How SmartCall Implements a Dual-Channel RAG Knowledge Base Within a Single Phone Call

The SmartCall open source project breaks down the implementation of an agent knowledge base in voice customer service scenarios, using two parallel channels: interceptor gating and Function Calling tools. The article points out that the server-side VAD of end-to-end real-time voice models will answer preemptively, so the core contradiction shifts from retrieval accuracy to whether retrieval can beat automatic model responses; the solution relies on fail-open and audio hold as its pivots. The article also provides a four-step extension process for integrating new sources such as RAGFlow and a ten-item pitfalls checklist.