English to German Law/Patents Law: Contract(s) recruitment contract between employment agency and employee, regarding employee's assignment at the "Client's" (the employer) premises (non-solicitation clause)

Privacy of contract
No term of the Agreement is intended to be enforceable by anyone other than the parties to this Agreement and the parties hereby expressly exclude any operation of the Contracts (Rights of Third Parties) Act 1999.
Kann mir hier jemand weiterhelfen? Ist hier einfach gemeint, dass die Parteien die Zusammenarbeit mit einer dritten Partei ausschließen? Aber dann ist mir "operation" nicht ganz klar.