diff --git a/lib/lib.go b/lib/lib.go
index 5c911b3..19c2581 100644
--- a/lib/lib.go
+++ b/lib/lib.go
@@ -54,7 +54,12 @@ type Context interface {
 // message, address
 
 type MsgHead interface {
+	fmt.Stringer
+	Slice() []string
+	Domain() string
 	Action() string
+	Class() string
+	Item() string
 }
 
 type Message interface {
@@ -62,6 +67,8 @@ type Message interface {
 	Head() MsgHead
 	Sender() Address
 	Payload() Payload
+	WithSender(Address) Message
+	WithPayload(Payload) Message
 }
 
 type Address interface {
diff --git a/lib/message/message.go b/lib/message/message.go
index accf767..5511515 100644
--- a/lib/message/message.go
+++ b/lib/message/message.go
@@ -1,31 +1,85 @@
 package message
 
 import (
+	"strings"
+
 	"git.sr.ht/~cco/go-scopes/lib"
 )
 
-// Message implementation(s)
+// message head
 
-type strMessage string
+type head struct {
+	domain, action, class, item string
+}
 
-func (msg strMessage) Head() lib.MsgHead {
+func (h *head) String() string {
+	return strings.Join(h.Slice(), "/")
+}
+
+func (h *head) Slice() []string {
+	return []string{h.domain, h.action, h.class, h.item}
+}
+
+func (h *head) Domain() string {
+	return h.domain
+}
+
+func (h *head) Action() string {
+	return h.action
+}
+
+func (h *head) Class() string {
+	return h.class
+}
+
+func (h *head) Item() string {
+	return h.item
+}
+
+// message
+
+type message struct {
+	*head
+	sender  lib.Address
+	payload lib.Payload
+}
+
+func (msg *message) Head() lib.MsgHead {
 	return msg
 }
 
-func (msg strMessage) Action() string {
-	return string(msg)
+func (msg *message) Sender() lib.Address {
+	return msg.sender
 }
 
-func (msg strMessage) Sender() lib.Address {
-	return nil
+func (msg *message) Payload() lib.Payload {
+	return msg.payload
 }
 
-func (msg strMessage) Payload() lib.Payload {
-	return nil
+func (msg *message) WithSender(s lib.Address) lib.Message {
+	msg.sender = s
+	return msg
 }
 
-func StrMessage(action string) lib.Message {
-	return strMessage(action)
+func (msg *message) WithPayload(p lib.Payload) lib.Message {
+	msg.payload = p
+	return msg
 }
 
-var Quit = StrMessage("quit")
+func NewMessage(args ...string) lib.Message {
+	args = append(args, "", "")[:4]
+	return &message{
+		head: &head{
+			domain: args[0],
+			action: args[1],
+			class:  args[2],
+			item:   args[3],
+		},
+	}
+}
+
+func SimpleMessage(action string) lib.Message {
+	return NewMessage("standard", action)
+}
+
+var Quit = SimpleMessage("quit")
diff --git a/tests/scopes_test.go b/tests/scopes_test.go
index fb7108c..6c74db5 100644
--- a/tests/scopes_test.go
+++ b/tests/scopes_test.go
@@ -39,14 +39,14 @@ func ConfigTest(t *testing.T) {
 func SendTest(t *testing.T) {
 	ctx := t.Ctx
 	rcvr := message.SimpleAddress("testing")
-	msg := message.StrMessage("demo")
+	msg := message.SimpleMessage("demo")
 	lib.Send(ctx, rcvr, msg)
 }
 
 func ClientTest(t *testing.T) {
 	ctx := t.Ctx
 	rcvr := message.SimpleAddress("test-client")
-	msg := message.StrMessage("demo")
+	msg := message.SimpleMessage("demo")
 	lib.Send(ctx, rcvr, msg)
 }
 
diff --git a/tests/unit_test.go b/tests/unit_test.go
index 6fe874a..3120e87 100644
--- a/tests/unit_test.go
+++ b/tests/unit_test.go
@@ -12,32 +12,33 @@ import (
 func TestUnit(tb *tbase.T) {
 	t := testing.SetUp(tb)
 	t.Run("address", AddressTest)
-	t.Run("strmsg", StrMessageTest)
+	t.Run("message", MessageTest)
 }
 
 func AddressTest(t *testing.T) {
 	var ad1 lib.Address = message.SimpleAddress("worker")
 	t.AssertEqual(fmt.Sprint(ad1), "#worker//")
-	astr := "https://scopes.cy7.eu#server/1abc/2cde"
+	astr := "@scopes.cy7.eu#server/1abc/2cde"
 	var ad2 lib.Address = message.ParseAddress(astr)
 	t.AssertEqual(fmt.Sprint(ad2), astr)
 	t.AssertEqual(fmt.Sprint(message.ParseAddress("worker")), "#worker//")
 	t.AssertEqual(ad1.Url(), "")
-	t.AssertEqual(ad2.Url(), "https://scopes.cy7.eu")
+	t.AssertEqual(ad2.Url(), "@scopes.cy7.eu")
 	sid, iid := ad1.Interaction()
 	t.AssertEqual(sid, "")
 	t.AssertEqual(iid, "")
 	sid, iid = ad2.Interaction()
 	t.AssertEqual(sid, "1abc")
 	t.AssertEqual(iid, "2cde")
-	ad1.SetUrl("https://scopes.cy7.eu")
+	ad1.SetUrl("@scopes.cy7.eu")
 	ad1.SetInteraction("1abc", "2cde")
-	t.AssertEqual(fmt.Sprint(ad1), "https://scopes.cy7.eu#worker/1abc/2cde")
+	t.AssertEqual(fmt.Sprint(ad1), "@scopes.cy7.eu#worker/1abc/2cde")
 }
 
-func StrMessageTest(t *testing.T) {
+func MessageTest(t *testing.T) {
 	t.AssertEqual(message.Quit.Action(), "quit")
-	var msg lib.Message = message.StrMessage("doit")
+	var msg lib.Message = message.SimpleMessage("doit")
 	t.AssertEqual(msg.Action(), "doit")
 	t.AssertEqual(msg.Head().Action(), "doit")
+	t.AssertEqual(fmt.Sprint(msg), "standard/doit//")
 }