Chatbot Agent for Food Ordering

Annapurna is a sophisticated GenAI-powered conversational agent built with LangGraph and FastAPI that helps customers browse restaurant menus and place orders seamlessly in natural language. This project demonstrates the power of AI agents in creating natural, intuitive food ordering experiences with some creative human like conversations, not the old robotic chatbots.

📱 Application Screenshots

Chat Interface

Main chat interface showing natural language interaction

Menu Browsing & Cart Management

Dynamic menu display and cart management features

🌟 Features

• Intelligent Conversational Interface: Natural language interaction for menu browsing and order placement
• Dynamic Menu Integration: Real-time menu fetching from external services
• Smart Cart Management: Add, modify, and track items in the shopping cart
• Multi-tenant Support: Support for multiple restaurant subdomains
• Memory-Enabled Conversations: Maintains context throughout the ordering session
• RESTful API: Clean API endpoints for frontend integration
• Extensible Architecture: Built with LangGraph for easy workflow modifications

🏗️ Architecture

This project uses a modern AI agent architecture:

• LangGraph: Orchestrates the conversational workflow and agent behavior
• FastAPI: Provides high-performance REST API endpoints
• LangChain: Powers the LLM integration and tool calling
• Google Gemini: LLM backend for natural language processing

Agent Workflow

The system implements a state-based conversational agent that:

1. Receives user messages
2. Processes intent and context
3. Calls appropriate tools (menu fetching, cart management)
4. Maintains conversation state and memory
5. Responds with helpful, contextual information

Agent workflow visualization showing the conversation flow and tool integration

📁 Project Structure

chatbot-agent/
├── backend/                    # Main backend application
│   ├── src/
│   │   ├── agents/            # Agent-related modules
│   │   │   ├── nodes/         # LangGraph nodes (chatbot, tools)
│   │   │   ├── prompts/       # System prompts and templates
│   │   │   ├── tools/         # Agent tools (cart, menu)
│   │   │   ├── graph.py       # LangGraph workflow definition
│   │   │   ├── state.py       # State management
│   │   │   └── output_structures.py
│   │   ├── api/               # FastAPI routes
│   │   │   └── routes/        # API endpoint definitions
│   │   ├── services/          # Business logic services
│   │   ├── configs/           # Configuration management
│   │   └── main.py           # FastAPI application entry point
│   ├── pyproject.toml        # Python dependencies
│   └── uv.lock              # Lock file for reproducible builds
├── training/                  # Training and development notebooks
│   ├── training-agent.ipynb  # Jupyter notebook for agent development
│   ├── menu.json            # Sample menu data
│   └── main.py              # Training scripts
├── docs/                     # Documentation and diagrams
│   ├── langgraph-flow.png   # Workflow visualization
│   └── screenshots/         # Application screenshots
└── README.md                # This file

🚀 Quick Start

Prerequisites

• Python 3.12+
• UV package manager (recommended) or pip
• Environment variables for API keys

Installation

1. Clone the repository

   git clone https://github.com/shashanksrajak/chatbot-agent-food-ordering.git
   cd chatbot-agent-food-ordering
   

2. Set up the backend environment

   cd backend
   uv sync  # or pip install -e .
   

3. Configure environment variables Create a .env file in the backend directory:

   GOOGLE_API_KEY=your_google_api_key
   MENU_BACKEND_URL=your_menu_service_url
   

4. Run the application

   cd backend
   uvicorn src.main:app --reload
   

   The API will be available at http://localhost:8000

API Documentation

Once running, access the interactive API documentation at:

• Swagger UI: http://localhost:8000/docs
• ReDoc: http://localhost:8000/redoc

🛠️ Usage

Basic Chat Interaction

curl -X POST "http://localhost:8000/chat" \
     -H "Content-Type: application/json" \
     -d '{
       "message": "Hi, I want to see your menu",
       "subdomain": "restaurant1",
       "restaurant_name": "name",
       "session_id": "user123"
     }'

Example Conversation Flow

1. User: "Hi, what's on your menu today?"
2. Agent: Fetches and displays the current menu
3. User: "I'd like to add a margherita pizza to my cart"
4. Agent: Adds the item and confirms the addition
5. User: "What's in my cart now?"
6. Agent: Shows current cart contents and total

Development

Running in Development Mode

# Backend with auto-reload
cd backend
uvicorn src.main:app --reload --host 0.0.0.0 --port 8000

# For development with detailed logging
uvicorn src.main:app --reload --log-level debug

Training and Experimentation

• Agent behavior experimentation
• Prompt engineering
• Menu data preprocessing
• Workflow testing

cd training
jupyter notebook training-agent.ipynb

🧪 Key Components

Agent Tools

• get_menu(): Fetches real-time menu data from external services
• add_to_cart(): Manages cart item additions with validation
• view_cart(): Displays current cart contents
• remove_from_cart(): Handles item removal and modifications

State Management

The agent maintains conversation state including:

• Current cart contents
• User preferences
• Conversation history
• Restaurant context (subdomain)

Memory System

Built-in memory management ensures:

• Context preservation across messages
• Session-based conversation tracking
• Stateful interactions

📝 License

🙏 Acknowledgments

• LangChain & LangGraph: For the powerful agent framework
• FastAPI: For the high-performance web framework
• Google Gemini: For the LLM capabilities
• Supabase: For the backend infrastructure

📧 Contact

Built with ❤️ using LangGraph and FastAPI