> For the complete documentation index, see [llms.txt](https://sommelier-finance.gitbook.io/sommelier-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sommelier-finance.gitbook.io/sommelier-documentation/smart-contracts/external-protocol-integration/building-adaptors/debt-adaptors.md).

# Debt Adaptors

Sommelier Cellars can incur leverage by borrowing assets from any lending protocol supported by an adaptor - to do this, a [debt adaptor](https://github.com/PeggyJV/cellar-contracts/blob/main/src/modules/adaptors/Aave/AaveDebtTokenAdaptor.sol) can be built. Debt adaptors are subject to the following guidelines:

* `isDebt` must return true.
* User deposits and withdrawals from the debt position should not be supported.
* `balanceOf` should report the total liability outstanding.
* Any function which incurs additional debt should only borrow up to liquidation thresholds and not cause a strategist to be able to liquidate their own Cellar.