The easiest thing to do is appear at the small claims hearing and testify. Unless the plaintiff has something on you that you arent telling us about, I dont see how the court can find you liable if you are only the agent for service of process.
If you want, when you show up at the small claims hearing, do not agree to have the matter heard before a judge pro tem. Ask for a regular judge to hear the matter.
Plus, if the court does find against you , you can file an appeal and have the matter heard before a regular judge.
Be sure and show up for the hearing. If you do not show up a default may be entered against you. An automatic appeal does not apply if you are defaulted. you would have to go to court and explain why you did not show up. If the court does not buy your reason, the judgment stands.