Operator guides from platforms like Retell commonly describe three generations. First came touch-tone DTMF trees—press 1 for billing. Second came directed dialogue: limited phrase spotting that still felt like a menu. Third is conversational AI: large language models that handle paraphrase, corrections, multi-intent asks, and tool calls into CRM or scheduling systems.
Marketing often calls everything “AI IVR.” Architecturally, keyword speech on a tree is not the same as an agentic voice agent that can book, update records, and brief a human. Buy for the third generation if your goal is resolution—not prettier routing.