Design a voice and chat AI receptionist for businesses

Businesses want an AI receptionist that answers their phone number and chats on their website, app and messaging channels. It answers from information the business has approved, performs actions the business allows (booking, taking messages and so on) and hands the conversation to a human when needed. Design the platform: onboarding a business and its knowledge, the voice pipeline (speech-to-text, the model, text-to-speech) and its latency budget, tool calls and permissions, handoff, multi-tenancy, safety and evaluation.