# Buffs and Modifiers

**URL:** <https://discourse.stonehearth.net/t/buffs-and-modifiers/27653>\
**Category:** Modding\
**Created:** [January 10, 2017, 10:02pm UTC](https://discourse.stonehearth.net/t/buffs-and-modifiers/27653 "2017-01-10T22:02:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![KuroNeko87](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.stonehearth.net/kuroneko87/32/36859_2.png) [@KuroNeko87](https://discourse.stonehearth.net/u/KuroNeko87)\
**Post date:** [January 10, 2017, 10:02pm UTC](https://discourse.stonehearth.net/t/buffs-and-modifiers/27653/1 "2017-01-10T22:02:38Z")

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Hello everyone! Kuroneko here with yet another question regarding to modding. I’ve grasped a lot of things about modding already by fooling around with my test mod and by asking questions here. You all have been a great help to me.

Moving on, I’m trying to modify the storage size for the backpack. I made an outfit with a backpack that I want certain hearthlings set to be only haulers to use. I’m trying to add it by using a buff. The problem is that I can’t find any documentation regarding what can be modified.

I found this in base\_human.json but don’t know how to modify it using an armor/buff.

` "stonehearth:storage": {
         "type": "backpack",
         "public": false,
         "capacity": 4
      }, `

Any help?

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**Author:** ![MaddyGrand](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.stonehearth.net/maddygrand/32/53393_2.png) [@MaddyGrand](https://discourse.stonehearth.net/u/MaddyGrand)\
**Post date:** [January 10, 2017, 10:04pm UTC](https://discourse.stonehearth.net/t/buffs-and-modifiers/27653/2 "2017-01-10T22:04:30Z")

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Try to find the Trappers character manifest ( it has a backpack upgrade on lvl 4 or 5 and this code should show you how to code it onto an item.

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**Author:** ![KuroNeko87](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.stonehearth.net/kuroneko87/32/36859_2.png) [@KuroNeko87](https://discourse.stonehearth.net/u/KuroNeko87)\
**Post date:** [January 10, 2017, 10:11pm UTC](https://discourse.stonehearth.net/t/buffs-and-modifiers/27653/3 "2017-01-10T22:11:39Z")

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Hmmm seems like it’s done with lua. Something else I have to learn then hahaha

Increase Size:

```auto
function TrapperClass:increase_backpack_size(args)
   local sc = self._sv._entity:get_component('stonehearth:storage')
   sc:change_max_capacity(args.backpack_size_increase)
end
```

Decrease Size:

```auto
function TrapperClass:decrease_backpack_size(args)
   local sc = self._sv._entity:get_component('stonehearth:storage')
   sc:change_max_capacity(args.backpack_size_increase * -1)
end
```

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<div class="post-metadata">

**Author:** ![MaddyGrand](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.stonehearth.net/maddygrand/32/53393_2.png) [@MaddyGrand](https://discourse.stonehearth.net/u/MaddyGrand)\
**Post date:** [January 10, 2017, 10:13pm UTC](https://discourse.stonehearth.net/t/buffs-and-modifiers/27653/4 "2017-01-10T22:13:11Z")

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Sure doesn’t look easy 😛