diff --git a/api-ref/source/parameters.yaml b/api-ref/source/parameters.yaml
index 6035277cc850..437f475246f7 100644
--- a/api-ref/source/parameters.yaml
+++ b/api-ref/source/parameters.yaml
@@ -3158,7 +3158,14 @@ OS-EXT-SRV-ATTR:instance_name:
   type: string
 OS-EXT-STS:power_state:
   description: |
-    The power state of the instance.
+    The power state of the instance. This is an enum value that is mapped as::
+
+      0: NOSTATE
+      1: RUNNING
+      3: PAUSED
+      4: SHUTDOWN
+      6: CRASHED
+      7: SUSPENDED
   in: body
   required: true
   type: integer