diff --git a/src/main/kotlin/com/nylas/models/EventVisibility.kt b/src/main/kotlin/com/nylas/models/EventVisibility.kt
index c44fa762..a234bfbd 100644
--- a/src/main/kotlin/com/nylas/models/EventVisibility.kt
+++ b/src/main/kotlin/com/nylas/models/EventVisibility.kt
@@ -4,6 +4,10 @@ import com.squareup.moshi.Json
 
 /**
  * Enum representation of visibility of the event, if the event is private or public.
+ *
+ * [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.
  */
 enum class EventVisibility {
   @Json(name = "default")