What document serves as a written agreement specifying the terms of the loan?

The document that serves as a written agreement specifying the terms of the loan is the promissory note. This is a legally binding document where the borrower agrees to repay the loan under specific terms, which include the amount borrowed, interest rate, repayment schedule, and any other conditions relevant to the loan.

While the mortgage agreement is related and documents the security for the loan, it primarily deals with the collateral and the lender's rights in case of default, rather than detailing the specific terms of repayment for the loan itself. The loan application is a document used to gather information from the borrower, and the credit report provides an overview of the borrower’s credit history but does not outline loan terms. Hence, the promissory note is the correct reference for outlining the specifics of the loan agreement between the borrower and lender.