diff --git a/nylas/models/events.py b/nylas/models/events.py
index 3fa7686..7a5a2df 100644
--- a/nylas/models/events.py
+++ b/nylas/models/events.py
@@ -10,7 +10,13 @@
 """ Literal representing the status of an Event. """
 
 Visibility = Literal["default", "public", "private"]
-""" Literal representation of visibility of the Event. """
+"""
+Literal representation of visibility of the Event.
+
+`default` is only valid for Google events, where it defers to the calendar's own sharing
+settings. Microsoft and EWS events only support `public` and `private`; sending `default`
+for these providers returns a 400 error.
+"""
 
 ParticipantStatus = Literal["noreply", "yes", "no", "maybe"]
 """ Literal representing the status of an Event participant. """