diff --git a/src/chat-messages.js b/src/chat-messages.js
index 912a418..5d33754 100644
--- a/src/chat-messages.js
+++ b/src/chat-messages.js
@@ -158,7 +158,7 @@ const ChatMessages = function (privateClient, publicClient) {
      * @param {string} options.channelName      - Name of room/channel (e.g. "#kosmos")
      * @param {string} [options.channelType]    - Type of channel ("room" or "person")
      * @param {date} options.date               - Date of archive day
-     * @param {boolean} options.isPublic        - Store logs in public folder (defaults to false)
+     * @param {boolean} [options.isPublic]      - Store logs in public folder (defaults to false)
      * @param {string} [options.previous]       - Date of previous log file as `YYYY/MM/DD`. Looked up automatically when not given
      * @param {string} [options.next]           - Date of next log file as `YYYY/MM/DD`. looked up automatically when not given
      *