diff --git a/vmm/src/api/openapi/cloud-hypervisor.yaml b/vmm/src/api/openapi/cloud-hypervisor.yaml
index c4dcae04c..8e48ced6f 100644
--- a/vmm/src/api/openapi/cloud-hypervisor.yaml
+++ b/vmm/src/api/openapi/cloud-hypervisor.yaml
@@ -195,6 +195,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/PciDeviceInfo'
+        204:
+          description: The new device was successfully (cold) added to the VM instance.
         404:
           description: The new device could not be added to the VM instance.
 
@@ -231,6 +233,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/PciDeviceInfo'
+        204:
+          description: The new disk was successfully (cold) added to the VM instance.
         500:
           description: The new disk could not be added to the VM instance.
 
@@ -251,6 +255,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/PciDeviceInfo'
+        204:
+          description: The new device was successfully (cold) added to the VM instance.
         500:
           description: The new device could not be added to the VM instance.
 
@@ -271,6 +277,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/PciDeviceInfo'
+        204:
+          description: The new device was successfully (cold) added to the VM instance.
         500:
           description: The new device could not be added to the VM instance.
 
@@ -291,6 +299,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/PciDeviceInfo'
+        204:
+          description: The new device was successfully (cold) added to the VM instance.
         500:
           description: The new device could not be added to the VM instance.
 
@@ -311,6 +321,8 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/PciDeviceInfo'
+        204:
+          description: The new device was successfully (cold) added to the VM instance.
         500:
           description: The new device could not be added to the VM instance.