An agreement, signed by an individual, containing a provision prohibiting that individual from soliciting a former employer’s customers or clients which is treated as a non-compete agreement. Therefore, these non-solicitation agreements must meet the requirements necessary to non-compete covenants, generally, to be enforceable.
If the prospective employee wishes for additional provisions/conditions to be included, the time to negotiate for inclusion, is prior to signing. The employer is more likely to agree, depending on how much they desire to hire this individual.
Definition of non compete and non solicitation agreement.
You can find various examples of Non-Compete and Non-Solicitation Agreements here.