diff --git a/z/errors.go b/z/errors.go
index 3f8a05c..986c29b 100644
--- a/z/errors.go
+++ b/z/errors.go
@@ -12,6 +12,8 @@ func (e NotEnoughArgs) Error() string {
 		"error: %v is not enough args, %v required", e.Count, e.Min)
 }
 
+// -------------------------------- -- --------------------------------
+
 type TooManyArgs struct {
 	Count int
 	Max   int
@@ -22,6 +24,8 @@ func (e TooManyArgs) Error() string {
 		"error: %v is too many args, %v maximum", e.Count, e.Max)
 }
 
+// -------------------------------- -- --------------------------------
+
 type WrongNumArgs struct {
 	Count int
 	Num   int
@@ -32,6 +36,8 @@ func (e WrongNumArgs) Error() string {
 		"error: %v is wrong number of args, %v required", e.Count, e.Num)
 }
 
+// -------------------------------- -- --------------------------------
+
 type MissingConf struct {
 	Path string
 }
@@ -40,6 +46,18 @@ func (e MissingConf) Error() string {
 	return fmt.Sprintf("missing conf value for %v", e.Path)
 }
 
+// -------------------------------- -- --------------------------------
+
+type MissingVar struct {
+	Path string
+}
+
+func (e MissingVar) Error() string {
+	return fmt.Sprintf("missing var for %v", e.Path)
+}
+
+// -------------------------------- -- --------------------------------
+
 type UsesConf struct {
 	Cmd *Cmd
 }
@@ -48,6 +66,8 @@ func (e UsesConf) Error() string {
 	return fmt.Sprintf("%v requires Z.Conf", e.Cmd.Name)
 }
 
+// -------------------------------- -- --------------------------------
+
 type UsesVars struct {
 	Cmd *Cmd
 }
@@ -56,6 +76,8 @@ func (e UsesVars) Error() string {
 	return fmt.Sprintf("%v requires Z.Vars", e.Cmd.Name)
 }
 
+// -------------------------------- -- --------------------------------
+
 type NoCallNoCommands struct {
 	Cmd *Cmd
 }
@@ -64,6 +86,8 @@ func (e NoCallNoCommands) Error() string {
 	return fmt.Sprintf("%v requires either Call or Commands", e.Cmd.Name)
 }
 
+// -------------------------------- -- --------------------------------
+
 type DefCmdReqCall struct {
 	Cmd *Cmd
 }
@@ -72,6 +96,8 @@ func (e DefCmdReqCall) Error() string {
 	return fmt.Sprintf("default (first) %q Commands requires Call", e.Cmd.Name)
 }
 
+// -------------------------------- -- --------------------------------
+
 type IncorrectUsage struct {
 	Cmd *Cmd
 }
@@ -80,6 +106,8 @@ func (e IncorrectUsage) Error() string {
 	return fmt.Sprintf("usage: %v %v", e.Cmd.Name, e.Cmd.GetUsage())
 }
 
+// -------------------------------- -- --------------------------------
+
 type MultiCallCmdNotFound struct {
 	CmdName string
 }
@@ -88,6 +116,8 @@ func (e MultiCallCmdNotFound) Error() string {
 	return fmt.Sprintf("multicall command not found: %v", e.CmdName)
 }
 
+// -------------------------------- -- --------------------------------
+
 type MultiCallCmdNotCmd struct {
 	CmdName string
 	It      any
@@ -98,6 +128,8 @@ func (e MultiCallCmdNotCmd) Error() string {
 		"multicall match for %v, but first in slice not *Z.Cmd: %T", e.CmdName, e.It)
 }
 
+// -------------------------------- -- --------------------------------
+
 type MultiCallCmdArgNotString struct {
 	CmdName string
 	It      any