ExternalPositionProxy is deployed by a persistent ExternalPositionFactory , which serves as an enduring registry of external position "types" (e.g., Compound CDP) and all valid ExternalPositionProxy instances (i.e., those created via the factory).ExternalPositionProxy is deployed with a VaultProxy as its owner.ExternalPositionProxy fetches its library via a getExternalPositionType() callback to its VaultProxy.ExternalPositionProxy should pass through a protected receiveCallFromVault() , guaranteeing the call passed through the owning VaultProxy .ExternalPositionManagerActions on the ExternalPositionManager extension:CreateExternalPosition -- create (deploy) a new external position and activate it on the VaultProxyCallOnExternalPosition -- make allowed arbitrary calls to interact with the external position, and transfer assets to / from the VaultProxyRemoveExternalPosition -- deactivate an external position from the VaultProxyReactivateExternalPosition -- reactivate an existing external position on the VaultProxyExternalPositionManager stores two updatable reference contracts per external position type, which contain all logic specific to that type:lib is the target library of the beacon ExternalPositionProxy, and contains the business logic for its local accounting and interactions with external protocolsparser is a contract used by the ExternalPositionManager to validate and parse call data for each specific action on its external position typeExternalPositionManager 's CallOnExternalPosition action via ComptrollerProxy.callOnExtension() with the desired payload to add 100 cDAI as collateralExternalPositionManager looks up its stored CompoundDebtPositionParser and forwards it the payloadCompoundDebtPositionParser validates the call, e.g., that cDAI is a valid cTokenCompoundDebtPositionParser formats the outgoing 100 cDAI into assetsToTransfer and amountsToTransfer arrays, which it returns to the ExternalPositionManagerExternalPositionManager passes the payload along with the data for assets to transfer (100 cDAI) and to receive (none) to the VaultProxyVaultProxy transfers 100 cDAI to the target ExternalPositionProxyVaultProxy calls ExternalPositionProxy.receiveCallFromVault() , passing in the payloadExternalPositionProxy calls back to the VaultProxy for the library to use for its type (Compound CDP), which it pulls from the ExternalPositionManagerExternalPositionProxy uses the returned CompoundDebtPositionLib to parse and execute the AddCollateralAssets action, adding cDAI to its internal accounting of its managed assets and interacting with Compound to use cDAI as collateral as needed.