Alternatively, get ready to leave. But before you do, push back against the founder. The next time he pushes directly to master, immediately revert the commit,

Alternatively, get ready to leave. But before you do, push back against the founder. The next time he pushes directly to master, immediately revert the commit, but cherry-pick it over to a development or staging branch instead. Then notify him what you've done and why (including that you're trying to prevent breaking changes being made on master, like happened previously). How the founder responds to this will determine whether you leave, or whether you stay a bit longer and perhaps gain the founder's trust. But still expect you'll have to leave. :/