diff --git a/docs/proposed/http-storage-node-protocol.rst b/docs/proposed/http-storage-node-protocol.rst
index 7f678d271..4f5a53906 100644
--- a/docs/proposed/http-storage-node-protocol.rst
+++ b/docs/proposed/http-storage-node-protocol.rst
@@ -692,7 +692,7 @@ It also includes potentially important details about the share.
 The request body MUST validate against this CDDL schema::
 
   {
-    reason: tstr
+    reason: tstr .size (1..32765)
   }
 
 For example::
@@ -704,6 +704,11 @@ If the identified **storage index** and **share number** are known to the server
 In this case the response SHOULD be ``OK``.
 If the response is not accepted then the response SHOULD be ``Not Found`` (404).
 
+Discussion
+``````````
+
+The seemingly odd length limit on ``reason`` is chosen so that the *encoded* representation of the message is limited to 32768.
+
 Reading
 ~~~~~~~