name",
+          "default",
+          "default_storage",
+        ]
       example:
         name: "resource class"
         cpu: 1.5
@@ -1164,7 +1194,20 @@ components:
           $ref: "#/components/schemas/K8sLabelList"
         node_affinities:
           $ref: "#/components/schemas/NodeAffinityList"
-      required: ["cpu", "memory", "gpu", "max_storage", "name", "id", "default", "default_storage"]
+        resource_pool_id:
+          $ref: "#/components/schemas/IntegerId"
+      required:
+        [
+          "cpu",
+          "memory",
+          "gpu",
+          "max_storage",
+          "name",
+          "id",
+          "default",
+          "default_storage",
+          "resource_pool_id",
+        ]
       example:
         name: "resource class"
         cpu: 1.5
@@ -1174,6 +1217,7 @@ components:
         default_storage: 10
         id: 1
         default: true
+        resource_pool_id: 1
     ResourceClassWithIdFiltered:
       type: object
       additionalProperties: false
@@ -1200,7 +1244,20 @@ components:
           $ref: "#/components/schemas/K8sLabelList"
         node_affinities:
           $ref: "#/components/schemas/NodeAffinityList"
-      required: ["cpu", "memory", "gpu", "max_storage", "name", "id", "default", "default_storage"]
+        resource_pool_id:
+          $ref: "#/components/schemas/IntegerId"
+      required:
+        [
+          "cpu",
+          "memory",
+          "gpu",
+          "max_storage",
+          "name",
+          "id",
+          "default",
+          "default_storage",
+          "resource_pool_id",
+        ]
       example:
         name: "resource class"
         cpu: 1.5
@@ -1211,6 +1268,7 @@ components:
         id: 1
         default: true
         matching: true
+        resource_pool_id: 1
     ResourceClasses:
       type: array
       items:
@@ -1229,6 +1287,7 @@ components:
           id: 1
           default: true
           default_storage: 10
+          resource_pool_id: 1
         - name: "resource class 2"
           cpu: 4.5
           memory: 10
@@ -1237,6 +1296,7 @@ components:
           max_storage: 10000
           id: 2
           default: false
+          resource_pool_id: 1
     ResourceClassesWithIdResponse:
       # Note: this needs to be separate from ResourceClassesWithId or it doesn't get generated
       type: array
@@ -1252,6 +1312,7 @@ components:
           id: 1
           default: true
           default_storage: 10
+          resource_pool_id: 1
         - name: "resource class 2"
           cpu: 4.5
           memory: 10
@@ -1260,6 +1321,7 @@ components:
           max_storage: 10000
           id: 2
           default: false
+          resource_pool_id: 1
     ResourceClassesPatchWithId:
       type: array
       items:
@@ -1360,6 +1422,21 @@ components:
             max_storage: 10000
         name: "resource pool name"
         cluster_id: "4QZ886777NTN8GHQ551GSVAXSA"
+    ResourceClassWithIdWithoutResourcePoolId:
+      allOf:
+        - $ref: "#/components/schemas/ResourceClass"
+        - properties:
+            id:
+              $ref: "#/components/schemas/IntegerId"
+        - required:
+            - "cpu"
+            - "memory"
+            - "gpu"
+            - "max_storage"
+            - "name"
+            - "id"
+            - "default"
+            - "default_storage"
     ResourcePoolPut:
       type: object
       additionalProperties: false
@@ -1367,7 +1444,10 @@ components:
         quota:
           $ref: "#/components/schemas/QuotaWithId"
         classes:
-          $ref: "#/components/schemas/ResourceClassesWithId"
+          type: array
+          items:
+            $ref: "#/components/schemas/ResourceClassWithIdWithoutResourcePoolId"
+          uniqueItems: true
         name:
           $ref: "#/components/schemas/Name"
         public:
@@ -1746,7 +1826,7 @@ components:
       properties:
         kind:
           type: string
-          enum: [ "firecrest" ]
+          enum: ["firecrest"]
           description: Kind of remote resource pool
           example: "firecrest"
         provider_id:
@@ -1799,7 +1879,7 @@ components:
       properties:
         kind:
           type: string
-          enum: [ "firecrest" ]
+          enum: ["firecrest"]
           description: Kind of remote resource pool
           example: "firecrest"
         provider_id:
@@ -1888,7 +1968,7 @@ components:
       description: A list of k8s labels used for tolerations and/or node affinity
       items:
         $ref: "#/components/schemas/NodeAffinity"
-      example: [{"key": "test-label-1", "required_during_scheduling": false}]
+      example: [{ "key": "test-label-1", "required_during_scheduling": false }]
       uniqueItems: true
       default: []
       minItems: 0
@@ -1897,7 +1977,7 @@ components:
       description: A list of k8s labels used for tolerations and/or node affinity
       items:
         $ref: "#/components/schemas/NodeAffinity"
-      example: [{"key": "test-label-1", "required_during_scheduling": false}]
+      example: [{ "key": "test-label-1", "required_during_scheduling": false }]
       uniqueItems: true
       default: []
       minItems: 0
@@ -1930,11 +2010,11 @@ components:
       type: string
       minLength: 26
       maxLength: 26
-      pattern: "^[0-7][0-9A-HJKMNP-TV-Z]{25}$"  # This is case-insensitive
+      pattern: "^[0-7][0-9A-HJKMNP-TV-Z]{25}$" # This is case-insensitive
     Protocol:
       description: Allowed Protocol strings
       type: string
-      enum: [ "http", "https" ]
+      enum: ["http", "https"]
     Port:
       type: integer
       minimum: 0
diff --git a/components/renku_data_services/crc/apispec.py b/components/renku_data_services/crc/apispec.py
index c6b31902f..19f395471 100644
--- a/components/renku_data_services/crc/apispec.py
+++ b/components/renku_data_services/crc/apispec.py
@@ -1,6 +1,6 @@
 # generated by datamodel-codegen:
 #   filename:  api.spec.yaml
-#   timestamp: 2025-12-12T08:13:17+00:00
+#   timestamp: 2026-01-15T12:13:55+00:00
 
 from __future__ import annotations
 
@@ -680,6 +680,12 @@ class ResourceClassWithId(BaseAPISpec):
         examples=[[{"key": "test-label-1", "required_during_scheduling": False}]],
         min_length=0,
     )
+    resource_pool_id: int = Field(
+        ...,
+        description="An integer ID used to identify different resources",
+        examples=[1],
+        ge=0,
+    )
 
 
 class ResourceClassWithIdFiltered(BaseAPISpec):
@@ -741,6 +747,44 @@ class ResourceClassWithIdFiltered(BaseAPISpec):
         examples=[[{"key": "test-label-1", "required_during_scheduling": False}]],
         min_length=0,
     )
+    resource_pool_id: int = Field(
+        ...,
+        description="An integer ID used to identify different resources",
+        examples=[1],
+        ge=0,
+    )
+
+
+class ResourceClassesWithId(RootModel[List[ResourceClassWithId]]):
+    root: List[ResourceClassWithId] = Field(
+        ...,
+        examples=[
+            [
+                {
+                    "name": "resource class 1",
+                    "cpu": 1.5,
+                    "memory": 2,
+                    "gpu": 0,
+                    "max_storage": 100,
+                    "id": 1,
+                    "default": True,
+                    "default_storage": 10,
+                    "resource_pool_id": 1,
+                },
+                {
+                    "name": "resource class 2",
+                    "cpu": 4.5,
+                    "memory": 10,
+                    "gpu": 2,
+                    "default_storage": 10,
+                    "max_storage": 10000,
+                    "id": 2,
+                    "default": False,
+                    "resource_pool_id": 1,
+                },
+            ]
+        ],
+    )
 
 
 class ResourceClassesWithIdResponse(RootModel[List[ResourceClassWithId]]):
@@ -757,6 +801,7 @@ class ResourceClassesWithIdResponse(RootModel[List[ResourceClassWithId]]):
                     "id": 1,
                     "default": True,
                     "default_storage": 10,
+                    "resource_pool_id": 1,
                 },
                 {
                     "name": "resource class 2",
@@ -767,6 +812,7 @@ class ResourceClassesWithIdResponse(RootModel[List[ResourceClassWithId]]):
                     "max_storage": 10000,
                     "id": 2,
                     "default": False,
+                    "resource_pool_id": 1,
                 },
             ]
         ],
@@ -824,7 +870,7 @@ class ResourcePoolPatch(BaseAPISpec):
     )
     hibernation_warning_period: Optional[int] = Field(
         None,
-        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be expired. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
+        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be hibernated. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
         ge=0,
         le=2147483647,
     )
@@ -838,6 +884,15 @@ class ResourcePoolPatch(BaseAPISpec):
     platform: Optional[RuntimePlatform] = None
 
 
+class ResourceClassWithIdWithoutResourcePoolId(ResourceClass):
+    id: int = Field(
+        ...,
+        description="An integer ID used to identify different resources",
+        examples=[1],
+        ge=0,
+    )
+
+
 class ResourcePool(BaseAPISpec):
     model_config = ConfigDict(
         extra="forbid",
@@ -878,7 +933,7 @@ class ResourcePool(BaseAPISpec):
     )
     hibernation_warning_period: Optional[int] = Field(
         None,
-        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be expired. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
+        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be hibernated. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
         ge=0,
         le=2147483647,
     )
@@ -897,33 +952,7 @@ class ResourcePoolPut(BaseAPISpec):
         extra="forbid",
     )
     quota: Optional[QuotaWithId] = None
-    classes: List[ResourceClassWithId] = Field(
-        ...,
-        examples=[
-            [
-                {
-                    "name": "resource class 1",
-                    "cpu": 1.5,
-                    "memory": 2,
-                    "gpu": 0,
-                    "max_storage": 100,
-                    "id": 1,
-                    "default": True,
-                    "default_storage": 10,
-                },
-                {
-                    "name": "resource class 2",
-                    "cpu": 4.5,
-                    "memory": 10,
-                    "gpu": 2,
-                    "default_storage": 10,
-                    "max_storage": 10000,
-                    "id": 2,
-                    "default": False,
-                },
-            ]
-        ],
-    )
+    classes: List[ResourceClassWithIdWithoutResourcePoolId]
     name: str = Field(
         ...,
         description="A name for a specific resource",
@@ -958,7 +987,7 @@ class ResourcePoolPut(BaseAPISpec):
     )
     hibernation_warning_period: Optional[int] = Field(
         None,
-        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be expired. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
+        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be hibernated. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
         ge=0,
         le=2147483647,
     )
@@ -1018,7 +1047,7 @@ class ResourcePoolWithId(BaseAPISpec):
     )
     hibernation_warning_period: Optional[int] = Field(
         None,
-        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be expired. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
+        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be hibernated. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
         ge=0,
         le=2147483647,
     )
@@ -1072,7 +1101,7 @@ class ResourcePoolWithIdFiltered(BaseAPISpec):
     )
     hibernation_warning_period: Optional[int] = Field(
         None,
-        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be expired. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
+        description="A duration in seconds, lower than `HibernationThreshold`,\nwhich indicates when to let the user know about a session that\nis going to be hibernated. If `0` is specified, some default\nvalue will be chosen. If no `HibernationThreshold` is defined,\nthis value is ignored.\n",
         ge=0,
         le=2147483647,
     )
diff --git a/components/renku_data_services/crc/core.py b/components/renku_data_services/crc/core.py
index b449e5a3d..eedd8cc9c 100644
--- a/components/renku_data_services/crc/core.py
+++ b/components/renku_data_services/crc/core.py
@@ -59,21 +59,36 @@ def validate_resource_class(body: apispec.ResourceClass) -> models.UnsavedResour
 
 @overload
 def validate_resource_class_patch_or_put(
-    body: apispec.ResourceClassPatch | apispec.ResourceClass, method: Literal["PATCH", "PUT"]
-) -> models.ResourceClassPatch: ...
+    body: apispec.ResourceClassPatchWithId
+    | apispec.ResourceClassWithIdWithoutResourcePoolId
+    | apispec.ResourceClassWithId,
+    method: Literal["PATCH", "PUT"],
+) -> models.ResourceClassPatchWithId: ...
 @overload
 def validate_resource_class_patch_or_put(
-    body: apispec.ResourceClassPatchWithId | apispec.ResourceClassWithId, method: Literal["PATCH", "PUT"]
-) -> models.ResourceClassPatchWithId: ...
+    body: apispec.ResourceClassPatch | apispec.ResourceClass, method: Literal["PATCH", "PUT"]
+) -> models.ResourceClassPatch: ...
 def validate_resource_class_patch_or_put(
     body: apispec.ResourceClassPatch
     | apispec.ResourceClassPatchWithId
+    | apispec.ResourceClassWithIdWithoutResourcePoolId
     | apispec.ResourceClass
     | apispec.ResourceClassWithId,
     method: Literal["PATCH", "PUT"],
 ) -> models.ResourceClassPatch | models.ResourceClassPatchWithId:
     """Validate the patch to a resource class."""
-    rc_id = body.id if isinstance(body, (apispec.ResourceClassPatchWithId, apispec.ResourceClassWithId)) else None
+    rc_id = (
+        body.id
+        if isinstance(
+            body,
+            (
+                apispec.ResourceClassPatchWithId,
+                apispec.ResourceClassWithId,
+                apispec.ResourceClassWithIdWithoutResourcePoolId,
+            ),
+        )
+        else None
+    )
     node_affinities: list[models.NodeAffinity] | None = [] if method == "PUT" else None
     if body.node_affinities:
         node_affinities = sorted(
@@ -278,6 +293,7 @@ def validate_resource_pool_update(existing: models.ResourcePool, update: models.
             default_storage=rc.default_storage if rc.default_storage is not None else existing_rc.default_storage,
             node_affinities=rc.node_affinities if rc.node_affinities is not None else existing_rc.node_affinities,
             tolerations=rc.tolerations if rc.tolerations is not None else existing_rc.tolerations,
+            resource_pool_id=existing.id,
         )
     quota: models.Quota | models.UnsavedQuota | ResetType = existing.quota if existing.quota else RESET
     if update.quota is RESET:
diff --git a/components/renku_data_services/crc/models.py b/components/renku_data_services/crc/models.py
index 1efbae22b..0907f2eec 100644
--- a/components/renku_data_services/crc/models.py
+++ b/components/renku_data_services/crc/models.py
@@ -101,6 +101,7 @@ class ResourceClass(ResourcesCompareMixin):
     max_storage: int
     gpu: int
     id: int
+    resource_pool_id: int
     default: bool = False
     default_storage: int = 1
     matching: Optional[bool] = None
diff --git a/components/renku_data_services/crc/orm.py b/components/renku_data_services/crc/orm.py
index 2c20f0efd..27dc03910 100644
--- a/components/renku_data_services/crc/orm.py
+++ b/components/renku_data_services/crc/orm.py
@@ -141,6 +141,8 @@ def dump(
                 and self.gpu >= matching_criteria.gpu
                 and self.max_storage >= matching_criteria.max_storage
             )
+        if self.resource_pool_id is None:
+            raise errors.ProgrammingError(message="Cannot dump a resource class without a reource pool id.")
         return models.ResourceClass(
             id=self.id,
             name=self.name,
@@ -154,6 +156,7 @@ def dump(
             tolerations=[toleration.key for toleration in self.tolerations],
             matching=matching,
             quota=self.resource_pool.quota if self.resource_pool else None,
+            resource_pool_id=self.resource_pool_id,
         )
 
 
diff --git a/components/renku_data_services/notebooks/api/classes/data_service.py b/components/renku_data_services/notebooks/api/classes/data_service.py
index 3abcee82c..6d0e7f805 100644
--- a/components/renku_data_services/notebooks/api/classes/data_service.py
+++ b/components/renku_data_services/notebooks/api/classes/data_service.py
@@ -140,6 +140,7 @@ async def get_default_class(self) -> ResourceClass:
             id=1,
             default_storage=1,
             default=True,
+            resource_pool_id=1,
         )
 
     async def find_acceptable_class(
diff --git a/test/bases/renku_data_services/data_api/test_resource_pools.py b/test/bases/renku_data_services/data_api/test_resource_pools.py
index 684dbd190..dc29d59bf 100644
--- a/test/bases/renku_data_services/data_api/test_resource_pools.py
+++ b/test/bases/renku_data_services/data_api/test_resource_pools.py
@@ -279,6 +279,7 @@ async def test_resource_class_filtering(
     matching_class = matching_classes[0]
     matching_class.pop("id")
     matching_class.pop("matching")
+    matching_class.pop("resource_pool_id")
     assert matching_class == new_classes[2]
     # Test without any filtering
     _, res = await sanic_client.get(
@@ -471,6 +472,7 @@ async def test_put_resource_class(
     res_cls_payload = {**res.json.get("classes", [])[0], "cpu": 5.0}
     res_cls_expected_response = {**res.json.get("classes", [])[0], "cpu": 5.0}
     res_cls_payload.pop("id", None)
+    res_cls_payload.pop("resource_pool_id", None)
     _, res = await sanic_client.put(
         "/api/data/resource_pools/1/classes/1",
         headers=admin_headers,
@@ -973,6 +975,7 @@ async def test_remove_all_tolerations_put(
     assert res_class["tolerations"][0] == "toleration1"
     new_class = deepcopy(res_class)
     new_class.pop("id")
+    new_class.pop("resource_pool_id")
     new_class["tolerations"] = []
     _, res = await sanic_client.put(
         f"/api/data/resource_pools/{rp_id}/classes/{res_class_id}",
@@ -1009,6 +1012,7 @@ async def test_remove_all_affinities_put(
     assert res_class["node_affinities"][0] == {"key": "affinity1", "required_during_scheduling": False}
     new_class = deepcopy(res_class)
     new_class.pop("id")
+    new_class.pop("resource_pool_id")
     new_class["node_affinities"] = []
     _, res = await sanic_client.put(
         f"/api/data/resource_pools/{rp_id}/classes/{res_class_id}",
@@ -1045,6 +1049,7 @@ async def test_put_tolerations(
     assert res_class["tolerations"][0] == "toleration1"
     new_class = deepcopy(res_class)
     new_class.pop("id")
+    new_class.pop("resource_pool_id")
     new_class["tolerations"] = ["toleration2", "toleration3"]
     _, res = await sanic_client.put(
         f"/api/data/resource_pools/{rp_id}/classes/{res_class_id}",
@@ -1081,6 +1086,7 @@ async def test_put_affinities(
     assert res_class["node_affinities"][0] == {"key": "affinity1", "required_during_scheduling": False}
     new_class = deepcopy(res_class)
     new_class.pop("id")
+    new_class.pop("resource_pool_id")
     new_class["node_affinities"] = [{"key": "affinity1", "required_during_scheduling": True}, {"key": "affinity2"}]
     _, res = await sanic_client.put(
         f"/api/data/resource_pools/{rp_id}/classes/{res_class_id}",
@@ -1281,6 +1287,8 @@ async def _resource_pools_request(
             check_payload["id"] = resource_pool_id
         if "id" not in check_payload["quota"]:
             check_payload["quota"]["id"] = rp["quota"]["id"]
+        for clss in check_payload.get("classes", []):
+            clss["resource_pool_id"] = resource_pool_id
 
     url = f"{base_url}/{resource_pool_id}"
 
@@ -1473,6 +1481,7 @@ async def test_resource_pool_patch_platform(
     put = deepcopy(resource_pool_payload_2)
     put["quota"] = rp["quota"]
     put["classes"] = rp["classes"]
+    [clss.pop("resource_pool_id") for clss in put["classes"]]
     put["platform"] = "linux/amd64"
 
     _, res = await sanic_client.put(f"/api/data/resource_pools/{rp_id}", headers=admin_headers, json=put)