non-compete agreement is an agreement signed by the emplyee to ensures that upon the termination of his employment contract, the former employee will not do any activities that places him in direct competition with his former employer and use informations or consumers relationships to compete with his former employer.
non-compete agreements have usually specific time period, precise geographic limitations ....

an agreement drafted by at the begining of some employment, it may be legal and may not legal,totally depends on lcoal laws. or state laws of every palce..