diff --git a/internal/domain/monitor.go b/internal/domain/monitor.go
index ffedeb2..260b307 100644
--- a/internal/domain/monitor.go
+++ b/internal/domain/monitor.go
@@ -18,7 +18,14 @@ type CreateMonitorParams struct {
 	groupID string
 }
 
-func NewCreateMonitorParams(tribeID int64, groupID string) (CreateMonitorParams, error) {
+func NewCreateMonitorParams(groupID string, tribeID int64) (CreateMonitorParams, error) {
+	if groupID == "" {
+		return CreateMonitorParams{}, ValidationError{
+			Field: "GroupID",
+			Err:   ErrRequired,
+		}
+	}
+
 	if tribeID < tribeIDMin {
 		return CreateMonitorParams{}, ValidationError{
 			Field: "TribeID",
@@ -28,13 +35,6 @@ func NewCreateMonitorParams(tribeID int64, groupID string) (CreateMonitorParams,
 		}
 	}
 
-	if groupID == "" {
-		return CreateMonitorParams{}, ValidationError{
-			Field: "GroupID",
-			Err:   ErrRequired,
-		}
-	}
-
 	return CreateMonitorParams{tribeID: tribeID, groupID: groupID}, nil
 }
 
diff --git a/internal/domain/monitor_test.go b/internal/domain/monitor_test.go
index 7cc911c..de0a155 100644
--- a/internal/domain/monitor_test.go
+++ b/internal/domain/monitor_test.go
@@ -1,8 +1,66 @@
 package domain_test
 
-import "testing"
+import (
+	"testing"
+
+	"gitea.dwysokinski.me/twhelp/dcbot/internal/domain"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+)
 
 func TestNewCreateMonitorParams(t *testing.T) {
 	t.Parallel()
 
+	tests := []struct {
+		name    string
+		tribeID int64
+		groupID string
+		err     error
+	}{
+		{
+			name:    "OK",
+			tribeID: 15,
+			groupID: uuid.NewString(),
+		},
+		{
+			name:    "ERR: GroupID cannot be blank",
+			groupID: "",
+			err: domain.ValidationError{
+				Field: "GroupID",
+				Err:   domain.ErrRequired,
+			},
+		},
+		{
+			name:    "ERR: TribeID < 1",
+			groupID: uuid.NewString(),
+			tribeID: 0,
+			err: domain.ValidationError{
+				Field: "TribeID",
+				Err: domain.MinError{
+					Min: 1,
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			res, err := domain.NewCreateMonitorParams(
+				tt.groupID,
+				tt.tribeID,
+			)
+			if tt.err != nil {
+				assert.ErrorIs(t, err, tt.err)
+				assert.Zero(t, res)
+				return
+			}
+			assert.NoError(t, err)
+			assert.Equal(t, tt.groupID, res.GroupID())
+			assert.Equal(t, tt.tribeID, res.TribeID())
+		})
+	}
 }