feat(server): add layer-separation generator task

Introduce the `layer-separation` generator (edit-elements node action)
that splits a source image into a clean background layer, foreground
image artifacts with bounding boxes, and editable text render data.

- New layer_separation.go builds the separated result and artifacts
- SubmitGeneratorTask routes layer-separation and move-object via a
  switch; standalone task completion + polling support
- Extend artifact metadata with BBox and GeneratorName across the
  domain, API types, mapper, .api schema, and API.md
- edit-elements gets a transparent manual-frame placeholder holding the
  separated foreground images and text layers beside the original

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/API.md

@@ -238,6 +238,25 @@ Returns the updated project, the assistant message, and generated nodes.
 
 The generation path uses the configured design agent runner. The default is the `sky-valley/pi` Go agent adapter, with local desktop/MCP agent behavior disabled.
 
+## Generator Tasks
+
+`POST /api/generator/tasks`
+
+```json
+{
+  "cid": "client-request-id",
+  "project_id": "project-id",
+  "generator_name": "layer-separation",
+  "input_args": {
+    "image_url": "https://cdn.example.com/source.png"
+  }
+}
+```
+
+`layer-separation` returns a task id that can be polled with `GET /api/generator/tasks?task_id=<id>&project_id=<project-id>`. Completed tasks return a clean background image, foreground image artifacts with `bbox`, and a `text_render_data` artifact for editable text reconstruction.
+
+The canvas `edit-elements` node action uses the same separation path but writes the separated result beside the original image. The original image remains unchanged; the clean background is a bottom image layer, and a transparent frame above it holds the separated foreground images and editable text layers.
+
 ## Chat History Replay
 
 `GET /api/projects/:id/history`

server/img_infinite_canvas.api

@@ -670,14 +670,16 @@ type GeneratorTaskQueueInfo {
 }
 
 type GeneratorTaskArtifactMetadata {
-	ArtifactId string `json:"artifact_id,optional"`
-	Format     string `json:"format,optional"`
-	Height     int64  `json:"height,optional"`
-	Label      string `json:"label,optional"`
-	NodeId     string `json:"node_id,optional"`
-	NodeName   string `json:"node_name,optional"`
-	SizeBytes  int64  `json:"size_bytes,optional"`
-	Width      int64  `json:"width,optional"`
+	ArtifactId    string  `json:"artifact_id,optional"`
+	BBox          []int64 `json:"bbox,optional"`
+	Format        string  `json:"format,optional"`
+	GeneratorName string  `json:"generator_name,optional"`
+	Height        int64   `json:"height,optional"`
+	Label         string  `json:"label,optional"`
+	NodeId        string  `json:"node_id,optional"`
+	NodeName      string  `json:"node_name,optional"`
+	SizeBytes     int64   `json:"size_bytes,optional"`
+	Width         int64   `json:"width,optional"`
 }
 
 type GeneratorTaskArtifact {
@@ -1013,3 +1015,4 @@ service img_infinite_canvas-api {
 	@handler deleteAsset
 	delete /assets (DeleteAssetRequest) returns (DeleteAssetResponse)
 }
+

server/internal/application/design_service.go

@@ -892,12 +892,14 @@ func (s *DesignService) RunNodeActionAsync(ctx context.Context, projectID string
 	now := s.now()
 	threadID := newID()
 	target := project.Nodes[nodeIndex]
-	if req.Action == "remove-background" || req.Action == "vectorize" || req.Action == "move-object" {
+	if req.Action == "remove-background" || req.Action == "vectorize" || req.Action == "move-object" || req.Action == "edit-elements" {
 		resultNode := newBackgroundRemovalPlaceholder(target)
 		if req.Action == "vectorize" {
 			resultNode = newVectorizePlaceholder(target)
 		} else if req.Action == "move-object" {
 			resultNode = newMoveObjectPlaceholder(target)
+		} else if req.Action == "edit-elements" {
+			resultNode = newLayerSeparationPlaceholder(target)
 		}
 		if req.Options == nil {
 			req.Options = make(map[string]string)
@@ -1845,7 +1847,10 @@ func (s *DesignService) completeNodeActionGeneration(ctx context.Context, projec
 	if req.Action == "vectorize" {
 		return s.completeVectorizeGeneration(ctx, projectID, threadID, target, req)
 	}
-	if req.Action == "edit-elements" || req.Action == "edit-text" {
+	if req.Action == "edit-elements" {
+		return s.completeLayerSeparationGeneration(ctx, projectID, threadID, target, req)
+	}
+	if req.Action == "edit-text" {
 		return s.completeEditableLayerGeneration(ctx, projectID, threadID, target, req)
 	}
 	editToolContent := "正在根据选中图片执行模型编辑，完成后会替换画布中的图片节点。"
@@ -4709,8 +4714,30 @@ func newMoveObjectPlaceholder(target design.Node) design.Node {
 	return result
 }
 
+func newLayerSeparationPlaceholder(target design.Node) design.Node {
+	result := target
+	result.ID = newID()
+	result.Type = design.NodeTypeFrame
+	result.Title = nodeActionWorkingTitle("edit-elements")
+	result.X = target.X + target.Width + 32
+	result.Y = target.Y
+	result.Content = target.Content
+	result.Tone = "frame"
+	result.Status = "generating"
+	result.ParentID = ""
+	result.LayerRole = "manual-frame"
+	result.FillColor = "transparent"
+	result.StrokeColor = "#C7C7C7"
+	result.StrokeWidth = 1
+	result.StrokeStyle = "solid"
+	result.MockupSurface = design.MockupSurface{}
+	result.MockupModel = design.MockupModel{}
+	result.MockupSourceContent = ""
+	return result
+}
+
 func nodeActionResultNodeID(target design.Node, req design.NodeActionRequest) string {
-	if (req.Action == "remove-background" || req.Action == "vectorize" || req.Action == "move-object") && len(req.Options) > 0 {
+	if (req.Action == "remove-background" || req.Action == "vectorize" || req.Action == "move-object" || req.Action == "edit-elements") && len(req.Options) > 0 {
 		if id := strings.TrimSpace(req.Options[nodeActionResultNodeIDOption]); id != "" {
 			return id
 		}

server/internal/application/generator_task.go

@@ -21,7 +21,9 @@ type generatorTaskMetadata struct {
 const (
 	removeBackgroundGeneratorName = "removeBG"
 	imageVectorizerGeneratorName  = "gpt-5.5-vectorizer"
+	layerSeparationGeneratorName  = "layer-separation"
 	moveObjectGeneratorName       = "move-object"
+	layerSeparationMessageName    = "layer_separation"
 )
 
 func (s *DesignService) GeneratorTask(ctx context.Context, projectID string, taskID string) (design.GeneratorTask, error) {
@@ -72,10 +74,17 @@ func (s *DesignService) SubmitGeneratorTask(ctx context.Context, req design.Gene
 	if generatorName == "" {
 		generatorName = moveObjectGeneratorName
 	}
-	if normalizeGeneratorTaskName(generatorName) != moveObjectGeneratorName {
+	switch normalizeGeneratorTaskName(generatorName) {
+	case moveObjectGeneratorName:
+		return s.submitMoveObjectTask(ctx, req)
+	case layerSeparationGeneratorName:
+		return s.submitLayerSeparationTask(ctx, req)
+	default:
 		return design.GeneratorTask{}, fmt.Errorf("%w: unsupported generator_name %s", design.ErrInvalidInput, req.GeneratorName)
 	}
+}
 
+func (s *DesignService) submitMoveObjectTask(ctx context.Context, req design.GeneratorTaskSubmitRequest) (design.GeneratorTask, error) {
 	input := normalizeMoveObjectInput(req.InputArgs)
 	if strings.TrimSpace(input.ImageURL) == "" {
 		return design.GeneratorTask{}, fmt.Errorf("%w: input_args.image_url is required", design.ErrInvalidInput)
@@ -101,6 +110,53 @@ func (s *DesignService) SubmitGeneratorTask(ctx context.Context, req design.Gene
 	return task, nil
 }
 
+func (s *DesignService) submitLayerSeparationTask(ctx context.Context, req design.GeneratorTaskSubmitRequest) (design.GeneratorTask, error) {
+	input := normalizeLayerSeparationInput(req.InputArgs)
+	if strings.TrimSpace(input.ImageURL) == "" {
+		return design.GeneratorTask{}, fmt.Errorf("%w: input_args.image_url is required", design.ErrInvalidInput)
+	}
+
+	taskID := newID()
+	price := generatorTaskPrice(input, layerSeparationGeneratorName)
+	task := design.GeneratorTask{
+		GeneratorTaskID:   taskID,
+		GeneratorName:     layerSeparationGeneratorName,
+		Status:            "submitted",
+		OriginalInputArgs: input,
+		QueueInfo:         generatorTaskQueueInfo(layerSeparationGeneratorName, input, price),
+	}
+	s.storeStandaloneGeneratorTask(task)
+	go s.completeStandaloneLayerSeparationTask(taskID, strings.TrimSpace(req.ProjectID), input)
+	return task, nil
+}
+
+func (s *DesignService) completeStandaloneLayerSeparationTask(taskID string, projectID string, input design.GeneratorTaskInputArgs) {
+	ctx, cancel := context.WithTimeout(context.Background(), generationBudget)
+	defer cancel()
+
+	imageURL := strings.TrimSpace(input.ImageURL)
+	target := design.Node{
+		ID:      "source",
+		Type:    design.NodeTypeImage,
+		Title:   "Source image",
+		Content: imageURL,
+		Status:  "success",
+	}
+	result, err := s.createLayerSeparationResult(ctx, standaloneArtifactProjectID(projectID, taskID), target, design.NodeActionRequest{
+		Action: "edit-elements",
+		Prompt: strings.TrimSpace(input.Prompt),
+	})
+	if err != nil {
+		s.markStandaloneGeneratorTaskFailed(taskID, err)
+		return
+	}
+	if len(result.Artifacts) == 0 {
+		s.markStandaloneGeneratorTaskFailed(taskID, fmt.Errorf("layer separation returned no artifacts"))
+		return
+	}
+	s.completeStandaloneGeneratorTask(taskID, result.Artifacts)
+}
+
 func (s *DesignService) completeStandaloneMoveObjectTask(taskID string, projectID string, input design.GeneratorTaskInputArgs) {
 	ctx, cancel := context.WithTimeout(context.Background(), generationBudget)
 	defer cancel()
@@ -218,6 +274,17 @@ func normalizeMoveObjectInput(input design.GeneratorTaskInputArgs) design.Genera
 	return input
 }
 
+func normalizeLayerSeparationInput(input design.GeneratorTaskInputArgs) design.GeneratorTaskInputArgs {
+	if strings.TrimSpace(input.ImageURL) == "" && len(input.Image) > 0 {
+		input.ImageURL = strings.TrimSpace(input.Image[0])
+	}
+	input.ImageURL = strings.TrimSpace(input.ImageURL)
+	input.Prompt = strings.TrimSpace(input.Prompt)
+	input.Resolution = strings.TrimSpace(input.Resolution)
+	input.AspectRatio = strings.TrimSpace(input.AspectRatio)
+	return input
+}
+
 func normalizeBox(box design.NormalizedBox) design.NormalizedBox {
 	width := clampUnit(box.Width)
 	height := clampUnit(box.Height)
@@ -427,6 +494,7 @@ func generatorTaskMessageCompleted(message design.Message) bool {
 	}
 	return name == "canvas_action" ||
 		name == "text_extraction" ||
+		name == layerSeparationMessageName ||
 		name == "mockup_model" ||
 		strings.TrimSpace(message.Role) == "assistant"
 }
@@ -470,6 +538,8 @@ func generatorTaskGeneratorNameFromMessages(messages []design.Message, taskID st
 			return "gpt-image-2"
 		case strings.Contains(strings.ToLower(message.Title), "rmbg"):
 			return removeBackgroundGeneratorName
+		case message.Name == layerSeparationMessageName:
+			return layerSeparationGeneratorName
 		case message.Name == "mockup_model":
 			return "mockup/model"
 		case message.Name == "text_extraction":
@@ -498,6 +568,10 @@ func generatorTaskArtifacts(messages []design.Message, taskID string) []design.G
 		if message.ThreadID != taskID || !isToolArtifactsMessage(message) {
 			continue
 		}
+		if message.Name == layerSeparationMessageName || message.ToolHint == layerSeparationMessageName {
+			artifacts = append(artifacts, parseLayerSeparationArtifacts(message.Content)...)
+			continue
+		}
 		artifacts = append(artifacts, parseGeneratorArtifacts(message.Content)...)
 	}
 	return artifacts
@@ -549,6 +623,55 @@ func parseGeneratorArtifacts(content string) []design.GeneratorTaskArtifact {
 	return artifacts
 }
 
+func parseLayerSeparationArtifacts(content string) []design.GeneratorTaskArtifact {
+	var raw []struct {
+		Type     string `json:"type"`
+		Content  string `json:"content"`
+		Metadata struct {
+			ArtifactID    string  `json:"artifact_id"`
+			BBox          []int64 `json:"bbox"`
+			Format        string  `json:"format"`
+			GeneratorName string  `json:"generator_name"`
+			Height        int64   `json:"height"`
+			Label         string  `json:"label"`
+			NodeID        string  `json:"node_id"`
+			NodeName      string  `json:"node_name"`
+			SizeBytes     int64   `json:"size_bytes"`
+			Width         int64   `json:"width"`
+		} `json:"metadata"`
+	}
+	if err := json.Unmarshal([]byte(content), &raw); err != nil {
+		return nil
+	}
+	artifacts := make([]design.GeneratorTaskArtifact, 0, len(raw))
+	for _, item := range raw {
+		artifactType := strings.TrimSpace(item.Type)
+		if artifactType == "" {
+			continue
+		}
+		if strings.TrimSpace(item.Content) == "" && artifactType != "text" {
+			continue
+		}
+		artifacts = append(artifacts, design.GeneratorTaskArtifact{
+			Type:    artifactType,
+			Content: item.Content,
+			Metadata: design.GeneratorTaskArtifactMetadata{
+				ArtifactID:    item.Metadata.ArtifactID,
+				BBox:          append([]int64(nil), item.Metadata.BBox...),
+				Format:        item.Metadata.Format,
+				GeneratorName: item.Metadata.GeneratorName,
+				Height:        item.Metadata.Height,
+				Label:         item.Metadata.Label,
+				NodeID:        item.Metadata.NodeID,
+				NodeName:      item.Metadata.NodeName,
+				SizeBytes:     item.Metadata.SizeBytes,
+				Width:         item.Metadata.Width,
+			},
+		})
+	}
+	return artifacts
+}
+
 func generatorArtifactFormat(format string, imageURL string) string {
 	format = strings.Trim(strings.ToLower(strings.TrimSpace(format)), ".")
 	if format != "" {
@@ -605,6 +728,8 @@ func generatorTaskPrice(input design.GeneratorTaskInputArgs, generatorName strin
 		return 4
 	case imageVectorizerGeneratorName:
 		return 14
+	case layerSeparationGeneratorName:
+		return 8
 	case moveObjectGeneratorName:
 		return 5
 	}
@@ -668,6 +793,8 @@ func generatorTaskNameForNodeAction(req design.NodeActionRequest) string {
 	switch normalizeNodeAction(req.Action) {
 	case "remove-background":
 		return removeBackgroundGeneratorName
+	case "edit-elements":
+		return layerSeparationGeneratorName
 	case "edit-text":
 		return "gpt-5.4-mini"
 	case "move-object":
@@ -749,6 +876,9 @@ func normalizeGeneratorTaskName(generatorName string) string {
 	if normalized == "move-object" || normalized == "moveobject" {
 		return moveObjectGeneratorName
 	}
+	if normalized == "layer-separation" || normalized == "layer_separation" || normalized == "edit-elements" || strings.HasSuffix(normalized, "/layer-separation") {
+		return layerSeparationGeneratorName
+	}
 	return name
 }
 

server/internal/application/layer_separation.go

@@ -0,0 +1,892 @@
+package application
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/png"
+	"math"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"img_infinite_canvas/internal/domain/design"
+)
+
+const (
+	layerSeparationForegroundLabel = "fg_image"
+	layerSeparationBackgroundLabel = "bg_image"
+	layerSeparationTextLabel       = "text_render_data"
+)
+
+type layerSeparationResult struct {
+	CanvasWidth    int64
+	CanvasHeight   int64
+	BackgroundID   string
+	BackgroundURL  string
+	Foregrounds    []layerSeparationForeground
+	TextExtraction design.TextExtraction
+	Artifacts      []design.GeneratorTaskArtifact
+}
+
+type layerSeparationForeground struct {
+	ID     string
+	URL    string
+	BBox   []int64
+	Width  int64
+	Height int64
+	Mask   *image.Alpha
+	Rect   image.Rectangle
+}
+
+type layerSeparationForegroundCandidate struct {
+	BBox   []int64
+	Width  int64
+	Height int64
+	Mask   *image.Alpha
+	Rect   image.Rectangle
+	Image  image.Image
+}
+
+func (s *DesignService) completeLayerSeparationGeneration(ctx context.Context, projectID string, threadID string, target design.Node, req design.NodeActionRequest) error {
+	resultNodeID := nodeActionResultNodeID(target, req)
+	if err := s.addGenerationStep(ctx, projectID, threadID, "tool", "图层分离", "正在拆分底图、前景元素和可编辑文字层。"); err != nil {
+		return s.markNodeActionFailed(detachedUserContext(ctx), projectID, threadID, resultNodeID, err)
+	}
+
+	resultTarget := target
+	resultTarget.ID = resultNodeID
+	result, err := s.createLayerSeparationResult(ctx, projectID, resultTarget, req)
+	if err != nil {
+		return s.markNodeActionFailed(detachedUserContext(ctx), projectID, threadID, resultNodeID, err)
+	}
+
+	project, err := s.repo.Get(ctx, projectID)
+	if err != nil {
+		return err
+	}
+	nodeIndex := findNodeIndex(project.Nodes, resultNodeID)
+	if nodeIndex < 0 {
+		project.Nodes = append(project.Nodes, newLayerSeparationPlaceholder(target))
+		nodeIndex = len(project.Nodes) - 1
+		project.Nodes[nodeIndex].ID = resultNodeID
+	}
+
+	frameNode := project.Nodes[nodeIndex]
+	if frameNode.Width <= 0 {
+		frameNode.Width = float64(result.CanvasWidth)
+	}
+	if frameNode.Height <= 0 {
+		frameNode.Height = float64(result.CanvasHeight)
+	}
+	frameNode.Type = design.NodeTypeFrame
+	frameNode.Title = "Frame"
+	frameNode.Content = ""
+	frameNode.Tone = "frame"
+	frameNode.Status = "success"
+	frameNode.ParentID = ""
+	frameNode.LayerRole = "manual-frame"
+	frameNode.FillColor = "transparent"
+	frameNode.StrokeColor = "#C7C7C7"
+	frameNode.StrokeWidth = 1
+	frameNode.StrokeStyle = "solid"
+	frameNode.MockupSurface = design.MockupSurface{}
+	frameNode.MockupModel = design.MockupModel{}
+	frameNode.MockupSourceContent = ""
+
+	now := s.now()
+	backgroundNode := newLayerSeparationBackgroundNode(frameNode, result)
+	foregroundNodes := newForegroundImageLayers(frameNode, result.Foregrounds, result.CanvasWidth, result.CanvasHeight)
+	editableTextNodes := newEditableTextLayers(frameNode, result.TextExtraction)
+	replacementNodes := make([]design.Node, 0, len(foregroundNodes)+len(editableTextNodes)+2)
+	replacementNodes = append(replacementNodes, backgroundNode, frameNode)
+	replacementNodes = append(replacementNodes, foregroundNodes...)
+	replacementNodes = append(replacementNodes, editableTextNodes...)
+	project.Nodes = append(project.Nodes[:nodeIndex], append(replacementNodes, project.Nodes[nodeIndex+1:]...)...)
+	project.Messages = append(project.Messages, layerSeparationArtifactsMessage(threadID, result.Artifacts, now.Add(-time.Millisecond)))
+	project.Messages = append(project.Messages, design.Message{
+		ID:        newID(),
+		Role:      "assistant",
+		Type:      "assistant",
+		Title:     nodeActionDoneTitle(req.Action),
+		Content:   nodeActionDoneContent(req.Action, req.Prompt),
+		ThreadID:  threadID,
+		ActionID:  threadID,
+		StepID:    newID(),
+		Name:      "canvas_action",
+		ToolHint:  "canvas_action",
+		Status:    "success",
+		CreatedAt: now,
+	})
+	project.Connections = nil
+	project.Status = projectStatusAfterCanvasTask(project.Nodes, design.StatusReady)
+	project.UpdatedAt = now
+	project = s.refreshCanvasSnapshot(project, now)
+
+	return s.repo.Save(ctx, project)
+}
+
+func (s *DesignService) createLayerSeparationResult(ctx context.Context, projectID string, target design.Node, req design.NodeActionRequest) (layerSeparationResult, error) {
+	sourceData, sourceContentType, err := loadImageContent(ctx, target.Content)
+	if err != nil {
+		return layerSeparationResult{}, err
+	}
+	source, _, err := image.Decode(bytes.NewReader(sourceData))
+	if err != nil {
+		return layerSeparationResult{}, err
+	}
+	bounds := source.Bounds()
+	canvasWidth := int64(bounds.Dx())
+	canvasHeight := int64(bounds.Dy())
+	canvas := image.NewRGBA(bounds)
+	draw.Draw(canvas, bounds, source, bounds.Min, draw.Src)
+
+	extraction, err := s.extractLayerSeparationText(ctx, target, req)
+	if err != nil {
+		return layerSeparationResult{}, err
+	}
+	for _, layer := range extraction.Layers {
+		removeTextLayerFromImage(canvas, layer)
+	}
+
+	foregrounds := make([]layerSeparationForeground, 0, 1)
+	if fullForeground, elementForegrounds, ok := s.createLayerSeparationForegroundCandidates(ctx, target, sourceData, sourceContentType, bounds, extraction); ok {
+		if len(extraction.Layers) == 0 {
+			if plainBackground, ok := plainLayerSeparationBackgroundImage(canvas, fullForeground.Mask, fullForeground.Rect); ok {
+				if foreground, ok := s.persistLayerSeparationForeground(ctx, projectID, fullForeground); ok {
+					foregrounds = append(foregrounds, foreground)
+				}
+				canvas = plainBackground
+			}
+		}
+		if len(foregrounds) == 0 {
+			for _, candidate := range elementForegrounds {
+				foreground, ok := s.persistLayerSeparationForeground(ctx, projectID, candidate)
+				if !ok {
+					continue
+				}
+				removeForegroundMaskFromImage(canvas, foreground.Mask, foreground.Rect)
+				foregrounds = append(foregrounds, foreground)
+			}
+		}
+		if len(foregrounds) == 0 && len(extraction.Layers) == 0 {
+			if foreground, ok := s.persistLayerSeparationForeground(ctx, projectID, fullForeground); ok {
+				removeForegroundMaskFromImage(canvas, foreground.Mask, foreground.Rect)
+				foregrounds = append(foregrounds, foreground)
+			}
+		}
+		if len(extraction.Layers) == 0 && len(foregrounds) == 1 {
+			if plainBackground, ok := plainLayerSeparationBackgroundImage(canvas, foregrounds[0].Mask, foregrounds[0].Rect); ok {
+				canvas = plainBackground
+			}
+		}
+	}
+
+	backgroundID := newID()
+	backgroundURL, backgroundSize, err := s.persistLayerSeparationImage(ctx, projectID, backgroundID, "background", canvas)
+	if err != nil {
+		return layerSeparationResult{}, err
+	}
+
+	textRenderData, err := layerSeparationTextRenderData(extraction, canvasWidth, canvasHeight)
+	if err != nil {
+		return layerSeparationResult{}, err
+	}
+
+	artifacts := make([]design.GeneratorTaskArtifact, 0, len(foregrounds)+2)
+	for _, foreground := range foregrounds {
+		artifacts = append(artifacts, design.GeneratorTaskArtifact{
+			Type:    "image",
+			Content: foreground.URL,
+			Metadata: design.GeneratorTaskArtifactMetadata{
+				ArtifactID:    foreground.ID,
+				BBox:          append([]int64(nil), foreground.BBox...),
+				Format:        generatorArtifactFormat("", foreground.URL),
+				GeneratorName: layerSeparationGeneratorName,
+				Height:        foreground.Height,
+				Label:         layerSeparationForegroundLabel,
+				NodeID:        foreground.ID,
+				NodeName:      "Foreground Layer",
+				SizeBytes:     0,
+				Width:         foreground.Width,
+			},
+		})
+	}
+	artifacts = append(artifacts, design.GeneratorTaskArtifact{
+		Type:    "image",
+		Content: backgroundURL,
+		Metadata: design.GeneratorTaskArtifactMetadata{
+			ArtifactID:    backgroundID,
+			Format:        generatorArtifactFormat("", backgroundURL),
+			GeneratorName: layerSeparationGeneratorName,
+			Height:        canvasHeight,
+			Label:         layerSeparationBackgroundLabel,
+			NodeID:        backgroundID,
+			NodeName:      "Image",
+			SizeBytes:     backgroundSize,
+			Width:         canvasWidth,
+		},
+	}, design.GeneratorTaskArtifact{
+		Type:    "text",
+		Content: textRenderData,
+		Metadata: design.GeneratorTaskArtifactMetadata{
+			ArtifactID:    newID(),
+			GeneratorName: layerSeparationGeneratorName,
+			Height:        canvasHeight,
+			Label:         layerSeparationTextLabel,
+			Width:         canvasWidth,
+		},
+	})
+
+	return layerSeparationResult{
+		CanvasWidth:    canvasWidth,
+		CanvasHeight:   canvasHeight,
+		BackgroundID:   backgroundID,
+		BackgroundURL:  backgroundURL,
+		Foregrounds:    foregrounds,
+		TextExtraction: extraction,
+		Artifacts:      artifacts,
+	}, nil
+}
+
+func (s *DesignService) extractLayerSeparationText(ctx context.Context, target design.Node, req design.NodeActionRequest) (design.TextExtraction, error) {
+	if extraction, ok, err := textExtractionFromOptions(req.Options); ok || err != nil {
+		return extraction, err
+	}
+	if s.textExtractor == nil {
+		return design.TextExtraction{}, nil
+	}
+	return s.extractTextExtraction(ctx, target, req)
+}
+
+func (s *DesignService) createLayerSeparationForegroundCandidates(ctx context.Context, target design.Node, sourceData []byte, sourceContentType string, bounds image.Rectangle, extraction design.TextExtraction) (layerSeparationForegroundCandidate, []layerSeparationForegroundCandidate, bool) {
+	if s.backgroundRemover == nil {
+		return layerSeparationForegroundCandidate{}, nil, false
+	}
+	removed, err := s.backgroundRemover.RemoveBackground(ctx, design.BackgroundRemovalRequest{
+		Image:       sourceData,
+		ContentType: sourceContentType,
+		Width:       bounds.Dx(),
+		Height:      bounds.Dy(),
+	})
+	if err != nil || len(removed.Image) == 0 {
+		return layerSeparationForegroundCandidate{}, nil, false
+	}
+	foregroundImage, _, err := image.Decode(bytes.NewReader(removed.Image))
+	if err != nil {
+		return layerSeparationForegroundCandidate{}, nil, false
+	}
+	foreground := image.NewNRGBA(foregroundImage.Bounds())
+	draw.Draw(foreground, foreground.Bounds(), foregroundImage, foregroundImage.Bounds().Min, draw.Src)
+	eraseTextLayersFromForeground(foreground, extraction)
+	foregroundBounds := foreground.Bounds()
+	rect, ok := alphaContentBounds(foreground, foregroundBounds, 12)
+	if !ok {
+		return layerSeparationForegroundCandidate{}, nil, false
+	}
+	mask, count := alphaMask(foreground, foregroundBounds, 12)
+	if count == 0 {
+		return layerSeparationForegroundCandidate{}, nil, false
+	}
+	full := newLayerSeparationForegroundCandidate(foreground, mask, rect, foregroundBounds)
+	return full, layerSeparationElementCandidates(foreground, foregroundBounds), true
+}
+
+func (s *DesignService) persistLayerSeparationForeground(ctx context.Context, projectID string, candidate layerSeparationForegroundCandidate) (layerSeparationForeground, bool) {
+	if candidate.Image == nil || candidate.Mask == nil || candidate.Rect.Empty() || len(candidate.BBox) < 4 {
+		return layerSeparationForeground{}, false
+	}
+	foregroundID := newID()
+	foregroundURL, _, err := s.persistLayerSeparationImage(ctx, projectID, foregroundID, "foreground", candidate.Image)
+	if err != nil {
+		return layerSeparationForeground{}, false
+	}
+	return layerSeparationForeground{
+		ID:     foregroundID,
+		URL:    foregroundURL,
+		BBox:   append([]int64(nil), candidate.BBox...),
+		Width:  candidate.Width,
+		Height: candidate.Height,
+		Mask:   candidate.Mask,
+		Rect:   candidate.Rect,
+	}, true
+}
+
+func newLayerSeparationForegroundCandidate(foreground *image.NRGBA, mask *image.Alpha, rect image.Rectangle, bounds image.Rectangle) layerSeparationForegroundCandidate {
+	return layerSeparationForegroundCandidate{
+		BBox: []int64{
+			int64(rect.Min.X - bounds.Min.X),
+			int64(rect.Min.Y - bounds.Min.Y),
+			int64(rect.Max.X - bounds.Min.X),
+			int64(rect.Max.Y - bounds.Min.Y),
+		},
+		Width:  int64(rect.Dx()),
+		Height: int64(rect.Dy()),
+		Mask:   mask,
+		Rect:   rect,
+		Image:  foregroundImageFromMask(foreground, mask, rect),
+	}
+}
+
+func eraseTextLayersFromForeground(foreground *image.NRGBA, extraction design.TextExtraction) {
+	if foreground == nil || len(extraction.Layers) == 0 {
+		return
+	}
+	bounds := foreground.Bounds()
+	if bounds.Dx()*bounds.Dy() < 4096 {
+		return
+	}
+	for _, layer := range extraction.Layers {
+		rect := normalizedTextMaskRect(bounds, layer)
+		if rect.Empty() {
+			continue
+		}
+		padding := clampInt(int(math.Round(math.Min(float64(rect.Dx()), float64(rect.Dy()))*0.14)), 2, 18)
+		rect = image.Rect(rect.Min.X-padding, rect.Min.Y-padding, rect.Max.X+padding, rect.Max.Y+padding).Intersect(bounds)
+		for y := rect.Min.Y; y < rect.Max.Y; y++ {
+			for x := rect.Min.X; x < rect.Max.X; x++ {
+				offset := foreground.PixOffset(x, y)
+				foreground.Pix[offset+3] = 0
+			}
+		}
+	}
+}
+
+func layerSeparationElementCandidates(foreground *image.NRGBA, bounds image.Rectangle) []layerSeparationForegroundCandidate {
+	if foreground == nil || bounds.Empty() {
+		return nil
+	}
+	width := bounds.Dx()
+	height := bounds.Dy()
+	visited := make([]bool, width*height)
+	components := make([]layerSeparationForegroundCandidate, 0, 4)
+	indexOf := func(x int, y int) int {
+		return (y-bounds.Min.Y)*width + (x - bounds.Min.X)
+	}
+	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+		for x := bounds.Min.X; x < bounds.Max.X; x++ {
+			index := indexOf(x, y)
+			if visited[index] || foreground.NRGBAAt(x, y).A <= 12 {
+				visited[index] = true
+				continue
+			}
+			mask, rect, count := layerSeparationComponentMask(foreground, bounds, visited, x, y, indexOf)
+			if !keepLayerSeparationElement(rect, count, bounds) {
+				continue
+			}
+			components = append(components, newLayerSeparationForegroundCandidate(foreground, mask, rect, bounds))
+		}
+	}
+	sort.Slice(components, func(i int, j int) bool {
+		leftArea := components[i].Rect.Dx() * components[i].Rect.Dy()
+		rightArea := components[j].Rect.Dx() * components[j].Rect.Dy()
+		return leftArea > rightArea
+	})
+	if len(components) > 12 {
+		components = components[:12]
+	}
+	return components
+}
+
+func layerSeparationComponentMask(foreground *image.NRGBA, bounds image.Rectangle, visited []bool, startX int, startY int, indexOf func(int, int) int) (*image.Alpha, image.Rectangle, int) {
+	mask := image.NewAlpha(bounds)
+	stack := []image.Point{{X: startX, Y: startY}}
+	minX, minY := startX, startY
+	maxX, maxY := startX+1, startY+1
+	count := 0
+	for len(stack) > 0 {
+		point := stack[len(stack)-1]
+		stack = stack[:len(stack)-1]
+		if point.X < bounds.Min.X || point.X >= bounds.Max.X || point.Y < bounds.Min.Y || point.Y >= bounds.Max.Y {
+			continue
+		}
+		index := indexOf(point.X, point.Y)
+		if visited[index] {
+			continue
+		}
+		visited[index] = true
+		if foreground.NRGBAAt(point.X, point.Y).A <= 12 {
+			continue
+		}
+		mask.SetAlpha(point.X, point.Y, color.Alpha{A: 255})
+		count++
+		if point.X < minX {
+			minX = point.X
+		}
+		if point.Y < minY {
+			minY = point.Y
+		}
+		if point.X+1 > maxX {
+			maxX = point.X + 1
+		}
+		if point.Y+1 > maxY {
+			maxY = point.Y + 1
+		}
+		stack = append(stack,
+			image.Point{X: point.X + 1, Y: point.Y},
+			image.Point{X: point.X - 1, Y: point.Y},
+			image.Point{X: point.X, Y: point.Y + 1},
+			image.Point{X: point.X, Y: point.Y - 1},
+		)
+	}
+	return mask, image.Rect(minX, minY, maxX, maxY), count
+}
+
+func keepLayerSeparationElement(rect image.Rectangle, count int, bounds image.Rectangle) bool {
+	if rect.Empty() || count <= 0 {
+		return false
+	}
+	totalArea := bounds.Dx() * bounds.Dy()
+	if totalArea <= 0 {
+		return false
+	}
+	if totalArea < 4096 {
+		return true
+	}
+	bboxArea := rect.Dx() * rect.Dy()
+	minArea := maxInt(96, totalArea/6000)
+	if count < minArea || bboxArea < minArea {
+		return false
+	}
+	if float64(bboxArea)/float64(totalArea) > 0.18 {
+		return false
+	}
+	if float64(rect.Dx())/float64(bounds.Dx()) > 0.62 || float64(rect.Dy())/float64(bounds.Dy()) > 0.62 {
+		return false
+	}
+	return true
+}
+
+func foregroundImageFromMask(foreground *image.NRGBA, mask *image.Alpha, rect image.Rectangle) image.Image {
+	cropped := image.NewNRGBA(image.Rect(0, 0, rect.Dx(), rect.Dy()))
+	for y := rect.Min.Y; y < rect.Max.Y; y++ {
+		for x := rect.Min.X; x < rect.Max.X; x++ {
+			if mask.AlphaAt(x, y).A == 0 {
+				continue
+			}
+			cropped.SetNRGBA(x-rect.Min.X, y-rect.Min.Y, foreground.NRGBAAt(x, y))
+		}
+	}
+	return cropped
+}
+
+func (s *DesignService) persistLayerSeparationImage(ctx context.Context, projectID string, nodeID string, suffix string, img image.Image) (string, int64, error) {
+	var output bytes.Buffer
+	if err := png.Encode(&output, img); err != nil {
+		return "", 0, err
+	}
+	if s.assets == nil {
+		data := output.Bytes()
+		return "data:image/png;base64," + base64.StdEncoding.EncodeToString(data), int64(len(data)), nil
+	}
+	data, contentType, err := encodeRasterAssetAsWebP(output.Bytes(), "image/png")
+	if err != nil {
+		return "", 0, err
+	}
+	object, err := s.assets.PutObject(ctx, design.AssetObjectRequest{
+		FileName:    fmt.Sprintf("%s-%s-%s.png", projectID, nodeID, suffix),
+		ContentType: contentType,
+		Data:        data,
+	})
+	if err != nil {
+		return "", 0, err
+	}
+	if strings.TrimSpace(object.PublicURL) == "" {
+		return "", 0, fmt.Errorf("layer separation upload returned empty public URL")
+	}
+	return object.PublicURL, int64(len(data)), nil
+}
+
+func newLayerSeparationBackgroundNode(frame design.Node, result layerSeparationResult) design.Node {
+	return design.Node{
+		ID:        result.BackgroundID,
+		Type:      design.NodeTypeImage,
+		Title:     "Image",
+		X:         frame.X,
+		Y:         frame.Y,
+		Width:     frame.Width,
+		Height:    frame.Height,
+		Content:   result.BackgroundURL,
+		Tone:      "visual",
+		Status:    "success",
+		LayerRole: "clean-image",
+	}
+}
+
+func newForegroundImageLayers(target design.Node, foregrounds []layerSeparationForeground, canvasWidth int64, canvasHeight int64) []design.Node {
+	if len(foregrounds) == 0 || canvasWidth <= 0 || canvasHeight <= 0 {
+		return nil
+	}
+	nodes := make([]design.Node, 0, len(foregrounds))
+	for index, foreground := range foregrounds {
+		if len(foreground.BBox) < 4 || strings.TrimSpace(foreground.URL) == "" {
+			continue
+		}
+		x1 := clampFloat(float64(foreground.BBox[0])/float64(canvasWidth), 0, 1)
+		y1 := clampFloat(float64(foreground.BBox[1])/float64(canvasHeight), 0, 1)
+		x2 := clampFloat(float64(foreground.BBox[2])/float64(canvasWidth), x1, 1)
+		y2 := clampFloat(float64(foreground.BBox[3])/float64(canvasHeight), y1, 1)
+		width := target.Width * (x2 - x1)
+		height := target.Height * (y2 - y1)
+		if width <= 1 || height <= 1 {
+			continue
+		}
+		nodes = append(nodes, design.Node{
+			ID:        foreground.ID,
+			Type:      design.NodeTypeImage,
+			Title:     fmt.Sprintf("Foreground Layer %d", index+1),
+			X:         target.X + target.Width*x1,
+			Y:         target.Y + target.Height*y1,
+			Width:     width,
+			Height:    height,
+			Content:   foreground.URL,
+			Tone:      "separated-element",
+			Status:    "success",
+			ParentID:  target.ID,
+			LayerRole: "foreground-image",
+		})
+	}
+	return nodes
+}
+
+func layerSeparationArtifactsMessage(threadID string, artifacts []design.GeneratorTaskArtifact, createdAt time.Time) design.Message {
+	content, _ := json.Marshal(toLayerSeparationArtifactWire(artifacts))
+	return design.Message{
+		ID:         newID(),
+		Role:       "tool",
+		Type:       "tool_use",
+		Title:      layerSeparationMessageName,
+		Content:    string(content),
+		ThreadID:   threadID,
+		ActionID:   threadID,
+		StepID:     newID(),
+		ToolCallID: "call_" + strings.ReplaceAll(newID(), "-", ""),
+		Name:       layerSeparationMessageName,
+		ToolHint:   layerSeparationMessageName,
+		Status:     "success",
+		CreatedAt:  createdAt,
+	}
+}
+
+func toLayerSeparationArtifactWire(artifacts []design.GeneratorTaskArtifact) []map[string]any {
+	items := make([]map[string]any, 0, len(artifacts))
+	for _, artifact := range artifacts {
+		items = append(items, map[string]any{
+			"type":    artifact.Type,
+			"content": artifact.Content,
+			"metadata": map[string]any{
+				"artifact_id":    artifact.Metadata.ArtifactID,
+				"bbox":           artifact.Metadata.BBox,
+				"format":         artifact.Metadata.Format,
+				"generator_name": artifact.Metadata.GeneratorName,
+				"height":         artifact.Metadata.Height,
+				"label":          artifact.Metadata.Label,
+				"node_id":        artifact.Metadata.NodeID,
+				"node_name":      artifact.Metadata.NodeName,
+				"size_bytes":     artifact.Metadata.SizeBytes,
+				"width":          artifact.Metadata.Width,
+			},
+		})
+	}
+	return items
+}
+
+func removeForegroundMaskFromImage(img *image.RGBA, mask *image.Alpha, rect image.Rectangle) {
+	if mask == nil || rect.Empty() {
+		return
+	}
+	bounds := img.Bounds()
+	rect = rect.Intersect(bounds)
+	if rect.Empty() {
+		return
+	}
+	radius := clampInt(int(math.Round(math.Min(float64(rect.Dx()), float64(rect.Dy()))*0.025)), 2, 10)
+	mask, count := dilateTextMask(mask, rect, radius)
+	if count == 0 {
+		return
+	}
+	source := image.NewRGBA(bounds)
+	draw.Draw(source, bounds, img, bounds.Min, draw.Src)
+	for y := rect.Min.Y; y < rect.Max.Y; y++ {
+		for x := rect.Min.X; x < rect.Max.X; x++ {
+			if mask.AlphaAt(x, y).A == 0 {
+				continue
+			}
+			img.SetRGBA(x, y, estimatedRectBackgroundColor(source, rect, x, y))
+		}
+	}
+	softenMaskedPixels(img, mask, rect)
+}
+
+func plainLayerSeparationBackgroundImage(img *image.RGBA, mask *image.Alpha, rect image.Rectangle) (*image.RGBA, bool) {
+	if img == nil || mask == nil || rect.Empty() {
+		return nil, false
+	}
+	bounds := img.Bounds()
+	if bounds.Empty() {
+		return nil, false
+	}
+	radius := clampInt(int(math.Round(math.Min(float64(rect.Dx()), float64(rect.Dy()))*0.02)), 3, 18)
+	expandedMask, _ := dilateTextMask(mask, bounds, radius)
+	stats, ok := unmaskedColorStats(img, expandedMask, bounds)
+	if !ok || stats.StdDev > 24 {
+		return nil, false
+	}
+	bg := image.NewRGBA(bounds)
+	fill := colorRGBA(int(math.Round(stats.R)), int(math.Round(stats.G)), int(math.Round(stats.B)), int(math.Round(stats.A)))
+	draw.Draw(bg, bounds, &image.Uniform{C: fill}, image.Point{}, draw.Src)
+	return bg, true
+}
+
+type layerSeparationColorStats struct {
+	Count  int64
+	R      float64
+	G      float64
+	B      float64
+	A      float64
+	StdDev float64
+}
+
+func unmaskedColorStats(img *image.RGBA, mask *image.Alpha, bounds image.Rectangle) (layerSeparationColorStats, bool) {
+	stride := clampInt(int(math.Ceil(float64(maxInt(bounds.Dx(), bounds.Dy()))/640)), 1, 12)
+	var count int64
+	var r, g, b, a float64
+	var rr, gg, bb float64
+	for y := bounds.Min.Y; y < bounds.Max.Y; y += stride {
+		for x := bounds.Min.X; x < bounds.Max.X; x += stride {
+			if mask.AlphaAt(x, y).A != 0 {
+				continue
+			}
+			c := img.RGBAAt(x, y)
+			cfR := float64(c.R)
+			cfG := float64(c.G)
+			cfB := float64(c.B)
+			cfA := float64(c.A)
+			r += cfR
+			g += cfG
+			b += cfB
+			a += cfA
+			rr += cfR * cfR
+			gg += cfG * cfG
+			bb += cfB * cfB
+			count++
+		}
+	}
+	if count < 32 {
+		return layerSeparationColorStats{}, false
+	}
+	divisor := float64(count)
+	meanR := r / divisor
+	meanG := g / divisor
+	meanB := b / divisor
+	varR := math.Max(0, rr/divisor-meanR*meanR)
+	varG := math.Max(0, gg/divisor-meanG*meanG)
+	varB := math.Max(0, bb/divisor-meanB*meanB)
+	return layerSeparationColorStats{
+		Count:  count,
+		R:      meanR,
+		G:      meanG,
+		B:      meanB,
+		A:      a / divisor,
+		StdDev: math.Sqrt((varR + varG + varB) / 3),
+	}, true
+}
+
+func alphaContentBounds(img image.Image, bounds image.Rectangle, threshold uint8) (image.Rectangle, bool) {
+	minX, minY := bounds.Max.X, bounds.Max.Y
+	maxX, maxY := bounds.Min.X, bounds.Min.Y
+	found := false
+	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+		for x := bounds.Min.X; x < bounds.Max.X; x++ {
+			if alphaAt(img, x, y) <= threshold {
+				continue
+			}
+			if x < minX {
+				minX = x
+			}
+			if y < minY {
+				minY = y
+			}
+			if x+1 > maxX {
+				maxX = x + 1
+			}
+			if y+1 > maxY {
+				maxY = y + 1
+			}
+			found = true
+		}
+	}
+	if !found {
+		return image.Rectangle{}, false
+	}
+	return image.Rect(minX, minY, maxX, maxY), true
+}
+
+func alphaMask(img image.Image, bounds image.Rectangle, threshold uint8) (*image.Alpha, int) {
+	mask := image.NewAlpha(bounds)
+	count := 0
+	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+		for x := bounds.Min.X; x < bounds.Max.X; x++ {
+			if alphaAt(img, x, y) <= threshold {
+				continue
+			}
+			mask.SetAlpha(x, y, color.Alpha{A: 255})
+			count++
+		}
+	}
+	return mask, count
+}
+
+func alphaAt(img image.Image, x int, y int) uint8 {
+	_, _, _, a := img.At(x, y).RGBA()
+	return uint8(a >> 8)
+}
+
+func cropImage(img image.Image, rect image.Rectangle) image.Image {
+	cropped := image.NewNRGBA(image.Rect(0, 0, rect.Dx(), rect.Dy()))
+	draw.Draw(cropped, cropped.Bounds(), img, rect.Min, draw.Src)
+	return cropped
+}
+
+type layerSeparationTextDocument struct {
+	Layers     []layerSeparationTextLayer `json:"layers"`
+	CanvasSize layerSeparationCanvasSize  `json:"canvas_size"`
+}
+
+type layerSeparationCanvasSize struct {
+	Width  int64 `json:"width"`
+	Height int64 `json:"height"`
+}
+
+type layerSeparationTextLayer struct {
+	TextInfo layerSeparationTextInfo `json:"text_info"`
+	X        float64                 `json:"x"`
+	Y        float64                 `json:"y"`
+	W        float64                 `json:"w"`
+	H        float64                 `json:"h"`
+}
+
+type layerSeparationTextInfo struct {
+	Text        string  `json:"text"`
+	FontSizePx  int64   `json:"font_size_px"`
+	FontFamily  string  `json:"font_family"`
+	FontWeight  any     `json:"font_weight"`
+	FontStyle   string  `json:"font_style"`
+	ColorCSS    string  `json:"color_css"`
+	TextAlign   string  `json:"text_align"`
+	Leading     float64 `json:"leading"`
+	Tracking    float64 `json:"tracking"`
+	Rotation    float64 `json:"rotation"`
+	LeadingTrim string  `json:"leading_trim"`
+}
+
+func layerSeparationTextRenderData(extraction design.TextExtraction, canvasWidth int64, canvasHeight int64) (string, error) {
+	doc := layerSeparationTextDocument{
+		Layers: make([]layerSeparationTextLayer, 0, len(extraction.Layers)),
+		CanvasSize: layerSeparationCanvasSize{
+			Width:  canvasWidth,
+			Height: canvasHeight,
+		},
+	}
+	for _, layer := range extraction.Layers {
+		text := strings.TrimSpace(layer.Text)
+		if text == "" {
+			continue
+		}
+		x := clamp01(layer.X)
+		y := clamp01(layer.Y)
+		width := clamp01(layer.Width)
+		height := clamp01(layer.Height)
+		if x+width > 1 {
+			width = 1 - x
+		}
+		if y+height > 1 {
+			height = 1 - y
+		}
+		if width <= 0 || height <= 0 {
+			continue
+		}
+		fontSize := layer.FontSize
+		if fontSize <= 0 {
+			fontSize = math.Max(10, float64(canvasHeight)*height*0.72)
+		}
+		lineHeight := layer.LineHeight
+		if lineHeight <= 0 {
+			lineHeight = 1.2
+		}
+		fontFamily := strings.TrimSpace(layer.FontFamily)
+		if fontFamily == "" {
+			fontFamily = "Inter"
+		}
+		doc.Layers = append(doc.Layers, layerSeparationTextLayer{
+			TextInfo: layerSeparationTextInfo{
+				Text:        text,
+				FontSizePx:  int64(math.Round(fontSize)),
+				FontFamily:  fontFamily,
+				FontWeight:  layerSeparationFontWeight(layer.FontWeight),
+				FontStyle:   layerSeparationFontStyle(layer.FontWeight),
+				ColorCSS:    layerSeparationColorCSS(layer.Color),
+				TextAlign:   layerSeparationTextAlign(layer.TextAlign),
+				Leading:     lineHeight,
+				Tracking:    layer.LetterSpacing,
+				Rotation:    layer.Rotation,
+				LeadingTrim: "CAP_HEIGHT",
+			},
+			X: x * float64(canvasWidth),
+			Y: y * float64(canvasHeight),
+			W: width * float64(canvasWidth),
+			H: height * float64(canvasHeight),
+		})
+	}
+	data, err := json.Marshal(doc)
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}
+
+func layerSeparationFontWeight(value string) any {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return 400
+	}
+	if weight, err := strconv.Atoi(value); err == nil {
+		return weight
+	}
+	return value
+}
+
+func layerSeparationFontStyle(value string) string {
+	if strings.Contains(strings.ToLower(strings.TrimSpace(value)), "italic") {
+		return "italic"
+	}
+	return "normal"
+}
+
+func layerSeparationTextAlign(value string) string {
+	switch strings.ToLower(strings.TrimSpace(value)) {
+	case "left":
+		return "start"
+	case "right":
+		return "end"
+	case "center":
+		return "center"
+	default:
+		return "start"
+	}
+}
+
+func layerSeparationColorCSS(value string) string {
+	parsed, ok := parseCanvasColor(value)
+	if !ok {
+		return "rgba(25, 25, 25, 1.0)"
+	}
+	alpha := float64(parsed.A) / 255
+	return fmt.Sprintf("rgba(%d, %d, %d, %.3g)", parsed.R, parsed.G, parsed.B, alpha)
+}

server/internal/application/layer_separation_test.go

@@ -0,0 +1,410 @@
+package application
+
+import (
+	"bytes"
+	"context"
+	"image"
+	"image/color"
+	"image/png"
+	"testing"
+	"time"
+
+	"img_infinite_canvas/internal/domain/design"
+	"img_infinite_canvas/internal/infrastructure/memory"
+)
+
+func TestRunEditElementsSeparatesBackgroundForegroundAndTextLayers(t *testing.T) {
+	ctx := context.Background()
+	repo := memory.NewProjectRepository()
+	assets := newFakeAssetStorage()
+	queue := &fakeJobQueue{}
+	extractor := &countingTextExtractor{
+		result: design.TextExtraction{
+			Layers: []design.ExtractedTextLayer{
+				{Text: "Hi", X: 0.5, Y: 0.05, Width: 0.2, Height: 0.1, FontSize: 18, FontFamily: "Inter", FontWeight: "700", Color: "#111111"},
+			},
+		},
+	}
+	remover := &fakeBackgroundRemover{result: design.BackgroundRemoval{
+		Image:       testLayerSeparationForegroundPNG(t),
+		ContentType: "image/png",
+		Width:       4,
+		Height:      4,
+	}}
+	service := NewDesignService(repo, nil, assets, nil, extractor)
+	service.SetJobQueue(queue)
+	service.SetBackgroundRemover(remover)
+
+	source := testLayerSeparationSourceDataURL()
+	project := design.Project{
+		ID:        "project-layer-separation",
+		Title:     "Layer separation",
+		Status:    design.StatusReady,
+		UpdatedAt: time.Now(),
+		Nodes: []design.Node{{
+			ID:      "image-1",
+			Type:    design.NodeTypeImage,
+			Title:   "Source",
+			X:       100,
+			Y:       120,
+			Width:   400,
+			Height:  400,
+			Content: source,
+			Status:  "success",
+		}},
+	}
+	if err := repo.Save(ctx, project); err != nil {
+		t.Fatal(err)
+	}
+
+	started, err := service.RunNodeActionAsync(ctx, project.ID, "image-1", design.NodeActionRequest{Action: "edit-elements"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(queue.jobs) != 1 {
+		t.Fatalf("expected one queued job, got %#v", queue.jobs)
+	}
+	if len(started.Nodes) != 2 {
+		t.Fatalf("expected source plus separated placeholder, got %#v", started.Nodes)
+	}
+	if started.Nodes[0].Status != "success" || started.Nodes[0].Content != source {
+		t.Fatalf("expected source node to remain unchanged, got %#v", started.Nodes[0])
+	}
+	if started.Nodes[1].Type != design.NodeTypeFrame || started.Nodes[1].Status != "generating" || started.Nodes[1].LayerRole != "manual-frame" || started.Nodes[1].ParentID != "" || started.Nodes[1].FillColor != "transparent" {
+		t.Fatalf("expected separated placeholder beside source, got %#v", started.Nodes[1])
+	}
+	if started.Nodes[1].Content != source {
+		t.Fatalf("expected separated placeholder to preview source image, got %#v", started.Nodes[1])
+	}
+	task, err := service.GeneratorTask(ctx, project.ID, started.LastThreadID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if task.GeneratorName != layerSeparationGeneratorName || task.Status != "submitted" {
+		t.Fatalf("expected submitted layer separation task, got %#v", task)
+	}
+
+	if err := service.ProcessJob(ctx, queue.jobs[0]); err != nil {
+		t.Fatal(err)
+	}
+	saved, err := repo.Get(ctx, project.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if saved.Status != design.StatusReady {
+		t.Fatalf("expected ready project, got %s", saved.Status)
+	}
+	if len(saved.Nodes) != 5 {
+		t.Fatalf("expected original, background, frame, foreground, and text nodes, got %#v", saved.Nodes)
+	}
+	if saved.Nodes[0].Status != "success" || saved.Nodes[0].Content != source {
+		t.Fatalf("expected original source to remain unchanged, got %#v", saved.Nodes[0])
+	}
+	background := saved.Nodes[1]
+	if background.Type != design.NodeTypeImage || background.LayerRole != "clean-image" || background.Status != "success" {
+		t.Fatalf("expected clean background node, got %#v", background)
+	}
+	if background.X != 532 || background.Y != 120 {
+		t.Fatalf("expected clean background at separated result origin, got %#v", background)
+	}
+	frame := saved.Nodes[2]
+	if frame.Type != design.NodeTypeFrame || frame.LayerRole != "manual-frame" || frame.Status != "success" {
+		t.Fatalf("expected separated frame beside source, got %#v", frame)
+	}
+	if frame.X != 532 || frame.Y != 120 {
+		t.Fatalf("expected frame beside source, got %#v", frame)
+	}
+	if frame.ParentID != "" || frame.FillColor != "transparent" {
+		t.Fatalf("expected top-level transparent separated frame, got %#v", frame)
+	}
+	if background.ParentID != "" {
+		t.Fatalf("expected clean background to be a bottom image layer outside frame, got %#v", background)
+	}
+	foreground := saved.Nodes[3]
+	if foreground.LayerRole != "foreground-image" || foreground.ParentID != frame.ID {
+		t.Fatalf("expected separated foreground node, got %#v", foreground)
+	}
+	if foreground.X != 632 || foreground.Y != 220 || foreground.Width != 200 || foreground.Height != 200 {
+		t.Fatalf("unexpected foreground geometry: %#v", foreground)
+	}
+	text := saved.Nodes[4]
+	if text.LayerRole != "editable-text" || text.ParentID != frame.ID || text.Content != "Hi" {
+		t.Fatalf("expected editable text node, got %#v", text)
+	}
+
+	task, err = service.GeneratorTask(ctx, project.ID, started.LastThreadID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if task.Status != "completed" {
+		t.Fatalf("expected completed task, got %s", task.Status)
+	}
+	if len(task.Artifacts) != 3 {
+		t.Fatalf("expected foreground, background, and text artifacts, got %#v", task.Artifacts)
+	}
+	if task.Artifacts[0].Metadata.Label != layerSeparationForegroundLabel || task.Artifacts[1].Metadata.Label != layerSeparationBackgroundLabel || task.Artifacts[2].Metadata.Label != layerSeparationTextLabel {
+		t.Fatalf("unexpected artifact labels: %#v", task.Artifacts)
+	}
+	if got := task.Artifacts[0].Metadata.BBox; len(got) != 4 || got[0] != 1 || got[1] != 1 || got[2] != 3 || got[3] != 3 {
+		t.Fatalf("unexpected foreground bbox: %#v", got)
+	}
+	if task.Artifacts[2].Type != "text" || !bytes.Contains([]byte(task.Artifacts[2].Content), []byte(`"text":"Hi"`)) {
+		t.Fatalf("expected text render data artifact, got %#v", task.Artifacts[2])
+	}
+}
+
+func TestSubmitLayerSeparationTaskCompletesStandaloneArtifacts(t *testing.T) {
+	ctx := context.Background()
+	assets := newFakeAssetStorage()
+	extractor := &countingTextExtractor{
+		result: design.TextExtraction{
+			Layers: []design.ExtractedTextLayer{{Text: "Title", X: 0.1, Y: 0.1, Width: 0.3, Height: 0.1}},
+		},
+	}
+	remover := &fakeBackgroundRemover{result: design.BackgroundRemoval{
+		Image:       testLayerSeparationForegroundPNG(t),
+		ContentType: "image/png",
+		Width:       4,
+		Height:      4,
+	}}
+	service := NewDesignService(nil, nil, assets, nil, extractor)
+	service.SetBackgroundRemover(remover)
+
+	task, err := service.SubmitGeneratorTask(ctx, design.GeneratorTaskSubmitRequest{
+		ProjectID:     "project-standalone-layer-separation",
+		GeneratorName: layerSeparationGeneratorName,
+		InputArgs: design.GeneratorTaskInputArgs{
+			ImageURL: testLayerSeparationSourceDataURL(),
+		},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	completed := waitForStandaloneGeneratorTask(t, service, task.GeneratorTaskID)
+	if completed.Status != "completed" {
+		t.Fatalf("expected completed standalone task, got %#v", completed)
+	}
+	if completed.GeneratorName != layerSeparationGeneratorName || len(completed.Artifacts) != 3 {
+		t.Fatalf("unexpected standalone task: %#v", completed)
+	}
+	if completed.Artifacts[0].Metadata.Label != layerSeparationForegroundLabel || completed.Artifacts[2].Metadata.Label != layerSeparationTextLabel {
+		t.Fatalf("unexpected standalone artifacts: %#v", completed.Artifacts)
+	}
+}
+
+func TestPlainLayerSeparationBackgroundUsesSolidColorWhenBackdropIsPlain(t *testing.T) {
+	img := image.NewRGBA(image.Rect(0, 0, 24, 24))
+	for y := 0; y < 24; y++ {
+		for x := 0; x < 24; x++ {
+			img.SetRGBA(x, y, color.RGBA{R: 188, G: 185, B: 178, A: 255})
+		}
+	}
+	mask := image.NewAlpha(img.Bounds())
+	rect := image.Rect(8, 4, 16, 22)
+	for y := rect.Min.Y; y < rect.Max.Y; y++ {
+		for x := rect.Min.X; x < rect.Max.X; x++ {
+			img.SetRGBA(x, y, color.RGBA{R: 32, G: 26, B: 22, A: 255})
+			mask.SetAlpha(x, y, color.Alpha{A: 255})
+		}
+	}
+
+	bg, ok := plainLayerSeparationBackgroundImage(img, mask, rect)
+	if !ok {
+		t.Fatal("expected plain background branch")
+	}
+	center := bg.RGBAAt(12, 12)
+	if center.R != 188 || center.G != 185 || center.B != 178 || center.A != 255 {
+		t.Fatalf("expected solid background color, got %#v", center)
+	}
+}
+
+func TestPlainLayerSeparationBackgroundSkipsComplexBackdrop(t *testing.T) {
+	img := image.NewRGBA(image.Rect(0, 0, 24, 24))
+	for y := 0; y < 24; y++ {
+		for x := 0; x < 24; x++ {
+			img.SetRGBA(x, y, color.RGBA{R: uint8(20 + x*8), G: uint8(40 + y*7), B: uint8(80 + (x+y)*3), A: 255})
+		}
+	}
+	mask := image.NewAlpha(img.Bounds())
+	rect := image.Rect(9, 6, 15, 20)
+	for y := rect.Min.Y; y < rect.Max.Y; y++ {
+		for x := rect.Min.X; x < rect.Max.X; x++ {
+			mask.SetAlpha(x, y, color.Alpha{A: 255})
+		}
+	}
+
+	if _, ok := plainLayerSeparationBackgroundImage(img, mask, rect); ok {
+		t.Fatal("expected complex background to use repair branch")
+	}
+}
+
+func TestLayerSeparationPosterKeepsComplexBackgroundAndExtractsSmallElements(t *testing.T) {
+	ctx := context.Background()
+	extractor := &countingTextExtractor{
+		result: design.TextExtraction{
+			Layers: []design.ExtractedTextLayer{{
+				Text:       "SALE",
+				X:          0.1,
+				Y:          0.1,
+				Width:      0.35,
+				Height:     0.125,
+				FontSize:   12,
+				FontFamily: "Inter",
+				FontWeight: "700",
+				Color:      "#111111",
+			}},
+		},
+	}
+	remover := &fakeBackgroundRemover{result: design.BackgroundRemoval{
+		Image:       testPosterForegroundPNG(t),
+		ContentType: "image/png",
+		Width:       80,
+		Height:      80,
+	}}
+	service := NewDesignService(nil, nil, nil, nil, extractor)
+	service.SetBackgroundRemover(remover)
+
+	result, err := service.createLayerSeparationResult(ctx, "project-poster-layer-separation", design.Node{
+		ID:      "poster",
+		Type:    design.NodeTypeImage,
+		Title:   "Poster",
+		Content: testPosterSourceDataURL(),
+		Status:  "success",
+	}, design.NodeActionRequest{Action: "edit-elements"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(result.TextExtraction.Layers) != 1 {
+		t.Fatalf("expected editable text extraction to remain, got %#v", result.TextExtraction.Layers)
+	}
+	if len(result.Foregrounds) != 1 {
+		t.Fatalf("expected only the small decorative foreground to be extracted, got %#v", result.Foregrounds)
+	}
+	if got := result.Foregrounds[0].BBox; len(got) != 4 || got[0] != 54 || got[1] != 44 || got[2] != 66 || got[3] != 56 {
+		t.Fatalf("unexpected decorative foreground bbox: %#v", got)
+	}
+
+	backgroundData, _, err := loadImageContent(ctx, result.BackgroundURL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	background, _, err := image.Decode(bytes.NewReader(backgroundData))
+	if err != nil {
+		t.Fatal(err)
+	}
+	topLeft := color.NRGBAModel.Convert(background.At(2, 2)).(color.NRGBA)
+	bottomRight := color.NRGBAModel.Convert(background.At(76, 76)).(color.NRGBA)
+	if topLeft == bottomRight {
+		t.Fatalf("expected complex poster background to be preserved, got solid-looking pixels %#v", topLeft)
+	}
+	textPixel := color.NRGBAModel.Convert(background.At(14, 12)).(color.NRGBA)
+	if textPixel.R < 32 && textPixel.G < 32 && textPixel.B < 32 {
+		t.Fatalf("expected text pixels to be removed from background, got %#v", textPixel)
+	}
+	ornamentPixel := color.NRGBAModel.Convert(background.At(59, 49)).(color.NRGBA)
+	if ornamentPixel.R > 200 && ornamentPixel.G < 80 && ornamentPixel.B < 80 {
+		t.Fatalf("expected extracted ornament to be removed from background, got %#v", ornamentPixel)
+	}
+	scenePixel := color.NRGBAModel.Convert(background.At(20, 48)).(color.NRGBA)
+	if scenePixel.B < 170 {
+		t.Fatalf("expected large poster scenery to stay on the background, got %#v", scenePixel)
+	}
+}
+
+func waitForStandaloneGeneratorTask(t *testing.T, service *DesignService, taskID string) design.GeneratorTask {
+	t.Helper()
+	deadline := time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		task, err := service.GeneratorTask(context.Background(), "", taskID)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if task.Status == "completed" || task.Status == "failed" {
+			return task
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+	task, _ := service.GeneratorTask(context.Background(), "", taskID)
+	t.Fatalf("timed out waiting for standalone task: %#v", task)
+	return design.GeneratorTask{}
+}
+
+func testLayerSeparationSourceDataURL() string {
+	img := image.NewNRGBA(image.Rect(0, 0, 4, 4))
+	for y := 0; y < 4; y++ {
+		for x := 0; x < 4; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 240, G: 240, B: 240, A: 255})
+		}
+	}
+	for y := 1; y < 3; y++ {
+		for x := 1; x < 3; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 200, G: 20, B: 30, A: 255})
+		}
+	}
+	return testPNGDataURLFromImage(img)
+}
+
+func testLayerSeparationForegroundPNG(t *testing.T) []byte {
+	t.Helper()
+	img := image.NewNRGBA(image.Rect(0, 0, 4, 4))
+	for y := 1; y < 3; y++ {
+		for x := 1; x < 3; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 200, G: 20, B: 30, A: 255})
+		}
+	}
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		t.Fatal(err)
+	}
+	return buf.Bytes()
+}
+
+func testPosterSourceDataURL() string {
+	img := image.NewNRGBA(image.Rect(0, 0, 80, 80))
+	for y := 0; y < 80; y++ {
+		for x := 0; x < 80; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: uint8(190 + x/3), G: uint8(186 + y/4), B: uint8(174 + (x+y)/8), A: 255})
+		}
+	}
+	for y := 38; y < 70; y++ {
+		for x := 8; x < 50; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 64, G: 106, B: 204, A: 255})
+		}
+	}
+	for y := 8; y < 18; y++ {
+		for x := 8; x < 36; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 17, G: 17, B: 17, A: 255})
+		}
+	}
+	for y := 44; y < 56; y++ {
+		for x := 54; x < 66; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 225, G: 32, B: 44, A: 255})
+		}
+	}
+	return testPNGDataURLFromImage(img)
+}
+
+func testPosterForegroundPNG(t *testing.T) []byte {
+	t.Helper()
+	img := image.NewNRGBA(image.Rect(0, 0, 80, 80))
+	for y := 8; y < 18; y++ {
+		for x := 8; x < 36; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 17, G: 17, B: 17, A: 255})
+		}
+	}
+	for y := 38; y < 70; y++ {
+		for x := 8; x < 50; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 64, G: 106, B: 204, A: 255})
+		}
+	}
+	for y := 44; y < 56; y++ {
+		for x := 54; x < 66; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{R: 225, G: 32, B: 44, A: 255})
+		}
+	}
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, img); err != nil {
+		t.Fatal(err)
+	}
+	return buf.Bytes()
+}

server/internal/domain/design/agent.go

@@ -107,14 +107,16 @@ type GeneratorTaskQueueInfo struct {
 }
 
 type GeneratorTaskArtifactMetadata struct {
-	ArtifactID string
-	Format     string
-	Height     int64
-	Label      string
-	NodeID     string
-	NodeName   string
-	SizeBytes  int64
-	Width      int64
+	ArtifactID    string
+	BBox          []int64
+	Format        string
+	GeneratorName string
+	Height        int64
+	Label         string
+	NodeID        string
+	NodeName      string
+	SizeBytes     int64
+	Width         int64
 }
 
 type GeneratorTaskArtifact struct {

server/internal/logic/mapper.go

@@ -133,14 +133,16 @@ func toAPIGeneratorTaskArtifacts(items []design.GeneratorTaskArtifact) []types.G
 			Type:    item.Type,
 			Content: item.Content,
 			Metadata: types.GeneratorTaskArtifactMetadata{
-				ArtifactId: item.Metadata.ArtifactID,
-				Format:     item.Metadata.Format,
-				Height:     item.Metadata.Height,
-				Label:      item.Metadata.Label,
-				NodeId:     item.Metadata.NodeID,
-				NodeName:   item.Metadata.NodeName,
-				SizeBytes:  item.Metadata.SizeBytes,
-				Width:      item.Metadata.Width,
+				ArtifactId:    item.Metadata.ArtifactID,
+				BBox:          append([]int64(nil), item.Metadata.BBox...),
+				Format:        item.Metadata.Format,
+				GeneratorName: item.Metadata.GeneratorName,
+				Height:        item.Metadata.Height,
+				Label:         item.Metadata.Label,
+				NodeId:        item.Metadata.NodeID,
+				NodeName:      item.Metadata.NodeName,
+				SizeBytes:     item.Metadata.SizeBytes,
+				Width:         item.Metadata.Width,
 			},
 		})
 	}

server/internal/types/types.go

@@ -417,14 +417,16 @@ type GeneratorTaskArtifact struct {
 }
 
 type GeneratorTaskArtifactMetadata struct {
-	ArtifactId string `json:"artifact_id,optional"`
-	Format     string `json:"format,optional"`
-	Height     int64  `json:"height,optional"`
-	Label      string `json:"label,optional"`
-	NodeId     string `json:"node_id,optional"`
-	NodeName   string `json:"node_name,optional"`
-	SizeBytes  int64  `json:"size_bytes,optional"`
-	Width      int64  `json:"width,optional"`
+	ArtifactId    string  `json:"artifact_id,optional"`
+	BBox          []int64 `json:"bbox,optional"`
+	Format        string  `json:"format,optional"`
+	GeneratorName string  `json:"generator_name,optional"`
+	Height        int64   `json:"height,optional"`
+	Label         string  `json:"label,optional"`
+	NodeId        string  `json:"node_id,optional"`
+	NodeName      string  `json:"node_name,optional"`
+	SizeBytes     int64   `json:"size_bytes,optional"`
+	Width         int64   `json:"width,optional"`
 }
 
 type GeneratorTaskData struct {