diff --git a/builtins/Bool.roc b/builtins/Bool.roc
index c69d6ae2ed..731440846c 100644
--- a/builtins/Bool.roc
+++ b/builtins/Bool.roc
@@ -1,7 +1,9 @@
-api Bool provides Bool.*, not, equal, notEqual
+interface Bool
+    exposes [ Bool, not, equal, notEqual ]
+    imports []
 
 ## Either #True or #False.
-Bool := False, True
+Bool : [ False, True ]
 
 ## Returns #False when given #True, and vice versa.
 not : Bool -> Bool