Data packs

JSON files in your mod’s content/ folder. Kiln applies them at world load, before the save is read, in mod load order. Unload the mod and they come off. Edit a file on a running server and they apply again within seconds.

{
  "format": 1,
  "items": {
    "Material_T1_Wood_Logs": { "maxStackSize": 1000 },
    "Weapon_T1_1H_SwordEpic_01": { "damageSetup.dmgMod": 1.25, "rarity": "Epic" }
  },
  "recipes": { "Ammo_Arrow_T1_Flint": { "outputs": { "mul": 2 } } },
  "loot": { "Material_T1_Wood_Logs": { "stackSizeMin": 5, "stackSizeMax": 20 } },
  "drops": { "*": { "count": { "mul": 2 } } }
}

Section	Changes
items	stack size, rarity, damage, armour, fuel, comfort, any item field
recipes	ingredients, results, crafting time, unlock
loot	random loot of chests and pickups, per item
drops	enemy drops and fixed chests, by table

The same files hold game data and new items.

Picking entries

By name ("Material_T1_Wood_Logs"), id ("0x2b0cf1d5"), pattern ("Material_*", "*"), or conditions on the game’s original values:

"*": { "@where": { "maxStackSize": ">1", "category": "Materials" },
       "maxStackSize": { "mul": 4, "max": 9999 } }

Don’t guess names or paths: use kiln catalog search (catalogs) or Content.Dump(), which writes every entry to kiln/data/content/dump.json. kiln lint checks them.

Values

A plain value sets the field: a number, true/false, a name ("Epic"), seconds for times. An object changes the game’s original value:

Op	Does
{"mul": 4}	multiply
{"add": 10}	add
{"min": 1, "max": 9999}	keep within limits
{"raiseOnly": true}	only ever raise it
{"set": 5}	set it

When two mods disagree

Later entries win within a pack, the later mod between packs, and code over packs. Conflicts and problems are logged per file and don’t stop the rest.

From code

Content.OnReady(_ =>
{
    Content.Items.Get("Material_T1_Wood_Logs")!.MaxStack = 2000;
    Content.Recipes.Get("Tool_basic_FishingRod_T0_PK")!.CraftingDuration =
        TimeSpan.FromSeconds(5);
});

OnReady runs after the packs at every world load. Content.Apply(json) takes the pack format from code.

What players see

Kiln players get the server’s values. Players without Kiln:

Change	Without Kiln
loot and drops	works: rolled on the server
stack size	right on the server; splitting may look odd for a moment
recipes	the server crafts by its recipe; their menu shows the old one
item stats	the server’s values apply; tooltips show the old numbers

Big stacks and removing mods

Safe while the server runs. After a restart without the mod, stacks above the game’s size are cut down the next time they move. That’s the game’s own rule.