diff --git a/src/NzbDrone.Core/Notifications/CustomScript/CustomScript.cs b/src/NzbDrone.Core/Notifications/CustomScript/CustomScript.cs
index 8662ee2a0..6749491f6 100644
--- a/src/NzbDrone.Core/Notifications/CustomScript/CustomScript.cs
+++ b/src/NzbDrone.Core/Notifications/CustomScript/CustomScript.cs
@@ -46,6 +46,7 @@ public override void OnGrab(GrabMessage message)
             environmentVariables.Add("Readarr_Release_BookCount", remoteBook.Books.Count.ToString());
             environmentVariables.Add("Readarr_Release_BookReleaseDates", string.Join(",", remoteBook.Books.Select(e => e.ReleaseDate)));
             environmentVariables.Add("Readarr_Release_BookTitles", string.Join("|", remoteBook.Books.Select(e => e.Title)));
+            environmentVariables.Add("Readarr_Release_BookIds", string.Join("|", remoteBook.Books.Select(e => e.Id.ToString())));
             environmentVariables.Add("Readarr_Release_Title", remoteBook.Release.Title);
             environmentVariables.Add("Readarr_Release_Indexer", remoteBook.Release.Indexer ?? string.Empty);
             environmentVariables.Add("Readarr_Release_Size", remoteBook.Release.Size.ToString());