A specific type of legal body, known as a Title IV-D court, would be the agency responsible for adjudicating any Texas child support issue in which you are involved. The name of these courts comes from a section of the Federal Social Security Act. This act requires states to uphold nationwide standards in the enforcement of your child support or related family law issues, such as medical support, determination of parental status or locating a missing parent.
As you might imagine, these courts are something of a hybrid: They receive federal as well as state funding as a result of their direct responsibility to the United States government. However, they are still Texas courts, which means that you and your parental counterpart should expect to be held to the relatively strict child support rules of the state.
For example, the National Conference of State Legislatures outlines the power that the IV-D agencies in Texas might have over your child support agreement in its 2015 annual update for the Lone Star State. The IV-D agency gained the power to begin the process of modifying your agreement if certain conditions are met, namely the changing of the caregiver and custodian of the child in question.
National regulations, state laws and the living situations of everyone involved with the contract all have the potential to result in changes to your child support agreement. As such, it might be difficult to determine how exactly your terms may or may not be enforced under special circumstances. Please consider this simply as educational material, not as legal advice.