file management sys

7 files changed, 1086 insertions, 32 deletions

diff --git a/backend/app/main.py b/backend/app/main.py
index 65fa3a3..261b45a 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -1,11 +1,14 @@
 from fastapi import FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import StreamingResponse
+from fastapi.responses import StreamingResponse, FileResponse
 from pydantic import BaseModel
 from app.schemas import NodeRunRequest, NodeRunResponse, MergeStrategy, Role, Message, Context, LLMConfig, ModelProvider, ReasoningEffort
 from app.services.llm import llm_streamer, generate_title
 from dotenv import load_dotenv
 import os
+import json
+import shutil
+from typing import List, Literal, Optional
 
 load_dotenv()
 
@@ -19,6 +22,131 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
+# --------- Project / Blueprint storage ---------
+DATA_ROOT = os.path.abspath(os.getenv("DATA_ROOT", os.path.join(os.getcwd(), "data")))
+DEFAULT_USER = "test"
+ARCHIVE_FILENAME = "archived_nodes.json"
+
+def ensure_user_root(user: str) -> str:
+    """
+    Ensures the new data root structure:
+    data/<user>/projects
+    data/<user>/archive
+    """
+    user_root = os.path.join(DATA_ROOT, user)
+    projects_root = os.path.join(user_root, "projects")
+    archive_root = os.path.join(user_root, "archive")
+    os.makedirs(projects_root, exist_ok=True)
+    os.makedirs(archive_root, exist_ok=True)
+    return user_root
+
+
+def projects_root(user: str) -> str:
+    return os.path.join(ensure_user_root(user), "projects")
+
+
+def archive_root(user: str) -> str:
+    return os.path.join(ensure_user_root(user), "archive")
+
+
+def migrate_legacy_layout(user: str):
+    """
+    Migrate from legacy ./projects/<user> and legacy archive folders to the new data/<user>/ structure.
+    """
+    legacy_root = os.path.abspath(os.path.join(os.getcwd(), "projects", user))
+    new_projects = projects_root(user)
+    if os.path.exists(legacy_root) and not os.listdir(new_projects):
+        try:
+            for name in os.listdir(legacy_root):
+                src = os.path.join(legacy_root, name)
+                dst = os.path.join(new_projects, name)
+                if not os.path.exists(dst):
+                    shutil.move(src, dst)
+        except Exception:
+            pass
+    # migrate legacy archive (archived/ or .cf_archived/)
+    legacy_archives = [
+        os.path.join(legacy_root, "archived", ARCHIVE_FILENAME),
+        os.path.join(legacy_root, ".cf_archived", ARCHIVE_FILENAME),
+    ]
+    new_archive_file = archived_path(user)
+    if not os.path.exists(new_archive_file):
+        for legacy in legacy_archives:
+            if os.path.exists(legacy):
+                os.makedirs(os.path.dirname(new_archive_file), exist_ok=True)
+                try:
+                    shutil.move(legacy, new_archive_file)
+                except Exception:
+                    pass
+
+def safe_path(user: str, relative_path: str) -> str:
+    root = projects_root(user)
+    norm = os.path.normpath(relative_path).lstrip(os.sep)
+    full = os.path.abspath(os.path.join(root, norm))
+    if not full.startswith(root):
+        raise HTTPException(status_code=400, detail="Invalid path")
+    return full
+
+class FSItem(BaseModel):
+    name: str
+    path: str  # path relative to user root
+    type: Literal["file", "folder"]
+    size: Optional[int] = None
+    mtime: Optional[float] = None
+    children: Optional[List["FSItem"]] = None
+
+FSItem.model_rebuild()
+
+def list_tree(user: str, relative_path: str = ".") -> List[FSItem]:
+    migrate_legacy_layout(user)
+    root = safe_path(user, relative_path)
+    items: List[FSItem] = []
+    for name in sorted(os.listdir(root)):
+        full = os.path.join(root, name)
+        rel = os.path.relpath(full, projects_root(user))
+        stat = os.stat(full)
+        if os.path.isdir(full):
+            items.append(FSItem(
+                name=name,
+                path=rel,
+                type="folder",
+                size=None,
+                mtime=stat.st_mtime,
+                children=list_tree(user, rel)
+            ))
+        else:
+            items.append(FSItem(
+                name=name,
+                path=rel,
+                type="file",
+                size=stat.st_size,
+                mtime=stat.st_mtime,
+                children=None
+            ))
+    return items
+
+class SaveBlueprintRequest(BaseModel):
+    user: str = DEFAULT_USER
+    path: str  # relative path including filename.json
+    content: dict
+
+class RenameRequest(BaseModel):
+    user: str = DEFAULT_USER
+    path: str
+    new_name: Optional[str] = None
+    new_path: Optional[str] = None
+
+class FolderRequest(BaseModel):
+    user: str = DEFAULT_USER
+    path: str  # relative folder path
+
+class DeleteRequest(BaseModel):
+    user: str = DEFAULT_USER
+    path: str
+    is_folder: bool = False
+
+# -----------------------------------------------
+
 @app.get("/")
 def read_root():
     return {"message": "ContextFlow Backend is running"}
@@ -117,3 +245,159 @@ async def summarize_endpoint(request: SummarizeRequest):
     from app.services.llm import summarize_content
     summary = await summarize_content(request.content, request.model)
     return SummarizeResponse(summary=summary)
+
+# ---------------- Project / Blueprint APIs ----------------
+@app.get("/api/projects/tree", response_model=List[FSItem])
+def get_project_tree(user: str = DEFAULT_USER):
+    """
+    List all files/folders for the user under the projects root.
+    """
+    ensure_user_root(user)
+    return list_tree(user)
+
+
+@app.post("/api/projects/create_folder")
+def create_folder(req: FolderRequest):
+    """
+    Create a folder (and parents) under the user's project root.
+    """
+    try:
+        folder_path = safe_path(req.user, req.path)
+        os.makedirs(folder_path, exist_ok=True)
+        return {"ok": True}
+    except HTTPException:
+        raise
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@app.post("/api/projects/save_blueprint")
+def save_blueprint(req: SaveBlueprintRequest):
+    """
+    Save a blueprint JSON to disk.
+    """
+    try:
+        full_path = safe_path(req.user, req.path)
+        os.makedirs(os.path.dirname(full_path), exist_ok=True)
+        with open(full_path, "w", encoding="utf-8") as f:
+            json.dump(req.content, f, ensure_ascii=False, indent=2)
+        return {"ok": True}
+    except HTTPException:
+        raise
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@app.get("/api/projects/file")
+def read_blueprint(user: str = DEFAULT_USER, path: str = ""):
+    """
+    Read a blueprint JSON file.
+    """
+    if not path:
+        raise HTTPException(status_code=400, detail="path is required")
+    full_path = safe_path(user, path)
+    if not os.path.isfile(full_path):
+        raise HTTPException(status_code=404, detail="file not found")
+    try:
+        with open(full_path, "r", encoding="utf-8") as f:
+            data = json.load(f)
+        return {"content": data}
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@app.get("/api/projects/download")
+def download_blueprint(user: str = DEFAULT_USER, path: str = ""):
+    """
+    Download a blueprint file.
+    """
+    if not path:
+        raise HTTPException(status_code=400, detail="path is required")
+    full_path = safe_path(user, path)
+    if not os.path.isfile(full_path):
+        raise HTTPException(status_code=404, detail="file not found")
+    return FileResponse(full_path, filename=os.path.basename(full_path), media_type="application/json")
+
+
+@app.post("/api/projects/rename")
+def rename_item(req: RenameRequest):
+    """
+    Rename or move a file or folder.
+    - If new_path is provided, it is treated as the target relative path (move).
+    - Else, new_name is used within the same directory.
+    """
+    try:
+        src = safe_path(req.user, req.path)
+        if not os.path.exists(src):
+            raise HTTPException(status_code=404, detail="source not found")
+        if req.new_path:
+            dst = safe_path(req.user, req.new_path)
+        else:
+            if not req.new_name:
+                raise HTTPException(status_code=400, detail="new_name or new_path required")
+            base_dir = os.path.dirname(src)
+            dst = os.path.join(base_dir, req.new_name)
+            # Ensure still inside user root
+            safe_path(req.user, os.path.relpath(dst, ensure_user_root(req.user)))
+        os.rename(src, dst)
+        return {"ok": True}
+    except HTTPException:
+        raise
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@app.post("/api/projects/delete")
+def delete_item(req: DeleteRequest):
+    """
+    Delete a file or folder.
+    """
+    try:
+        target = safe_path(req.user, req.path)
+        if not os.path.exists(target):
+            raise HTTPException(status_code=404, detail="not found")
+        if os.path.isdir(target):
+            if not req.is_folder:
+                # Prevent deleting folder accidentally unless flagged
+                raise HTTPException(status_code=400, detail="set is_folder=True to delete folder")
+            shutil.rmtree(target)
+        else:
+            os.remove(target)
+        return {"ok": True}
+    except HTTPException:
+        raise
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
+# ----------------------------------------------------------
+
+# --------------- Archived Nodes APIs ----------------------
+def archived_path(user: str) -> str:
+    root = archive_root(user)
+    return os.path.join(root, ARCHIVE_FILENAME)
+
+
+@app.get("/api/projects/archived")
+def get_archived_nodes(user: str = DEFAULT_USER):
+    migrate_legacy_layout(user)
+    path = archived_path(user)
+    if not os.path.exists(path):
+        return {"archived": []}
+    try:
+        with open(path, "r", encoding="utf-8") as f:
+            return {"archived": json.load(f)}
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@app.post("/api/projects/archived")
+def save_archived_nodes(payload: dict):
+    user = payload.get("user", DEFAULT_USER)
+    data = payload.get("archived", [])
+    try:
+        path = archived_path(user)
+        os.makedirs(os.path.dirname(path), exist_ok=True)
+        with open(path, "w", encoding="utf-8") as f:
+            json.dump(data, f, ensure_ascii=False, indent=2)
+        return {"ok": True}
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=str(e))
diff --git a/backend/data/test/archive/archived_nodes.json b/backend/data/test/archive/archived_nodes.json
new file mode 100644
index 0000000..0637a08
--- /dev/null
+++ b/backend/data/test/archive/archived_nodes.json
@@ -0,0 +1 @@
+[]
\ No newline at end of file
diff --git a/backend/data/test/projects/untitled.json b/backend/data/test/projects/untitled.json
new file mode 100644
index 0000000..592b817
--- /dev/null
+++ b/backend/data/test/projects/untitled.json
@@ -0,0 +1,40 @@
+{
+  "version": 1,
+  "nodes": [
+    {
+      "id": "node_1765320756261",
+      "type": "llmNode",
+      "position": {
+        "x": 110.96800241241141,
+        "y": 456.9765614414304
+      },
+      "data": {
+        "label": "New Question",
+        "model": "gpt-5.1",
+        "temperature": 0.7,
+        "systemPrompt": "",
+        "userPrompt": "",
+        "mergeStrategy": "smart",
+        "reasoningEffort": "medium",
+        "messages": [],
+        "traces": [],
+        "outgoingTraces": [],
+        "forkedTraces": [],
+        "mergedTraces": [],
+        "response": "",
+        "status": "idle",
+        "inputs": 1,
+        "activeTraceIds": []
+      },
+      "width": 200,
+      "height": 64
+    }
+  ],
+  "edges": [],
+  "viewport": {
+    "x": 412.49738834764497,
+    "y": 114.22860771179165,
+    "zoom": 0.5743491774985177
+  },
+  "theme": "light"
+}
\ No newline at end of file
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 5776091..8ae93c7 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1,4 +1,4 @@
-import { useCallback, useRef, useState } from 'react';
+import { useCallback, useEffect, useRef, useState } from 'react';
 import ReactFlow, { 
   Background, 
   Controls, 
@@ -47,7 +47,10 @@ function Flow() {
     theme,
     toggleTheme,
     autoLayout,
-    findNonOverlappingPosition
+    findNonOverlappingPosition,
+    setLastViewport,
+    saveCurrentBlueprint,
+    currentBlueprintPath
   } = useFlowStore();
 
   const reactFlowWrapper = useRef<HTMLDivElement>(null);
@@ -190,6 +193,22 @@ function Flow() {
     createNodeFromArchive(archiveId, position);
   };
 
+  // Ctrl/Cmd + S manual save
+  useEffect(() => {
+    const handler = (e: KeyboardEvent) => {
+      const isMac = navigator.platform.toLowerCase().includes('mac');
+      if ((isMac ? e.metaKey : e.ctrlKey) && e.key.toLowerCase() === 's') {
+        e.preventDefault();
+        const path = currentBlueprintPath;
+        if (path) {
+          saveCurrentBlueprint(path, getViewport());
+        }
+      }
+    };
+    window.addEventListener('keydown', handler);
+    return () => window.removeEventListener('keydown', handler);
+  }, [currentBlueprintPath, saveCurrentBlueprint, getViewport]);
+
   return (
     <div className={`w-screen h-screen flex ${theme === 'dark' ? 'dark bg-gray-900' : 'bg-white'}`}>
       <LeftSidebar isOpen={isLeftOpen} onToggle={() => setIsLeftOpen(!isLeftOpen)} />
@@ -206,6 +225,7 @@ function Flow() {
           onNodesChange={onNodesChange}
           onEdgesChange={onEdgesChange}
           onConnect={onConnect}
+          onMoveEnd={(_, viewport) => setLastViewport(viewport)}
           nodeTypes={nodeTypes}
           edgeTypes={edgeTypes}
           defaultEdgeOptions={{ type: 'merged' }}
diff --git a/frontend/src/components/LeftSidebar.tsx b/frontend/src/components/LeftSidebar.tsx
index 1eaa62c..1b7ccb2 100644
--- a/frontend/src/components/LeftSidebar.tsx
+++ b/frontend/src/components/LeftSidebar.tsx
@@ -1,6 +1,10 @@
-import React, { useState } from 'react';
-import { Folder, FileText, Archive, ChevronLeft, ChevronRight, Trash2, MessageSquare } from 'lucide-react';
-import useFlowStore from '../store/flowStore';
+import React, { useEffect, useMemo, useRef, useState, useCallback } from 'react';
+import { useReactFlow } from 'reactflow';
+import { 
+  Folder, FileText, Archive, ChevronLeft, ChevronRight, Trash2, MessageSquare, 
+  MoreVertical, Download, Upload, Plus, RefreshCw, Edit3 
+} from 'lucide-react';
+import useFlowStore, { type FSItem, type BlueprintDocument } from '../store/flowStore';
 
 interface LeftSidebarProps {
   isOpen: boolean;
@@ -9,14 +13,325 @@ interface LeftSidebarProps {
 
 const LeftSidebar: React.FC<LeftSidebarProps> = ({ isOpen, onToggle }) => {
   const [activeTab, setActiveTab] = useState<'project' | 'files' | 'archive'>('project');
-  const { archivedNodes, removeFromArchive, createNodeFromArchive, theme } = useFlowStore();
+  const {
+    archivedNodes,
+    removeFromArchive,
+    createNodeFromArchive,
+    theme,
+    projectTree,
+    currentBlueprintPath,
+    saveStatus,
+    refreshProjectTree,
+    loadArchivedNodes,
+    readBlueprintFile,
+    loadBlueprint,
+    saveBlueprintFile,
+    saveCurrentBlueprint,
+    createProjectFolder,
+    renameProjectItem,
+    deleteProjectItem,
+    setCurrentBlueprintPath,
+    serializeBlueprint,
+    clearBlueprint
+  } = useFlowStore();
+  const { setViewport, getViewport } = useReactFlow();
   const isDark = theme === 'dark';
+  const fileInputRef = useRef<HTMLInputElement | null>(null);
+  const [contextMenu, setContextMenu] = useState<{ x: number; y: number; item?: FSItem } | null>(null);
+  const [currentFolder, setCurrentFolder] = useState<string>('.');
+  const [dragItem, setDragItem] = useState<FSItem | null>(null);
+  const [showSaveStatus, setShowSaveStatus] = useState(false);
+  const [expanded, setExpanded] = useState<Set<string>>(() => new Set(['.']));
   
   const handleDragStart = (e: React.DragEvent, archiveId: string) => {
     e.dataTransfer.setData('archiveId', archiveId);
     e.dataTransfer.effectAllowed = 'copy';
   };
 
+  const joinPath = (folder: string, name: string) => {
+    if (!folder || folder === '.' || folder === '/') return name;
+    return `${folder.replace(/\\/g, '/').replace(/\/+$/, '')}/${name}`;
+  };
+
+  const stripJson = (name: string) => name.endsWith('.json') ? name.slice(0, -5) : name;
+
+  const findChildren = useCallback((folder: string, list: FSItem[] = projectTree): FSItem[] => {
+    const norm = folder.replace(/\\/g, '/').replace(/^\.\/?/, '');
+    if (folder === '.' || folder === '' || folder === '/') return list;
+    for (const item of list) {
+      if (item.type === 'folder') {
+        if (item.path === norm) return item.children || [];
+        const found = findChildren(folder, item.children || []);
+        if (found) return found;
+      }
+    }
+    return [];
+  }, [projectTree]);
+
+  const ensureUniqueName = useCallback((base: string, targetFolder: string, isFolder: boolean) => {
+    const siblings = findChildren(targetFolder).map(i => i.name);
+    const ext = isFolder ? '' : '.json';
+    const rawBase = stripJson(base);
+    let candidate = rawBase + ext;
+    let idx = 1;
+    while (siblings.includes(candidate)) {
+      idx += 1;
+      candidate = `${rawBase} (${idx})${ext}`;
+    }
+    return candidate;
+  }, [findChildren]);
+
+  // Load project tree on mount and when tab switches to project
+  useEffect(() => {
+    if (activeTab === 'project') {
+      refreshProjectTree().catch(() => {});
+    }
+  }, [activeTab, refreshProjectTree]);
+
+  // Load archived nodes on mount
+  useEffect(() => {
+    loadArchivedNodes().catch(() => {});
+  }, [loadArchivedNodes]);
+
+  // Context menu handlers
+  const openContextMenu = (e: React.MouseEvent, item?: FSItem) => {
+    e.preventDefault();
+    e.stopPropagation();
+    setContextMenu({ x: e.clientX, y: e.clientY, item });
+  };
+
+  const closeContextMenu = () => setContextMenu(null);
+
+  const promptName = (message: string, defaultValue: string) => {
+    const val = window.prompt(message, defaultValue);
+    return val?.trim() || null;
+  };
+
+  const handleCreateFolder = async (base: string) => {
+    const input = promptName('Folder name', 'new-folder');
+    if (!input) return;
+    const name = ensureUniqueName(input, base, true);
+    await createProjectFolder(joinPath(base, name));
+  };
+
+  const handleNewBlueprint = async (base: string) => {
+    const input = promptName('Blueprint file name', 'untitled');
+    if (!input) return;
+    const name = ensureUniqueName(input, base, false);
+    const path = joinPath(base, name);
+    // Create empty blueprint and save immediately
+    const empty: BlueprintDocument = {
+      version: 1,
+      nodes: [],
+      edges: [],
+      viewport: getViewport(),
+      theme,
+    };
+    await saveBlueprintFile(path, empty.viewport);
+    await loadBlueprint(empty);
+    setCurrentBlueprintPath(path);
+  };
+
+  const handleRename = async (item: FSItem) => {
+    const newName = promptName('Rename to', item.name);
+    if (!newName || newName === item.name) return;
+    await renameProjectItem(item.path, newName);
+  };
+
+  const handleDelete = async (item: FSItem) => {
+    const currentPath = currentBlueprintPath;
+    const isDeletingOpen =
+      currentPath === item.path ||
+      (item.type === 'folder' && currentPath && (currentPath === item.path || currentPath.startsWith(`${item.path}/`)));
+    const ok = window.confirm(
+      isDeletingOpen
+        ? `The opened blueprint is in this ${item.type}. Delete and clear canvas?`
+        : `Delete ${item.name}?`
+    );
+    if (!ok) return;
+    await deleteProjectItem(item.path, item.type === 'folder');
+    if (isDeletingOpen) {
+      clearBlueprint();
+    }
+    await refreshProjectTree();
+  };
+
+  const handleLoadFile = async (item: FSItem) => {
+    if (item.type !== 'file') return;
+    try {
+      const doc = await readBlueprintFile(item.path);
+      const vp = loadBlueprint(doc);
+      setCurrentBlueprintPath(item.path);
+      if (vp) {
+        setViewport(vp);
+      }
+    } catch (e) {
+      console.error(e);
+      alert('Not a valid blueprint JSON.');
+    }
+  };
+
+  const handleDownload = async (item: FSItem) => {
+    if (item.type !== 'file') return;
+    const url = `${import.meta.env.VITE_BACKEND_URL || 'http://localhost:8000'}/api/projects/download?user=test&path=${encodeURIComponent(item.path)}`;
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = item.name;
+    a.click();
+  };
+
+  const handleUploadClick = () => fileInputRef.current?.click();
+
+  const promptForPath = (base: string) => {
+    const input = window.prompt('Save as (filename without extension)', 'untitled')?.trim();
+    if (!input) return null;
+    const name = ensureUniqueName(input, base, false);
+    return joinPath(base, name);
+  };
+
+  const handleSave = async () => {
+    let path = currentBlueprintPath;
+    if (!path) {
+      const p = promptForPath(currentFolder);
+      if (!p) return;
+      path = p;
+      setCurrentBlueprintPath(path);
+    }
+    const viewport = getViewport();
+    await saveCurrentBlueprint(path, viewport);
+  };
+
+  const handleUploadFiles = async (files: FileList, targetFolder: string) => {
+    for (const file of Array.from(files)) {
+      if (!file.name.toLowerCase().endsWith('.json')) continue;
+      const text = await file.text();
+      try {
+        const json = JSON.parse(text);
+        const viewport = json.viewport;
+        const uniqueName = ensureUniqueName(file.name, targetFolder, false);
+        await saveBlueprintFile(joinPath(targetFolder, uniqueName), viewport);
+      } catch {
+        // skip invalid json
+      }
+    }
+    await refreshProjectTree();
+  };
+
+  // Fade-out for "Saved" indicator
+  useEffect(() => {
+    if (saveStatus === 'saved') {
+      setShowSaveStatus(true);
+      const t = window.setTimeout(() => setShowSaveStatus(false), 1000);
+      return () => window.clearTimeout(t);
+    }
+    if (saveStatus === 'saving' || saveStatus === 'error') {
+      setShowSaveStatus(true);
+      return;
+    }
+    setShowSaveStatus(false);
+  }, [saveStatus]);
+
+  const handleFileInputChange = async (e: React.ChangeEvent<HTMLInputElement>) => {
+    const files = e.target.files;
+    if (files && files.length > 0) {
+      await handleUploadFiles(files, currentFolder);
+      e.target.value = '';
+    }
+  };
+
+  // Drag move blueprint into folder
+  const onItemDragStart = (e: React.DragEvent, item: FSItem) => {
+    setDragItem(item);
+    e.dataTransfer.effectAllowed = 'move';
+  };
+  const onItemDragOver = (e: React.DragEvent, item: FSItem) => {
+    if (item.type === 'folder') {
+      e.preventDefault();
+      e.dataTransfer.dropEffect = 'move';
+    }
+  };
+  const onItemDrop = async (e: React.DragEvent, target: FSItem) => {
+    e.preventDefault();
+    if (!dragItem || target.type !== 'folder') return;
+    const newPath = joinPath(target.path, dragItem.name);
+    if (newPath === dragItem.path) return;
+    await renameProjectItem(dragItem.path, undefined, newPath);
+    setDragItem(null);
+  };
+
+  const toggleFolder = (path: string) => {
+    setExpanded(prev => {
+      const next = new Set(prev);
+      if (next.has(path)) next.delete(path);
+      else next.add(path);
+      return next;
+    });
+  };
+
+  const renderTree = useCallback((items: FSItem[], depth = 0) => {
+    return items.map(item => {
+      const isActive = currentBlueprintPath === item.path;
+      const isExpanded = expanded.has(item.path);
+      const padding = depth * 12;
+      const hasChildren = (item.children?.length || 0) > 0;
+      return (
+        <div key={item.path}>
+          <div
+            className={`flex items-center justify-between px-2 py-1 rounded cursor-pointer ${
+              isActive
+                ? isDark ? 'bg-blue-900/40 border border-blue-700' : 'bg-blue-50 border-blue-200 border'
+                : isDark ? 'hover:bg-gray-700' : 'hover:bg-gray-100'
+            }`}
+            style={{ paddingLeft: padding + 8 }}
+            onContextMenu={(e) => openContextMenu(e, item)}
+            onClick={() => {
+              if (item.type === 'folder') {
+                toggleFolder(item.path);
+                setCurrentFolder(item.path);
+              } else {
+                setCurrentFolder(item.path.split('/').slice(0, -1).join('/') || '.');
+              }
+            }}
+            onDoubleClick={() => {
+              if (item.type === 'file') {
+                handleLoadFile(item);
+                setCurrentFolder(item.path.split('/').slice(0, -1).join('/') || '.');
+              }
+            }}
+            draggable
+            onDragStart={(e) => onItemDragStart(e, item)}
+            onDragOver={(e) => onItemDragOver(e, item)}
+            onDrop={(e) => onItemDrop(e, item)}
+          >
+            <div className="flex items-center gap-2">
+              {item.type === 'folder' ? (
+                <button
+                  className="w-4 text-left"
+                  onClick={(e) => { e.stopPropagation(); toggleFolder(item.path); }}
+                  title={hasChildren ? undefined : 'Empty folder'}
+                >
+                  {isExpanded ? '▾' : '▸'}
+                </button>
+              ) : (
+                <span className="w-4" />
+              )}
+              {item.type === 'folder' ? <Folder size={14} /> : <FileText size={14} />}
+              <span className="truncate">{stripJson(item.name)}</span>
+            </div>
+            <button className="p-1 rounded hover:bg-gray-200 dark:hover:bg-gray-700" onClick={(e) => { e.stopPropagation(); openContextMenu(e as any, item); }}>
+              <MoreVertical size={14} />
+            </button>
+          </div>
+          {item.type === 'folder' && isExpanded && item.children && item.children.length > 0 && (
+            <div>
+              {renderTree(item.children, depth + 1)}
+            </div>
+          )}
+        </div>
+      );
+    });
+  }, [isDark, currentBlueprintPath, expanded, handleLoadFile]);
+
   if (!isOpen) {
     return (
       <div className={`border-r h-screen flex flex-col items-center py-4 w-12 z-10 transition-all duration-300 ${
@@ -40,9 +355,18 @@ const LeftSidebar: React.FC<LeftSidebarProps> = ({ isOpen, onToggle }) => {
   }
 
   return (
-    <div className={`w-64 border-r h-screen flex flex-col shadow-xl z-10 transition-all duration-300 ${
+    <div 
+      className={`w-[14%] min-w-[260px] max-w-[360px] border-r h-screen flex flex-col shadow-xl z-10 transition-all duration-300 ${
       isDark ? 'border-gray-700 bg-gray-800' : 'border-gray-200 bg-white'
-    }`}>
+    }`} 
+      onClick={() => setContextMenu(null)}
+      onContextMenu={(e) => {
+        // Default empty-area context menu
+        if (activeTab === 'project') {
+          openContextMenu(e);
+        }
+      }}
+    >
       {/* Header */}
       <div className={`p-3 border-b flex justify-between items-center ${
         isDark ? 'border-gray-700 bg-gray-900' : 'border-gray-200 bg-gray-50'
@@ -93,9 +417,103 @@ const LeftSidebar: React.FC<LeftSidebarProps> = ({ isOpen, onToggle }) => {
       {/* Content Area */}
       <div className={`flex-1 overflow-y-auto p-4 text-sm ${isDark ? 'text-gray-400' : 'text-gray-500'}`}>
         {activeTab === 'project' && (
-          <div className="flex flex-col items-center justify-center h-full opacity-50">
-            <Folder size={48} className="mb-2" />
-            <p>Project settings coming soon</p>
+          <div 
+            className="space-y-2"
+          >
+            <div 
+              className="flex items-center gap-2 mb-2"
+              onContextMenu={(e) => { e.preventDefault(); e.stopPropagation(); }}
+            >
+              <button
+                onClick={() => refreshProjectTree()}
+                className={`p-1 rounded ${isDark ? 'hover:bg-gray-700' : 'hover:bg-gray-200'}`}
+                title="Refresh"
+              >
+                <RefreshCw size={14} />
+              </button>
+              <button
+                onClick={() => handleNewBlueprint(currentFolder)}
+                className={`p-1 rounded ${isDark ? 'hover:bg-gray-700' : 'hover:bg-gray-200'}`}
+                title="New Blueprint"
+              >
+                <Plus size={14} />
+              </button>
+              <button
+                onClick={() => handleCreateFolder(currentFolder)}
+                className={`p-1 rounded ${isDark ? 'hover:bg-gray-700' : 'hover:bg-gray-200'}`}
+                title="New Folder"
+              >
+                <Folder size={14} />
+              </button>
+              <button
+                onClick={handleUploadClick}
+                className={`p-1 rounded ${isDark ? 'hover:bg-gray-700' : 'hover:bg-gray-200'}`}
+                title="Upload Blueprint"
+              >
+                <Upload size={14} />
+              </button>
+              <button
+                onClick={handleSave}
+                className={`p-1 rounded ${isDark ? 'hover:bg-gray-700' : 'hover:bg-gray-200'}`}
+                title="Save (Ctrl+S)"
+              >
+                <Edit3 size={14} />
+              </button>
+              <span 
+                className={`text-xs transition-opacity duration-300 ${
+                  saveStatus === 'saved' ? 'text-green-500' : saveStatus === 'saving' ? 'text-blue-500' : saveStatus === 'error' ? 'text-red-500' : isDark ? 'text-gray-500' : 'text-gray-400'
+                }`}
+                style={{ opacity: showSaveStatus && saveStatus !== 'idle' ? 1 : 0 }}
+              >
+                {saveStatus === 'saved' ? 'Saved' : saveStatus === 'saving' ? 'Saving...' : saveStatus === 'error' ? 'Save failed' : ''}
+              </span>
+              <input
+                ref={fileInputRef}
+                type="file"
+                accept=".json,application/json"
+                multiple
+                className="hidden"
+                onChange={handleFileInputChange}
+              />
+            </div>
+            {!currentBlueprintPath && (
+              <div className={`text-xs italic ${isDark ? 'text-gray-500' : 'text-gray-400'}`}>
+                No file open; Save will create a new file.
+              </div>
+            )}
+
+            <div 
+              className={`${isDark ? 'border-gray-700' : 'border-gray-200'} border-t border-dashed mx-1`} 
+              onContextMenu={(e) => { e.preventDefault(); e.stopPropagation(); }}
+            />
+
+            <div
+              onContextMenu={(e) => {
+                if (activeTab === 'project') {
+                  openContextMenu(e);
+                }
+              }}
+              onDragOver={(e) => { 
+                if (e.dataTransfer.types.includes('Files')) { e.preventDefault(); }
+              }}
+              onDrop={async (e) => {
+                if (e.dataTransfer.files?.length) {
+                  e.preventDefault();
+                  await handleUploadFiles(e.dataTransfer.files, currentFolder);
+                }
+              }}
+            >
+              {projectTree.length === 0 ? (
+                <div className="flex flex-col items-center justify-center h-40 opacity-50">
+                  <Folder size={32} className="mb-2" />
+                  <p className="text-xs text-center">No files. Right-click to add.</p>
+                </div>
+              ) : (
+                <div className="space-y-1">
+                  {renderTree(projectTree, 0)}
+                </div>
+              )}
+            </div>
           </div>
         )}
         {activeTab === 'files' && (
@@ -127,6 +545,7 @@ const LeftSidebar: React.FC<LeftSidebarProps> = ({ isOpen, onToggle }) => {
                         ? 'bg-gray-700 border-gray-600 hover:bg-gray-600 hover:border-gray-500' 
                         : 'bg-gray-50 border-gray-200 hover:bg-gray-100 hover:border-gray-300'
                     }`}
+                    title={`Label: ${archived.label}\nModel: ${archived.model}\nSystem: ${archived.systemPrompt || '(empty)'}\nUser: ${(archived.userPrompt || '').slice(0,80)}${(archived.userPrompt || '').length>80?'…':''}\nResp: ${(archived.response || '').slice(0,80)}${(archived.response || '').length>80?'…':''}`}
                   >
                     <div className="flex items-center justify-between">
                       <div className="flex items-center gap-2">
@@ -151,6 +570,50 @@ const LeftSidebar: React.FC<LeftSidebarProps> = ({ isOpen, onToggle }) => {
           </div>
         )}
       </div>
+
+      {/* Context Menu */}
+      {contextMenu && (
+        <div
+          className={`fixed z-50 rounded-md shadow-lg border py-1 text-sm ${isDark ? 'bg-gray-800 border-gray-700 text-gray-200' : 'bg-white border-gray-200 text-gray-700'}`}
+          style={{ top: contextMenu.y, left: contextMenu.x }}
+          onClick={(e) => e.stopPropagation()}
+        >
+          {(() => {
+            const item = contextMenu.item;
+            const targetFolder = item
+              ? (item.type === 'folder' ? item.path : item.path.split('/').slice(0, -1).join('/') || '.')
+              : '.'; // empty area => root
+            const commonNew = (
+              <>
+                <button className="block w-full text-left px-3 py-1 hover:bg-gray-100 dark:hover:bg-gray-700" onClick={() => { closeContextMenu(); handleCreateFolder(targetFolder); }}>New Folder</button>
+                <button className="block w-full text-left px-3 py-1 hover:bg-gray-100 dark:hover:bg-gray-700" onClick={() => { closeContextMenu(); handleNewBlueprint(targetFolder); }}>New Blueprint</button>
+                <button className="block w-full text-left px-3 py-1 hover:bg-gray-100 dark:hover:bg-gray-700" onClick={() => { closeContextMenu(); handleUploadClick(); }}>Upload</button>
+              </>
+            );
+            if (!item) {
+              return commonNew;
+            }
+            if (item.type === 'file') {
+              return (
+                <>
+                  {commonNew}
+                  <button className="block w-full text-left px-3 py-1 hover:bg-gray-100 dark:hover:bg-gray-700" onClick={() => { closeContextMenu(); handleDownload(item); }}>Download</button>
+                  <button className="block w-full text-left px-3 py-1 hover:bg-gray-100 dark:hover:bg-gray-700" onClick={() => { closeContextMenu(); handleRename(item); }}>Rename</button>
+                  <button className="block w-full text-left px-3 py-1 text-red-500 hover:bg-red-50 dark:hover:bg-red-900/40" onClick={() => { closeContextMenu(); handleDelete(item); }}>Delete</button>
+                </>
+              );
+            }
+            // folder
+            return (
+              <>
+                {commonNew}
+                <button className="block w-full text-left px-3 py-1 hover:bg-gray-100 dark:hover:bg-gray-700" onClick={() => { closeContextMenu(); handleRename(item); }}>Rename</button>
+                <button className="block w-full text-left px-3 py-1 text-red-500 hover:bg-red-50 dark:hover:bg-red-900/40" onClick={() => { closeContextMenu(); handleDelete(item); }}>Delete</button>
+              </>
+            );
+          })()}
+        </div>
+      )}
     </div>
   );
 };
diff --git a/frontend/src/components/Sidebar.tsx b/frontend/src/components/Sidebar.tsx
index 06c8704..3008ba3 100644
--- a/frontend/src/components/Sidebar.tsx
+++ b/frontend/src/components/Sidebar.tsx
@@ -1875,6 +1875,9 @@ const Sidebar: React.FC<SidebarProps> = ({ isOpen, onToggle, onInteract }) => {
                   .map((trace) => {
                     const isSelected = mergeSelectedIds.includes(trace.id);
                     const isDragging = mergeDraggedId === trace.id;
+                    const traceColors = trace.isMerged && trace.mergedColors && trace.mergedColors.length > 0
+                      ? trace.mergedColors
+                      : [trace.color];
                     
                     return (
                       <div 
@@ -1898,7 +1901,22 @@ const Sidebar: React.FC<SidebarProps> = ({ isOpen, onToggle, onInteract }) => {
                           onChange={() => toggleMergeSelection(trace.id)}
                         />
                         
-                        <div className="w-3 h-3 rounded-full" style={{ backgroundColor: trace.color }}></div>
+                        <div className="flex -space-x-1">
+                          {traceColors.slice(0, 3).map((c, idx) => (
+                            <div 
+                              key={idx}
+                              className="w-3 h-3 rounded-full border-2"
+                              style={{ backgroundColor: c, borderColor: isDark ? '#1f2937' : '#fff' }}
+                            />
+                          ))}
+                          {traceColors.length > 3 && (
+                            <div className={`w-3 h-3 rounded-full flex items-center justify-center text-[8px] ${
+                              isDark ? 'bg-gray-700 text-gray-400' : 'bg-gray-200 text-gray-500'
+                            }`}>
+                              +{traceColors.length - 3}
+                            </div>
+                          )}
+                        </div>
                         
                         <div className="flex-1">
                           <span className={`font-mono text-sm ${isDark ? 'text-gray-300' : 'text-gray-600'}`}>
diff --git a/frontend/src/store/flowStore.ts b/frontend/src/store/flowStore.ts
index 5ed66e6..56ade75 100644
--- a/frontend/src/store/flowStore.ts
+++ b/frontend/src/store/flowStore.ts
@@ -15,7 +15,32 @@ import {
   getOutgoers
 } from 'reactflow';
 
+// --- Project / Blueprint types ---
+export interface ViewportState {
+  x: number;
+  y: number;
+  zoom: number;
+}
+
+export interface BlueprintDocument {
+  version: number;
+  nodes: Node<NodeData>[];
+  edges: Edge[];
+  viewport?: ViewportState;
+  theme?: 'light' | 'dark';
+}
+
+export interface FSItem {
+  name: string;
+  path: string; // path relative to user root
+  type: 'file' | 'folder';
+  size?: number | null;
+  mtime?: number | null;
+  children?: FSItem[];
+}
+
 export type NodeStatus = 'idle' | 'loading' | 'success' | 'error';
+export type SaveStatus = 'idle' | 'saving' | 'saved' | 'error';
 
 export interface Message {
   id?: string;
@@ -90,6 +115,10 @@ export interface ArchivedNode {
   systemPrompt: string;
   temperature: number;
   reasoningEffort: 'low' | 'medium' | 'high';
+  userPrompt?: string;
+  response?: string;
+  enableGoogleSearch?: boolean;
+  mergeStrategy?: 'raw' | 'smart';
 }
 
 interface FlowState {
@@ -98,6 +127,10 @@ interface FlowState {
   selectedNodeId: string | null;
   archivedNodes: ArchivedNode[];  // Stored node templates
   theme: 'light' | 'dark';
+  projectTree: FSItem[];
+  currentBlueprintPath?: string;
+  lastViewport?: ViewportState;
+  saveStatus: SaveStatus;
 
   onNodesChange: OnNodesChange;
   onEdgesChange: OnEdgesChange;
@@ -140,6 +173,22 @@ interface FlowState {
     config: Partial<NodeData>
   ) => string; // Returns new node ID
 
+  // Blueprint serialization / persistence
+  serializeBlueprint: (viewport?: ViewportState) => BlueprintDocument;
+  loadBlueprint: (doc: BlueprintDocument) => ViewportState | undefined;
+  saveBlueprintFile: (path: string, viewport?: ViewportState) => Promise<void>;
+  readBlueprintFile: (path: string) => Promise<BlueprintDocument>;
+  refreshProjectTree: () => Promise<FSItem[]>;
+  createProjectFolder: (path: string) => Promise<void>;
+  renameProjectItem: (path: string, newName?: string, newPath?: string) => Promise<void>;
+  deleteProjectItem: (path: string, isFolder?: boolean) => Promise<void>;
+  setCurrentBlueprintPath: (path?: string) => void;
+  setLastViewport: (viewport: ViewportState) => void;
+  saveCurrentBlueprint: (path?: string, viewport?: ViewportState) => Promise<void>;
+  clearBlueprint: () => void;
+  loadArchivedNodes: () => Promise<void>;
+  saveArchivedNodes: () => Promise<void>;
+
   // Merge trace functions
   createMergedTrace: (
     nodeId: string,
@@ -172,12 +221,37 @@ const getStableColor = (str: string) => {
   return `hsl(${hue}, 70%, 60%)`; 
 };
 
-const useFlowStore = create<FlowState>((set, get) => ({
+const API_BASE = import.meta.env.VITE_BACKEND_URL || 'http://localhost:8000';
+const DEFAULT_USER = 'test';
+
+const jsonFetch = async <T>(url: string, options?: RequestInit): Promise<T> => {
+  const res = await fetch(url, options);
+  if (!res.ok) {
+    const detail = await res.text();
+    throw new Error(detail || `Request failed: ${res.status}`);
+  }
+  return res.json() as Promise<T>;
+};
+
+const useFlowStore = create<FlowState>((set, get) => {
+
+  const validateBlueprint = (doc: any): BlueprintDocument => {
+    if (!doc || typeof doc !== 'object') throw new Error('Invalid blueprint: not an object');
+    if (typeof doc.version !== 'number') throw new Error('Invalid blueprint: missing version');
+    if (!Array.isArray(doc.nodes) || !Array.isArray(doc.edges)) throw new Error('Invalid blueprint: nodes/edges missing');
+    return doc as BlueprintDocument;
+  };
+
+  return {
   nodes: [],
   edges: [],
   selectedNodeId: null,
   archivedNodes: [],
   theme: 'light' as const,
+  projectTree: [],
+  currentBlueprintPath: undefined,
+  lastViewport: undefined,
+  saveStatus: 'idle',
 
   toggleTheme: () => {
     const newTheme = get().theme === 'light' ? 'dark' : 'light';
@@ -190,6 +264,10 @@ const useFlowStore = create<FlowState>((set, get) => ({
     }
   },
 
+  setLastViewport: (viewport: ViewportState) => {
+    set({ lastViewport: viewport });
+  },
+
   findNonOverlappingPosition: (baseX: number, baseY: number) => {
     const { nodes } = get();
     // Estimate larger dimensions to be safe, considering dynamic handles
@@ -1036,18 +1114,24 @@ const useFlowStore = create<FlowState>((set, get) => ({
       model: node.data.model,
       systemPrompt: node.data.systemPrompt,
       temperature: node.data.temperature,
-      reasoningEffort: node.data.reasoningEffort || 'medium'
+      reasoningEffort: node.data.reasoningEffort || 'medium',
+      userPrompt: node.data.userPrompt,
+      response: node.data.response,
+      enableGoogleSearch: node.data.enableGoogleSearch,
+      mergeStrategy: node.data.mergeStrategy
     };
     
     set(state => ({
       archivedNodes: [...state.archivedNodes, archived]
     }));
+    setTimeout(() => get().saveArchivedNodes().catch(() => {}), 0);
   },
 
   removeFromArchive: (archiveId: string) => {
     set(state => ({
       archivedNodes: state.archivedNodes.filter(a => a.id !== archiveId)
     }));
+    setTimeout(() => get().saveArchivedNodes().catch(() => {}), 0);
   },
 
   createNodeFromArchive: (archiveId: string, position: { x: number; y: number }) => {
@@ -1063,15 +1147,16 @@ const useFlowStore = create<FlowState>((set, get) => ({
         model: archived.model,
         temperature: archived.temperature,
         systemPrompt: archived.systemPrompt,
-        userPrompt: '',
-        mergeStrategy: 'smart',
+        userPrompt: archived.userPrompt || '',
         reasoningEffort: archived.reasoningEffort,
+        enableGoogleSearch: archived.enableGoogleSearch,
+        mergeStrategy: archived.mergeStrategy || 'smart',
         traces: [],
         outgoingTraces: [],
         forkedTraces: [],
         mergedTraces: [],
         activeTraceIds: [],
-        response: '',
+        response: archived.response || '',
         status: 'idle',
         inputs: 1
       }
@@ -1313,6 +1398,139 @@ const useFlowStore = create<FlowState>((set, get) => ({
     return newNodeId;
   },
 
+  // -------- Blueprint serialization / persistence --------
+  setCurrentBlueprintPath: (path?: string) => {
+    set({ currentBlueprintPath: path });
+  },
+
+  serializeBlueprint: (viewport?: ViewportState): BlueprintDocument => {
+    return {
+      version: 1,
+      nodes: get().nodes,
+      edges: get().edges,
+      viewport: viewport || get().lastViewport,
+      theme: get().theme,
+    };
+  },
+
+  loadBlueprint: (doc: BlueprintDocument): ViewportState | undefined => {
+    set({
+      nodes: (doc.nodes || []) as LLMNode[],
+      edges: (doc.edges || []) as Edge[],
+      theme: doc.theme || get().theme,
+      selectedNodeId: null,
+      lastViewport: doc.viewport || get().lastViewport,
+    });
+    // Recompute traces after loading
+    setTimeout(() => get().propagateTraces(), 0);
+    return doc.viewport;
+  },
+
+  saveBlueprintFile: async (path: string, viewport?: ViewportState) => {
+    const payload = get().serializeBlueprint(viewport);
+    await jsonFetch(`${API_BASE}/api/projects/save_blueprint`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        user: DEFAULT_USER,
+        path,
+        content: payload,
+      }),
+    });
+    set({ currentBlueprintPath: path, lastViewport: payload.viewport });
+    await get().refreshProjectTree();
+  },
+
+  readBlueprintFile: async (path: string): Promise<BlueprintDocument> => {
+    const res = await jsonFetch<{ content: BlueprintDocument }>(
+      `${API_BASE}/api/projects/file?user=${encodeURIComponent(DEFAULT_USER)}&path=${encodeURIComponent(path)}`
+    );
+    return validateBlueprint(res.content);
+  },
+
+  refreshProjectTree: async () => {
+    const tree = await jsonFetch<FSItem[]>(
+      `${API_BASE}/api/projects/tree?user=${encodeURIComponent(DEFAULT_USER)}`
+    );
+    set({ projectTree: tree });
+    return tree;
+  },
+
+  createProjectFolder: async (path: string) => {
+    await jsonFetch(`${API_BASE}/api/projects/create_folder`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ user: DEFAULT_USER, path }),
+    });
+    await get().refreshProjectTree();
+  },
+
+  renameProjectItem: async (path: string, newName?: string, newPath?: string) => {
+    if (!newName && !newPath) {
+      throw new Error('newName or newPath is required');
+    }
+    await jsonFetch(`${API_BASE}/api/projects/rename`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ user: DEFAULT_USER, path, new_name: newName, new_path: newPath }),
+    });
+    await get().refreshProjectTree();
+  },
+
+  deleteProjectItem: async (path: string, isFolder = false) => {
+    await jsonFetch(`${API_BASE}/api/projects/delete`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ user: DEFAULT_USER, path, is_folder: isFolder }),
+    });
+    await get().refreshProjectTree();
+  },
+
+  saveCurrentBlueprint: async (path?: string, viewport?: ViewportState) => {
+    const targetPath = path || get().currentBlueprintPath;
+    if (!targetPath) {
+      throw new Error('No blueprint path. Please provide a file name.');
+    }
+    set({ saveStatus: 'saving' });
+    try {
+      await get().saveBlueprintFile(targetPath, viewport);
+      set({ saveStatus: 'saved', currentBlueprintPath: targetPath });
+    } catch (e) {
+      console.error(e);
+      set({ saveStatus: 'error' });
+      throw e;
+    }
+  },
+
+  clearBlueprint: () => {
+    set({
+      nodes: [],
+      edges: [],
+      selectedNodeId: null,
+      currentBlueprintPath: undefined,
+      lastViewport: undefined,
+      saveStatus: 'idle',
+    });
+  },
+
+  loadArchivedNodes: async () => {
+    const res = await jsonFetch<{ archived: ArchivedNode[] }>(
+      `${API_BASE}/api/projects/archived?user=${encodeURIComponent(DEFAULT_USER)}`
+    );
+    set({ archivedNodes: res.archived || [] });
+  },
+
+  saveArchivedNodes: async () => {
+    const payload = { user: DEFAULT_USER, archived: get().archivedNodes };
+    await jsonFetch(`${API_BASE}/api/projects/archived`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(payload),
+    });
+  },
+
+  // --------------------------------------------------------
+
   // Compute merged messages based on strategy
   // Optional tracesOverride parameter to use latest traces during propagation
   computeMergedMessages: (nodeId: string, sourceTraceIds: string[], strategy: MergeStrategy, tracesOverride?: Trace[]): Message[] => {
@@ -1487,10 +1705,13 @@ const useFlowStore = create<FlowState>((set, get) => ({
     const node = nodes.find(n => n.id === nodeId);
     if (!node) return '';
 
-    // Get colors from source traces
-    const colors = sourceTraceIds
-      .map(id => node.data.traces.find((t: Trace) => t.id === id)?.color)
-      .filter((c): c is string => c !== undefined);
+    // Get colors from source traces (preserve multi-colors for merged parents)
+    const colors = sourceTraceIds.flatMap(id => {
+      const t = node.data.traces.find((tr: Trace) => tr.id === id);
+      if (!t) return [];
+      if (t.mergedColors && t.mergedColors.length > 0) return t.mergedColors;
+      return t.color ? [t.color] : [];
+    });
 
     // Compute merged messages
     const messages = computeMergedMessages(nodeId, sourceTraceIds, strategy);
@@ -1533,12 +1754,15 @@ const useFlowStore = create<FlowState>((set, get) => ({
     const newSourceTraceIds = updates.sourceTraceIds || current.sourceTraceIds;
     const newStrategy = updates.strategy || current.strategy;
 
-    // Recompute colors if source traces changed
+    // Recompute colors if source traces changed (preserve multi-colors)
     let newColors = current.colors;
     if (updates.sourceTraceIds) {
-      newColors = updates.sourceTraceIds
-        .map(id => node.data.traces.find((t: Trace) => t.id === id)?.color)
-        .filter((c): c is string => c !== undefined);
+      newColors = updates.sourceTraceIds.flatMap(id => {
+        const t = node.data.traces.find((tr: Trace) => tr.id === id);
+        if (!t) return [];
+        if (t.mergedColors && t.mergedColors.length > 0) return t.mergedColors;
+        return t.color ? [t.color] : [];
+      });
     }
 
     // Recompute messages if source or strategy changed
@@ -1919,10 +2143,13 @@ const useFlowStore = create<FlowState>((set, get) => ({
           // Get prepend messages for this merged trace
           const mergedPrepend = prependMessages.get(merged.id) || [];
           
-          // Update colors from current traces
-          const updatedColors = merged.sourceTraceIds
-            .map(id => uniqueIncoming.find(t => t.id === id)?.color)
-            .filter((c): c is string => c !== undefined);
+          // Update colors from current traces (preserve multi-colors)
+          const updatedColors = merged.sourceTraceIds.flatMap(id => {
+            const t = uniqueIncoming.find(trace => trace.id === id);
+            if (!t) return [];
+            if (t.mergedColors && t.mergedColors.length > 0) return t.mergedColors;
+            return t.color ? [t.color] : [];
+          });
           
           // Combine all messages for this merged trace
           const mergedMessages = [...mergedPrepend, ...filteredMessages, ...myResponseMsg];
@@ -2017,7 +2244,8 @@ const useFlowStore = create<FlowState>((set, get) => ({
         };
       })
     }));
-  }
-}));
+  },
+  };
+});
 
 export default useFlowStore;