Texas Estates Code - EST § 112.152. Nontestamentary Nature of Transfers Under Agreement

(a) Transfers at death resulting from community property survivorship agreements made in accordance with this chapter are effective by reason of the agreements involved and are not testamentary transfers.

(b) Except as expressly provided otherwise by this title, transfers described by Subsection (a) are not subject to the provisions of this title applicable to testamentary transfers.