Build an AI Powered Phone Agent 📞🤖 with Retell, Google Calendar and RAG

This Workflow simulates an AI-powered phone agent with two main functions:

1. 📅 Appointment Booking – It can schedule appointments directly into Google Calendar.
2. 🧠 RAG-based Information Retrieval – It provides answers using a Retrieval-Augmented Generation (RAG) system. For example, it can respond to questions such as store opening hours, return policies, or product details.

The guide also explains how to purchase a dedicated phone number (with a +1 prefix) and link it to the AI agent. This setup is cost-effective, as it uses a FREE $10 credit to operate without additional charges in the beginning.

✨ Advantages

• 🕐 24/7 Availability – The AI agent can answer calls and assist customers at any time.
• 🤖 Automation – It reduces the workload on human staff by handling repetitive tasks like appointment scheduling and FAQ responses.
• 🔌 Easy Integration – Built with n8n, it’s flexible and customizable for various platforms and tools.
• 💸 Low-cost Setup – Using the free credit, businesses can get started without an upfront investment.

📦 Use Cases

• 🛍 E-commerce – Answer common product questions or order inquiries.
• 🏬 Retail Stores – Provide store hours, address info, and return policies.
• 🍽 Restaurants – Take reservations or share menu information.
• 💼 Service Providers – Book appointments or consultations.
• 📞 Any Local Business – Offer phone support without needing a live operator.

How It Works

This Workflow simulates an AI-powered phone agent with two primary functions:

1. Appointment Booking

   • The workflow captures call events (e.g., call_ended or call_analyzed) and extracts key details (transcript, caller info, duration, etc.).
   • Using OpenAI, it summarizes the conversation and parses structured data (e.g., names, contact info, dates).
   • For scheduling, it converts user-provided dates into Google Calendar-compatible formats and creates events automatically.

2. RAG-Based Information Retrieval

   • When a query is received (e.g., store hours, product details), the workflow retrieves relevant information from a Qdrant vector store.
   • An AI agent processes the query using the retrieved data and responds via a webhook, ensuring accurate, context-aware answers.

Set Up Steps

1. Prepare Qdrant Vector Store

   • Create/refresh a Qdrant collection (via HTTP requests).
   • Upload and vectorize documents (e.g., from Google Drive) using OpenAI embeddings.

2. Configure RetellAI Agent

   • Sign up for RetellAI, create an agent, and set the webhook URLs (n8n_call for call events, n8n_rag_function for RAG queries).
   • Purchase a Twilio phone number and link it to the agent.

3. n8n Workflow Setup

   • Connect OpenAI, Qdrant, Google Calendar, and Telegram nodes with credentials.
   • Customize prompts for summarization, date parsing, and RAG responses.
   • Test the workflow to ensure data flows from call events → processing → actions (e.g., calendar bookings, Telegram alerts).

4. Deploy

   • Trigger the workflow via RetellAI webhooks during calls.
   • Monitor outputs (e.g., call summaries in Telegram, calendar events).

Note: Replace placeholders (e.g., QDRANTURL, COLLECTION, CHAT_ID) with actual values.

Need help customizing?

Contact me for consulting and support or add me on Linkedin.