You should have a discussion with boss or HR. Also talk with others to see their experience. I have worked at one company that gave annual bonuses, depending

You should have a discussion with boss or HR. Also talk with others to see their experience. I have worked at one company that gave annual bonuses, depending on company performance. Your bonus might be automatic after X months, because they do not want you to take a bonus and bounce immediately. It may be a company annual event. Need to discuss this with people. Place I work now had a very strict rule of, if it is not in the offer letter, you will not get it. Are you willing to leave over it? Because if they did this to you, how much can you trust them? I wish you the best. Was the bonus a key reason you took the job?