> ## Documentation Index
> Fetch the complete documentation index at: https://docs.summerengine.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Loot table editor: a Summer App for game teams
> A shared editor for your loot tables: weights per drop, the real chance per roll and per kill, and a tool that sets a drop to an exact chance. Manifest, seed data, agent edits and the look check.
**Draft.** Summer Apps is in a closed test. This page goes live after the end-to-end test on production.
## What your team gets
* One loot table at a time (pick it from a menu): every drop with its weight, quantity and rarity.
* The real numbers: chance per roll (weight divided by the table's total weight) and chance per kill or open (with the table's number of rolls).
* A pie chart of the table. Edit weights in place and save.
* Your agent changes drops by asking ("halve the Moonfang chance from wolves", "make the Ember Staff a 2% drop from the boss chest").
## Ask your agent
Build us a Summer App called "Loot tables": pick a loot table from a menu, then see
every drop with weight, quantity, rarity, chance per roll (weight / total weight) and
chance per kill (1 - (1 - chance per roll) ^ rolls). Weights are editable in place with
a save bar, and a pie chart shows the table. Give agents a set\_chance tool that sets one
drop to an exact chance per roll. Seed it with our loot tables using summer\_app\_data with
"as": "seed". Follow the summer-apps and summer-apps-design skills, then check it with
summer\_app\_screenshot (default, width 390, theme dark) and fix what it reports.
## The manifest
```json theme={null}
{
"name": "Loot tables",
"purpose": "Drop weights and real drop chances for every loot table.",
"permissions": ["data"],
"collections": {
"tables": {
"description": "One loot table",
"fields": {
"name": { "type": "string", "required": true },
"source": { "type": "string", "description": "The enemy or chest that rolls it" },
"rolls": { "type": "integer", "required": true, "description": "Drops rolled per kill or open" }
}
},
"drops": {
"description": "One possible drop in a loot table",
"fields": {
"table": { "type": "string", "required": true, "description": "Record id of the loot table" },
"item": { "type": "string", "required": true },
"weight": { "type": "number", "required": true, "description": "Chance per roll = weight / sum of weights in the table" },
"minQty": { "type": "integer" },
"maxQty": { "type": "integer" },
"rarity": { "type": "string", "description": "common, rare, epic or legendary" }
}
}
},
"agentTools": [
{
"name": "set_chance",
"description": "Set one drop's weight so its chance per roll is exactly percent. Other weights stay. Returns the new weight and chances.",
"input": {
"type": "object",
"properties": {
"drop": { "type": "string", "description": "Record id of the drop" },
"percent": { "type": "number", "exclusiveMinimum": 0, "exclusiveMaximum": 100 }
},
"required": ["drop", "percent"]
}
}
]
}
```
## Seed the data
```json theme={null}
{
"appId": "",
"as": "seed",
"ops": [
{ "op": "put", "collection": "tables", "recordId": "wolf", "data": { "name": "Grey Wolf", "source": "Grey Wolf", "rolls": 1 } },
{ "op": "put", "collection": "tables", "recordId": "boss-chest", "data": { "name": "Bell Keeper chest", "source": "Bell Keeper", "rolls": 3 } },
{ "op": "put", "collection": "drops", "recordId": "wolf-pelt", "data": { "table": "wolf", "item": "Wolf Pelt", "weight": 60, "minQty": 1, "maxQty": 2, "rarity": "common" } },
{ "op": "put", "collection": "drops", "recordId": "wolf-fang", "data": { "table": "wolf", "item": "Wolf Fang", "weight": 30, "minQty": 1, "maxQty": 1, "rarity": "common" } },
{ "op": "put", "collection": "drops", "recordId": "wolf-draught", "data": { "table": "wolf", "item": "Healing Draught", "weight": 9, "minQty": 1, "maxQty": 1, "rarity": "rare" } },
{ "op": "put", "collection": "drops", "recordId": "wolf-moonfang", "data": { "table": "wolf", "item": "Moonfang", "weight": 1, "minQty": 1, "maxQty": 1, "rarity": "legendary" } },
{ "op": "put", "collection": "drops", "recordId": "chest-gold", "data": { "table": "boss-chest", "item": "Gold Pouch", "weight": 50, "minQty": 20, "maxQty": 60, "rarity": "common" } },
{ "op": "put", "collection": "drops", "recordId": "chest-cloak", "data": { "table": "boss-chest", "item": "Moss Cloak", "weight": 30, "minQty": 1, "maxQty": 1, "rarity": "rare" } },
{ "op": "put", "collection": "drops", "recordId": "chest-staff", "data": { "table": "boss-chest", "item": "Ember Staff", "weight": 20, "minQty": 1, "maxQty": 1, "rarity": "epic" } }
]
}
```
Each table's weights add up to 100 here, so a weight is the chance per roll in percent. That is not required: chances always come from the total.
## An agent edit: "halve the Moonfang chance from wolves"
Read the drops:
```json theme={null}
{ "appId": "", "collection": "drops" }
```
In the answer, `wolf-moonfang` has `"weight": 1` and a `revision`, here `1`. Halve the weight:
```json theme={null}
{
"appId": "",
"ops": [
{ "op": "patch", "collection": "drops", "recordId": "wolf-moonfang", "patch": { "weight": 0.5 }, "ifRevision": 1 }
]
}
```
The Moonfang chance per wolf goes from 1% to about 0.5% (0.5 of 99.5). A `conflict` means someone changed the drop: read again and retry. For an exact chance, call the app's tool while the person has it open: `summer_app_call` with `{ "tool": "set_chance", "input": { "drop": "chest-staff", "percent": 2 } }`.
## Check the look
After every publish:
* `summer_app_screenshot { "appId": "" }`
* `summer_app_screenshot { "appId": "", "width": 390 }`
* `summer_app_screenshot { "appId": "", "theme": "dark" }`
* `summer_app_screenshot { "appId": "", "params": { "table": "boss-chest" } }` if the app opens a table from launch params.
Check the chances by hand once: a wolf drops Wolf Pelt 60% per kill, and the boss chest (3 rolls) drops the Ember Staff 48.8% per open.
## What it uses
**SDK:** `summer.ready` (its `params` for the starting table); `summer.data.collection("tables")` and `summer.data.collection("drops")` with `.list()`, `.get()`, `.patch()` and `.subscribe()`; `summer.data.commands()` to save table edits in one revision; `summer.agent.tool("set_chance")`; `summer.page.declare()` with a `choice` field for the table.
**Kit:** `summer-page`; `summer-section` with `summer-select` in `slot="aside"` to pick the table; `summer-stats` and `summer-stat` (drops, rolls, the rarest drop's chance per kill); `summer-table` (`row-key="id"`, `sortable`; an `editable` weight column with `format: "number"`; chance columns with `format: "percent"` and `digits: 1`, which take a fraction from 0 to 1); `summer-chart` (`kind="pie"`, `x="item"`, `y` `["weight"]`); `summer-save-bar`; `summer-dialog` with `summer-form` to add a drop.
The chances, and the weight for an exact chance:
```js theme={null}
function chances(drops, rolls) {
const total = drops.reduce((sum, d) => sum + d.weight, 0);
return drops.map((d) => {
const perRoll = total ? d.weight / total : 0;
return { ...d, perRoll, perKill: 1 - (1 - perRoll) ** rolls };
});
}
// The weight w that gives drop d a chance p, keeping the other weights: w = p * others / (1 - p)
summer.agent.tool("set_chance", async ({ drop, percent }) => {
const drops = summer.data.collection("drops");
const target = await drops.get(drop);
if (!target) throw new Error(`No drop ${drop}`);
const { records } = await drops.list({ limit: 500 });
const others = records.filter((r) => r.data.table === target.data.table && r.recordId !== drop).reduce((sum, r) => sum + r.data.weight, 0);
const p = percent / 100;
const weight = Math.round((p * others / (1 - p)) * 1000) / 1000;
await drops.patch(drop, { weight }, { ifRevision: target.revision });
return { drop, weight };
});
```
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