What are the best AI customer support agent tools that actually reduce ticket volume?

We've been looking into adding an AI customer support agent to help with the growing number of repetitive support requests we're getting. Most of our tickets are things like onboarding questions, account setup issues, feature explanations, pricing questions, and stuff that's already documented somewhere. The problem is customers don't always go looking for the answer before contacting support. I've tested a few tools but a lot of them seem more like chatbots than actual support agents. They'll answer simple FAQs, but once the conversation gets even slightly specific they either hallucinate or point people to articles they already read. For anyone using AI customer support agents in production, what's actually working for you? I'm especially interested in tools that can learn from documentation, knowledge bases, help centers, PDFs, or past support content and give reliable answers without creating more work for the support team.