diff --git a/data/stock_limits.lua b/data/stock_limits.lua
new file mode 100644
index 0000000..5a86db0
--- /dev/null
+++ b/data/stock_limits.lua
@@ -0,0 +1,20 @@
+-- Stock limits: maximum quantities to keep in storage.
+-- When an item exceeds its limit, the excess is pushed to the trash dropper.
+-- Set up a dropper facing lava, cactus, or void to destroy excess items.
+--
+-- Format: ["mod:item"] = maxCount
+-- Only items listed here are subject to auto-discard; everything else is unlimited.
+
+return {
+    ["minecraft:cobblestone"]        = 8192,   -- 128 slots (~5 chests)
+    ["minecraft:stone"]              = 4096,
+    ["minecraft:smooth_stone"]       = 4096,
+    ["minecraft:cobbled_deepslate"]  = 4096,
+    ["minecraft:netherrack"]         = 2048,
+    ["minecraft:dirt"]               = 2048,
+    ["minecraft:gravel"]             = 2048,
+    ["minecraft:andesite"]           = 2048,
+    ["minecraft:diorite"]            = 2048,
+    ["minecraft:granite"]            = 2048,
+    ["minecraft:tuff"]               = 1024,
+}