diff --git a/libwccl/ops/functions/bool/predicates/ann.h b/libwccl/ops/functions/bool/predicates/ann.h
index 6b7d878b0fc89fd7a78dc83a4b89778c483c7696..e9b8d149f83e3393601a5d8dd3dfece576e81f06 100644
--- a/libwccl/ops/functions/bool/predicates/ann.h
+++ b/libwccl/ops/functions/bool/predicates/ann.h
@@ -24,6 +24,7 @@ public:
 	{
 		BOOST_ASSERT(check_from);
 		BOOST_ASSERT(check_to);
+		BOOST_ASSERT(!annotation_name.empty());
 	}
 
 	Ann(
@@ -35,6 +36,7 @@ public:
 	{
 		BOOST_ASSERT(check_from_);
 		BOOST_ASSERT(check_to_);
+		BOOST_ASSERT(!annotation_name.empty());
 	}
 
 
diff --git a/libwccl/ops/functions/bool/predicates/annsub.h b/libwccl/ops/functions/bool/predicates/annsub.h
index da32dc02c2f665dfccaa3bd4d094a43ca7cc648e..0d2c235c4afb6d997e26aba470250ca6eb0dac66 100644
--- a/libwccl/ops/functions/bool/predicates/annsub.h
+++ b/libwccl/ops/functions/bool/predicates/annsub.h
@@ -21,6 +21,7 @@ public:
 	{
 		BOOST_ASSERT(check_from);
 		BOOST_ASSERT(check_to);
+		BOOST_ASSERT(!annotation_name.empty());
 	}
 
 	AnnSub(
@@ -32,6 +33,7 @@ public:
 	{
 		BOOST_ASSERT(check_from_);
 		BOOST_ASSERT(check_to_);
+		BOOST_ASSERT(!annotation_name.empty());
 	}