# Interactions

#### **setBounds**

Updates the bounds for a specific parameter. Only callable by the Keeper (Governor role).

```solidity

function setBounds(ParamKey key, Bounds calldata newBounds) external;

```

**Parameters**

| Name        | Type       | Description                                                         |
| ----------- | ---------- | ------------------------------------------------------------------- |
| `key`       | `ParamKey` | The parameter key to update (A, SwapFee, MintFee, etc.)             |
| `newBounds` | `Bounds`   | The new bounds structure containing max, min, and percentage limits |

#### **aParams**

Returns the bounds for the amplification coefficient - most commonly queried parameter.

```solidity

function aParams() external view returns (Bounds memory);
```

#### **swapFeeParams / mintFeeParams / redeemFeeParams**

Returns bounds for fee parameters - commonly needed for fee calculations.

```solidity

function swapFeeParams() external view returns (Bounds memory);
function mintFeeParams() external view returns (Bounds memory);
function redeemFeeParams() external view returns (Bounds memory);
```

#### **Data Structures**

#### **Bounds Structure**

```solidity
struct Bounds {
    uint256 max;              // Maximum hard cap for the parameter value
    uint256 min;              // Minimum hard cap for the parameter value
    uint64 maxDecreasePct;    // Maximum decrease per transaction (1e10 = 100%)
    uint64 maxIncreasePct;    // Maximum increase per transaction (1e10 = 100%)
}
```

#### **ParamKey Enum**

```solidity
enum ParamKey {
    A,                        // Amplification coefficient
    SwapFee,                  // Swap fee parameter
    MintFee,                  // Mint fee parameter
    RedeemFee,                // Redeem fee parameter
    OffPeg,                   // Off-peg multiplier
    ExchangeRateFee,          // Exchange rate fee factor
    DecayPeriod,              // Fee multiplier decay period
    RateChangeSkipPeriod,     // Rate change skip period
    FeeErrorMargin,           // Fee error margin
    YieldErrorMargin,         // Yield error margin
    MinRampTime,              // Minimum ramp time
    BufferPercent             // Buffer percentage
}

```