diff --git a/src/lib.rs b/src/lib.rs
index 3f44254..75697c4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -45,6 +45,8 @@ pub struct Instance {
     id: String, // item / ending id
 }
 
+/// a Room can have many Exits in different positions,
+/// optionally with a transition and dialogue
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct ExitInstance {
     position: Position,