Entrepreneurship in residence role

EIR is basically a junior version of CoS role (based on my experience as EIR). EIR role is primarily coming from VCs. Hence the definition of EIR changes from one startup to another. When I worked as an EIR, my role was to create bandwidth for CEO by taking low level work out of his plate. This gave me an exposure to a lot of things that happen in a startup. Eventually led me to take lead of one of the dept later. For your case, I would suggest to get an understanding of what is the expectation.