diff --git a/schema/errors.go b/schema/errors.go
index bab1b03..33a3deb 100644
--- a/schema/errors.go
+++ b/schema/errors.go
@@ -16,5 +16,5 @@ package schema
 
 import "errors"
 
-// errInvalidProtoIsNil is returned when trying to convert a proto schema to a schema object.
+// errInvalidProtoIsNil is returned when trying to convert a proto schema to a schema object and the proto is nil.
 var errInvalidProtoIsNil = errors.New("invalid proto: nil")