Hi, I was employed by a small US startup a year ago for some side work to get some experience. After a few months I saw it wasn't gonna work out (I wasn't getting paid because the company was barely making profits) so I slowly faded away and stopped working. The CEO was understanding. However we never officially ended our relationship (through email or something). Only some unofficial chats that hint we are no longer together. I signed a contract at the start of my work that said employment is at will. Re-reading now the contract is probably not enforceable given many clauses don't make much sense, I was naive back then and signed it regardless.
I'm planning to make a startup in the next months, and I want to be clear of any IP claims that the CEO may make in the future (highly unlikely but in case we get very successful, you never know), because I did them "while employed", (if the contract was never officially canceled I could theoretically be still employed even now right?). I'm also worried that potential investors might ask me all my previous signed contracts (to make sure the IP belongs solely to the company), but I have no official documents of the relationship ending, only the chats. So it might scare off potential investors.
I haven't talked to the CEO for quite some time. What evidence do I need in order to be clear that I'm out of this contract? Do I need to ask him for something? We have friendly relations but I wouldn't wanna go into much detail with him, just wanna get clear of the contract (which potentially is unenforceable, but I'm not a lawyer).