The personnel manager and the candidate have already negotiated the terms and conditions of employment orally and the written offer of employment only confirms these oral agreements. Job postings can vary greatly depending on the job description and job offered and the associated conditions/benefits. A retainer agreement for ongoing customer services. Sections for retainer payments, service limits, and other legal safeguards. If these conditions are met, the agreement is a contract. From an economic point of view, it is generally considered that both parties intended to conclude a contract. .