How to create an ai agent that actually does something useful, not just a demo?

I've been reading about AI agents for a while now and every time I go down the rabbit hole I end up with the same feeling: these things look impressive in a controlled demo and then fall apart the moment you try to apply them to a real workflow. Most of the tutorials I've found on how to create an AI agent are either toy examples (summarize this PDF, answer questions about a CSV) or they're so abstract that I can't figure out how to map them to an actual business process. My team handles a pretty complex sales ops workflow with data spread across a CRM, a few internal tools, and some manual handoff steps that nobody has ever properly documented. The idea of an agent that could handle even part of that is appealing, but I'm genuinely skeptical that the tech is there yet outside of well-funded enterprise pilots. Has anyone actually deployed something that runs in production, not just a proof of concept that lives in a notebook? I want specifics: what tool or platform did you use, what workflow did it actually take over, and where did it break or disappoint you. I'm not looking for hype, I'm looking for someone who has been through the frustration and can tell me what's real.