diff --git a/client.go b/client.go
index 9b252eb..a1bcfe7 100644
--- a/client.go
+++ b/client.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/gorilla/websocket"
+	"github.com/jordanorelli/astro-domu/internal/wire"
 	"github.com/jordanorelli/blammo"
 )
 
@@ -19,11 +20,11 @@ type client struct {
 	port    int
 	lastSeq int
 	conn    *websocket.Conn
-	outbox  chan requestBody
+	outbox  chan wire.Request
 }
 
 func (c *client) run(ctx context.Context) {
-	c.outbox = make(chan requestBody)
+	c.outbox = make(chan wire.Request)
 
 	dialer := websocket.Dialer{
 		HandshakeTimeout: 3 * time.Second,
@@ -92,23 +93,9 @@ func (c *client) run(ctx context.Context) {
 	}
 }
 
-func (c *client) send(cmd string, args map[string]interface{}) {
-	eargs := make(map[string]json.RawMessage, len(args))
-	for k, v := range args {
-		b, err := json.Marshal(v)
-		if err != nil {
-			c.Error("failed to marshal an argument: %v", err)
-			return
-		}
-		eargs[k] = json.RawMessage(b)
-	}
+func (c *client) send(v wire.Value) {
 	c.lastSeq++
-	req := requestBody{
-		Seq:     c.lastSeq,
-		Command: cmd,
-		Args:    eargs,
-	}
-	c.outbox <- req
+	c.outbox <- wire.NewRequest(c.lastSeq, v)
 }
 
 func (c *client) readLoop() {
diff --git a/internal/wire/request.go b/internal/wire/request.go
index 9064657..f23a6d4 100644
--- a/internal/wire/request.go
+++ b/internal/wire/request.go
@@ -2,6 +2,14 @@ package wire
 
 type Request struct {
 	Seq  int         `json:"seq"`
-	Type string      `json:"type"`
+	Type Tag         `json:"type"`
 	Body interface{} `json:"body"`
 }
+
+func NewRequest(seq int, v Value) Request {
+	return Request{
+		Seq:  seq,
+		Type: v.NetTag(),
+		Body: v,
+	}
+}
diff --git a/internal/wire/self.go b/internal/wire/self.go
new file mode 100644
index 0000000..dc5d3f4
--- /dev/null
+++ b/internal/wire/self.go
@@ -0,0 +1,9 @@
+package wire
+
+type Self_Move struct {
+	Delta bool `json:"delta"`
+	X     int  `json:"x"`
+	Y     int  `json:"y"`
+}
+
+func (Self_Move) NetTag() Tag { return T_Client_Move }
diff --git a/internal/wire/tag.go b/internal/wire/tag.go
index 2b41c65..2bacf7a 100644
--- a/internal/wire/tag.go
+++ b/internal/wire/tag.go
@@ -11,6 +11,7 @@ const (
 	T_None Tag = iota
 	T_Error
 	T_OK
+	T_Client_Move
 )
 
 func (t Tag) String() string {
@@ -19,6 +20,8 @@ func (t Tag) String() string {
 		return "error"
 	case T_OK:
 		return "ok"
+	case T_Client_Move:
+		return "self/move"
 	default:
 		panic("unknown type tag")
 	}
@@ -37,6 +40,9 @@ func (t *Tag) UnmarshalJSON(b []byte) error {
 	case "ok":
 		*t = T_OK
 		return nil
+	case "self/move":
+		*t = T_Client_Move
+		return nil
 	default:
 		return fmt.Errorf("unknown type tag: %q", name)
 	}
diff --git a/ui_mode.go b/ui_mode.go
index 2cda515..7675c1f 100644
--- a/ui_mode.go
+++ b/ui_mode.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"github.com/gdamore/tcell/v2"
+	"github.com/jordanorelli/astro-domu/internal/wire"
 )
 
 type uiMode interface {
@@ -22,16 +23,16 @@ func (m *boxWalker) handleEvent(ui *ui, e tcell.Event) bool {
 		if key == tcell.KeyRune {
 			switch v.Rune() {
 			case 'w':
-				ui.client.send("self/move", map[string]interface{}{"delta": []int{0, -1}})
+				ui.client.send(wire.Self_Move{Delta: true, X: 0, Y: -1})
 				m.move(0, -1)
 			case 'a':
-				ui.client.send("self/move", map[string]interface{}{"delta": []int{-1, 0}})
+				ui.client.send(wire.Self_Move{Delta: true, X: -1, Y: 0})
 				m.move(-1, 0)
 			case 's':
-				ui.client.send("self/move", map[string]interface{}{"delta": []int{0, 1}})
+				ui.client.send(wire.Self_Move{Delta: true, X: 0, Y: 1})
 				m.move(0, 1)
 			case 'd':
-				ui.client.send("self/move", map[string]interface{}{"delta": []int{1, 0}})
+				ui.client.send(wire.Self_Move{Delta: true, X: 1, Y: 0})
 				m.move(1, 0)
 			}
 		}