> ## Documentation Index
> Fetch the complete documentation index at: https://docs.biconomy.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Risk and inventory
> The four protections, how much a ladder can fill, fill tracking, stopping.
## Protections
Block cap, age fade and move premium are set in one `board-controls` message per ladder and stay in force until you send new ones. Auto-dark is the `expiresAt` on every message.
| Dial | Field | Effect | Default | Typical |
| ------------ | ----------------------- | ----------------------------------------------------------------------------------- | --------- | -------------------------- |
| Block cap | `blockCap` | maximum `tokenIn` the ladder fills in one block, across all takers | `0` (off) | a fraction of the top size |
| Age fade | `widenPpmPerSqrtSecond` | extra discount of this many ppm times the square root of the quote's age in seconds | `0` (off) | 50 to 200 |
| Move premium | `premiumPpm` | extra discount in ppm after a price change | `0` (off) | a few hundred |
| | `premiumBlocks` | blocks the premium lasts, counting the commit block | `0` (off) | 1 or 2 |
| Auto-dark | `expiresAt` | the ladder stops quoting after this time | required | 10 to 30 s |
Age fade at `widenPpmPerSqrtSecond = 100`:
| Quote age | Extra discount |
| --------- | -------------- |
| 1 s | 100 ppm (1 bp) |
| 4 s | 200 ppm |
| 25 s | 500 ppm |
```json theme={null}
{
"type": "board-controls",
"payload": {
"mm": "0xYourSigner",
"tokenIn": "0x8b414aD7005EeFd315aF2A16538885Eae229bab7",
"tokenOut": "0xAbbdbbbd6d56593A9c5656c06cB30D61E4a544Df",
"nonce": "",
"blockCap": "5000000000000000000",
"widenPpmPerSqrtSecond": "100",
"premiumPpm": "500",
"premiumBlocks": "1",
"signature": "",
"chainId": 84532
}
}
```
Aggregators see the block cap before trading: `board()` reports what is left in the current block, and the venue routes the rest of an order to other makers. `controls(mm, tokenIn, tokenOut)` on the executor returns your settings.
## Maximum payout per ladder
A ladder fills at most its top size, counted across every taker. A new `price-ladder` or `offsets` message resets the count. The maximum payout is fixed when you sign:
| Step | Cumulative size | Price | Pays at most |
| ----- | --------------- | ------- | -------------- |
| 1 | 2 WETH | 2000.00 | 4,000.00 USDC |
| 2 | 5 WETH | 1999.40 | 5,998.20 USDC |
| 3 | 12 WETH | 1998.20 | 13,987.40 USDC |
| 4 | 20 WETH | 1995.50 | 15,964.00 USDC |
| Total | 20 WETH | | 39,949.60 USDC |
Keep at least that much `tokenOut` in the provider. A fill that finds less reverts.
| Mode | Top size limits |
| ------- | --------------------------------------------------------- |
| Rewrite | fills per ladder update |
| Reprice | fills per `offsets` message, across any number of anchors |
## Fill tracking
| Data | Source |
| ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------- |
| Inventory | `balanceOf` on your provider |
| Filled and remaining size | `board(mm, tokenIn, tokenOut)`: `filled`, `remaining` |
| Filled this block | `controls(mm, tokenIn, tokenOut)`: `filledThisBlock` |
| Each fill | `MMFillExecuted(mmProvider, mmSigner, receiver, tokenIn, tokenOut, amountIn, amountOut, avgPrice, filledAfter)` on the executor |
| Messages that reached the chain | `LadderCommitted`, `OffsetsCommitted`, `AnchorCommitted`, `ControlsCommitted` on the executor |
`mmProvider` and `mmSigner` are indexed. A trade split across makers emits one `MMFillExecuted` per maker.
## Stop quoting
| Action | Effect |
| ------------------------------------------------------------------ | --------------------------------------- |
| Stop sending | ladders expire at their `expiresAt` |
| Send a tombstone: a ladder with a dust top size and a higher nonce | replaces outstanding quotes immediately |
| `setApprovedExecutor` to another address | all fills revert |
| `withdraw` | provider is empty; fills revert |
To resume, send new messages with higher nonces.