diff --git a/api/v1/swagger/definitions/hold.yaml b/api/v1/swagger/definitions/hold.yaml
index 810f2647db..af3cd55087 100644
--- a/api/v1/swagger/definitions/hold.yaml
+++ b/api/v1/swagger/definitions/hold.yaml
@@ -135,5 +135,10 @@ properties:
       - object
       - "null"
     description: Pickup library
+  _strings:
+    type:
+      - object
+      - "null"
+    description: A list of stringified coded values
 
 additionalProperties: false
diff --git a/api/v1/swagger/paths/holds.yaml b/api/v1/swagger/paths/holds.yaml
index 4fe775fb36..8181cfd044 100644
--- a/api/v1/swagger/paths/holds.yaml
+++ b/api/v1/swagger/paths/holds.yaml
@@ -101,6 +101,7 @@
         items:
           type: string
           enum:
+            - +strings
             - cancellation_requested
             - biblio
             - deleted_biblio
diff --git a/api/v1/swagger/paths/patrons_holds.yaml b/api/v1/swagger/paths/patrons_holds.yaml
index 827cffd8bb..af4623cd62 100644
--- a/api/v1/swagger/paths/patrons_holds.yaml
+++ b/api/v1/swagger/paths/patrons_holds.yaml
@@ -28,6 +28,7 @@
         items:
           type: string
           enum:
+            - +strings
             - cancellation_requested
             - biblio
             - deleted_biblio