diff --git a/inventoryClient.lua b/inventoryClient.lua
index d7b9518..56803ce 100644
--- a/inventoryClient.lua
+++ b/inventoryClient.lua
@@ -229,12 +229,25 @@ local function monCenter(y, text, fg, bg)      ui.monCenter(y, text, fg, bg) end
 local function monBar(x, y, w, r, bc, bgc)     ui.monBar(x, y, w, r, bc, bgc) end
 local function drawButton(x, y, t, fg, bg, pl, pr) return ui.drawButton(x, y, t, fg, bg, pl, pr) end
 
+-------------------------------------------------
+-- Command ID generation (idempotency)
+-------------------------------------------------
+
+local cmdCounter = 0
+local function newCommandId()
+    cmdCounter = cmdCounter + 1
+    return string.format("client_%d_%d_%d", os.getComputerID(), os.epoch("utc"), cmdCounter)
+end
+
 -------------------------------------------------
 -- Send command to master
 -------------------------------------------------
 
 local function sendToMaster(message)
     if not networkModem then return end
+    if not message.commandId then
+        message.commandId = newCommandId()
+    end
     networkModem.transmit(ORDER_CHANNEL, CLIENT_CHANNEL, message)
 end
 
@@ -1310,7 +1323,7 @@ local function main()
 
                 elseif channel == CLIENT_CHANNEL and type(message) == "table" and message.type == "craft_result" then
                     -- Craft result from master
-                    statusMessage = message.message or ""
+                    statusMessage = message.error or (message.success and "Craft complete" or "Craft failed")
                     statusColor = message.success and colors.lime or colors.red
                     statusTimer = 5
                     smelterNeedsRedraw = true