> For the complete documentation index, see [llms.txt](https://docs.usefarlight.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.usefarlight.com/protocol/idle-capital.md). # Idle capital between fills How unmatched lender USDG is parked in a whitelisted Morpho vault through IdleVaultAdapter and withdrawn in the same transaction as a fill. Standing offers only work if lenders are willing to hold capital in reserve. USDG sitting in a wallet costs its owner the yield it could have earned, and nobody keeps much of it waiting for long. Farlight uses the design Morpho Optimizer applied on top of Aave and Compound: unmatched capital rests in a pooled market and is withdrawn at the instant a fill arrives. Think of it as station-keeping. The capital holds its position, earns while it waits, and moves the moment it is called. ## How parking works 1. The lender enables `parkIdle` on their offers and approves the `IdleVaultAdapter`. 2. The adapter deposits the lender's USDG into a **whitelisted Morpho Blue USDG vault** on Robinhood Chain. The vault shares stay in the lender's own account; Farlight holds an allowance over them, never custody. 3. The lender's standing offers remain live, and the relayer treats the vault balance as available capacity. 4. When one of those offers is matched, `LoanDesk` instructs the adapter to withdraw exactly the fill amount from the vault and forward it to the borrower, all inside the same transaction. 5. When the loan is repaid, the proceeds return to the vault automatically, provided the lender still has `parkIdle` set. While waiting, the lender earns the vault's pool rate. Once matched, they earn the peer-to-peer rate. ## Approved vaults Only vaults approved through the PolicyController are eligible. The whitelist holds a single well-established USDG vault with a conservative curator. Adding a second is a timelocked parameter change with a published rationale. See [Parameter governance](/transparency/governance.md). ## The risks a parked lender accepts Parking is opt-in for a reason: it adds exposures that the core protocol does not carry. * **Vault risk.** A parked lender is exposed to the vault's underlying Morpho markets and to the curator's decisions. * **Withdrawal liquidity.** If the vault is fully utilised at the moment of a match, the just-in-time withdrawal fails and that slice's fill reverts. The relayer watches vault liquidity and does not propose a slice it cannot fund. * **Composability surface.** The adapter adds one contract to the origination path. It is small, operates only through allowances, and is covered by every audit. ## Fee The idle-capital yield share, 5% of vault yield, is listed on the fee page as scheduled. It applies only once it has been enabled through the timelock; until then there is no fee on parking. ## What the adapter cannot do * Send capital anywhere other than the whitelisted vault or an origination. * Rehypothecate vault shares. * Switch to a different vault without a timelocked, publicly logged change. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.usefarlight.com/protocol/idle-capital.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.