A founders agreement is a written contract among co-founders that defines equity, roles, vesting, IP assignment, and what happens when a co-founder leaves. It is signed at or near incorporation and is usually the single most important document the founders sign before they take outside capital.
A standard founders agreement covers the equity split (with the underlying logic so it can be defended later), founder vesting schedules (typically four years with a one-year cliff), an IP assignment clause that transfers any pre-formation work to the company, decision-making rules (which decisions are unanimous, majority, or unilateral by role), and "what if" provisions for departure, including buyback rights on unvested shares an...