diff --git a/src/app/script/cels_class.cpp b/src/app/script/cels_class.cpp
index ad867a1cf..023988455 100644
--- a/src/app/script/cels_class.cpp
+++ b/src/app/script/cels_class.cpp
@@ -10,9 +10,11 @@
 
 #include "app/script/luacpp.h"
 #include "doc/cels_range.h"
+#include "doc/layer.h"
 #include "doc/sprite.h"
 
 #include <algorithm>
+#include <iterator>
 
 namespace app {
 namespace script {
@@ -22,8 +24,11 @@ using namespace doc;
 namespace {
 
 struct CelsObj {
-  Sprite* sprite;
-  CelsObj(Sprite* sprite) : sprite(sprite) { }
+  CelList cels;
+  CelsObj(CelsRange&& range) {
+    std::copy(range.begin(), range.end(), std::back_inserter(cels));
+  }
+  CelsObj(CelList&& cels) : cels(std::move(cels)) { }
   CelsObj(const CelsObj&) = delete;
   CelsObj& operator=(const CelsObj&) = delete;
 };
@@ -37,7 +42,7 @@ int Cels_gc(lua_State* L)
 int Cels_len(lua_State* L)
 {
   auto obj = get_obj<CelsObj>(L, 1);
-  lua_pushinteger(L, obj->sprite->cels().size());
+  lua_pushinteger(L, obj->cels.size());
   return 1;
 }
 
@@ -45,13 +50,9 @@ int Cels_index(lua_State* L)
 {
   auto obj = get_obj<CelsObj>(L, 1);
   const int i = lua_tointeger(L, 2);
-  if (i < 1 || i > obj->sprite->cels().size())
+  if (i < 1 || i > obj->cels.size())
     return luaL_error(L, "index out of bounds %d", i);
-
-  auto it = obj->sprite->cels().begin();
-  std::advance(it, i-1);          // TODO improve this
-
-  push_ptr<Cel>(L, *it);
+  push_ptr<Cel>(L, obj->cels[i-1]);
   return 1;
 }
 
@@ -74,7 +75,15 @@ void register_cels_class(lua_State* L)
 
 void push_sprite_cels(lua_State* L, Sprite* sprite)
 {
-  push_new<CelsObj>(L, sprite);
+  push_new<CelsObj>(L, sprite->cels());
+}
+
+void push_layer_cels(lua_State* L, Layer* layer)
+{
+  CelList cels;
+  if (layer->isImage())
+    static_cast<LayerImage*>(layer)->getCels(cels);
+  push_new<CelsObj>(L, std::move(cels));
 }
 
 } // namespace script
diff --git a/src/app/script/engine.cpp b/src/app/script/engine.cpp
index f4c0500f2..0bacdb45e 100644
--- a/src/app/script/engine.cpp
+++ b/src/app/script/engine.cpp
@@ -16,6 +16,8 @@
 #include "base/chrono.h"
 #include "base/fs.h"
 #include "base/fstream_path.h"
+#include "doc/anidir.h"
+#include "doc/blend_mode.h"
 #include "doc/color_mode.h"
 
 #include <fstream>
@@ -154,6 +156,14 @@ Engine::Engine()
   setfield_integer(L, "INDEXED", doc::ColorMode::INDEXED);
   lua_pop(L, 1);
 
+  lua_newtable(L);
+  lua_pushvalue(L, -1);
+  lua_setglobal(L, "AniDir");
+  setfield_integer(L, "FORWARD", doc::AniDir::FORWARD);
+  setfield_integer(L, "REVERSE", doc::AniDir::REVERSE);
+  setfield_integer(L, "PING_PONG", doc::AniDir::PING_PONG);
+  lua_pop(L, 1);
+
   lua_newtable(L);
   lua_pushvalue(L, -1);
   lua_setglobal(L, "BlendMode");
diff --git a/src/app/script/engine.h b/src/app/script/engine.h
index 2ec290793..679878920 100644
--- a/src/app/script/engine.h
+++ b/src/app/script/engine.h
@@ -85,6 +85,7 @@ namespace app {
   void push_cel_image(lua_State* L, doc::Cel* cel);
   void push_sprite_cel(lua_State* L, doc::Cel* cel);
   void push_sprite_cels(lua_State* L, doc::Sprite* sprite);
+  void push_layer_cels(lua_State* L, doc::Layer* layer);
   void push_sprite_frame(lua_State* L, doc::Sprite* sprite, doc::frame_t frame);
   void push_sprite_frames(lua_State* L, doc::Sprite* sprite);
   void push_sprite_layers(lua_State* L, doc::Sprite* sprite);
@@ -101,6 +102,7 @@ namespace app {
   app::Color convert_args_into_color(lua_State* L, int index);
   doc::color_t convert_args_into_pixel_color(lua_State* L, int index);
   doc::Palette* get_palette_from_arg(lua_State* L, int index);
+  doc::Image* may_get_image_from_arg(lua_State* L, int index);
 
 } // namespace script
 } // namespace app
diff --git a/src/app/script/image_class.cpp b/src/app/script/image_class.cpp
index c4155c8c8..f108aee7c 100644
--- a/src/app/script/image_class.cpp
+++ b/src/app/script/image_class.cpp
@@ -172,5 +172,14 @@ void push_cel_image(lua_State* L, doc::Cel* cel)
   push_new<ImageObj>(L, cel->imageRef(), cel);
 }
 
+doc::Image* may_get_image_from_arg(lua_State* L, int index)
+{
+  auto obj = may_get_obj<ImageObj>(L, index);
+  if (obj)
+    return obj->image.get();
+  else
+    return nullptr;
+}
+
 } // namespace script
 } // namespace app
diff --git a/src/app/script/layer_class.cpp b/src/app/script/layer_class.cpp
index d0b0d03bf..591ca929e 100644
--- a/src/app/script/layer_class.cpp
+++ b/src/app/script/layer_class.cpp
@@ -97,6 +97,13 @@ int Layer_get_isBackground(lua_State* L)
   return 1;
 }
 
+int Layer_get_cels(lua_State* L)
+{
+  auto layer = get_ptr<Layer>(L, 1);
+  push_layer_cels(L, layer);
+  return 1;
+}
+
 int Layer_set_name(lua_State* L)
 {
   auto layer = get_ptr<Layer>(L, 1);
@@ -148,6 +155,7 @@ const Property Layer_properties[] = {
   { "isGroup", Layer_get_isGroup, nullptr },
   { "isTransparent", Layer_get_isTransparent, nullptr },
   { "isBackground", Layer_get_isBackground, nullptr },
+  { "cels", Layer_get_cels, nullptr },
   { "color", UserData_get_color<Layer>, UserData_set_color<Layer> },
   { "data", UserData_get_text<Layer>, UserData_set_text<Layer> },
   { nullptr, nullptr, nullptr }
diff --git a/src/app/script/luacpp.h b/src/app/script/luacpp.h
index f5dff0bf9..47ca45cff 100644
--- a/src/app/script/luacpp.h
+++ b/src/app/script/luacpp.h
@@ -58,6 +58,15 @@ template <typename T> T* get_obj(lua_State* L, int index) {
   return (T*)luaL_checkudata(L, index, get_mtname<T>());
 }
 
+// Returns nil if the index doesn't have the given metatable
+template <typename T> T* may_get_ptr(lua_State* L, int index) {
+  T** ptr = (T**)luaL_testudata(L, index, get_mtname<T>());
+  if (ptr)
+    return *ptr;
+  else
+    return nullptr;
+}
+
 // Returns nil if the index doesn't have the given metatable
 template <typename T> T* may_get_obj(lua_State* L, int index) {
   return (T*)luaL_testudata(L, index, get_mtname<T>());
diff --git a/src/app/script/slice_class.cpp b/src/app/script/slice_class.cpp
index 7a317e706..831fc0193 100644
--- a/src/app/script/slice_class.cpp
+++ b/src/app/script/slice_class.cpp
@@ -8,6 +8,8 @@
 #include "config.h"
 #endif
 
+#include "app/cmd/set_slice_key.h"
+#include "app/cmd/set_slice_name.h"
 #include "app/script/engine.h"
 #include "app/script/luacpp.h"
 #include "app/script/userdata.h"
@@ -37,20 +39,6 @@ int Slice_get_sprite(lua_State* L)
   return 1;
 }
 
-int Slice_get_fromFrame(lua_State* L)
-{
-  auto slice = get_ptr<Slice>(L, 1);
-  lua_pushinteger(L, slice->fromFrame());
-  return 1;
-}
-
-int Slice_get_toFrame(lua_State* L)
-{
-  auto slice = get_ptr<Slice>(L, 1);
-  lua_pushinteger(L, slice->toFrame());
-  return 1;
-}
-
 int Slice_get_name(lua_State* L)
 {
   auto slice = get_ptr<Slice>(L, 1);
@@ -88,6 +76,60 @@ int Slice_get_pivot(lua_State* L)
   return 1;
 }
 
+int Slice_set_name(lua_State* L)
+{
+  auto slice = get_ptr<Slice>(L, 1);
+  const char* name = lua_tostring(L, 2);
+  if (name) {
+    Tx tx;
+    tx(new cmd::SetSliceName(slice, name));
+    tx.commit();
+  }
+  return 0;
+}
+
+int Slice_set_bounds(lua_State* L)
+{
+  auto slice = get_ptr<Slice>(L, 1);
+  gfx::Rect bounds = convert_args_into_rect(L, 2);
+  SliceKey key;
+  if (const SliceKey* srcKey = slice->getByFrame(0))
+    key = *srcKey;
+  key.setBounds(bounds);
+  Tx tx;
+  tx(new cmd::SetSliceKey(slice, 0, key));
+  tx.commit();
+  return 0;
+}
+
+int Slice_set_center(lua_State* L)
+{
+  auto slice = get_ptr<Slice>(L, 1);
+  gfx::Rect center = convert_args_into_rect(L, 2);
+  SliceKey key;
+  if (const SliceKey* srcKey = slice->getByFrame(0))
+    key = *srcKey;
+  key.setCenter(center);
+  Tx tx;
+  tx(new cmd::SetSliceKey(slice, 0, key));
+  tx.commit();
+  return 0;
+}
+
+int Slice_set_pivot(lua_State* L)
+{
+  auto slice = get_ptr<Slice>(L, 1);
+  gfx::Point pivot = convert_args_into_point(L, 2);
+  SliceKey key;
+  if (const SliceKey* srcKey = slice->getByFrame(0))
+    key = *srcKey;
+  key.setPivot(pivot);
+  Tx tx;
+  tx(new cmd::SetSliceKey(slice, 0, key));
+  tx.commit();
+  return 0;
+}
+
 const luaL_Reg Slice_methods[] = {
   { "__eq", Slice_eq },
   { nullptr, nullptr }
@@ -95,12 +137,10 @@ const luaL_Reg Slice_methods[] = {
 
 const Property Slice_properties[] = {
   { "sprite", Slice_get_sprite, nullptr },
-  { "fromFrame", Slice_get_fromFrame, nullptr },
-  { "toFrame", Slice_get_toFrame, nullptr },
-  { "name", Slice_get_name, nullptr },
-  { "bounds", Slice_get_bounds, nullptr },
-  { "center", Slice_get_center, nullptr },
-  { "pivot", Slice_get_pivot, nullptr },
+  { "name", Slice_get_name, Slice_set_name },
+  { "bounds", Slice_get_bounds, Slice_set_bounds },
+  { "center", Slice_get_center, Slice_set_center },
+  { "pivot", Slice_get_pivot, Slice_set_pivot },
   { "color", UserData_get_color<Slice>, UserData_set_color<Slice> },
   { "data", UserData_get_text<Slice>, UserData_set_text<Slice> },
   { nullptr, nullptr, nullptr }
diff --git a/src/app/script/sprite_class.cpp b/src/app/script/sprite_class.cpp
index a62b803ff..cf5450ddc 100644
--- a/src/app/script/sprite_class.cpp
+++ b/src/app/script/sprite_class.cpp
@@ -9,6 +9,11 @@
 #endif
 
 #include "app/app.h"
+#include "app/cmd/add_layer.h"
+#include "app/cmd/clear_cel.h"
+#include "app/cmd/remove_frame_tag.h"
+#include "app/cmd/remove_layer.h"
+#include "app/cmd/remove_slice.h"
 #include "app/cmd/set_sprite_size.h"
 #include "app/cmd/set_transparent_color.h"
 #include "app/commands/commands.h"
@@ -23,9 +28,11 @@
 #include "app/transaction.h"
 #include "app/tx.h"
 #include "app/ui/doc_view.h"
+#include "doc/frame_tag.h"
 #include "doc/layer.h"
 #include "doc/mask.h"
 #include "doc/palette.h"
+#include "doc/slice.h"
 #include "doc/sprite.h"
 
 namespace app {
@@ -178,6 +185,243 @@ int Sprite_setPalette(lua_State* L)
   return 0;
 }
 
+int Sprite_newLayer(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  doc::Layer* newLayer = new doc::LayerImage(sprite);
+
+  Tx tx;
+  tx(new cmd::AddLayer(sprite->root(), newLayer, sprite->root()->lastLayer()));
+  tx.commit();
+
+  push_ptr(L, newLayer);
+  return 1;
+}
+
+int Sprite_newGroup(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  doc::Layer* newGroup = new doc::LayerGroup(sprite);
+
+  Tx tx;
+  tx(new cmd::AddLayer(sprite->root(), newGroup, sprite->root()->lastLayer()));
+  tx.commit();
+
+  push_ptr(L, newGroup);
+  return 1;
+}
+
+int Sprite_deleteLayer(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  auto layer = may_get_ptr<Layer>(L, 2);
+  if (!layer && lua_isstring(L, 2)) {
+    const char* layerName = lua_tostring(L, 2);
+    if (layerName) {
+      for (Layer* child : sprite->allLayers()) {
+        if (child->name() == layerName) {
+          layer = child;
+          break;
+        }
+      }
+    }
+  }
+  if (layer) {
+    Tx tx;
+    tx(new cmd::RemoveLayer(layer));
+    tx.commit();
+    return 0;
+  }
+  else {
+    return luaL_error(L, "layer not found");
+  }
+}
+
+int Sprite_newFrame(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  doc::frame_t frame = sprite->lastFrame()+1;
+  if (lua_gettop(L) >= 2) {
+    frame = lua_tointeger(L, 2)-1;
+    if (frame < 0)
+      return luaL_error(L, "frame index out of bounds %d", frame+1);
+  }
+
+  Doc* doc = static_cast<Doc*>(sprite->document());
+
+  Tx tx;
+  doc->getApi(tx).addFrame(sprite, frame);
+  tx.commit();
+
+  push_sprite_frame(L, sprite, frame);
+  return 1;
+}
+
+int Sprite_newEmptyFrame(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  doc::frame_t frame = sprite->lastFrame()+1;
+  if (lua_gettop(L) >= 1) {
+    frame = lua_tointeger(L, 2)-1;
+    if (frame < 0)
+      return luaL_error(L, "frame index out of bounds %d", frame+1);
+  }
+
+  Doc* doc = static_cast<Doc*>(sprite->document());
+
+  Tx tx;
+  DocApi(doc, tx).addEmptyFrame(sprite, frame);
+  tx.commit();
+
+  push_sprite_frame(L, sprite, frame);
+  return 1;
+}
+
+int Sprite_deleteFrame(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  doc::frame_t frame = lua_tointeger(L, 2)-1;
+  if (frame < 0 || frame > sprite->lastFrame())
+    return luaL_error(L, "frame index out of bounds %d", frame+1);
+
+  Doc* doc = static_cast<Doc*>(sprite->document());
+
+  Tx tx;
+  doc->getApi(tx).removeFrame(sprite, frame);
+  tx.commit();
+  return 0;
+}
+
+int Sprite_newCel(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  auto layerBase = get_ptr<Layer>(L, 2);
+  if (!layerBase->isImage())
+    return luaL_error(L, "unexpected kinf of layer in Sprite:newCel()");
+
+  frame_t frame = lua_tointeger(L, 3)-1;
+  if (frame < 0 || frame > sprite->lastFrame())
+    return luaL_error(L, "frame index out of bounds %d", frame+1);
+
+  LayerImage* layer = static_cast<LayerImage*>(layerBase);
+  ImageRef image(nullptr);
+  gfx::Point pos(0, 0);
+
+  Image* srcImage = may_get_image_from_arg(L, 4);
+  if (srcImage) {
+    image.reset(Image::createCopy(srcImage));
+    pos = convert_args_into_point(L, 5);
+  }
+  else {
+    image.reset(Image::create(sprite->spec()));
+  }
+
+  auto cel = new Cel(frame, image);
+  cel->setPosition(pos);
+
+  Doc* doc = static_cast<Doc*>(sprite->document());
+
+  Tx tx;
+  DocApi api = doc->getApi(tx);
+  if (layer->cel(frame))
+    api.clearCel(layer, frame);
+  api.addCel(layer, cel);
+  tx.commit();
+
+  push_ptr(L, cel);
+  return 1;
+}
+
+int Sprite_deleteCel(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  (void)sprite;                 // unused
+
+  auto cel = may_get_ptr<doc::Cel>(L, 2);
+  if (!cel) {
+    if (auto layer = may_get_ptr<doc::Layer>(L, 2)) {
+      doc::frame_t frame = lua_tointeger(L, 3);
+      if (layer->isImage())
+        cel = static_cast<doc::LayerImage*>(layer)->cel(frame);
+    }
+  }
+
+  if (cel) {
+    Tx tx;
+    tx(new cmd::ClearCel(cel));
+    tx.commit();
+    return 0;
+  }
+  else {
+    return luaL_error(L, "cel not found");
+  }
+}
+
+int Sprite_newTag(lua_State* L)
+{
+  auto sprite = get_ptr<doc::Sprite>(L, 1);
+  auto from = lua_tointeger(L, 2)-1;
+  auto to = lua_tointeger(L, 3)-1;
+  auto tag = new doc::FrameTag(from, to);
+  sprite->frameTags().add(tag);
+  push_ptr(L, tag);
+  return 1;
+}
+
+int Sprite_deleteTag(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  auto tag = may_get_ptr<FrameTag>(L, 2);
+  if (!tag && lua_isstring(L, 2)) {
+    const char* tagName = lua_tostring(L, 2);
+    if (tagName)
+      tag = sprite->frameTags().getByName(tagName);
+  }
+  if (tag) {
+    Tx tx;
+    tx(new cmd::RemoveFrameTag(sprite, tag));
+    tx.commit();
+    return 0;
+  }
+  else {
+    return luaL_error(L, "tag not found");
+  }
+}
+
+int Sprite_newSlice(lua_State* L)
+{
+  auto sprite = get_ptr<doc::Sprite>(L, 1);
+  auto slice = new doc::Slice();
+
+  gfx::Rect bounds = convert_args_into_rect(L, 2);
+  if (!bounds.isEmpty())
+    slice->insert(0, doc::SliceKey(bounds));
+
+  sprite->slices().add(slice);
+  push_ptr(L, slice);
+  return 1;
+}
+
+int Sprite_deleteSlice(lua_State* L)
+{
+  auto sprite = get_ptr<Sprite>(L, 1);
+  doc::Slice* slice = may_get_ptr<Slice>(L, 2);
+  if (!slice && lua_isstring(L, 2)) {
+    const char* sliceName = lua_tostring(L, 2);
+    if (sliceName)
+      slice = sprite->slices().getByName(sliceName);
+  }
+  if (slice) {
+    Tx tx;
+    tx(new cmd::RemoveSlice(sprite, slice));
+    tx.commit();
+    return 0;
+  }
+  else {
+    return luaL_error(L, "slice not found");
+  }
+}
+
 int Sprite_get_filename(lua_State* L)
 {
   auto sprite = get_ptr<Sprite>(L, 1);
@@ -312,6 +556,23 @@ const luaL_Reg Sprite_methods[] = {
   { "saveCopyAs", Sprite_saveCopyAs },
   { "loadPalette", Sprite_loadPalette },
   { "setPalette", Sprite_setPalette },
+  // Layers
+  { "newLayer", Sprite_newLayer },
+  { "newGroup", Sprite_newGroup },
+  { "deleteLayer", Sprite_deleteLayer },
+  // Frames
+  { "newFrame", Sprite_newFrame },
+  { "newEmptyFrame", Sprite_newEmptyFrame },
+  { "deleteFrame", Sprite_deleteFrame },
+  // Cel
+  { "newCel", Sprite_newCel },
+  { "deleteCel", Sprite_deleteCel },
+  // Tag
+  { "newTag", Sprite_newTag },
+  { "deleteTag", Sprite_deleteTag },
+  // Slices
+  { "newSlice", Sprite_newSlice },
+  { "deleteSlice", Sprite_deleteSlice },
   { nullptr, nullptr }
 };
 
diff --git a/src/app/script/tag_class.cpp b/src/app/script/tag_class.cpp
index 94fd074d5..83e51e1f2 100644
--- a/src/app/script/tag_class.cpp
+++ b/src/app/script/tag_class.cpp
@@ -31,17 +31,24 @@ int Tag_eq(lua_State* L)
   return 1;
 }
 
+int Tag_get_sprite(lua_State* L)
+{
+  auto tag = get_ptr<FrameTag>(L, 1);
+  push_ptr(L, tag->owner()->sprite());
+  return 1;
+}
+
 int Tag_get_fromFrame(lua_State* L)
 {
   auto tag = get_ptr<FrameTag>(L, 1);
-  lua_pushinteger(L, tag->fromFrame());
+  lua_pushinteger(L, tag->fromFrame()+1);
   return 1;
 }
 
 int Tag_get_toFrame(lua_State* L)
 {
   auto tag = get_ptr<FrameTag>(L, 1);
-  lua_pushinteger(L, tag->toFrame());
+  lua_pushinteger(L, tag->toFrame()+1);
   return 1;
 }
 
@@ -69,7 +76,7 @@ int Tag_get_aniDir(lua_State* L)
 int Tag_set_fromFrame(lua_State* L)
 {
   auto tag = get_ptr<FrameTag>(L, 1);
-  const int fromFrame = lua_tointeger(L, 2);
+  const int fromFrame = lua_tointeger(L, 2)-1;
   Tx tx;
   tx(new cmd::SetFrameTagRange(tag, fromFrame,
                                std::max(fromFrame, tag->toFrame())));
@@ -80,7 +87,7 @@ int Tag_set_fromFrame(lua_State* L)
 int Tag_set_toFrame(lua_State* L)
 {
   auto tag = get_ptr<FrameTag>(L, 1);
-  const int toFrame = lua_tointeger(L, 2);
+  const int toFrame = lua_tointeger(L, 2)-1;
   Tx tx;
   tx(new cmd::SetFrameTagRange(tag,
                                std::min(tag->fromFrame(), toFrame),
@@ -117,6 +124,7 @@ const luaL_Reg Tag_methods[] = {
 };
 
 const Property Tag_properties[] = {
+  { "sprite", Tag_get_sprite, nullptr },
   { "fromFrame", Tag_get_fromFrame, Tag_set_fromFrame },
   { "toFrame", Tag_get_toFrame, Tag_set_toFrame },
   { "frames", Tag_get_frames, nullptr },