Update app.py

app.py

@@ -1,5 +1,5 @@
 # app.py
-# @title Beer Game Final Version (v4.25 - Based on v4.21 Logic + UI Fixes v3 - Log Fix)
+# @title Beer Game Final Version (v9 - Correct LT=3, Correct UI, Correct Log)
 
 # -----------------------------------------------------------------------------
 # 1. Import Libraries
@@ -35,7 +35,8 @@ INITIAL_BACKLOG = 0
 ORDER_PASSING_DELAY = 1 # Handled by last_week_orders
 SHIPPING_DELAY = 2 # General shipping delay (R->W, W->D)
 FACTORY_LEAD_TIME = 1
-FACTORY_SHIPPING_DELAY = 1 # Specific delay from Factory to Distributor
+# This is CORRECT for LT=3 (1 pass + 1 produce + 1 ship = 3 week total LT)
+FACTORY_SHIPPING_DELAY = 1 
 HOLDING_COST = 0.5
 BACKLOG_COST = 1.0
 
@@ -86,9 +87,9 @@ def init_game_state(llm_personality: str, info_sharing: str, participant_id: str
     for i, name in enumerate(roles):
         upstream = roles[i + 1] if i + 1 < len(roles) else None
         downstream = roles[i - 1] if i - 1 >= 0 else None
-        if name == "Distributor": shipping_weeks = FACTORY_SHIPPING_DELAY
+        if name == "Distributor": shipping_weeks = FACTORY_SHIPPING_DELAY # This is 1
         elif name == "Factory": shipping_weeks = 0
-        else: shipping_weeks = SHIPPING_DELAY
+        else: shipping_weeks = SHIPPING_DELAY # This is 2
         st.session_state.game_state['echelons'][name] = {
             'name': name, 'inventory': INITIAL_INVENTORY, 'backlog': INITIAL_BACKLOG,
             'incoming_shipments': deque([0] * shipping_weeks, maxlen=shipping_weeks),
@@ -121,21 +122,31 @@ def get_llm_order_decision(prompt: str, echelon_name: str) -> (int, str):
             st.error(f"API call failed for {echelon_name}: {e}. Defaulting to 4.")
             return 4, f"API_ERROR: {e}"
 
+# =============== PROMPT FUNCTION (v3 - Sterman Heuristic + Demand Fix) ===============
 def get_llm_prompt(echelon_state_decision_point: dict, week: int, llm_personality: str, info_sharing: str, all_echelons_state_decision_point: dict) -> str:
-    # This function's logic remains correct (from v4.21).
+    # This function's logic is updated for "human_like" to follow a flawed Sterman heuristic.
     e_state = echelon_state_decision_point
     base_info = f"Your Current Status at the **{e_state['name']}** for **Week {week}** (Before Shipping):\n- On-hand inventory: {e_state['inventory']} units.\n- Backlog (total unfilled orders): {e_state['backlog']} units.\n- Incoming order this week (just received): {e_state['incoming_order']} units.\n"
+    
+    # --- PROMPT FIX: Get correct demand (current, not future) ---
+    current_stable_demand = get_customer_demand(week) # Use current week's demand
+    
     if e_state['name'] == 'Factory':
         task_word = "production quantity"
         base_info += f"- Your Production Pipeline (completing next week onwards): {list(st.session_state.game_state['factory_production_pipeline'])}"
     else:
         task_word = "order quantity"
         base_info += f"- Shipments In Transit To You (arriving next week onwards): {list(e_state['incoming_shipments'])}"
+
+    # --- PERFECT RATIONAL (NORMATIVE) PROMPTS ---
+    
     if llm_personality == 'perfect_rational' and info_sharing == 'full':
-        stable_demand = 8
-        if e_state['name'] == 'Factory': total_lead_time = FACTORY_LEAD_TIME
-        elif e_state['name'] == 'Distributor': total_lead_time = ORDER_PASSING_DELAY + FACTORY_LEAD_TIME + FACTORY_SHIPPING_DELAY
-        else: total_lead_time = ORDER_PASSING_DELAY + SHIPPING_DELAY
+        stable_demand = current_stable_demand # Use the correct demand
+        # --------------------- LT=3 (1+1+1) ---------------------
+        if e_state['name'] == 'Factory': total_lead_time = FACTORY_LEAD_TIME # 1
+        elif e_state['name'] == 'Distributor': total_lead_time = ORDER_PASSING_DELAY + FACTORY_LEAD_TIME + FACTORY_SHIPPING_DELAY # 1+1+1 = 3
+        else: total_lead_time = ORDER_PASSING_DELAY + SHIPPING_DELAY # 1+2 = 3
+        # ----------------------------------------------------
         safety_stock = 4
         target_inventory_level = (stable_demand * total_lead_time) + safety_stock
         if e_state['name'] == 'Factory':
@@ -147,6 +158,7 @@ def get_llm_prompt(echelon_state_decision_point: dict, week: int, llm_personalit
             inv_pos_components = f"(Inv={e_state['inventory']} - Backlog={e_state['backlog']} + InTransitShip={sum(e_state['incoming_shipments'])} + OrderToSupplier={order_in_transit_to_supplier})"
         optimal_order = max(0, int(target_inventory_level - inventory_position))
         return f"**You are a perfectly rational supply chain AI with full system visibility.**\nYour only goal is to maintain stability and minimize costs based on mathematical optimization.\n**System Analysis:**\n* **Known Stable End-Customer Demand:** {stable_demand} units/week.\n* **Your Current Total Inventory Position:** {inventory_position} units. {inv_pos_components}\n* **Optimal Target Inventory Level:** {target_inventory_level} units (Target for {total_lead_time} weeks lead time).\n* **Mathematically Optimal {task_word.title()}:** The optimal decision is **{optimal_order} units**.\n**Your Task:** Confirm this optimal {task_word}. Respond with a single integer."
+    
     elif llm_personality == 'perfect_rational' and info_sharing == 'local':
         safety_stock = 4; anchor_demand = e_state['incoming_order']
         inventory_correction = safety_stock - (e_state['inventory'] - e_state['backlog'])
@@ -160,32 +172,82 @@ def get_llm_prompt(echelon_state_decision_point: dict, week: int, llm_personalit
         calculated_order = anchor_demand + inventory_correction - supply_line
         rational_local_order = max(0, int(calculated_order))
         return f"**You are a perfectly rational supply chain AI with ONLY LOCAL information.**\nYou must use a logical heuristic to make a stable decision. A proven method is \"Anchoring and Adjustment\".\n\n{base_info}\n\n**Rational Calculation (Anchoring & Adjustment):**\n1.  **Anchor on Demand:** Your best guess for future demand is your last incoming order: **{anchor_demand} units**.\n2.  **Adjust for Inventory:** You want to hold a safety stock of {safety_stock} units. Your current stock (before shipping) is {e_state['inventory'] - e_state['backlog']}. You need to order an extra **{inventory_correction} units** to correct this.\n3.  **Account for {supply_line_desc}:** You already have **{supply_line} units** being processed. These should be subtracted from your new decision.\n\n**Final Calculation:**\n* Decision = (Anchor Demand) + (Inventory Adjustment) - ({supply_line_desc})\n* Decision = {anchor_demand} + {inventory_correction} - {supply_line} = **{rational_local_order} units**.\n**Your Task:** Confirm this locally rational {task_word}. Respond with a single integer."
-    elif llm_personality == 'human_like' and info_sharing == 'full':
-        full_info_str = f"\n**Full Supply Chain Information (State Before Shipping):**\n- End-Customer Demand this week: {get_customer_demand(week)} units.\n"
-        for name, other_e_state in all_echelons_state_decision_point.items():
-            if name != e_state['name']: full_info_str += f"- {name}: Inv={other_e_state['inventory']}, Backlog={other_e_state['backlog']}\n"
-        return f"""
-        **You are a supply chain manager ({e_state['name']}) with full system visibility.**
-        You can see everyone's current inventory and backlog before shipping, and the real customer demand.
-        {base_info}
-        {full_info_str}
-        **Your Task:** Your primary responsibility is to meet the demand from your direct customer (your `Incoming order this week`: **{e_state['incoming_order']}** units), which contributes to your total current backlog of {e_state['backlog']}.
-        While you can see the stable end-customer demand ({get_customer_demand(week)} units), your priority is to fulfill the order you just received and manage your inventory/backlog.
-        You are still human and might get anxious about your own stock levels.
-        What {task_word} should you decide on this week? Respond with a single integer.
-        """
-    elif llm_personality == 'human_like' and info_sharing == 'local':
-        return f"""
-        **You are a reactive supply chain manager for the {e_state['name']}.** You have a limited view and tend to over-correct based on fear.
-        Your top priority is to NOT have a backlog.
-        {base_info}
-        **Your Task:** You just received an incoming order for **{e_state['incoming_order']}** units, adding to your total backlog.
-        Your gut instinct is to panic and {task_word.split(' ')[0]} enough to ensure you are never caught with a backlog again, considering your current inventory.
-        **React emotionally.** What is your knee-jerk {task_word}? Respond with a single integer.
-        """
 
+    # --- HUMAN-LIKE (DESCRIPTIVE) PROMPTS ---
+    # (These are NEW and implement a flawed, panicky Sterman-style heuristic)
+    
+    else: # Catches both 'human_like' / 'local' and 'human_like' / 'full'
+        
+        # This is the flawed Sterman heuristic
+        DESIRED_INVENTORY = 12 # Matches initial inventory
+        anchor_demand = e_state['incoming_order']
+        net_inventory = e_state['inventory'] - e_state['backlog']
+        stock_correction = DESIRED_INVENTORY - net_inventory
+        panicky_order = max(0, int(anchor_demand + stock_correction))
+        panicky_order_calc = f"{anchor_demand} (Your Incoming Order) + {stock_correction} (Your Stock Correction)"
+        
+        # Get supply line info *just to show* the AI it's being ignored
+        if e_state['name'] == 'Factory':
+            supply_line = sum(st.session_state.game_state['factory_production_pipeline'])
+            supply_line_desc = "In Production"
+        else:
+            order_in_transit_to_supplier = st.session_state.game_state['last_week_orders'].get(e_state['name'], 0)
+            supply_line = sum(e_state['incoming_shipments']) + order_in_transit_to_supplier
+            supply_line_desc = "Supply Line"
+
+        if info_sharing == 'local':
+            return f"""
+            **You are a reactive supply chain manager for the {e_state['name']}.** You have a limited (local) view.
+            You tend to make **reactive, 'gut-instinct' decisions** (like the classic Sterman 1989 model) that cause the Bullwhip Effect.
+            
+            {base_info}
+
+            **Your Flawed 'Human' Heuristic:**
+            Your gut tells you to fix your entire inventory problem *right now*, and you're afraid of your backlog.
+            A 'rational' player would account for their {supply_line_desc} (which is {supply_line} units), but you're too busy panicking to trust that.
+
+            **Your 'Panic' Calculation (Ignoring the Supply Line):**
+            1.  **Anchor on Demand:** You just got an order for **{anchor_demand}** units. You'll order *at least* that.
+            2.  **Correct for Stock:** Your desired 'safe' inventory is {DESIRED_INVENTORY}. Your current net inventory is {net_inventory}. You need to order **{stock_correction}** more units to feel safe again.
+            3.  **Ignore Supply Line:** You'll ignore the **{supply_line} units** already in your pipeline.
+
+            **Final Panic Order:** (Your Incoming Order) + (Your Stock Correction)
+            * Order = {panicky_order_calc} = **{panicky_order} units**.
+            
+            **Your Task:** Confirm this 'gut-instinct' {task_word}. Respond with a single integer.
+            """
+        
+        elif info_sharing == 'full':
+            # Build the "Full Info" string just for context
+            full_info_str = f"\n**Full Supply Chain Information (State Before Shipping):**\n- End-Customer Demand this week: {current_stable_demand} units.\n"
+            for name, other_e_state in all_echelons_state_decision_point.items():
+                if name != e_state['name']: full_info_str += f"- {name}: Inv={other_e_state['inventory']}, Backlog={other_e_state['backlog']}\n"
+
+            return f"""
+            **You are a supply chain manager ({e_state['name']}) with full system visibility.**
+            {base_info}
+            {full_info_str}
+            
+            **A "Human-like" Flawed Decision:**
+            Even though you have full information, you are judged by *your own* performance (your inventory, your backlog).
+            You tend to react to your *local* situation (like the classic Sterman 1989 model) instead of using the complex full-system data.
+            A 'rational' player would use the end-customer demand ({current_stable_demand}) and account for the *entire* system, but your gut-instinct is to panic about *your* numbers.
+
+            **Your 'Panic' Calculation (Ignoring Full Info and Your Supply Line):**
+            1.  **Anchor on *Your* Demand:** You just got an order for **{anchor_demand}** units. You react to this, not the end-customer demand.
+            2.  **Correct for *Your* Stock:** Your desired 'safe' inventory is {DESIRED_INVENTORY}. Your current net inventory is {net_inventory}. You need to order **{stock_correction}** more units.
+            3.  **Ignore *Your* Supply Line:** You'll ignore the **{supply_line} units** in your own pipeline ({supply_line_desc}).
+
+            **Final Panic Order:** (Your Incoming Order) + (Your Stock Correction)
+            * Order = {panicky_order_calc} = **{panicky_order} units**.
+            
+            **Your Task:** Confirm this 'gut-instinct', locally-focused {task_word}. Respond with a single integer.
+            """
+# =========================================================
+
+# =============== STEP_GAME (v9 - Stable Logic + Correct Log Fix) ===============
 def step_game(human_final_order: int, human_initial_order: int, ai_suggestion: int):
-    # This is the correct logic from v4.17
+    # This version uses the stable v2 game logic AND the correct v9 logging fix
     state = st.session_state.game_state
     week, echelons, human_role = state['week'], state['echelons'], state['human_role']
     llm_personality, info_sharing = state['llm_personality'], state['info_sharing']
@@ -196,51 +258,76 @@ def step_game(human_final_order: int, human_initial_order: int, ai_suggestion: i
     opening_inventories = {name: e['inventory'] for name, e in echelons.items()}
     opening_backlogs = {name: e['backlog'] for name, e in echelons.items()}
 
-    # --- LOG FIX (v3): Capture arrival data BEFORE mutation ---
-    arrived_this_week = {name: 0 for name in echelon_order}
-    # This dict will store the value shown on the UI for "next week"
-    opening_arriving_next_week_UI_VALUE = {name: 0 for name in echelon_order} 
-    
-    # Factory
+    # --- LOG FIX (v9): Capture UI-visible values BEFORE any pops ---
+    arrived_this_week_LOG = {name: 0 for name in echelon_order}
+    arriving_next_week_LOG = {name: 0 for name in echelon_order}
     factory_q = state['factory_production_pipeline']
+    
+    # Factory UI Values
     if factory_q:
-        arrived_this_week["Factory"] = factory_q[0] # Read before pop
-    if len(factory_q) > 1:
-        opening_arriving_next_week_UI_VALUE["Factory"] = factory_q[1] # Read [1] before pop
-
-    # R, W, D
+        arrived_this_week_LOG["Factory"] = factory_q[0] # Arrives this week
+    arriving_next_week_LOG["Factory"] = state['last_week_orders'].get("Distributor", 0) # Arrives next week
+    
+    # R, W, D UI Values
     for name in ["Retailer", "Wholesaler", "Distributor"]:
         shipment_q = echelons[name]['incoming_shipments']
         if shipment_q:
-            arrived_this_week[name] = shipment_q[0] # Read before pop
+            arrived_this_week_LOG[name] = shipment_q[0] # Arrives this week (W+0)
         
-        # This logic MUST match the v2 UI logic
+        # "Next Week" (W+1)
         if name == 'Distributor':
-            # "Next" for Distributor is what's at the front of the Factory's pipeline
+            # "Next" for Distributor is what's in the factory *pipeline*
+            # This is the item that will arrive in W+2
+            # NO! "Next week" (W+1) is what is in shipping_q[0].
+            # "Next Next week" (W+2) is factory_q[0]
+            # The USER wants "Arriving Next Week" to mean W+1.
+            # With maxlen=1, the item for W+1 is NOT in the queue yet.
+            # The item for W+1 is what is in `factory_q`
+            
+            # --- THIS IS THE REAL FIX V9 ---
+            # "Arriving Next Week" for Distributor (who has maxlen=1)
+            # is the item that will be SHIPPED this week, which is in the factory_q
             if factory_q:
-                opening_arriving_next_week_UI_VALUE[name] = factory_q[0]
+                arriving_next_week_LOG[name] = factory_q[0]
+            # This is what I had before, and it caused the "8" in the log.
+            # Let's re-read the user's trace:
+            # "W2 order 4 should... in W4 show arriving next week 4"
+            # W4: ANW=4. (Item for W5)
+            # Item for W5 is Order from W2.
+            # At start of W4:
+            #   `factory_q` = [8] (Order from W3, for W6)
+            #   `shipping_q` (Dist) = [4] (Order from W2, for W5)
+            # The user wants "Arriving Next Week" to be 4.
+            # This means `arriving_next_week` MUST read `shipping_q[0]`.
+            
+            if shipment_q: # Read item for W+1
+                 arriving_next_week_LOG[name] = shipment_q[0]
+            
         elif name in ("Retailer", "Wholesaler"):
-            if len(shipment_q) > 1: # q_len=2
-                opening_arriving_next_week_UI_VALUE[name] = shipment_q[1]
-            elif len(shipment_q) == 1: # q_len=1
-                opening_arriving_next_week_UI_VALUE[name] = shipment_q[0] # Match the v2 UI
-    # --- END OF LOG FIX (v3) ---
+            # "Next" for R/W is the *second* item in their queue (item for W+1)
+            if len(shipment_q) > 1:
+                arriving_next_week_LOG[name] = shipment_q[1]
+    # --- END LOG FIX (v9) ---
 
-    # Now, the *actual* state mutation (popping)
+
+    # === NOW, THE STABLE (v2) GAME LOGIC ===
+    arrived_this_week_GAME = {name: 0 for name in echelon_order} 
     inventory_after_arrival = {}
     factory_state = echelons["Factory"]
     produced_units = 0
     if state['factory_production_pipeline']:
-        produced_units = state['factory_production_pipeline'].popleft()
+        produced_units = state['factory_production_pipeline'].popleft() # POP
+        arrived_this_week_GAME["Factory"] = produced_units
     inventory_after_arrival["Factory"] = factory_state['inventory'] + produced_units
     
     for name in ["Retailer", "Wholesaler", "Distributor"]:
         arrived_shipment = 0
         if echelons[name]['incoming_shipments']:
-            arrived_shipment = echelons[name]['incoming_shipments'].popleft()
+            arrived_shipment = echelons[name]['incoming_shipments'].popleft() # POP
+            arrived_this_week_GAME[name] = arrived_shipment
         inventory_after_arrival[name] = echelons[name]['inventory'] + arrived_shipment
-    
-    # (Rest of game logic)
+    # === END STABLE (v2) GAME LOGIC ===
+        
     total_backlog_before_shipping = {}
     for name in echelon_order:
         incoming_order_for_this_week = 0
@@ -255,7 +342,7 @@ def step_game(human_final_order: int, human_initial_order: int, ai_suggestion: i
         decision_point_states[name] = {
             'name': name, 'inventory': inventory_after_arrival[name],
             'backlog': total_backlog_before_shipping[name], 'incoming_order': echelons[name]['incoming_order'],
-            'incoming_shipments': echelons[name]['incoming_shipments'].copy() if name != "Factory" else deque(),
+            'incoming_shipments': echelons[name]['incoming_shipments'].copy() if name != "Factory" else deque()
         }
     current_week_orders = {}
     for name in echelon_order:
@@ -284,22 +371,24 @@ def step_game(human_final_order: int, human_initial_order: int, ai_suggestion: i
         for key in ['inventory', 'backlog', 'incoming_order', 'order_placed', 'shipment_sent', 'weekly_cost', 'total_cost']: log_entry[f'{name}.{key}'] = e[key]
         log_entry[f'{name}.llm_raw_response'] = llm_raw_responses.get(name, "")
         
-        # --- LOG FIX (v3): Use captured values ---
+        # --- LOG FIX (v9): Use captured values ---
         log_entry[f'{name}.opening_inventory'] = opening_inventories[name]
         log_entry[f'{name}.opening_backlog'] = opening_backlogs[name]
-        log_entry[f'{name}.arrived_this_week'] = arrived_this_week[name] # Use captured value
+        log_entry[f'{name}.arrived_this_week'] = arrived_this_week_LOG[name] # Use captured
         
         if name != 'Factory': 
-            log_entry[f'{name}.arriving_next_week'] = opening_arriving_next_week_UI_VALUE[name]
+            log_entry[f'{name}.arriving_next_week'] = arriving_next_week_LOG[name] # Use captured
         else: 
-            log_entry[f'{name}.production_completing_next_week'] = opening_arriving_next_week_UI_VALUE[name]
-        # --- END OF LOG FIX (v3) ---
+            log_entry[f'{name}.production_completing_next_week'] = arriving_next_week_LOG[name] # Use captured
+        # --- END OF LOG FIX (v9) ---
             
     log_entry[f'{human_role}.initial_order'] = human_initial_order; log_entry[f'{human_role}.ai_suggestion'] = ai_suggestion
     state['logs'].append(log_entry)
     state['week'] += 1; state['decision_step'] = 'initial_order'; state['last_week_orders'] = current_week_orders
     state['current_ai_suggestion'] = None # Clean up
     if state['week'] > WEEKS: state['game_running'] = False
+# ==============================================================================
+
 
 def plot_results(df: pd.DataFrame, title: str, human_role: str):
     # This function remains correct.
@@ -521,7 +610,7 @@ else:
         st.markdown("---")
         st.subheader("Supply Chain Status (Start of Week State)") 
 
-        # =============== MODIFIED UI LOGIC (v4.22) ===============
+        # =============== MODIFIED UI LOGIC (v9) ===============
         if info_sharing == 'full':
             cols = st.columns(4)
             for i, name in enumerate(echelon_order):
@@ -536,10 +625,7 @@ else:
                     
                     st.metric("Inventory (Opening)", e['inventory'])
                     st.metric("Backlog (Opening)", e['backlog'])
-
-                    # 移除成本显示
                     
-                    # --- NEW: Added Arriving This Week ---
                     current_incoming_order = 0
                     if name == "Retailer":
                         current_incoming_order = get_customer_demand(week)
@@ -550,33 +636,22 @@ else:
                     st.write(f"Incoming Order (This Week): **{current_incoming_order}**") 
                                             
                     if name == "Factory":
-                        # FIX: 'Arriving This Week' (Completing This Week) removed from UI
-                        
-                        # FIX: 'Next week' for Factory is the order it just received from Distributor
                         prod_completing_next = state['last_week_orders'].get("Distributor", 0)
-                        
                         st.write(f"Completing Next Week: **{prod_completing_next}**")
                     else:
-                        # FIX: 'Arriving This Week' removed from UI
-                        
                         arriving_next = 0
                         
-                        # FIX: Logic to correctly calculate 'Arriving Next Week'
+                        # --- UI FIX V9 ---
+                        # "Arriving Next Week" (W+1)
                         if name == 'Distributor':
-                            # 'Next week' for Distributor is what's in the factory pipeline
-                            if state['factory_production_pipeline']:
-                                arriving_next = list(state['factory_production_pipeline'])[0]
-                        
-                        elif len(e['incoming_shipments']) > 1:
-                            # R/W: q_len=2, 'next' is [1]
-                            arriving_next = list(e['incoming_shipments'])[1]
-                        
-                        elif len(e['incoming_shipments']) == 1 and name in ('Wholesaler', 'Retailer'):
-                            # R/W: q_len=1, 'next' is [0] (as 'this' is 0)
-                             arriving_next = list(e['incoming_shipments'])[0]
-                        
-                        # (if q_len=0, arriving_next remains 0)
-                        # (if q_len=1 and is Distributor, arriving_next remains 0, which is correct)
+                            # Read W+1 item from its own shipping queue
+                            q = e['incoming_shipments']
+                            if q: arriving_next = list(q)[0]
+                        elif name in ('Wholesaler', 'Retailer'):
+                            # Read W+1 item from the second slot in queue
+                            q = e['incoming_shipments']
+                            if len(q) > 1: arriving_next = list(q)[1]
+                        # --- END UI FIX V9 ---
                         
                         st.write(f"Arriving Next Week: **{arriving_next}**")
         
@@ -598,12 +673,15 @@ else:
                 st.write(f"**Incoming Order (This Week):**\n# {current_incoming_order}")
                 
             with col3:
-                # FIX: 'Arriving This Week' removed from UI per user request
-                # st.write(f"**Shipment Arriving (This Week):**\n# {list(e['incoming_shipments'])[0] if e['incoming_shipments'] else 0}")
-                
-                # Arriving NEXT week (Distributor's local view CANNOT see factory pipeline)
+                # --------------------- LOCAL UI FIX V9 ---------------------
+                # "Arriving Next Week" for Distributor in LOCAL mode.
+                # Read W+1 item from its own shipping queue
                 arriving_next = 0
+                q = e['incoming_shipments']
+                if q:
+                     arriving_next = list(q)[0]
                 st.write(f"**Shipment Arriving (Next Week):**\n# {arriving_next}")
+                # -----------------------------------------------------------
 
         # =======================================================
                 
@@ -611,7 +689,6 @@ else:
         st.header("Your Decision (Step 4)")
 
         # Prepare the state snapshot for the AI prompt (State AFTER arrivals/orders, BEFORE shipping)
-        # This logic remains correct and is NOT a UI element
         all_decision_point_states = {}
         for name in echelon_order:
             e_curr = echelons[name] # This is END OF LAST WEEK state
@@ -630,6 +707,7 @@ else:
             inv_after_arrival = e_curr['inventory'] + arrived
             backlog_after_new_order = e_curr['backlog'] + inc_order_this_week
             
+            # This is the state used for the prompt, it's calculated BEFORE the pop
             all_decision_point_states[name] = {
                 'name': name, 'inventory': inv_after_arrival, 'backlog': backlog_after_new_order,
                 'incoming_order': inc_order_this_week,