User Operations

ObligationKey

All user-facing functions identify an obligation through an ObligationKey. This key combines the user's address with an optional seed, allowing a single address to hold multiple isolated positions (standard, earn, looping, etc).

Rust

pub struct ObligationKey {
    pub user: Address,
    pub seed: Option<BytesN<32>>,
}

TypeScript

export interface ObligationKey {
  seed: Option<Buffer>;
  user: string;
}

Seed value	Obligation type	Description
None	Standard	General-purpose supply-and-borrow obligation
Some(...)	Earn	Deposit-only obligation (no borrowing). The contract computes the seed internally.
Some(...)	Multiply	Isolated obligation for leveraged (looping) positions. The seed is derived from the deposit/borrow token pair.

Authorization is always against the user address inside the key.

Most user operations also accept an optional referrer: Option<Address> parameter. If the referrer is registered in the pool's fee configuration, they receive an immediate share of the origination fee.

---

Deposits & Withdrawals

deposit

Supply assets to a pool and receive jTokens (supply shares) in your obligation.

Rust

fn deposit(
    user: ObligationKey,
    pool_address: Address,
    amount: i128,
    referrer: Option<Address>,
) -> Result<(), MCError>

TypeScript

deposit: (
  {user, pool_address, amount, referrer}:
    {user: string, pool_address: string, amount: i128, referrer: Option<string>},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
user	ObligationKey	Obligation receiving the deposit
pool_address	Address	Target pool address
amount	i128	Amount to deposit
referrer	Option<Address>	Optional referrer for fee sharing

---

withdraw

Redeem jTokens for underlying assets. The actual amount withdrawn is capped to maintain the position's LTV at the pool's available liquidity limit.

Rust

fn withdraw(
    user: ObligationKey,
    pool_address: Address,
    amount: i128,
    referrer: Option<Address>,
) -> Result<(), MCError>

TypeScript

withdraw: (
  {user, pool_address, amount, referrer}:
    {user: string, pool_address: string, amount: i128, referrer: Option<string>},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
user	ObligationKey	Obligation to withdraw from
pool_address	Address	Pool to withdraw from
amount	i128	Desired withdrawal amount. Use i128::MAX to withdraw maximum available
referrer	Option<Address>	Optional referrer for fee sharing

---

Collateral Management

add_collateral

Lock assets as collateral. Collateral does not earn interest but is always available for healthy withdrawals.

Rust

fn add_collateral(
    user: ObligationKey,
    pool_address: Address,
    amount: i128,
    referrer: Option<Address>,
) -> Result<(), MCError>

TypeScript

add_collateral: (
  {user, pool_address, amount, referrer}:
    {user: string, pool_address: string, amount: i128, referrer: Option<string>},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
user	ObligationKey	Obligation to add collateral to
pool_address	Address	Pool to lock collateral in
amount	i128	Amount of collateral to add
referrer	Option<Address>	Optional referrer for fee sharing

---

remove_collateral

Unlock and withdraw collateral. The actual amount removed is capped to maintain the position's LTV at the pool's Open LTV.

Rust

fn remove_collateral(
    user: ObligationKey,
    pool_address: Address,
    amount: i128,
    referrer: Option<Address>,
) -> Result<(), MCError>

TypeScript

remove_collateral: (
  {user, pool_address, amount, referrer}:
    {user: string, pool_address: string, amount: i128, referrer: Option<string>},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
user	ObligationKey	Obligation to remove collateral from
pool_address	Address	Pool with locked collateral
amount	i128	Desired amount to remove. Use i128::MAX to remove all available collateral
referrer	Option<Address>	Optional referrer for fee sharing

---

Borrows

borrow

Borrow assets against previously supplied collateral.

Rust

fn borrow(
    user: ObligationKey,
    pool_address: Address,
    amount: i128,
    referrer: Option<Address>,
) -> Result<(), MCError>

TypeScript

borrow: (
  {user, pool_address, amount, referrer}:
    {user: string, pool_address: string, amount: i128, referrer: Option<string>},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
user	ObligationKey	Obligation borrowing against
pool_address	Address	Pool to borrow from
amount	i128	Amount to borrow. Use i128::MAX to borrow the maximum healthy amount
referrer	Option<Address>	Optional referrer for fee sharing

---

repay

Repay borrowed assets. If the provided amount exceeds the total debt, only the outstanding debt is repaid.

Rust

fn repay(
    user: ObligationKey,
    pool_address: Address,
    amount: i128,
    referrer: Option<Address>,
) -> Result<(), MCError>

TypeScript

repay: (
  {user, pool_address, amount, referrer}:
    {user: string, pool_address: string, amount: i128, referrer: Option<string>},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
user	ObligationKey	Obligation borrowing against
pool_address	Address	Pool to borrow from
amount	i128	Amount to repay. Provide a slightly larger amount than your liability to close the debt completely (including continuously accrued rate)
referrer	Option<Address>	Optional referrer for fee sharing

---

Liquidation

liquidate

Liquidate an unhealthy position (health factor < 1.0). The liquidator repays debt and receives collateral at a discount.

Rust

fn liquidate(
    liquidator: Address,
    borrower: ObligationKey,
    borrow_pool_address: Address,
    collateral_pool_address: Address,
    repay_amount: i128,
    demanded_collateral_amount: i128,
) -> Result<(), MCError>

TypeScript

liquidate: (
  {liquidator, borrower, borrower_obligation_seed,
   borrow_pool_address, collateral_pool_address,
   repay_amount, min_demanded_collateral_amount}: {
    liquidator: string,
    borrower: string,
    borrower_obligation_seed: Option<Buffer>,
    borrow_pool_address: string,
    collateral_pool_address: string,
    repay_amount: i128,
    min_demanded_collateral_amount: i128,
  },
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
liquidator	Address	Address performing the liquidation
borrower	ObligationKey	Obligation being liquidated (any type via seed)
borrow_pool_address	Address	Pool of debt being repaid
collateral_pool_address	Address	Pool of collateral being seized
repay_amount	i128	Amount of debt to repay
demanded_collateral_amount	i128	Minimum collateral the liquidator finds sufficient

---

Flash Loans

flash_loan

Borrow without collateral. The loan must be repaid (with fee) within the caller callback. Follows the ERC-3156 standard.

Rust

fn flash_loan(
    contract: Address,
    caller: Address,
    pool_address: Address,
    amount: i128,
) -> Result<(), MCError>

TypeScript

flash_loan: (
  {contract, caller, pool_address, amount}:
    {contract: string, caller: string, pool_address: string, amount: i128},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

Parameter	Type	Description
contract	Address	Contract that leverages the flash loaned amount and adheres to the ERC3156 standard
caller	Address	Original caller (for auth)
pool_address	Address	Pool to borrow from
amount	i128	Amount to borrow

---

Bad Debt Coverage

Bad debt coverage is a two-phase, permissionless process:

1. issue_cover_bad_debt: Sends cover requests to the Insurance Fund for every bad-debt borrow position on the obligation.
2. claim_cover_bad_debt_results: After off-chain review, claims the results from the Insurance Fund.

issue_cover_bad_debt

Rust

fn issue_cover_bad_debt(user: ObligationKey) -> Result<(), MCError>

TypeScript

issue_cover_bad_debt: (
  {user}: {user: string},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

claim_cover_bad_debt_results

Rust

fn claim_cover_bad_debt_results(user: ObligationKey) -> Result<(), MCError>

TypeScript

claim_cover_bad_debt_results: (
  {user}: {user: string},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

---

Fee Distribution

distribute_pool_fees

Distribute a pool's accumulated fees to the configured beneficiaries. Permissionless.

Rust

fn distribute_pool_fees(pool_address: Address) -> Result<(), MCError>

TypeScript

distribute_pool_fees: (
  {pool_address}: {pool_address: string},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

distribute_all_pools_fees

Distribute fees for every pool in the market. Permissionless.

Rust

fn distribute_all_pools_fees() -> Result<(), MCError>

TypeScript

distribute_all_pools_fees: (
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

---

Batch Operations

submit_requests_batch

Submit multiple operations in a single atomic transaction. Users can combine deposits, borrows, swaps, and liquidations in one batch to build advanced strategies like leveraged positions.

Rust

fn submit_requests_batch(
    user: ObligationKey,
    requests: Vec<Request>,
    referrer: Option<Address>,
) -> Result<(), MCError>

TypeScript

submit_requests_batch: (
  {user, requests, referrer}:
    {user: string, requests: Array<Request>, referrer: Option<string>},
  options?: MethodOptions
) => Promise<AssembledTransaction<Result<void>>>

The Request enum has 10 variants:

Rust

pub enum Request {
    Deposit(StandardRequest),
    Borrow(StandardRequest),
    Withdraw(StandardRequest),
    Repay(StandardRequest),
    AddCollateral(StandardRequest),
    RemoveCollateral(StandardRequest),
    FlashBorrow(StandardRequest),
    SwapExactTokens(SwapExactTokensRequest),
    SwapForExactTokens(SwapForExactTokensRequest),
    Liquidate(LiquidateRequest),
}

TypeScript

// The TS SDK flattens batch requests into a struct + enum:
export interface Request {
  amount: i128;
  pool_address: string;
  request_type: u32;
}

export enum RequestType {
  Deposit = 0,
  Borrow = 1,
  Withdraw = 2,
  Repay = 3,
  AddCollateral = 4,
  RemoveCollateral = 5,
}

See Request & Response Types: Request Types for the full struct definitions.

Example: Leveraged Position via Batch

A leveraged position can be composed by submitting a batch like:

1. FlashBorrow the borrow asset
2. SwapExactTokens borrow asset → deposit asset
3. Deposit the deposit asset
4. Borrow the borrow asset
5. Flash loan is auto-repaid at the end of the batch