Legal agreement not to perform an activity similar to that performed by another individual or business. This contractual provision may be necessary to keep trade secrets, prevent taking away existing clients using the current business's methods, or otherwise seriously impair the activities of the existing business.. Foe example, a real estate broker who signs a covenant not to complete may prohibit him from opening up a real estate brokerage firm within 50 miles for a two-year period. this restriction is particularly important when the employee is highly qualified and will likely develop a strong customer following. However, if the restriction is very excessive, it may be legally unenforceable.