Callcenter.js acts as a robust bridge, allowing AI assistants like Claude to autonomously initiate and manage phone calls over standard VoIP (Voice over IP) networks. It integrates OpenAI's Real-Time Voice API with SIP-based VoIP connections, translating natural language instructions into real-world conversations. This tool provides an MCP server for seamless integration with AI agents, a command-line interface for direct calls, and a TypeScript API for programmatic control, empowering AI to handle tasks such as ordering food or scheduling appointments.