I want to make sure that visitors on an active conversation with an agent receive a message while they wait for the agent's next response. Can I add a trigger that sends a message if an agent has not responded to a chat session after a period of time?
No, we do not have a condition that checks if the visitor has been responded to or not. You can create a trigger to check if the visitor sent a message but it does not stop the trigger when the customer's message was responded to by an agent.
Also, you can send a proactive message while the visitor is waiting to be served. We have a default trigger called Chat Rescuer that is active by default on your account.
For more information about Chat triggers, see these articles: