diff --git a/gql.go b/gql.go
index 4c064a1..cdccfcc 100644
--- a/gql.go
+++ b/gql.go
@@ -1287,7 +1287,7 @@ func (ext *GQLExt) Process(ctx *Context, node *Node, source NodeID, signal Signa
   switch sig := signal.(type) {
   case *ErrorSignal:
     // TODO: Forward to resolver if waiting for it
-    response_chan := ext.FreeResponseChannel(sig.Header().ReqID)
+    response_chan := ext.FreeResponseChannel(sig.ReqID)
     if response_chan != nil {
       select {
       case response_chan <- sig:
diff --git a/gql_node.go b/gql_node.go
index f75de80..2dcf2b1 100644
--- a/gql_node.go
+++ b/gql_node.go
@@ -113,14 +113,14 @@ func ResolveNodes(ctx *ResolveContext, p graphql.ResolveParams, ids []NodeID) ([
     msgs := Messages{}
     msgs = msgs.Add(ctx.Context, ctx.Server.ID, ctx.Key, read_signal, id)
 
-    response_chan := ctx.Ext.GetResponseChannel(read_signal.ID)
-    resp_channels[read_signal.ID] = response_chan
-    indices[read_signal.ID] = i
+    response_chan := ctx.Ext.GetResponseChannel(read_signal.ID())
+    resp_channels[read_signal.ID()] = response_chan
+    indices[read_signal.ID()] = i
 
     // TODO: Send all at once instead of creating Messages for each
     err = ctx.Context.Send(msgs)
     if err != nil {
-      ctx.Ext.FreeResponseChannel(read_signal.ID)
+      ctx.Ext.FreeResponseChannel(read_signal.ID())
       return nil, err
     }
 
diff --git a/lockable.go b/lockable.go
index caa17ff..0076c8f 100644
--- a/lockable.go
+++ b/lockable.go
@@ -46,7 +46,7 @@ func UnlockLockable(ctx *Context, owner *Node, target NodeID) (uuid.UUID, error)
   msgs := Messages{}
   signal := NewLockSignal("unlock")
   msgs = msgs.Add(ctx, owner.ID, owner.Key, signal, target)
-  return signal.Header().ID, ctx.Send(msgs)
+  return signal.ID(), ctx.Send(msgs)
 }
 
 // Send the signal to lock a node from itself
@@ -54,7 +54,7 @@ func LockLockable(ctx *Context, owner *Node, target NodeID) (uuid.UUID, error) {
   msgs := Messages{}
   signal := NewLockSignal("lock")
   msgs = msgs.Add(ctx, owner.ID, owner.Key, signal, target)
-  return signal.Header().ID, ctx.Send(msgs)
+  return signal.ID(), ctx.Send(msgs)
 }
 
 func (ext *LockableExt) HandleErrorSignal(ctx *Context, node *Node, source NodeID, signal *ErrorSignal) Messages {
@@ -89,27 +89,27 @@ func (ext *LockableExt) HandleLinkSignal(ctx *Context, node *Node, source NodeID
     case "add":
       _, exists := ext.Requirements[signal.NodeID]
       if exists == true {
-        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "already_requirement"), source)
+        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "already_requirement"), source)
       } else {
         if ext.Requirements == nil {
           ext.Requirements = map[NodeID]ReqState{}
         }
         ext.Requirements[signal.NodeID] = Unlocked
-        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "req_added"), source)
+        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "req_added"), source)
       }
     case "remove":
       _, exists := ext.Requirements[signal.NodeID]
       if exists == false {
-        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "can't link: not_requirement"), source)
+        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "can't link: not_requirement"), source)
       } else {
         delete(ext.Requirements, signal.NodeID)
-        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "req_removed"), source)
+        msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "req_removed"), source)
       }
     default:
-      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "unknown_action"), source)
+      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "unknown_action"), source)
     }
   } else {
-    msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_unlocked"), source)
+    msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "not_unlocked"), source)
   }
   return msgs
 }
@@ -123,7 +123,7 @@ func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID
   case "locked":
     state, found := ext.Requirements[source]
     if found == false && source != node.ID {
-      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "got 'locked' from non-requirement"), source)
+      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "got 'locked' from non-requirement"), source)
     } else if state == Locking {
       if ext.State == Locking {
         ext.Requirements[source] = Locked
@@ -151,7 +151,7 @@ func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID
   case "unlocked":
     state, found := ext.Requirements[source]
     if found == false {
-      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_requirement"), source)
+      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "not_requirement"), source)
     } else if state == Unlocking {
       ext.Requirements[source] = Unlocked
       reqs := 0
@@ -188,7 +188,7 @@ func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID
         msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("locked"), new_owner)
       } else {
         ext.State = Locking
-        id := signal.ID
+        id := signal.ID()
         ext.ReqID = &id
         new_owner := source
         ext.PendingOwner = &new_owner
@@ -202,7 +202,7 @@ func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID
         }
       }
     } else {
-      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_unlocked"), source)
+      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "not_unlocked"), source)
     }
   case "unlock":
     if ext.State == Locked {
@@ -214,7 +214,7 @@ func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID
         msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("unlocked"), new_owner)
       } else if source == *ext.Owner {
         ext.State = Unlocking
-        id := signal.ID
+        id := signal.ID()
         ext.ReqID = &id
         ext.PendingOwner = nil
         for id, state := range(ext.Requirements) {
@@ -227,7 +227,7 @@ func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID
         }
       }
     } else {
-      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_locked"), source)
+      msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID(), "not_locked"), source)
     }
   default:
     ctx.Log.Logf("lockable", "LOCK_ERR: unkown state %s", signal.State)
@@ -239,7 +239,7 @@ func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID
 // LockSignal and LinkSignal Direct signals are processed to update the requirement/dependency/lock state
 func (ext *LockableExt) Process(ctx *Context, node *Node, source NodeID, signal Signal) Messages {
   messages := Messages{}
-  switch signal.Header().Direction {
+  switch signal.Direction() {
   case Up:
     if ext.Owner != nil {
       if *ext.Owner != node.ID {
diff --git a/lockable_test.go b/lockable_test.go
index 1a3d520..0f64d12 100644
--- a/lockable_test.go
+++ b/lockable_test.go
@@ -153,9 +153,7 @@ func TestLock(t *testing.T) {
 
   id, err := LockLockable(ctx, l1, l1.ID)
   fatalErr(t, err)
-  _, err = WaitForSignal(l1_listener.Chan, time.Millisecond*10, func(sig *ErrorSignal) bool {
-    return sig.Error == "not_unlocked" && sig.Header().ReqID == id
-  })
+  _, err = WaitForResponse(l1_listener.Chan, time.Millisecond*10, id)
   fatalErr(t, err)
 
   _, err = UnlockLockable(ctx, l0, l5.ID)
diff --git a/node.go b/node.go
index ec5b7d8..fae514d 100644
--- a/node.go
+++ b/node.go
@@ -148,7 +148,7 @@ func (node *Node) QueueSignal(time time.Time, signal Signal) {
 func (node *Node) DequeueSignal(id uuid.UUID) error {
   idx := -1
   for i, q := range(node.SignalQueue) {
-    if q.Signal.Header().ID == id {
+    if q.Signal.ID() == id {
       idx = i
       break
     }
@@ -293,21 +293,21 @@ func nodeLoop(ctx *Context, node *Node) error {
           ctx.Log.Logf("policy", "SIGNAL_POLICY_DENY: %s->%s - %+v(%+s)", princ_id, node.ID, reflect.TypeOf(msg.Signal), msg.Signal)
           ctx.Log.Logf("policy", "SIGNAL_POLICY_SOURCE: %s", msg.Source)
           msgs := Messages{}
-          msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(msg.Signal.Header().ID, "acl denied"), msg.Source)
+          msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(msg.Signal.ID(), "acl denied"), msg.Source)
           ctx.Send(msgs)
           continue
         } else if resp == Pending {
           ctx.Log.Logf("policy", "SIGNAL_POLICY_PENDING: %s->%s - %s - %+v", princ_id, node.ID, msg.Signal.Permission(), pends)
-          timeout_signal := NewACLTimeoutSignal(msg.Signal.Header().ID)
+          timeout_signal := NewACLTimeoutSignal(msg.Signal.ID())
           node.QueueSignal(time.Now().Add(100*time.Millisecond), timeout_signal)
           msgs := Messages{}
           for policy_type, sigs := range(pends) {
             for _, m := range(sigs) {
               msgs = append(msgs, m)
-              node.PendingSignals[m.Signal.Header().ID] = PendingSignal{policy_type, false, msg.Signal.Header().ID}
+              node.PendingSignals[m.Signal.ID()] = PendingSignal{policy_type, false, msg.Signal.ID()}
             }
           }
-          node.PendingACLs[msg.Signal.Header().ID] = PendingACL{len(msgs), timeout_signal.ID, msg.Signal.Permission(), princ_id, msgs, []Signal{}, msg.Signal, msg.Source}
+          node.PendingACLs[msg.Signal.ID()] = PendingACL{len(msgs), timeout_signal.ID(), msg.Signal.Permission(), princ_id, msgs, []Signal{}, msg.Signal, msg.Source}
           ctx.Send(msgs)
           continue
         } else if resp == Allow {
@@ -327,7 +327,7 @@ func nodeLoop(ctx *Context, node *Node) error {
       t := node.NextSignal.Time
       i := -1
       for j, queued := range(node.SignalQueue) {
-        if queued.Signal.Header().ID == node.NextSignal.Signal.Header().ID {
+        if queued.Signal.ID() == node.NextSignal.Signal.ID() {
           i = j
           break
         }
@@ -349,55 +349,58 @@ func nodeLoop(ctx *Context, node *Node) error {
 
     ctx.Log.Logf("node", "NODE_SIGNAL_QUEUE[%s]: %+v", node.ID, node.SignalQueue)
 
-    info, waiting := node.PendingSignals[signal.Header().ReqID]
-    if waiting == true {
-      if info.Found == false {
-        info.Found = true
-        node.PendingSignals[signal.Header().ReqID] = info
-        ctx.Log.Logf("pending", "FOUND_PENDING_SIGNAL: %s - %s", node.ID, signal)
-        req_info, exists := node.PendingACLs[info.ID]
-        if exists == true {
-          req_info.Counter -= 1
-          req_info.Responses = append(req_info.Responses, signal)
-
-          idx := -1
-          for i, p := range(node.Policies) {
-            if p.ID() == info.Policy {
-              idx = i
-              break
-            }
-          }
-          if idx == -1 {
-            ctx.Log.Logf("policy", "PENDING_FOR_NONEXISTENT_POLICY: %s - %s", node.ID, info.Policy)
-            delete(node.PendingACLs, info.ID)
-          } else {
-            allowed := node.Policies[idx].ContinueAllows(ctx, req_info, signal)
-            if allowed == Allow {
-              ctx.Log.Logf("policy", "DELAYED_POLICY_ALLOW: %s - %s", node.ID, req_info.Signal)
-              signal = req_info.Signal
-              source = req_info.Source
-              err := node.DequeueSignal(req_info.TimeoutID)
-              if err != nil {
-                panic("dequeued a passed signal")
-              }
-              delete(node.PendingACLs, info.ID)
-            } else if req_info.Counter == 0 {
-              ctx.Log.Logf("policy", "DELAYED_POLICY_DENY: %s - %s", node.ID, req_info.Signal)
-              // Send the denied response
-              msgs := Messages{}
-              msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(req_info.Signal.Header().ID, "ACL_DENIED"), req_info.Source)
-              err := ctx.Send(msgs)
-              if err != nil {
-                ctx.Log.Logf("signal", "SEND_ERR: %s", err)
-              }
-              err = node.DequeueSignal(req_info.TimeoutID)
-              if err != nil {
-                panic("dequeued a passed signal")
+    response, ok := signal.(ResponseSignal)
+    if ok == true {
+      info, waiting := node.PendingSignals[response.ResponseID()]
+      if waiting == true {
+        if info.Found == false {
+          info.Found = true
+          node.PendingSignals[response.ResponseID()] = info
+          ctx.Log.Logf("pending", "FOUND_PENDING_SIGNAL: %s - %s", node.ID, signal)
+          req_info, exists := node.PendingACLs[info.ID]
+          if exists == true {
+            req_info.Counter -= 1
+            req_info.Responses = append(req_info.Responses, signal)
+
+            idx := -1
+            for i, p := range(node.Policies) {
+              if p.ID() == info.Policy {
+                idx = i
+                break
               }
+            }
+            if idx == -1 {
+              ctx.Log.Logf("policy", "PENDING_FOR_NONEXISTENT_POLICY: %s - %s", node.ID, info.Policy)
               delete(node.PendingACLs, info.ID)
             } else {
-              node.PendingACLs[info.ID] = req_info
-              continue
+              allowed := node.Policies[idx].ContinueAllows(ctx, req_info, signal)
+              if allowed == Allow {
+                ctx.Log.Logf("policy", "DELAYED_POLICY_ALLOW: %s - %s", node.ID, req_info.Signal)
+                signal = req_info.Signal
+                source = req_info.Source
+                err := node.DequeueSignal(req_info.TimeoutID)
+                if err != nil {
+                  panic("dequeued a passed signal")
+                }
+                delete(node.PendingACLs, info.ID)
+              } else if req_info.Counter == 0 {
+                ctx.Log.Logf("policy", "DELAYED_POLICY_DENY: %s - %s", node.ID, req_info.Signal)
+                // Send the denied response
+                msgs := Messages{}
+                msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(req_info.Signal.ID(), "ACL_DENIED"), req_info.Source)
+                err := ctx.Send(msgs)
+                if err != nil {
+                  ctx.Log.Logf("signal", "SEND_ERR: %s", err)
+                }
+                err = node.DequeueSignal(req_info.TimeoutID)
+                if err != nil {
+                  panic("dequeued a passed signal")
+                }
+                delete(node.PendingACLs, info.ID)
+              } else {
+                node.PendingACLs[info.ID] = req_info
+                continue
+              }
             }
           }
         }
@@ -421,7 +424,7 @@ func nodeLoop(ctx *Context, node *Node) error {
     case *ReadSignal:
       result := node.ReadFields(ctx, sig.Extensions)
       msgs := Messages{}
-      msgs = msgs.Add(ctx, node.ID, node.Key, NewReadResultSignal(sig.ID, node.ID, node.Type, result), source)
+      msgs = msgs.Add(ctx, node.ID, node.Key, NewReadResultSignal(sig.ID(), node.ID, node.Type, result), source)
       ctx.Send(msgs)
 
     default:
diff --git a/signal.go b/signal.go
index 98f7b2a..17bf402 100644
--- a/signal.go
+++ b/signal.go
@@ -14,27 +14,64 @@ const (
   Direct
 )
 
+type TimeoutSignal struct {
+  SignalHeader
+}
+
+func NewTimeoutSignal() *TimeoutSignal {
+  return &TimeoutSignal{
+    NewSignalHeader(Direct),
+  }
+}
+
+// Timeouts are internal only, no permission allows sending them
+func (signal TimeoutSignal) Permission() Tree {
+  return nil
+}
+
 type SignalHeader struct {
-  Direction SignalDirection `gv:"direction"`
-  ID uuid.UUID `gv:"id"`
-  ReqID uuid.UUID `gv:"req_id"`
+  Id uuid.UUID `gv:"id"`
+  Dir SignalDirection `gv:"direction"`
 }
 
-func (header SignalHeader) Header() SignalHeader {
-  return header
+func (signal SignalHeader) ID() uuid.UUID {
+  return signal.Id
+}
+
+func (signal SignalHeader) Direction() SignalDirection {
+  return signal.Dir
 }
 
 func (header SignalHeader) String() string {
-   return fmt.Sprintf("SignalHeader(%d, %s->%s)", header.Direction, header.ID, header.ReqID)
+   return fmt.Sprintf("SignalHeader(%d, %s)", header.Dir, header.Id)
+}
+
+type ResponseSignal interface {
+  Signal
+  ResponseID() uuid.UUID
+}
+
+type ResponseHeader struct {
+  SignalHeader
+  ReqID uuid.UUID `gv:"req_id"`
+}
+
+func (header ResponseHeader) ResponseID() uuid.UUID {
+  return header.ReqID
+}
+
+func (header ResponseHeader) String() string {
+   return fmt.Sprintf("ResponseHeader(%d, %s->%s)", header.Dir, header.Id, header.ReqID)
 }
 
 type Signal interface {
   fmt.Stringer
-  Header() SignalHeader
+  ID() uuid.UUID
+  Direction() SignalDirection
   Permission() Tree
 }
 
-func WaitForResponse(listener chan Signal, timeout time.Duration, req_id uuid.UUID) (Signal, error) {
+func WaitForResponse(listener chan Signal, timeout time.Duration, req_id uuid.UUID) (ResponseSignal, error) {
   var timeout_channel <- chan time.Time
   if timeout > 0 {
     timeout_channel = time.After(timeout)
@@ -46,8 +83,13 @@ func WaitForResponse(listener chan Signal, timeout time.Duration, req_id uuid.UU
       if signal == nil {
         return nil, fmt.Errorf("LISTENER_CLOSED")
       }
-      if signal.Header().ReqID == req_id {
-        return signal, nil
+      resp_signal, ok := signal.(ResponseSignal)
+      if ok == false {
+        continue
+      }
+
+      if resp_signal.ResponseID() == req_id {
+        return resp_signal, nil
       }
     case <-timeout_channel:
       return nil, fmt.Errorf("LISTENER_TIMEOUT")
@@ -82,22 +124,17 @@ func WaitForSignal[S Signal](listener chan Signal, timeout time.Duration, check
 }
 
 func NewSignalHeader(direction SignalDirection) SignalHeader {
-  id := uuid.New()
-  header := SignalHeader{
-    ID: id,
-    ReqID: id,
-    Direction: direction,
+  return SignalHeader{
+    uuid.New(),
+    direction,
   }
-  return header
 }
 
-func NewRespHeader(req_id uuid.UUID, direction SignalDirection) SignalHeader {
-  header := SignalHeader{
-    ID: uuid.New(),
-    ReqID: req_id,
-    Direction: direction,
+func NewResponseHeader(req_id uuid.UUID, direction SignalDirection) ResponseHeader {
+  return ResponseHeader{
+    NewSignalHeader(direction),
+    req_id,
   }
-  return header
 }
 
 type CreateSignal struct {
@@ -145,7 +182,7 @@ func NewStopSignal() *StopSignal {
 }
 
 type SuccessSignal struct {
-  SignalHeader
+  ResponseHeader
 }
 func (signal SuccessSignal) Permission() Tree {
   return Tree{
@@ -156,12 +193,12 @@ func (signal SuccessSignal) Permission() Tree {
 }
 func NewSuccessSignal(req_id uuid.UUID) Signal {
   return &SuccessSignal{
-    NewRespHeader(req_id, Direct),
+    NewResponseHeader(req_id, Direct),
   }
 }
 
 type ErrorSignal struct {
-  SignalHeader
+  ResponseHeader
   Error string
 }
 func (signal ErrorSignal) String() string {
@@ -176,13 +213,13 @@ func (signal ErrorSignal) Permission() Tree {
 }
 func NewErrorSignal(req_id uuid.UUID, fmt_string string, args ...interface{}) Signal {
   return &ErrorSignal{
-    NewRespHeader(req_id, Direct),
+    NewResponseHeader(req_id, Direct),
     fmt.Sprintf(fmt_string, args...),
   }
 }
 
 type ACLTimeoutSignal struct {
-  SignalHeader
+  ResponseHeader
 }
 func (signal ACLTimeoutSignal) Permission() Tree {
   return Tree{
@@ -191,7 +228,7 @@ func (signal ACLTimeoutSignal) Permission() Tree {
 }
 func NewACLTimeoutSignal(req_id uuid.UUID) *ACLTimeoutSignal {
   sig := &ACLTimeoutSignal{
-    NewRespHeader(req_id, Direct),
+    NewResponseHeader(req_id, Direct),
   }
   return sig
 }
@@ -292,7 +329,7 @@ func NewReadSignal(exts map[ExtType][]string) *ReadSignal {
 }
 
 type ReadResultSignal struct {
-  SignalHeader
+  ResponseHeader
   NodeID NodeID
   NodeType NodeType
   Extensions map[ExtType]map[string]SerializedValue
@@ -306,7 +343,7 @@ func (signal ReadResultSignal) Permission() Tree {
 }
 func NewReadResultSignal(req_id uuid.UUID, node_id NodeID, node_type NodeType, exts map[ExtType]map[string]SerializedValue) *ReadResultSignal {
   return &ReadResultSignal{
-    NewRespHeader(req_id, Direct),
+    NewResponseHeader(req_id, Direct),
     node_id,
     node_type,
     exts,