Stablecoin Delegate Contracts

Overview

Stablecoin delegates connect MultiliquidSwap to a specific Liquidity Provider (LP). Each delegate defines how assets move, which collateral it accepts, where reserves are held, how LP fees are configured, and which administrative controls apply. The selected stablecoinDelegateID gives every route a clear LP domain. That domain owns the settlement policy even when the route exchanges two RWAs or two stablecoins.

LP-Owned Configuration

LP admins manage accepted assets, fee schedules, custody, liquidity, and delegate-level controls.

Atomic Settlement

Delegates move or mint assets only when called by the registered MultiliquidSwap contract.

Transparent Reserves

Hot custody and informational cold-storage addresses are directly readable on-chain.

Composable Liquidity

Delegates can designate an auto-liquidity stablecoin for prefund and sweep workflows.

Base contract: src/prod/StablecoinDelegateBase.sol

Delegate Architecture

MultiliquidSwap calculates resolved amounts and calls one of four settlement methods. The delegate then performs the token-specific transfer, mint, or burn operations.

Production Delegate Families

Family	Settlement model
Balance sheet	Transfers existing inventory between users, custody, and the protocol vault
Mint/burn	Mints the delegated stablecoin on issuance and burns it on redemption
Yield-bearing Treasury	Mints and burns Treasury while tracking credits, rates, and yield multipliers

All families inherit the same custody, LP-admin, whitelist, fee, blacklist, pause, and upgrade framework.

Settlement Interface

struct DelegateParams {
    address user;
    address receiver;
    address vault;
    uint256 protocolFeeAmt;
    uint256 lpFeeAmt;
    address assetInAddress;
    uint256 assetInAmount;
    address assetOutAddress;
    uint256 assetOutAmount;
}

Function	Route family	Delegate responsibility
`deployStablecoin`	RWA → stablecoin	Receive the RWA and deliver the configured stablecoin
`receiveStablecoin`	Stablecoin → RWA	Receive or burn stablecoin and deliver the RWA
`exchangeRWAs`	RWA → RWA	Receive one accepted RWA and deliver another
`exchangeStablecoins`	Stablecoin → stablecoin	Exchange the delegated stablecoin against an accepted counterparty stablecoin

Each method is callable only by the role assigned to MultiliquidSwap, is non-reentrant, and respects delegate pause and blacklist state.

User and Receiver

user is the source of the input asset and receiver is the destination for the output asset. Delegates validate both identities and send output directly to the requested receiver.

Protocol and LP Fees

protocolFeeAmt contains the protocol amounts resolved by MultiliquidSwap. lpFeeAmt contains the explicit LP fee for the route. The concrete delegate determines whether those amounts are transferred from custody, taken from input, or minted according to the stablecoin’s settlement model.

Balance-Sheet Settlement

BalanceSheetStablecoinDelegate uses pre-existing liquidity:

RWA inputs move from the user to balanceSheetCustodyAddress.
RWA outputs move from RWA custody to the receiver.
Stablecoin inputs move into stablecoinCustodyAddress.
Stablecoin outputs and applicable protocol fees move out of stablecoin custody.
RWA and stablecoin custody accounts approve the delegate as ERC-20 spender.

This model supports stablecoins that do not expose mint and burn permissions to the delegate.

Mint-and-Burn Settlement

MintBurnStablecoinDelegate represents integrations that expose controlled mint and burn authority:

RWA → stablecoin routes mint stablecoin output to the receiver.
Stablecoin → RWA routes burn the user’s delegated stablecoin.
RWA → RWA routes can mint protocol and LP fees without moving the delegated stablecoin through the user’s wallet.
Stablecoin → stablecoin routes mint or burn the delegated stablecoin and custody the counterparty stablecoin.

Concrete implementations can adapt the base behavior to a token’s native mint and burn interface.

Treasury Yield Delegate

TreasuryDelegate combines stablecoin settlement with on-chain yield accounting.

Credits and Yield

credits[user] tracks released backing credits.
New deposits enter a 24-hour withheld-credit queue.
totalWithheldCredits[user] provides the aggregate pending amount.
yieldMultiplier[user] converts released credits into effective redeemable value.
lastAccrualDay[user] records the user’s synchronized rate day.

RWA-backed deposits begin earning from their deposit timestamp. Stablecoin-backed deposits apply the configured earning-start rules. Withheld credits remain redeemable at face value and merge into released credits as they mature.

Daily Rates

Rate posters submit sequential gross APY values. The delegate subtracts the portfolio management fee and stores the resulting net APY and derived daily compounding rate.

function postDailyRate(uint256 dayNumber, uint256 grossRate) external;
function correctDailyRate(uint256 dayNumber, uint256 grossRate) external;

The delegate supports an optional maximum daily rate and a bounded fallback window for partial-day stablecoin withdrawal yield.

Interest Accrual

function accrueInterest(
    address user,
    uint256 maxDays,
    uint256 maxRecords
) external returns (
    uint256 daysProcessed,
    uint256 recordsProcessed,
    bool daysComplete,
    bool recordsComplete
);

maxDays bounds posted-rate processing and maxRecords bounds withheld-credit merging. Both values must be nonzero. batchAccrueInterest synchronizes multiple users without explicit per-user limits. Swap settlement synchronizes the relevant user’s Treasury state before final pricing. Read-only quoteSwap uses stored state without changing it.

LP Administration

LP admins are stored independently from OpenZeppelin role membership and can add or remove other LP admins.

Asset Eligibility

function whitelistRWA(address rwa, bool accepted) external;
function whitelistStablecoin(address stablecoin, bool accepted) external;

The RWA whitelist determines which RWA tokens the LP domain will accept or deliver. The stablecoin whitelist determines which counterparty stablecoins can be exchanged against the delegated stablecoin. These delegate lists complement protocol-level asset acceptance, RWA recipient whitelist adapters, token-native compliance, and optional RWA delegates.

Fee Configuration

LP admins configure WAD-scaled rates through the delegate:

function setRWADiscountRate(bytes32 rwaID, uint256 rate) external;
function setRWARedemptionFee(bytes32 rwaID, uint256 rate) external;
function setStablecoinAcceptanceFee(address stablecoin, uint256 rate) external;
function setStablecoinRedemptionFee(address stablecoin, uint256 rate) external;

The delegate forwards these settings to its registered stablecoin domain in MultiliquidSwap. Rates must remain below 1e18.

Auto-Liquidity

function setAutoLiquidityStablecoinID(
    bytes32 autoLiquidityStablecoinID
) external;

The selected asset is used by MultiliquidSwap for eligible prefund and sweep legs. Passing bytes32(0) disables automatic liquidity for the delegate.

Custody

function setRWACustodyAddress(address custodyAddress) external;
function setStablecoinCustodyAddress(address custodyAddress) external;

Both hot custody addresses must be configured before settlement. They can point to separate accounts and are exposed independently on-chain. Delegates also maintain informational reserve disclosures:

function getRWAColdStorageAddresses()
    external
    view
    returns (address[] memory);

function getStablecoinColdStorageAddresses()
    external
    view
    returns (address[] memory);

LP admins can add and remove entries for both reserve categories.

Delegate Controls

LP admins can:

Apply an additional delegate-level blacklist
Pause and unpause LP settlement
Withdraw stablecoin held directly by the delegate
Update hot custody accounts
Manage LP-admin membership

Multiliquid’s PAUSE_ROLE has a separate pauseMultiliquid and unpauseMultiliquid path for protocol operations.

Token Allowances

Stablecoin delegates execute ERC-20 transferFrom calls and are the token spender for user and custody transfers. Typical integrations configure:

User allowance to the selected delegate for each input token
RWA custody allowance to the delegate for RWA output inventory
Stablecoin custody allowance to the delegate for stablecoin output and fee inventory

Protocol-level standing swap allowances and EIP-712 permits authorize the operator; they do not replace ERC-20 token allowances.

Access Control

Authority	Capabilities
`DEFAULT_ADMIN_ROLE`	UUPS upgrades and OpenZeppelin role administration
LP admin	Whitelists, fee schedules, custody, reserve disclosures, LP blacklist, and LP pause controls
`MULTILIQUID_SWAP_CONTRACT`	Settlement entrypoints
`PAUSE_ROLE`	Protocol pause and unpause path
Treasury `RATE_POSTER_ROLE`	Sequential daily-rate posting
Treasury `OPERATOR_ROLE`	Rate correction and yield operating parameters

Core Events

The base delegate emits events for:

RWA and stablecoin whitelist updates
RWA discounts and redemption fees
Stablecoin acceptance and redemption fees
Auto-liquidity configuration
Hot custody changes
Cold-storage additions and removals
Delegate blacklist changes
LP-admin membership
Pause, unpause, and upgrades

TreasuryDelegate additionally emits daily-rate, interest-accrual, credit, management-fee, and yield-multiplier events.

Next: RWA Delegate Contracts

Explore asset-specific stateful risk controls

Overview

Core Components

Applications

Integration

Overview

LP-Owned Configuration

Atomic Settlement

Transparent Reserves

Composable Liquidity

Delegate Architecture

Production Delegate Families

Settlement Interface

User and Receiver

Protocol and LP Fees

Balance-Sheet Settlement

Mint-and-Burn Settlement

Treasury Yield Delegate

Credits and Yield

Daily Rates

Interest Accrual

LP Administration

Asset Eligibility

Fee Configuration

Auto-Liquidity

Custody

Delegate Controls

Token Allowances

Access Control

Core Events

Next: RWA Delegate Contracts

​Overview

LP-Owned Configuration

Atomic Settlement

Transparent Reserves

Composable Liquidity

​Delegate Architecture

​Production Delegate Families

​Settlement Interface

​User and Receiver

​Protocol and LP Fees

​Balance-Sheet Settlement

​Mint-and-Burn Settlement

​Treasury Yield Delegate

​Credits and Yield

​Daily Rates

​Interest Accrual

​LP Administration

​Asset Eligibility

​Fee Configuration

​Auto-Liquidity

​Custody

​Delegate Controls

​Token Allowances

​Access Control

​Core Events

Next: RWA Delegate Contracts

Overview

Delegate Architecture

Production Delegate Families

Settlement Interface

User and Receiver

Protocol and LP Fees

Balance-Sheet Settlement

Mint-and-Burn Settlement

Treasury Yield Delegate

Credits and Yield

Daily Rates

Interest Accrual

LP Administration

Asset Eligibility

Fee Configuration

Auto-Liquidity

Custody

Delegate Controls

Token Allowances

Access Control

Core Events