diff --git a/ecs_composex/specs/services.x-ecs.spec.json b/ecs_composex/specs/services.x-ecs.spec.json
index cfdb96fe..c722075e 100644
--- a/ecs_composex/specs/services.x-ecs.spec.json
+++ b/ecs_composex/specs/services.x-ecs.spec.json
@@ -20,16 +20,7 @@
     },
     "OperatingSystemFamily": {
       "type": "string",
-      "enum": [
-        "LINUX",
-        "WINDOWS_SERVER_2004_CORE",
-        "WINDOWS_SERVER_2016_FULL",
-        "WINDOWS_SERVER_2019_CORE",
-        "WINDOWS_SERVER_2019_FULL",
-        "WINDOWS_SERVER_2022_CORE",
-        "WINDOWS_SERVER_2022_FULL",
-        "WINDOWS_SERVER_20H2_CORE"
-      ],
+      "pattern": "LINUX|^WINDOWS[\\S]+",
       "description": "https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ecs-taskdefinition-runtimeplatform.html#cfn-ecs-taskdefinition-runtimeplatform-operatingsystemfamily"
     },
     "CapacityProviderStrategy": {
diff --git a/ecs_composex/specs/x-cluster.spec.json b/ecs_composex/specs/x-cluster.spec.json
index c4428542..4ed08875 100644
--- a/ecs_composex/specs/x-cluster.spec.json
+++ b/ecs_composex/specs/x-cluster.spec.json
@@ -62,6 +62,36 @@
           "default": false
         }
       }
+    },
+    "CapacityProviders": {
+      "type": "object",
+      "description": "Allows to define one or more Capacity Providers that will re-use or create ASGs.",
+      "patternProperties": {
+        "x-": {},
+        "^[a-zA-Z0-9-]+$": {
+          "$ref": "#/properties/CapacityProvider"
+        }
+      }
+    },
+    "CapacityProvider": {
+      "type": "object",
+      "description": "Capacity Provider definition",
+      "properties": {
+        "LaunchTemplateArn": {
+          "type": "string",
+          "description": "Set the ARN (with version) of the LaunchTemplate that you want to use for this Capacity Provider. If not set, new one will be created.",
+          "pattern": "^arn:aws[\\S]+$"
+        },
+        "AutoscalingGroupArn": {
+          "type": "string",
+          "description": "Set to the ARN of the AutoScaling group you wish to re-use for this CapacityProvider. If not set, a new one will be created."
+        },
+        "InstanceType": {
+          "type": "string",
+          "description": "For new LT & ASG, set the instance type you wish to use.",
+          "default": "t4g.medium"
+        }
+      }
     }
   },
   "oneOf": [