Texas Government Code - GOV'T § 1502.064. Credit Agreement for Reserve Fund

(a) The governing body of a municipality may provide that in lieu of or in addition to providing a cash reserve, a credit agreement, as defined by Section 1371.001, may be used to provide the reserve.

(b) A credit agreement obtained to provide a reserve must be submitted to the attorney general for examination and approval.  After approval by the attorney general, the credit agreement is incontestable in any court or other forum for any reason and is a valid and binding obligation of the municipality in accordance with its terms for all purposes.