This repository is a production-grade application for building real-time voice agents, primarily designed as an educational course but structured for actual deployment. It implements a complete voice call center system capable of receiving and making phone calls via Twilio, transcribing speech using various STT models (Moonshine, Whisper, Faster Whisper), reasoning with LLMs (Groq), searching property data using Superlinked and Qdrant, and generating speech using TTS models (Kokoro, Orpheus). The architecture is a modular monolith built with FastAPI, utilizing Docker for containerization and RunPod for GPU-accelerated model inference. While the repository includes Jupyter notebooks for educational purposes (Lesson 1-4), the core value lies in the `src/realtime_phone_agents` package, which encapsulates the agent logic, avatar system, and infrastructure integrations. The code demonstrates high craftsmanship in handling async audio streaming, managing external API dependencies, and implementing a flexible avatar registry system. It is suitable for engineers looking to build voice AI applications or understand the integration of LLMs with real-time audio pipelines.