diff --git a/.tasks/2025-11-08_3_backpack.md b/.tasks/2025-11-08_3_backpack.md
index 3ed02c8..5ea2196 100644
--- a/.tasks/2025-11-08_3_backpack.md
+++ b/.tasks/2025-11-08_3_backpack.md
@@ -26,6 +26,20 @@ PWF插件框架, 通过`PluginInterface`管理插件生命周期, `WPSAPI`提供
 
 # 任务进度
 
+2025-11-08_15:11:43
+- 已修改: Plugins/WPSBackpackSystem.py
+- 更改: 定义背包系统插件结构, 建立物品等级枚举、数据库表模型、跨插件接口与指令回调
+- 原因: 实现背包系统基础能力供其他插件注册物品与查询用户背包
+- 阻碍因素: 无
+- 状态: 未确认
+
+2025-11-08_15:29:00
+- 已修改: PWF/CoreModules/plugin_interface.py Plugins/WPSBackpackSystem.py
+- 更改: 调整插件加载逻辑确保在wake_up前创建数据库表, 移除插件内部重复建表调用
+- 原因: 解决首次运行背包插件报错“no such table: backpack_items”
+- 阻碍因素: 无
+- 状态: 成功
+
 # 最终审查
 
 
diff --git a/PWF b/PWF
index 6c53a3a..4d3d841 160000
--- a/PWF
+++ b/PWF
@@ -1 +1 @@
-Subproject commit 6c53a3a18f0d461ebbbe20bed33783c86561f428
+Subproject commit 4d3d841ddac30a060c333cb248d629437234d635
diff --git a/Plugins/WPSAPI.py b/Plugins/WPSAPI.py
index 76bca0c..bca3616 100644
--- a/Plugins/WPSAPI.py
+++ b/Plugins/WPSAPI.py
@@ -180,7 +180,10 @@ class BasicWPSInterface(PluginInterface):
         if webhook_url == "" or webhook_url == None:
             return None
 
-        result = await self.get_message_sender_function(webhook_url, self.get_message_sender_type())(message)
+        result = await self.get_message_sender_function(webhook_url, self.get_message_sender_type())(f"""<at user_id="{user_id}"></at>
+---
+{message}
+""")
         if get_internal_verbose():
             logger.Log("Info", f"Webhook URL: {webhook_url}, Message: {LimitStringLength(message)}, Result: {result}")
         return None
diff --git a/Plugins/WPSBackpackSystem.py b/Plugins/WPSBackpackSystem.py
index e69de29..18ed6b9 100644
--- a/Plugins/WPSBackpackSystem.py
+++ b/Plugins/WPSBackpackSystem.py
@@ -0,0 +1,305 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from enum import Enum
+from typing import Dict, List, Optional, Tuple, override
+
+from PWF.Convention.Runtime.Architecture import Architecture
+from PWF.Convention.Runtime.GlobalConfig import ConsoleFrontColor, ProjectConfig
+from PWF.CoreModules.database import get_db
+
+from .WPSAPI import WPSAPI
+
+logger: ProjectConfig = Architecture.Get(ProjectConfig)
+
+
+class BackpackItemTier(Enum):
+    """背包物品等级定义"""
+
+    COMMON = ("普通", "#C0C0C0")
+    RARE = ("稀有", "#4DA6FF")
+    EPIC = ("史诗", "#B266FF")
+    LEGENDARY = ("传说", "#FF9933")
+
+    def __init__(self, display_name: str, color_hex: str):
+        self.display_name = display_name
+        self.color_hex = color_hex
+
+    @classmethod
+    def from_string(cls, value: str) -> "BackpackItemTier":
+        for tier in cls:
+            if tier.name == value or tier.display_name == value:
+                return tier
+        raise ValueError(f"Unknown backpack item tier: {value}")
+
+    def to_markdown_label(self, content: str) -> str:
+        return f'<font color="{self.color_hex}">{content}</font>'
+
+
+@dataclass(frozen=True)
+class BackpackItemDefinition:
+    item_id: str
+    name: str
+    tier: BackpackItemTier
+
+
+@dataclass(frozen=True)
+class BackpackUserItem:
+    item_id: str
+    quantity: int
+    definition: BackpackItemDefinition
+
+
+class WPSBackpackSystem(WPSAPI):
+    """背包基础系统，负责物品注册与用户物品存取"""
+
+    ITEMS_TABLE = "backpack_items"
+    USER_ITEMS_TABLE = "backpack_user_items"
+
+    def __init__(self) -> None:
+        super().__init__()
+        self._item_cache: Dict[str, BackpackItemDefinition] = {}
+
+    @override
+    def dependencies(self) -> List[type]:
+        return [WPSAPI]
+
+    @override
+    def is_enable_plugin(self) -> bool:
+        return True
+
+    @override
+    def register_db_model(self):
+        from PWF.CoreModules.plugin_interface import DatabaseModel
+
+        return [
+            DatabaseModel(
+                table_name=self.ITEMS_TABLE,
+                column_defs={
+                    "item_id": "TEXT PRIMARY KEY",
+                    "name": "TEXT NOT NULL",
+                    "tier": "TEXT NOT NULL",
+                },
+            ),
+            DatabaseModel(
+                table_name=self.USER_ITEMS_TABLE,
+                column_defs={
+                    "user_id": "INTEGER NOT NULL",
+                    "item_id": "TEXT NOT NULL",
+                    "quantity": "INTEGER NOT NULL DEFAULT 0",
+                    "PRIMARY KEY (user_id, item_id)": "",
+                },
+            ),
+        ]
+
+    @override
+    def wake_up(self) -> None:
+        logger.Log(
+            "Info",
+            f"{ConsoleFrontColor.GREEN}WPSBackpackSystem 插件已加载{ConsoleFrontColor.RESET}",
+        )
+        self.register_plugin("背包")
+        self.register_plugin("backpack")
+        self._warm_item_cache()
+
+    def _warm_item_cache(self) -> None:
+        cursor = get_db().conn.cursor()
+        cursor.execute(
+            f"SELECT item_id, name, tier FROM {self.ITEMS_TABLE}"
+        )
+        rows = cursor.fetchall()
+        for row in rows:
+            tier = BackpackItemTier.from_string(row["tier"])
+            self._item_cache[row["item_id"]] = BackpackItemDefinition(
+                item_id=row["item_id"],
+                name=row["name"],
+                tier=tier,
+            )
+
+    # region 对外接口
+
+    def register_item(
+        self,
+        item_id: str,
+        name: str,
+        tier: BackpackItemTier,
+    ) -> None:
+        if not item_id or not name:
+            raise ValueError("item_id and name must be provided")
+        cursor = get_db().conn.cursor()
+        cursor.execute(
+            f"""
+            INSERT INTO {self.ITEMS_TABLE} (item_id, name, tier)
+            VALUES (?, ?, ?)
+            ON CONFLICT(item_id) DO UPDATE
+                SET name = excluded.name,
+                    tier = excluded.tier
+            """,
+            (item_id, name, tier.name),
+        )
+        get_db().conn.commit()
+        self._item_cache[item_id] = BackpackItemDefinition(item_id, name, tier)
+
+    def add_item(
+        self,
+        user_id: int,
+        item_id: str,
+        delta: int,
+    ) -> int:
+        if delta == 0:
+            definition = self._get_definition(item_id)
+            return self._get_user_quantity(user_id, item_id, definition)
+        if delta < 0:
+            raise ValueError("delta must be positive when using add_item")
+        definition = self._get_definition(item_id)
+        cursor = get_db().conn.cursor()
+        cursor.execute(
+            f"""
+            INSERT INTO {self.USER_ITEMS_TABLE} (user_id, item_id, quantity)
+            VALUES (?, ?, ?)
+            ON CONFLICT(user_id, item_id) DO UPDATE
+                SET quantity = {self.USER_ITEMS_TABLE}.quantity + excluded.quantity
+            """,
+            (user_id, item_id, delta),
+        )
+        get_db().conn.commit()
+        return self._get_user_quantity(user_id, item_id, definition)
+
+    def set_item_quantity(
+        self,
+        user_id: int,
+        item_id: str,
+        quantity: int,
+    ) -> int:
+        if quantity < 0:
+            raise ValueError("quantity must be non-negative")
+        definition = self._get_definition(item_id)
+        cursor = get_db().conn.cursor()
+        cursor.execute(
+            f"""
+            INSERT INTO {self.USER_ITEMS_TABLE} (user_id, item_id, quantity)
+            VALUES (?, ?, ?)
+            ON CONFLICT(user_id, item_id) DO UPDATE
+                SET quantity = excluded.quantity
+            """,
+            (user_id, item_id, quantity),
+        )
+        get_db().conn.commit()
+        return self._get_user_quantity(user_id, item_id, definition)
+
+    def get_user_items(self, user_id: int) -> List[BackpackUserItem]:
+        cursor = get_db().conn.cursor()
+        cursor.execute(
+            f"""
+            SELECT ui.item_id, ui.quantity, i.name, i.tier
+            FROM {self.USER_ITEMS_TABLE} ui
+            JOIN {self.ITEMS_TABLE} i ON ui.item_id = i.item_id
+            WHERE ui.user_id = ? AND ui.quantity > 0
+            ORDER BY ui.quantity DESC
+            """,
+            (user_id,),
+        )
+        rows = cursor.fetchall()
+        result: List[BackpackUserItem] = []
+        for row in rows:
+            definition = self._item_cache.get(row["item_id"])
+            if not definition:
+                try:
+                    definition = BackpackItemDefinition(
+                        item_id=row["item_id"],
+                        name=row["name"],
+                        tier=BackpackItemTier.from_string(row["tier"]),
+                    )
+                except ValueError:
+                    continue
+            result.append(
+                BackpackUserItem(
+                    item_id=row["item_id"],
+                    quantity=row["quantity"],
+                    definition=definition,
+                )
+            )
+        return result
+
+    # endregion
+
+    def _get_definition(self, item_id: str) -> BackpackItemDefinition:
+        if item_id in self._item_cache:
+            return self._item_cache[item_id]
+        cursor = get_db().conn.cursor()
+        cursor.execute(
+            f"SELECT item_id, name, tier FROM {self.ITEMS_TABLE} WHERE item_id = ?",
+            (item_id,),
+        )
+        row = cursor.fetchone()
+        if not row:
+            raise ValueError(f"Item {item_id} not registered in backpack system")
+        definition = BackpackItemDefinition(
+            item_id=row["item_id"],
+            name=row["name"],
+            tier=BackpackItemTier.from_string(row["tier"]),
+        )
+        self._item_cache[item_id] = definition
+        return definition
+
+    def _get_user_quantity(
+        self,
+        user_id: int,
+        item_id: str,
+        definition: BackpackItemDefinition,
+    ) -> int:
+        cursor = get_db().conn.cursor()
+        cursor.execute(
+            f"""
+            SELECT quantity
+            FROM {self.USER_ITEMS_TABLE}
+            WHERE user_id = ? AND item_id = ?
+            """,
+            (user_id, item_id),
+        )
+        row = cursor.fetchone()
+        quantity = int(row["quantity"]) if row else 0
+        if quantity == 0:
+            cursor.execute(
+                f"""
+                DELETE FROM {self.USER_ITEMS_TABLE}
+                WHERE user_id = ? AND item_id = ?
+                """,
+                (user_id, item_id),
+            )
+            get_db().conn.commit()
+        return quantity
+
+    def _format_backpack_markdown(self, user_items: List[BackpackUserItem]) -> str:
+        if not user_items:
+            return "# 🎒 背包一览\n> 当前背包空空如也，去冒险获取一些物品吧！"
+
+        lines = ["# 🎒 背包一览"]
+        sorted_items = sorted(
+            user_items,
+            key=lambda item: (
+                list(BackpackItemTier).index(item.definition.tier),
+                -item.quantity,
+                item.definition.name,
+            ),
+        )
+        for entry in sorted_items:
+            tier_label = entry.definition.tier.to_markdown_label(
+                entry.definition.tier.display_name
+            )
+            lines.append(
+                f"- {tier_label} · {entry.definition.name} × **{entry.quantity}**"
+            )
+        return "\n".join(lines)
+
+    @override
+    async def callback(self, message: str, chat_id: int, user_id: int) -> Optional[str]:
+        message = self.parse_message_after_at(message).strip()
+        user_items = self.get_user_items(user_id)
+        markdown = self._format_backpack_markdown(user_items)
+        await self.send_markdown_message(markdown, chat_id, user_id)
+        return None
+
+
+__all__ = ["WPSBackpackSystem", "BackpackItemTier", "BackpackItemDefinition"]
+