diff --git a/seal5/model.py b/seal5/model.py
index f536c224..15b9abac 100644
--- a/seal5/model.py
+++ b/seal5/model.py
@@ -138,6 +138,8 @@ class Seal5InstrAttribute(Enum):
     IS_TERMINATOR = auto()
     IS_BRANCH = auto()
     COMPRESSED = auto()
+    USES = auto()
+    DEFS = auto()
 
 
 class Seal5OperandAttribute(Enum):