> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hyperlane.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Managing HWR Limits

> Manage Hyperlane Warp Route Limits on xERC20 and FiatToken

## xERC20 Deployments

Hyperlane Warp Routes (HWR) support [`xERC20` tokens](https://github.com/defi-wonderland/xERC20). Follow these steps to configure `xERC20` for HWR usage:

1. **Ownership Transfer**:

* Ensure that the ownership of the [`xERC20` contract](https://github.com/defi-wonderland/xERC20/blob/main/solidity/contracts/XERC20.sol) is transferred to a secure multisig for security purposes. This step is crucial to prevent unauthorized changes.
* The `xERC20` contract uses OpenZeppelin's `Ownable` interface. Use the `transferOwnership` function to complete this step.

2. **Mint Limit Configuration**:

* The minting and burning limits for the HWR contract are managed through the [`setLimits`](https://github.com/defi-wonderland/xERC20/blob/main/solidity/contracts/XERC20.sol#L85) function in the `xERC20` contract. This function must be called by the contract owner.
  * The `xERC20` contract uses a 24-hour window to manage limits. This is defined by the [`_DURATION`](https://github.com/defi-wonderland/xERC20/blob/main/solidity/contracts/XERC20.sol#L13) variable, which is set to 1 days (24 hours). The current available limits are calculated dynamically using the [`_getCurrentLimit`](https://github.com/defi-wonderland/xERC20/blob/main/solidity/contracts/XERC20.sol#L234) function.
  * If 24 hours (`_DURATION`) have passed since the last use, the limit will automatically restore to the full `maxLimit`.
* Ensure limits are appropriate for the expected volume to prevent disruptions. Review and adjust the limits based on transaction volumes and expected usage patterns.

## FiatToken Deployments

HWRs support [Circle's Bridged USDC in the form of a minter for `FiatToken`](https://github.com/circlefin/stablecoin-evm) (See more on the repo for documentation). There are three roles that are relevant on the `FiatToken` and `MasterMinter` contracts:

1. **`MasterMinter` owner** is the account that can set controllers and minters.
2. **`MasterMinter` controller** is the account that can set the mint limits for its assigned minters.
3. **`MasterMinter` minter** is the account that can actually call `mint` on `FiatToken`.

The owner and controller should typically be set to a Safe multisig for enhanced security, the minter is the HWR contract address on the local chain. Mint limits for `FiatToken` are absolute, meaning they do not reset automatically and must be updated if required.

There are three actions that should be set on the `MasterMinter` contract to be ready for usage:

1. **Remove the previous test controller:**:

* As the owner, remove the previous test controller via the [`removeController(address _controller)` function](https://github.com/circlefin/stablecoin-evm/blob/master/contracts/minting/Controller.sol#L87C14-L87C51)

2. **Set the controller and minter:**

* As the owner, you should set the controller and minter via the [`configureController(address controller, address worker)` function](https://github.com/circlefin/stablecoin-evm/blob/master/contracts/minting/Controller.sol#L70). The controller can be the same as the owner, the minter should be the HWR address.

3. **Set the mint limit for the minter:**

* As the controller, you should set the mint limit for the minter via the [`configureMinter(uint256 _newAllowance)` function](https://github.com/circlefin/stablecoin-evm/blob/master/contracts/minting/MintController.sol#L116). This limit is not being continuously reset, so either set it to a sufficiently large value (like `cast max-uint`) or monitor the usage and adjust accordingly.