diff --git a/tempest/lib/services/compute/servers_client.py b/tempest/lib/services/compute/servers_client.py
index f027772..a687137 100644
--- a/tempest/lib/services/compute/servers_client.py
+++ b/tempest/lib/services/compute/servers_client.py
@@ -435,7 +435,12 @@
         return rest_client.ResponseBody(resp, body)
 
     def update_attached_volume(self, server_id, attachment_id, **kwargs):
-        """Swaps a volume attached to an instance for another volume"""
+        """Swaps a volume attached to an instance for another volume
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://docs.openstack.org/api-ref/compute/#update-a-volume-attachment
+        """
         post_body = json.dumps({'volumeAttachment': kwargs})
         resp, body = self.put('servers/%s/os-volume_attachments/%s' %
                               (server_id, attachment_id),
diff --git a/tempest/lib/services/volume/v3/snapshot_manage_client.py b/tempest/lib/services/volume/v3/snapshot_manage_client.py
index 43fd328..a9e1f74 100644
--- a/tempest/lib/services/volume/v3/snapshot_manage_client.py
+++ b/tempest/lib/services/volume/v3/snapshot_manage_client.py
@@ -22,7 +22,12 @@
     """Snapshot manage client."""
 
     def manage_snapshot(self, **kwargs):
-        """Manage a snapshot."""
+        """Manage a snapshot.
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://docs.openstack.org/api-ref/block-storage/v3/index.html#manage-an-existing-snapshot
+        """
         post_body = json.dumps({'snapshot': kwargs})
         url = 'os-snapshot-manage'
         resp, body = self.post(url, post_body)
diff --git a/tempest/lib/services/volume/v3/volumes_client.py b/tempest/lib/services/volume/v3/volumes_client.py
index e60382a..14a3c48 100644
--- a/tempest/lib/services/volume/v3/volumes_client.py
+++ b/tempest/lib/services/volume/v3/volumes_client.py
@@ -142,7 +142,12 @@
         return rest_client.ResponseBody(resp, body)
 
     def upload_volume(self, volume_id, **kwargs):
-        """Uploads a volume in Glance."""
+        """Uploads a volume in Glance.
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://docs.openstack.org/api-ref/block-storage/v3/index.html#upload-volume-to-image
+        """
         post_body = json.dumps({'os-volume_upload_image': kwargs})
         url = 'volumes/%s/action' % (volume_id)
         resp, body = self.post(url, post_body)
@@ -248,7 +253,12 @@
         return rest_client.ResponseBody(resp, body)
 
     def update_volume_readonly(self, volume_id, **kwargs):
-        """Update the Specified Volume readonly."""
+        """Update the Specified Volume readonly.
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://docs.openstack.org/api-ref/block-storage/v3/index.html#updates-volume-read-only-access-mode-flag
+        """
         post_body = json.dumps({'os-update_readonly_flag': kwargs})
         url = 'volumes/%s/action' % (volume_id)
         resp, body = self.post(url, post_body)