diff --git a/cmd/bspwm/main.go b/cmd/bspwm/main.go
index 68094c8..7f2aae8 100644
--- a/cmd/bspwm/main.go
+++ b/cmd/bspwm/main.go
@@ -65,7 +65,7 @@ func _main() error {
 	handler.AddDomain[domains.Todo](h, "monitor")
 	handler.AddDomain[domains.Wm](h, "wm")
 	handler.AddDomain[domains.Todo](h, "rule")
-	handler.AddDomain[domains.Todo](h, "config")
+	handler.AddDomain[domains.Config](h, "config")
 	handler.AddDomain[domains.Todo](h, "subscribe")
 	handler.AddDomain[domains.Todo](h, "quit")
 	handler.AddDomain[domains.Query](h, "query")
diff --git a/src/bsp/cfg/cfg.go b/src/bsp/cfg/cfg.go
index b22d399..df847cb 100644
--- a/src/bsp/cfg/cfg.go
+++ b/src/bsp/cfg/cfg.go
@@ -73,9 +73,6 @@ func (m *Modifier[T]) FillDefaults() {
 		ft := rt.Field(i)
 		k := ft.Tag.Get("cfg")
 		dv := ft.Tag.Get("default")
-		if dv == "" {
-			continue
-		}
 		m.Set(k, dv)
 	}
 	return
@@ -92,10 +89,13 @@ func (m *Modifier[T]) setup() {
 		kind := ft.Type.Elem().Kind()
 		switch kind {
 		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-			m.setters[k] = func(v string) error {
-				val, err := strconv.ParseUint(v, 10, 64)
-				if err != nil {
-					return copies.NewInvalidValueErr(k, v)
+			m.setters[k] = func(v string) (err error) {
+				var val uint64
+				if v != "" {
+					val, err = strconv.ParseUint(v, 10, 64)
+					if err != nil {
+						return copies.NewInvalidValueErr(k, v)
+					}
 				}
 				if fv.IsNil() {
 					fv.Set(reflect.New(ft.Type.Elem()))
@@ -110,10 +110,13 @@ func (m *Modifier[T]) setup() {
 				return fmt.Sprintf("%v", fv.Elem()), nil
 			}
 		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-			m.setters[k] = func(v string) error {
-				val, err := strconv.Atoi(v)
-				if err != nil {
-					return copies.NewInvalidValueErr(k, v)
+			m.setters[k] = func(v string) (err error) {
+				var val int
+				if v != "" {
+					val, err = strconv.Atoi(v)
+					if err != nil {
+						return copies.NewInvalidValueErr(k, v)
+					}
 				}
 				if fv.IsNil() {
 					fv.Set(reflect.New(ft.Type.Elem()))
@@ -133,7 +136,7 @@ func (m *Modifier[T]) setup() {
 				switch strings.ToLower(v) {
 				case "true", "on":
 					b = true
-				case "false", "off":
+				case "false", "off", "":
 					b = false
 				default:
 					return copies.NewInvalidValueErr(k, v)
diff --git a/src/bsp/cfg/cfg_test.go b/src/bsp/cfg/cfg_test.go
index 4b2b4f1..654c236 100644
--- a/src/bsp/cfg/cfg_test.go
+++ b/src/bsp/cfg/cfg_test.go
@@ -24,8 +24,6 @@ type s1 struct {
 func TestModifierS1(t *testing.T) {
 	s := &s1{}
 	m := cfg.NewModifier(s)
-	m.FillDefaults()
-	assert.EqualValues(t, *m.Ref.C, "crabs")
 
 	m.Set("b", "on")
 	assert.EqualValues(t, *m.Ref.B, true)
@@ -33,4 +31,7 @@ func TestModifierS1(t *testing.T) {
 	m.Set("d", "442")
 	assert.EqualValues(t, *m.Ref.D, 442)
 
+	m.FillDefaults()
+	assert.EqualValues(t, *m.Ref.C, "crabs")
+
 }
diff --git a/src/handler/domains/config.go b/src/handler/domains/config.go
index 13782b3..a29b12f 100644
--- a/src/handler/domains/config.go
+++ b/src/handler/domains/config.go
@@ -1,8 +1,6 @@
 package domains
 
 import (
-	"fmt"
-
 	"tuxpa.in/t/wm/src/copies"
 	"tuxpa.in/t/wm/src/sock"
 )
@@ -61,6 +59,6 @@ func (n *Config) parse(msg *sock.Msg) (bool, error) {
 		if msg.HasNext() {
 			return false, &copies.ErrInvalidArgumentCount{Name: "2 or 3", Value: len(msg.Args())}
 		}
-		return false, fmt.Errorf(`unknown option: '%s'`, arg)
+		return false, nil
 	}
 }
diff --git a/src/handler/handler.go b/src/handler/handler.go
index cf41984..f731a4d 100644
--- a/src/handler/handler.go
+++ b/src/handler/handler.go
@@ -33,11 +33,11 @@ func (h *Handler) Run(msg *sock.Msg) {
 	if msg.Err(err) {
 		return
 	}
-	err = msg.Reply(string(resp))
+	err = msg.Reply(resp)
 	if msg.Err(err) {
 		return
 	}
-	msg.Reply("")
+	msg.Reply(nil)
 }
 
 func (h *Handler) run(msg *sock.Msg) ([]byte, error) {
diff --git a/src/sock/msg.go b/src/sock/msg.go
index bfad81a..754633e 100644
--- a/src/sock/msg.go
+++ b/src/sock/msg.go
@@ -56,17 +56,19 @@ func (m *Msg) Err(e error) bool {
 	wr.Flush()
 	return true
 }
-func (m *Msg) Reply(ans string) error {
+func (m *Msg) Reply(xs []byte) error {
 	if !m.closed.CompareAndSwap(false, true) {
 		return nil
 	}
 	defer m.c.Close()
 	wr := bufio.NewWriter(m.c)
-	_, err := wr.Write([]byte(ans))
+	_, err := wr.Write(xs)
 	if err != nil {
 		return err
 	}
-	wr.Write([]byte("\n"))
+	if len(xs) != 0 {
+		wr.Write([]byte("\n"))
+	}
 	wr.Write([]byte{0})
 	wr.Flush()
 	return nil