diff --git a/backend/app/core/session_alias_store.py b/backend/app/core/session_alias_store.py
new file mode 100644
index 0000000..153d1c1
--- /dev/null
+++ b/backend/app/core/session_alias_store.py
@@ -0,0 +1,173 @@
+from __future__ import annotations
+
+import sqlite3
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any
+
+
+class SessionAliasStore:
+    def __init__(self) -> None:
+        backend_root = Path(__file__).resolve().parents[2]
+        data_dir = backend_root / "data"
+        data_dir.mkdir(parents=True, exist_ok=True)
+        self.db_path = data_dir / "nanobot_sessions.db"
+        self._init_db()
+
+    def _connect(self) -> sqlite3.Connection:
+        conn = sqlite3.connect(str(self.db_path))
+        conn.row_factory = sqlite3.Row
+        return conn
+
+    def _init_db(self) -> None:
+        with self._connect() as conn:
+            conn.execute(
+                """
+                CREATE TABLE IF NOT EXISTS session_cache (
+                    session_key TEXT PRIMARY KEY,
+                    created_at TEXT,
+                    updated_at TEXT,
+                    alias TEXT,
+                    pinned INTEGER NOT NULL DEFAULT 0,
+                    archived INTEGER NOT NULL DEFAULT 0,
+                    last_seen_at TEXT NOT NULL
+                )
+                """
+            )
+            cols = {
+                str(row["name"])
+                for row in conn.execute("PRAGMA table_info(session_cache)").fetchall()
+            }
+            if "pinned" not in cols:
+                conn.execute("ALTER TABLE session_cache ADD COLUMN pinned INTEGER NOT NULL DEFAULT 0")
+            if "archived" not in cols:
+                conn.execute("ALTER TABLE session_cache ADD COLUMN archived INTEGER NOT NULL DEFAULT 0")
+
+    def sync_sessions(self, sessions: list[dict[str, Any]]) -> None:
+        now = datetime.now(timezone.utc).isoformat()
+        keys: list[str] = []
+        with self._connect() as conn:
+            for item in sessions:
+                key = str(item.get("key") or "").strip()
+                if not key:
+                    continue
+                keys.append(key)
+                created_at = str(item.get("created_at") or "")
+                updated_at = str(item.get("updated_at") or "")
+                conn.execute(
+                    """
+                    INSERT INTO session_cache (session_key, created_at, updated_at, last_seen_at)
+                    VALUES (?, ?, ?, ?)
+                    ON CONFLICT(session_key) DO UPDATE SET
+                      created_at = excluded.created_at,
+                      updated_at = excluded.updated_at,
+                      last_seen_at = excluded.last_seen_at
+                    """,
+                    (key, created_at, updated_at, now),
+                )
+
+            if keys:
+                placeholders = ",".join("?" for _ in keys)
+                conn.execute(
+                    f"DELETE FROM session_cache WHERE session_key NOT IN ({placeholders})",
+                    keys,
+                )
+            else:
+                conn.execute("DELETE FROM session_cache")
+
+    def list_cached_sessions(self) -> list[dict[str, Any]]:
+        with self._connect() as conn:
+            rows = conn.execute(
+                """
+                SELECT session_key, created_at, updated_at, alias, pinned, archived
+                FROM session_cache
+                ORDER BY pinned DESC, archived ASC, updated_at DESC
+                """
+            ).fetchall()
+        return [self._row_to_session_item(row) for row in rows]
+
+    def sync_and_list(self, sessions: list[dict[str, Any]]) -> list[dict[str, Any]]:
+        self.sync_sessions(sessions)
+        return self.list_cached_sessions()
+
+    def set_alias(self, session_key: str, alias: str) -> None:
+        now = datetime.now(timezone.utc).isoformat()
+        clean_alias = alias.strip()
+        with self._connect() as conn:
+            conn.execute(
+                """
+                INSERT INTO session_cache (session_key, created_at, updated_at, alias, last_seen_at)
+                VALUES (?, '', '', ?, ?)
+                ON CONFLICT(session_key) DO UPDATE SET
+                  alias = excluded.alias,
+                  last_seen_at = excluded.last_seen_at
+                """,
+                (session_key, clean_alias, now),
+            )
+
+    def update_alias_meta(
+        self,
+        session_key: str,
+        alias: str | None = None,
+        pinned: bool | None = None,
+        archived: bool | None = None,
+    ) -> dict[str, Any]:
+        now = datetime.now(timezone.utc).isoformat()
+        with self._connect() as conn:
+            row = conn.execute(
+                "SELECT alias, pinned, archived FROM session_cache WHERE session_key = ?",
+                (session_key,),
+            ).fetchone()
+            current_alias = (str(row["alias"]) if row and row["alias"] else "")
+            current_pinned = bool(row["pinned"]) if row else False
+            current_archived = bool(row["archived"]) if row else False
+            next_alias = current_alias if alias is None else alias.strip()
+            next_pinned = current_pinned if pinned is None else bool(pinned)
+            next_archived = current_archived if archived is None else bool(archived)
+            conn.execute(
+                """
+                INSERT INTO session_cache (session_key, created_at, updated_at, alias, pinned, archived, last_seen_at)
+                VALUES (?, '', '', ?, ?, ?, ?)
+                ON CONFLICT(session_key) DO UPDATE SET
+                  alias = excluded.alias,
+                  pinned = excluded.pinned,
+                  archived = excluded.archived,
+                  last_seen_at = excluded.last_seen_at
+                """,
+                (session_key, next_alias, int(next_pinned), int(next_archived), now),
+            )
+        return {"alias": next_alias or None, "pinned": next_pinned, "archived": next_archived}
+
+    def get_alias(self, session_key: str) -> str | None:
+        with self._connect() as conn:
+            row = conn.execute(
+                "SELECT alias FROM session_cache WHERE session_key = ?",
+                (session_key,),
+            ).fetchone()
+        if not row:
+            return None
+        alias = row["alias"]
+        return str(alias) if alias else None
+
+    def delete_session(self, session_key: str) -> None:
+        with self._connect() as conn:
+            conn.execute("DELETE FROM session_cache WHERE session_key = ?", (session_key,))
+
+    def _row_to_session_item(self, row: sqlite3.Row) -> dict[str, Any]:
+        alias = (row["alias"] or "").strip()
+        fallback = str(row["session_key"]).replace("api:", "")
+        title = alias or fallback
+        pinned = bool(row["pinned"]) if "pinned" in row.keys() else False
+        archived = bool(row["archived"]) if "archived" in row.keys() else False
+        return {
+            "key": row["session_key"],
+            "created_at": row["created_at"],
+            "updated_at": row["updated_at"],
+            "metadata": {"title": title},
+            "alias": alias or None,
+            "pinned": pinned,
+            "archived": archived,
+        }
+
+
+session_alias_store = SessionAliasStore()
diff --git a/backend/main.py b/backend/main.py
index 53fc541..f1d1815 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -1,5 +1,5 @@
 from typing import List, Optional
-from fastapi import FastAPI, HTTPException, Body
+from fastapi import FastAPI, HTTPException
 from fastapi.responses import StreamingResponse
 from fastapi.middleware.cors import CORSMiddleware
 from pydantic import BaseModel
@@ -11,6 +11,7 @@ from app.connectors.postgres import postgres_connector
 from app.connectors.clickhouse import clickhouse_connector
 from app.connectors.minio import minio_connector
 from app.core.nanobot import nanobot_service
+from app.core.session_alias_store import session_alias_store
 from app.agent.nl2sql import process_nl2sql, NL2SQLRequest, NL2SQLResponse
 
 app = FastAPI()
@@ -74,10 +75,21 @@ class ChatRequest(BaseModel):
     skill_ids: Optional[List[str]] = None
     model_id: Optional[str] = None
 
+
+class SessionAliasUpdateRequest(BaseModel):
+    title: Optional[str] = None
+    pinned: Optional[bool] = None
+    archived: Optional[bool] = None
+
 @app.post("/nanobot/chat")
 async def nanobot_chat(request: ChatRequest):
     try:
-        response = await nanobot_service.process_message(request.message, skill_ids=request.skill_ids, model_id=request.model_id)
+        response = await nanobot_service.process_message(
+            request.message,
+            session_id=request.session_id,
+            skill_ids=request.skill_ids,
+            model_id=request.model_id,
+        )
         return {"response": response}
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))
@@ -115,21 +127,22 @@ async def nanobot_chat_stream(request: ChatRequest):
 @app.get("/nanobot/sessions")
 def get_sessions():
     if not nanobot_service.agent:
-        return []
-    # session_manager has list_sessions()
+        return session_alias_store.list_cached_sessions()
     sessions = nanobot_service.agent.sessions.list_sessions()
-    return sessions
+    return session_alias_store.sync_and_list(sessions)
 
 @app.get("/nanobot/sessions/{session_id}")
 def get_session(session_id: str):
     if not nanobot_service.agent:
         raise HTTPException(status_code=400, detail="Nanobot not running")
     session = nanobot_service.agent.sessions.get_or_create(session_id)
+    alias = session_alias_store.get_alias(session_id)
     return {
         "key": session.key,
         "created_at": session.created_at,
         "updated_at": session.updated_at,
         "metadata": session.metadata,
+        "alias": alias,
         "messages": session.messages
     }
 
@@ -145,18 +158,19 @@ def delete_session(session_id: str):
         path = nanobot_service.agent.sessions._get_session_path(session_id)
         if path.exists():
             path.unlink()
+        session_alias_store.delete_session(session_id)
         return {"status": "success"}
     raise HTTPException(status_code=404, detail="Session not found")
 
 @app.put("/nanobot/sessions/{session_id}")
-def update_session(session_id: str, title: str = Body(..., embed=True)):
-    if not nanobot_service.agent:
-        raise HTTPException(status_code=400, detail="Nanobot not running")
-    
-    session = nanobot_service.agent.sessions.get_or_create(session_id)
-    session.metadata["title"] = title
-    nanobot_service.agent.sessions.save(session)
-    return {"status": "success", "title": title}
+def update_session(session_id: str, payload: SessionAliasUpdateRequest):
+    updated = session_alias_store.update_alias_meta(
+        session_key=session_id,
+        alias=payload.title,
+        pinned=payload.pinned,
+        archived=payload.archived,
+    )
+    return {"status": "success", **updated}
 
 @app.post("/api/v1/agent/nl2sql", response_model=NL2SQLResponse)
 async def run_nl2sql(request: NL2SQLRequest):
diff --git a/frontend/src/components/ChatInterface.tsx b/frontend/src/components/ChatInterface.tsx
index 373a5d9..e8e1633 100644
--- a/frontend/src/components/ChatInterface.tsx
+++ b/frontend/src/components/ChatInterface.tsx
@@ -17,6 +17,7 @@ interface Message {
   id: string;
   role: 'user' | 'assistant';
   content: string;
+  awaitingFirstToken?: boolean;
 }
 
 interface ModelConfig {
@@ -131,10 +132,12 @@ export function ChatInterface() {
          setMessages(prev => [...prev, {
             id: assistantId,
             role: "assistant",
-            content: ""
+            content: "",
+            awaitingFirstToken: true
          }]);
 
          const token = localStorage.getItem("token");
+         const effectiveModelId = selectedModelId || currentModel?.id || "";
          const response = await fetch("/nanobot/chat/stream", {
            method: "POST",
            headers: {
@@ -144,7 +147,7 @@ export function ChatInterface() {
            body: JSON.stringify({
                message: newMessage.content,
                session_id: activeSessionKey,
-               model_id: selectedModelId,
+               model_id: effectiveModelId,
              }),
          });
 
@@ -178,7 +181,7 @@ export function ChatInterface() {
                streamedText = `${streamedText}${payload.content}`;
                setMessages((prev) =>
                  prev.map((msg) =>
-                   msg.id === assistantId ? { ...msg, content: streamedText } : msg
+                    msg.id === assistantId ? { ...msg, content: streamedText, awaitingFirstToken: false } : msg
                  )
                );
              }
@@ -187,7 +190,7 @@ export function ChatInterface() {
                streamedText = payload.content;
                setMessages((prev) =>
                  prev.map((msg) =>
-                   msg.id === assistantId ? { ...msg, content: payload.content || "" } : msg
+                    msg.id === assistantId ? { ...msg, content: payload.content || "", awaitingFirstToken: false } : msg
                  )
                );
              }
@@ -197,6 +200,19 @@ export function ChatInterface() {
              }
            }
          }
+
+         if (!streamedText) {
+           const fallback = await api.post<{ response: string }>("/nanobot/chat", {
+             message: newMessage.content,
+             session_id: activeSessionKey,
+             model_id: effectiveModelId,
+           });
+           setMessages((prev) =>
+             prev.map((msg) =>
+              msg.id === assistantId ? { ...msg, content: fallback.response || "暂无回复", awaitingFirstToken: false } : msg
+             )
+           );
+         }
       } else {
          // Fallback to existing NL2SQL or other skills (e.g. for "表格问答" or "深度问数")
          const source = selectedDataSource.split('-')[0]; // postgres-main -> postgres
@@ -235,6 +251,7 @@ export function ChatInterface() {
     } finally {
         setIsLoading(false);
         setVizLoading(false);
+        window.dispatchEvent(new Event("nanobot:sessions-changed"));
     }
   };
 
@@ -372,11 +389,18 @@ export function ChatInterface() {
                     }`}
                   >
                     {msg.role === "assistant" ? (
-                      <div className="prose prose-sm prose-zinc max-w-none prose-p:leading-normal prose-p:my-2 prose-headings:my-3 prose-ul:my-2 prose-li:my-0.5 prose-pre:bg-zinc-50 prose-pre:text-zinc-800 prose-pre:border prose-pre:border-zinc-200">
-                        <ReactMarkdown remarkPlugins={[remarkGfm]} rehypePlugins={[rehypeRaw]}>
-                          {msg.content}
-                        </ReactMarkdown>
-                      </div>
+                      msg.awaitingFirstToken && !msg.content ? (
+                        <div className="flex items-center gap-2 text-zinc-500 text-sm py-1">
+                          <Loader2 className="h-4 w-4 animate-spin" />
+                          <span>模型思考中，请稍候...</span>
+                        </div>
+                      ) : (
+                        <div className="prose prose-sm prose-zinc max-w-none prose-p:leading-normal prose-p:my-2 prose-headings:my-3 prose-ul:my-2 prose-li:my-0.5 prose-pre:bg-zinc-50 prose-pre:text-zinc-800 prose-pre:border prose-pre:border-zinc-200">
+                          <ReactMarkdown remarkPlugins={[remarkGfm]} rehypePlugins={[rehypeRaw]}>
+                            {msg.content}
+                          </ReactMarkdown>
+                        </div>
+                      )
                     ) : (
                       msg.content
                     )}
diff --git a/frontend/src/components/Sidebar.tsx b/frontend/src/components/Sidebar.tsx
index b42944c..d5022a0 100644
--- a/frontend/src/components/Sidebar.tsx
+++ b/frontend/src/components/Sidebar.tsx
@@ -1,7 +1,7 @@
 import { Sheet, SheetContent, SheetTrigger } from "@/components/ui/sheet";
 import { Button } from "@/components/ui/button";
 import { ScrollArea } from "@/components/ui/scroll-area";
-import { Menu, LayoutDashboard, Plus, MoreVertical, User, Search, Wrench, Settings, Brain, Trash2, Pencil } from "lucide-react";
+import { Menu, LayoutDashboard, Plus, MoreVertical, User, Search, Wrench, Settings, Brain, Trash2, Pencil, Pin, Archive } from "lucide-react";
 import { useState, useRef, useEffect } from "react";
 import { Link, useNavigate, useLocation } from "react-router-dom";
 import { useAuthStore } from "@/store/authStore";
@@ -14,6 +14,9 @@ interface SessionInfo {
   key: string;
   created_at: string;
   updated_at: string;
+  alias?: string | null;
+  pinned?: boolean;
+  archived?: boolean;
   metadata?: {
     title?: string;
   };
@@ -26,6 +29,8 @@ function Section({
   onSelect,
   onDelete,
   onRename,
+  onTogglePinned,
+  onToggleArchived,
   activeKey
 }: {
   title: string;
@@ -34,6 +39,8 @@ function Section({
   onSelect: (key: string) => void;
   onDelete: (key: string) => void;
   onRename: (key: string, currentTitle: string) => void;
+  onTogglePinned: (key: string, pinned: boolean) => void;
+  onToggleArchived: (key: string, archived: boolean) => void;
   activeKey: string | null;
 }) {
   return (
@@ -64,11 +71,64 @@ function Section({
                   <MoreVertical className="h-4 w-4" />
                 </DropdownMenuTrigger>
                 <DropdownMenuContent align="end" className="w-32">
-                  <DropdownMenuItem onClick={(e) => { e.stopPropagation(); onRename(item.key, displayTitle); }}>
+                  <DropdownMenuItem
+                    onClick={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onRename(item.key, displayTitle);
+                    }}
+                    onSelect={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onRename(item.key, displayTitle);
+                    }}
+                  >
                     <Pencil className="mr-2 h-4 w-4" />
                     <span>重命名</span>
                   </DropdownMenuItem>
-                  <DropdownMenuItem onClick={(e) => { e.stopPropagation(); onDelete(item.key); }} className="text-red-600 focus:text-red-600 focus:bg-red-50">
+                  <DropdownMenuItem
+                    onClick={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onTogglePinned(item.key, !!item.pinned);
+                    }}
+                    onSelect={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onTogglePinned(item.key, !!item.pinned);
+                    }}
+                  >
+                    <Pin className="mr-2 h-4 w-4" />
+                    <span>{item.pinned ? "取消置顶" : "置顶"}</span>
+                  </DropdownMenuItem>
+                  <DropdownMenuItem
+                    onClick={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onToggleArchived(item.key, !!item.archived);
+                    }}
+                    onSelect={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onToggleArchived(item.key, !!item.archived);
+                    }}
+                  >
+                    <Archive className="mr-2 h-4 w-4" />
+                    <span>{item.archived ? "取消归档" : "归档"}</span>
+                  </DropdownMenuItem>
+                  <DropdownMenuItem
+                    onClick={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onDelete(item.key);
+                    }}
+                    onSelect={(e) => {
+                      e.preventDefault();
+                      e.stopPropagation();
+                      onDelete(item.key);
+                    }}
+                    className="text-red-600 focus:text-red-600 focus:bg-red-50"
+                  >
                     <Trash2 className="mr-2 h-4 w-4" />
                     <span>删除会话</span>
                   </DropdownMenuItem>
@@ -110,9 +170,17 @@ function SidebarBody() {
 
   useEffect(() => {
     fetchSessions();
-    // Set up polling to refresh session list
-    const interval = setInterval(fetchSessions, 5000);
-    return () => clearInterval(interval);
+  }, [location.pathname, location.search]);
+
+  useEffect(() => {
+    const onFocus = () => fetchSessions();
+    const onSessionsChanged = () => fetchSessions();
+    window.addEventListener("focus", onFocus);
+    window.addEventListener("nanobot:sessions-changed", onSessionsChanged);
+    return () => {
+      window.removeEventListener("focus", onFocus);
+      window.removeEventListener("nanobot:sessions-changed", onSessionsChanged);
+    };
   }, []);
 
   useEffect(() => {
@@ -142,11 +210,12 @@ function SidebarBody() {
   const handleDeleteSession = async (key: string) => {
     if (!window.confirm("确定要删除这个会话吗？")) return;
     try {
-      await api.delete(`/nanobot/sessions/${key}`);
+      await api.delete(`/nanobot/sessions/${encodeURIComponent(key)}`);
       if (activeSessionKey === key) {
         navigate("/");
       }
       fetchSessions();
+      window.dispatchEvent(new Event("nanobot:sessions-changed"));
     } catch (e) {
       console.error("Failed to delete session", e);
     }
@@ -161,14 +230,69 @@ function SidebarBody() {
   const handleRename = async () => {
     if (!sessionToRename || !newTitle.trim()) return;
     try {
-      await api.put(`/nanobot/sessions/${sessionToRename.key}`, { title: newTitle.trim() });
+      const nextTitle = newTitle.trim();
+      await api.put(`/nanobot/sessions/${encodeURIComponent(sessionToRename.key)}`, { title: nextTitle });
+      setSessions((prev) =>
+        prev.map((item) =>
+          item.key === sessionToRename.key
+            ? { ...item, alias: nextTitle, metadata: { ...(item.metadata || {}), title: nextTitle } }
+            : item
+        )
+      );
       setRenameDialogOpen(false);
       fetchSessions();
+      window.dispatchEvent(new Event("nanobot:sessions-changed"));
     } catch (e) {
       console.error("Failed to rename session", e);
     }
   };
 
+  const handleTogglePinned = async (key: string, pinned: boolean) => {
+    const nextPinned = !pinned;
+    try {
+      await api.put(`/nanobot/sessions/${encodeURIComponent(key)}`, { pinned: nextPinned });
+      setSessions((prev) =>
+        prev
+          .map((item) => (item.key === key ? { ...item, pinned: nextPinned } : item))
+          .sort((a, b) => {
+            const ap = a.pinned ? 1 : 0;
+            const bp = b.pinned ? 1 : 0;
+            if (bp !== ap) return bp - ap;
+            const aa = a.archived ? 1 : 0;
+            const ba = b.archived ? 1 : 0;
+            if (aa !== ba) return aa - ba;
+            return (b.updated_at || "").localeCompare(a.updated_at || "");
+          })
+      );
+      window.dispatchEvent(new Event("nanobot:sessions-changed"));
+    } catch (e) {
+      console.error("Failed to toggle pinned", e);
+    }
+  };
+
+  const handleToggleArchived = async (key: string, archived: boolean) => {
+    const nextArchived = !archived;
+    try {
+      await api.put(`/nanobot/sessions/${encodeURIComponent(key)}`, { archived: nextArchived });
+      setSessions((prev) =>
+        prev
+          .map((item) => (item.key === key ? { ...item, archived: nextArchived } : item))
+          .sort((a, b) => {
+            const ap = a.pinned ? 1 : 0;
+            const bp = b.pinned ? 1 : 0;
+            if (bp !== ap) return bp - ap;
+            const aa = a.archived ? 1 : 0;
+            const ba = b.archived ? 1 : 0;
+            if (aa !== ba) return aa - ba;
+            return (b.updated_at || "").localeCompare(a.updated_at || "");
+          })
+      );
+      window.dispatchEvent(new Event("nanobot:sessions-changed"));
+    } catch (e) {
+      console.error("Failed to toggle archived", e);
+    }
+  };
+
   return (
     <div className="h-full flex flex-col bg-zinc-50/30 border-r border-zinc-200 relative">
       {/* Header */}
@@ -214,6 +338,8 @@ function SidebarBody() {
           onSelect={handleSelectSession}
           onDelete={handleDeleteSession}
           onRename={openRenameDialog}
+          onTogglePinned={handleTogglePinned}
+          onToggleArchived={handleToggleArchived}
           activeKey={activeSessionKey}
         />
       </ScrollArea>