Vat

Purpose

The core accounting contract of the protocol, VAT tracks system-wide balances, including user Vaults, collateral types, and debt. It ensures that all collateral and debt are properly accounted for and enforces system solvency.

Key Responsibilities

• Tracks collateral and debt balances for all users and collateral types.

• Ensures Vault operations (e.g., minting and repaying USDD) adhere to protocol parameters.

• Integrates with other contracts to trigger auctions or manage liquidations.

Key Methods

• slip(ilk, usr, wad) Adjusts the balance of a specific collateral type (ilk) for a user (usr).

  • Example Use: Adding or removing collateral from a user's Vault.

• frob(ilk, u, v, w, dink, dart) Adjusts collateral (dink) and debt (dart) for a Vault.

  • Example Use: Minting new USDD or repaying debt.

• grab(ilk, u, v, w, dink, dart) Executes adjustments on collateral and debt during liquidation.

• fold(ilk, u, rate) Increase the Ilk.rate with rate, and hence the debt balances of all Vaults collateralized with the specified Ilk are updated implicitly.

• file(what, data) / file(what, ilk, data) Sets or updates system-wide parameters like debt ceilings, stability fees, or collateralization thresholds.

  • Example Use: Setting a collateral type’s maximum mintable USDD.