The phrase "agent route" refers to the path taken by a person or entity who is acting on behalf of someone else, called an agent. It means the specific way or method the agent uses to reach a goal or complete a task. Full definition
I For clients who seek traditional publishing — the bulk of my clients — the normal query letter - literary agent route still seems best. (freshinkbookediting.com)
The event also features publishers from small presses for writers wanting to explore options other than the traditional agent route. (stephaniescott.net)