
Quoting
Texas Business and Commercial Code, ยง 15.50
Criteria for Enforceability of Covenants Not To Compete
(a) Notwithstanding Section 15.05 of this code, and subject to any applicable provision of Subsection (b), a covenant not to compete is enforceable if it is ancillary to or part of an otherwise enforceable agreement at the time the agreement is made to the extent that it contains limitations as to time, geographical area, and scope of activity to be restrained that are reasonable and do not impose a greater restraint than is necessary to protect the goodwill or other business interest of the promisee.