1 files changed, 13 insertions, 2 deletions
diff --git a/src/LivingVillage.Kernel/Occupation.fs b/src/LivingVillage.Kernel/Occupation.fs
index c207395..45ef428 100644
--- a/src/LivingVillage.Kernel/Occupation.fs
+++ b/src/LivingVillage.Kernel/Occupation.fs
@@ -194,14 +194,25 @@ module Occupation =
 
     /// 挂在玩家侧的职业状态，随存档 v3 保存（design §2）。
     /// Today = 当日任务（§3）；TaskToken 保留为 v3 前缀占位扩展位（恒 0，暂未启用）。
+    /// Backpack = 玩家背包侧车（design §2.4-1）：开局 = profile.InitialInventory 的纯数据副本，
+    /// 不进 `Sim.World`、不动 `Sim.step` 数值路径；键值对保持声明顺序以稳定序列化。
     type State =
         { Profile: Profile
           TaskToken: int
           Today: DailyTask option
-          StoryStage: int }
+          StoryStage: int
+          Backpack: (Sim.ItemKind * int) list }
 
     let stateOf (kind: Kind) : State =
-        { Profile = profileOf kind; TaskToken = 0; Today = None; StoryStage = 0 }
+        { Profile = profileOf kind
+          TaskToken = 0
+          Today = None
+          StoryStage = 0
+          Backpack = (profileOf kind).InitialInventory }
+
+    /// 背包内某物品数量（纯函数；无则 0）。
+    let backpackQuantity (item: Sim.ItemKind) (state: State) : int =
+        state.Backpack |> List.sumBy (fun (kind, quantity) -> if kind = item then quantity else 0)
 
     // ---- 既有事件通道 → 任务信号桥（design §3：完成判定统一走 InteractionEvent）----