fix(server): complete generator task when thread settles or project ready

Treat a generator task as completed when it produces artifacts, when a
task message reaches a terminal state, or when the project is ready —
even if the project is still exploring another concurrent thread. Adds
generatorTaskMessageCompleted to classify terminal task messages and
covers ready-without-messages and concurrent-thread cases with tests.

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

server/internal/application/generator_task.go

@@ -384,7 +384,7 @@ func generatorTaskMetadataFromMessages(messages []design.Message, taskID string)
 func generatorTaskStatus(project design.Project, taskID string) string {
 	messages := project.Messages
 	status := "submitted"
-	completed := false
+	completed := len(generatorTaskArtifacts(messages, taskID)) > 0
 	for _, message := range messages {
 		if message.ThreadID != taskID {
 			continue
@@ -392,9 +392,11 @@ func generatorTaskStatus(project design.Project, taskID string) string {
 		if message.Role == "error" || message.Status == "failed" {
 			return "failed"
 		}
+		if generatorTaskMessageCompleted(message) {
+			completed = true
+		}
 		switch message.Status {
 		case "success", "cancelled":
-			completed = true
 		case "running", "streaming", "submitted":
 			status = "submitted"
 		}
@@ -405,15 +407,30 @@ func generatorTaskStatus(project design.Project, taskID string) string {
 	if project.Status == design.StatusFailed {
 		return "failed"
 	}
-	if project.Status == design.StatusExploring {
+	if completed || project.Status == design.StatusReady {
-		return status
-	}
-	if len(generatorTaskArtifacts(messages, taskID)) > 0 || completed {
 		return "completed"
 	}
 	return status
 }
 
+func generatorTaskMessageCompleted(message design.Message) bool {
+	status := strings.ToLower(strings.TrimSpace(message.Status))
+	if status != "success" && status != "cancelled" {
+		return false
+	}
+	name := strings.TrimSpace(message.Name)
+	if name == "agent_planner" || name == "generator_task" {
+		return false
+	}
+	if isToolArtifactsMessage(message) {
+		return true
+	}
+	return name == "canvas_action" ||
+		name == "text_extraction" ||
+		name == "mockup_model" ||
+		strings.TrimSpace(message.Role) == "assistant"
+}
+
 func generatorTaskHasActiveCanvasWork(project design.Project, taskID string) bool {
 	taskID = strings.TrimSpace(taskID)
 	lastThreadID := strings.TrimSpace(project.LastThreadID)

server/internal/application/generator_task_test.go

@@ -114,3 +114,77 @@ func TestGeneratorTaskStatusCompletesWhenCanvasSettles(t *testing.T) {
 		t.Fatalf("expected settled canvas task to complete, got %s", task.Status)
 	}
 }
+
+func TestGeneratorTaskStatusCompletesReadyProjectWithoutTaskMessages(t *testing.T) {
+	threadID := "thread-without-messages"
+	project := design.Project{
+		ID:           "project-ready-without-messages",
+		LastThreadID: threadID,
+		Status:       design.StatusReady,
+		UpdatedAt:    time.Now(),
+		Nodes: []design.Node{
+			{
+				ID:      "image-1",
+				Type:    design.NodeTypeImage,
+				Title:   "Generated image",
+				Content: "http://localhost:19000/canvas-assets/done.png",
+				Status:  "success",
+			},
+		},
+	}
+
+	task := generatorTaskFromProject(project, threadID)
+	if task.Status != "completed" {
+		t.Fatalf("expected ready project without task messages to complete, got %s", task.Status)
+	}
+}
+
+func TestGeneratorTaskStatusCompletesFinishedThreadWhileProjectStillExploring(t *testing.T) {
+	threadID := "thread-done"
+	activeThreadID := "thread-active"
+	now := time.Now()
+	project := design.Project{
+		ID:           "project-concurrent",
+		LastThreadID: activeThreadID,
+		Status:       design.StatusExploring,
+		UpdatedAt:    now,
+		Nodes: []design.Node{
+			{
+				ID:      "done-image",
+				Type:    design.NodeTypeImage,
+				Title:   "Done image",
+				Content: "http://localhost:19000/canvas-assets/done.png",
+				Status:  "success",
+			},
+			{
+				ID:      "active-image",
+				Type:    design.NodeTypeImage,
+				Title:   "Active image",
+				Content: "pending prompt",
+				Status:  "generating",
+			},
+		},
+		Messages: []design.Message{
+			generatorTaskMetadataMessage(threadID, removeBackgroundGeneratorName, design.GeneratorTaskInputArgs{}, 4, now.Add(-2*time.Second)),
+			{ID: "user", Role: "user", Type: "user", Name: "canvas_action", Status: "running", ThreadID: threadID},
+			toolArtifactsMessage(threadID, "remove background", []design.Node{
+				{
+					ID:      "done-image",
+					Type:    design.NodeTypeImage,
+					Title:   "Done image",
+					Content: "http://localhost:19000/canvas-assets/done.png",
+					Status:  "success",
+					Width:   1024,
+					Height:  1024,
+				},
+			}, now.Add(-time.Second)),
+			{ID: "assistant", Role: "assistant", Type: "assistant", Name: "canvas_action", Status: "success", ThreadID: threadID},
+			{ID: "active-tool", Role: "tool", Type: "tool", Title: "GPT Image 2", Status: "running", ThreadID: activeThreadID},
+		},
+	}
+
+	task := generatorTaskFromProject(project, threadID)
+	if task.Status != "completed" {
+		t.Fatalf("expected finished thread to complete while another task runs, got %s", task.Status)
+	}
+}