diff --git a/site/specs/messaging.yml b/site/specs/messaging.yml
index d35c5bbda..ca0b8a90f 100644
--- a/site/specs/messaging.yml
+++ b/site/specs/messaging.yml
@@ -1833,9 +1833,12 @@ components:
           items:
             type: string
             format: uri
+            maxLength: 4096
           description: >-
             A list of URLs to include as media attachments as part of the
             message.
+
+            Each URL can be at most 4096 characters.
           example:
             - https://dev.bandwidth.com/images/bandwidth-logo.png
             - https://dev.bandwidth.com/images/github_logo.png