Begin adding section on Transform Reply Variables

docs/development/README.md

@@ -304,10 +304,17 @@ The `override` and `overrideCurrent` props that are passed to the `ChatMode` are
 
 Standard nodes appear on the left-side of the chat as if they are coming from the 'bot'. Reply nodes are shown on the right-side of the chat as coming from the user of the application. 
 
-If information other than text such as video, images, or complex or dynamic visualizations needs to be displayed as coming from a bot, then creating a custom widget for a Standard Node is appropriate. Similarly, if a user is replying to the bot in a form that can't easily be represented as text, or is stored as an object or other encoded data, then a custom Reply Node widget is appropriate for visualizing their reply.
+If information other than text such as video, images, or complex or dynamic visualizations needs to be displayed as coming from a bot, then creating a custom widget for a Standard Node is appropriate. 
+
+If a user is replying to the bot in a form that can't easily be represented as text, then a custom widget for a reply node is appropriate. If the value of a variable is encoded, and needs to be decoded or specially formatted as text, then consider using a `transformReplyVariables` function hook instead. 
 
 The a Reply Node's widget will receive almost identical props as the original Standard Node that the reply is in response to. The only differences being that the top-level `reply` property will be `true` instead of `undefined`, and the Node's `event.value` will store the reply value passed to `upilCore`.
 
+### Transform Reply Variables
+
+The `transformReplyVariables` function hook allows the developer to transform a variable's value before it's displayed as a reply from a user. The return value must be formatted as text. If more advanced visualization methods are required, consider using a custom widget to replace the built-in text-based reply instead.
+
+
 ### Override function signature
 
 ```js