diff --git a/go/dev/interactive.go b/go/dev/interactive.go
index acee162..8af1f08 100644
--- a/go/dev/interactive.go
+++ b/go/dev/interactive.go
@@ -12,13 +12,15 @@ import (
 func main() {
 	var dir string
 	var root string
+	var size uint
 	flag.StringVar(&dir, "d", ".", "resource dir to read from")
+	flag.UintVar(&size, "s", 0, "max size of output")
 	flag.StringVar(&root, "root", "root", "entry point symbol")
 	flag.Parse()
 	fmt.Fprintf(os.Stderr, "starting session at symbol '%s' using resource dir: %s\n", root, dir)
 
 	ctx := context.Background()
-	en := engine.NewDefaultEngine(dir)
+	en := engine.NewSizedEngine(dir, uint32(size))
 	err := engine.Loop(&en, root, ctx, os.Stdin, os.Stdout)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "loop exited with error: %v", err)
diff --git a/go/engine/default.go b/go/engine/default.go
index 94af301..f79dff2 100644
--- a/go/engine/default.go
+++ b/go/engine/default.go
@@ -10,5 +10,15 @@ func NewDefaultEngine(dir string) Engine {
 	st := state.NewState(0)
 	rs := resource.NewFsResource(dir)
 	ca := cache.NewCache()
-	return NewEngine(&st, &rs, ca)
+	return NewEngine(Config{}, &st, &rs, ca)
+}
+
+func NewSizedEngine(dir string, size uint32) Engine {
+	st := state.NewState(0)
+	rs := resource.NewFsResource(dir)
+	ca := cache.NewCache()
+	cfg := Config{
+		OutputSize: size,
+	}
+	return NewEngine(cfg, &st, &rs, ca)
 }
diff --git a/go/engine/engine.go b/go/engine/engine.go
index bb71cb8..8f712c1 100644
--- a/go/engine/engine.go
+++ b/go/engine/engine.go
@@ -7,15 +7,17 @@ import (
 	"log"
 
 	"git.defalsify.org/festive/cache"
+	"git.defalsify.org/festive/render"
 	"git.defalsify.org/festive/resource"
 	"git.defalsify.org/festive/state"
 	"git.defalsify.org/festive/vm"
 )
 
-//type Config struct {
+type Config struct {
+	OutputSize uint32
 //	FlagCount uint32
 //	CacheSize uint32
-//}
+}
 
 // Engine is an execution engine that handles top-level errors when running user inputs against currently exposed bytecode.
 type Engine struct {
@@ -26,12 +28,16 @@ type Engine struct {
 }
 
 // NewEngine creates a new Engine
-func NewEngine(st *state.State, rs resource.Resource, ca cache.Memory) Engine {
+func NewEngine(cfg Config, st *state.State, rs resource.Resource, ca cache.Memory) Engine {
+	var szr *render.Sizer
+	if cfg.OutputSize > 0 {
+		szr = render.NewSizer(cfg.OutputSize)
+	}
 	engine := Engine{
 		st: st,
 		rs: rs,
 		ca: ca,
-		vm: vm.NewVm(st, rs, ca, nil),
+		vm: vm.NewVm(st, rs, ca, szr),
 	}
 	return engine
 }
diff --git a/go/engine/engine_test.go b/go/engine/engine_test.go
index d518f85..90e3c25 100644
--- a/go/engine/engine_test.go
+++ b/go/engine/engine_test.go
@@ -75,7 +75,7 @@ func TestEngineInit(t *testing.T) {
 	rs := NewFsWrapper(dataDir, &st)
 	ca := cache.NewCache().WithCacheSize(1024)
 	
-	en := NewEngine(&st, &rs, ca)
+	en := NewEngine(Config{}, &st, &rs, ca)
 	err := en.Init("root", ctx)
 	if err != nil {
 		t.Fatal(err)
@@ -114,7 +114,9 @@ func TestEngineInit(t *testing.T) {
 
 it has more lines
 0:to foo
-1:go bar`
+1:go bar
+2:see long`
+
 	if !bytes.Equal(b, []byte(expect)) {
 		t.Fatalf("expected\n\t%s\ngot:\n\t%s\n", expect, b)
 	}
@@ -127,7 +129,7 @@ func TestEngineExecInvalidInput(t *testing.T) {
 	rs := NewFsWrapper(dataDir, &st)
 	ca := cache.NewCache().WithCacheSize(1024)
 
-	en := NewEngine(&st, &rs, ca)
+	en := NewEngine(Config{}, &st, &rs, ca)
 	err := en.Init("root", ctx)
 	if err != nil {
 		t.Fatal(err)
diff --git a/go/engine/loop_test.go b/go/engine/loop_test.go
index 4179956..d105012 100644
--- a/go/engine/loop_test.go
+++ b/go/engine/loop_test.go
@@ -20,7 +20,7 @@ func TestLoopCorrect(t *testing.T) {
 	rs := resource.NewFsResource(dataDir)
 	ca := cache.NewCache().WithCacheSize(1024)
 	
-	en := NewEngine(&st, &rs, ca)
+	en := NewEngine(Config{}, &st, &rs, ca)
 	err := en.Init("root", ctx)
 	if err != nil {
 		t.Fatal(err)
diff --git a/go/render/size.go b/go/render/size.go
index f9f4062..fcbe1c5 100644
--- a/go/render/size.go
+++ b/go/render/size.go
@@ -38,7 +38,6 @@ func(szr *Sizer) Set(key string, size uint16) error {
 }
 
 func(szr *Sizer) Check(s string) (uint32, bool) {
-	log.Printf("sizercheck %s", s)
 	l := uint32(len(s))
 	if szr.outputSize > 0 {
 		if l > szr.outputSize {
@@ -84,7 +83,6 @@ func(szr *Sizer) GetAt(values map[string]string, idx uint16) (map[string]string,
 			c := szr.crsrs[idx]
 			v = v[c:]
 			nl := strings.Index(v, "\n")
-			log.Printf("k %v v %v c %v nl %v", k, v, c, nl)
 			if nl > 0 {
 				v = v[:nl]
 			}
diff --git a/go/testdata/testdata.go b/go/testdata/testdata.go
index c57af68..240b9c7 100644
--- a/go/testdata/testdata.go
+++ b/go/testdata/testdata.go
@@ -66,10 +66,12 @@ func foo() error {
 	b := []byte{}
 	b = vm.NewLine(b, vm.MOUT, []string{"0", "to foo"}, nil, nil)
 	b = vm.NewLine(b, vm.MOUT, []string{"1", "go bar"}, nil, nil)
+	b = vm.NewLine(b, vm.MOUT, []string{"2", "see long"}, nil, nil)
 	b = vm.NewLine(b, vm.LOAD, []string{"inky"}, []byte{20}, nil)
 	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
 	b = vm.NewLine(b, vm.INCMP, []string{"0", "_"}, nil, nil)
 	b = vm.NewLine(b, vm.INCMP, []string{"1", "baz"}, nil, nil)
+	b = vm.NewLine(b, vm.INCMP, []string{"2", "long"}, nil, nil)
 	//b = vm.NewLine(b, vm.CATCH, []string{"_catch"}, []byte{1}, []uint8{1})
 
 	data := make(map[string]string)
@@ -106,6 +108,33 @@ func baz() error {
 	return out("baz", b, tpl, nil)
 }
 
+func long() error {
+	b := []byte{}
+	b = vm.NewLine(b, vm.LOAD, []string{"longdata"}, []byte{0x00}, nil)
+	b = vm.NewLine(b, vm.MAP, []string{"longdata"}, nil, nil)
+	b = vm.NewLine(b, vm.MOUT, []string{"0", "back"}, nil, nil)
+	b = vm.NewLine(b, vm.MNEXT, []string{"00", "nexxt"}, nil, nil)
+	b = vm.NewLine(b, vm.MPREV, []string{"11", "prevv"}, nil, nil)
+	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
+	b = vm.NewLine(b, vm.INCMP, []string{"0", "_"}, nil, nil)
+
+	tpl := `data
+{{.longdata}}`
+
+	data := make(map[string]string)
+	data["longdata"] = `INKY 12
+PINKY 5555
+BLINKY 3t7
+CLYDE 11
+TINKYWINKY 22
+DIPSY 666
+LALA 111
+POO 222
+`
+
+	return out("long", b, tpl, data)
+}
+
 func defaultCatch() error {
 	b := []byte{}
 	b = vm.NewLine(b, vm.MOUT, []string{"0", "back"}, nil, nil)
@@ -123,7 +152,7 @@ func generate() error {
 		return err
 	}
 
-	fns := []genFunc{root, foo, bar, baz, defaultCatch}
+	fns := []genFunc{root, foo, bar, baz, long, defaultCatch}
 	for _, fn := range fns {
 		err = fn()
 		if err != nil {
diff --git a/go/vm/runner.go b/go/vm/runner.go
index 6ead8c3..7265461 100644
--- a/go/vm/runner.go
+++ b/go/vm/runner.go
@@ -209,7 +209,6 @@ func(vm *Vm) RunLoad(b []byte, ctx context.Context) ([]byte, error) {
 	if err != nil {
 		return b, err
 	}
-
 	r, err := refresh(sym, vm.rs, ctx)
 	if err != nil {
 		return b, err