[1.18] Villager AI Help

I'm new to Forge, but I thought injecting some AI into Villagers would be relatively simple— just create a class that extends Goal, and use targetSelector (or goalSelector).addGoal inside an EntityJoinWorldEvent listener. But during testing, I discovered that all running and available goals are always empty for Villagers. Below is the test code— running near an established Village just returns empty lists.

@SubscribeEvent
public void test(EntityEvent event) {
    if (event.getEntity() instanceof Villager) {
        Villager villager = (Villager) event.getEntity();
        if (villager.goalSelector != null) {
            LOGGER.info("available goals: {}",
                    villager.goalSelector.getAvailableGoals()
                            .stream()
                            .map(goal -> new Object[]{goal.getGoal(), goal.getFlags(), goal.getPriority()})
                            .toList()
            );
            LOGGER.info("current goals: {}",
                    villager.goalSelector.getRunningGoals()
                            .map(goal -> new Object[]{goal.getGoal(), goal.getFlags(), goal.getPriority()})
                            .toList()
            );
        }
        if (villager.targetSelector != null) {
            LOGGER.info("available target goals: {}",
                    villager.targetSelector.getAvailableGoals()
                            .stream()
                            .map(goal -> new Object[]{goal.getGoal(), goal.getFlags(), goal.getPriority()})
                            .toList()
            );

            LOGGER.info("current target goals: {}",
                    villager.targetSelector.getRunningGoals()
                            .map(goal -> new Object[]{goal.getGoal(), goal.getFlags(), goal.getPriority()})
                            .toList()
            );
        }
    }
}

Why is this the case, and how will it affect Goals that I add myself?