[Ketho]

Originally Posted by Xruptor determine if an item was used from the Reagent Bank during crafting

PLAYERREAGENTBANKSLOTS_CHANGED fires when an item is crafted from the reagent bank, or an item was deposited/withdrawn/moved in the reagent bank

-- assume the player just crafted something
local function OnEvent(self, event, reagentSlot)
    local inventoryID = ReagentBankButtonIDToInvSlotID(reagentSlot)
    local itemID = GetInventoryItemID("player", inventoryID)
    local itemLink = select(2, GetItemInfo(itemID))
 
    print(format("item %d %s was used from your reagent bank", itemID, itemLink))
    print("reagentSlot:", reagentSlot)
    print("inventoryID:", inventoryID)
end
 
local f = CreateFrame("Frame")
f:RegisterEvent("PLAYERREAGENTBANKSLOTS_CHANGED")
f:SetScript("OnEvent", OnEvent)

item 2840 [Copper Bar] was used from your reagent bank
reagentSlot: 1
inventoryID: 99
You create: [Handful of Copper Bolts].

Originally Posted by Xruptor use GetTradeSkillReagentInfo and grab the playerReagentCount to determine if the reagent count is greater than what the player has in their inventory.

Probably something like that, yes