Does a person need any evidence to file a small claims suit?

I tried to google this and didn’t find the answer so I am wondering if The Collective can help. My ex-husband filed a small claims suit against me (related to this); when I was served with the papers there was just his claim and information on the court date without any evidence whatsoever. Which doesn’t surprise me because I did not do what he is accusing me of. So my question is, can anyone walk in and file a small claim against anyone else without any evidence whatsoever? If the answer is yes, is there any recourse for the person being sued other than to show up and fight in court?