diff --git a/query.go b/query.go
index 00c6a5a..d83ec3d 100644
--- a/query.go
+++ b/query.go
@@ -8,7 +8,8 @@ import (
 
 // List of available operators.
 const (
-	EQ int = iota
+	NOOP int = iota // No operation, skip query verification in circuit
+	EQ
 	LT
 	GT
 	IN
@@ -24,11 +25,12 @@ type Query struct {
 
 // QueryOperators represents operators for atomic circuits
 var QueryOperators = map[string]int{
-	"$eq":  EQ,
-	"$lt":  LT,
-	"$gt":  GT,
-	"$in":  IN,
-	"$nin": NIN,
+	"$noop": NOOP,
+	"$eq":   EQ,
+	"$lt":   LT,
+	"$gt":   GT,
+	"$in":   IN,
+	"$nin":  NIN,
 }
 
 // Comparer value.
diff --git a/query_test.go b/query_test.go
index 1153588..c3ef6b2 100644
--- a/query_test.go
+++ b/query_test.go
@@ -1,10 +1,10 @@
 package circuits
 
 import (
-"math/big"
-"testing"
+	"math/big"
+	"testing"
 
-"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/require"
 )
 
 func TestScalarCompare(t *testing.T) {
@@ -64,7 +64,7 @@ func TestScalarCompare(t *testing.T) {
 			name:     "testing unknown operator",
 			x:        big.NewInt(0),
 			y:        big.NewInt(1),
-			operator: 4, // unknown operator.
+			operator: 6, // unknown operator.
 			expected: false,
 			withErr:  true,
 		},