Shares over the startup comapany

Hello, I am actually working on a product for a startup that decides the future of the company. We are three man team, one among which is CEO of the startup, myself as the core developer and other one takes care of outsourcing - documentations. The CEO promised both of us will be granted ownership of the company, now when the relationship reached the agreements. He has given agreement that states, I'm the employee who owns restricted shares 20% common stocks of the company that is vested over 10 years. speaking of the salary - It's equal to other directors : like mentioned in the agreement but there's no solid amount in the agreement. I find something fishy, I think this is not the actual thing he promised. This is merely an employee who has equal rights as a director but not actually a director. The stocks that will vest only after 10 years after which I can redeem. I may be fired before that and wont get any stocks. So I want to know is this the justice done to the core developer who has the future of the product in hand? Also what other optional claim do I have? Basically what is the justified claim that I could make?