SQL Voice Agent with MCP

Natural language SQL agent using PostgreSQL, MCP protocol, and local LLM (Ollama).

Prerequisites

1. Install System Dependencies

# PostgreSQL
sudo apt update
sudo apt install postgresql postgresql-contrib

# Node.js (for MCP server)
curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
sudo apt install -y nodejs

# Python
sudo apt install python3 python3-pip

2. Install Ollama

# Install Ollama
curl -fsSL https://ollama.com/install.sh | sh

# Pull the model
ollama pull llama3.2:3b
# OR for better accuracy:
# ollama pull phi3:mini

3. Install Official PostgreSQL MCP Server

npm install -g @modelcontextprotocol/server-postgres

Setup

1. Clone Repository

git clone <your-repo-url>
cd <your-repo-name>

2. Install Python Dependencies

pip install -r requirements.txt

3. Setup PostgreSQL Database

# Start PostgreSQL
sudo systemctl start postgresql
sudo systemctl enable postgresql

# Create database and user
sudo -u postgres psql << 'EOF'
CREATE USER student_user WITH PASSWORD 'student123';
CREATE DATABASE student_db OWNER student_user;
\c student_db
GRANT ALL ON SCHEMA public TO student_user;
\q
EOF

# Load sample data
sudo -u postgres psql -d student_db -f schema.sql

4. Verify Setup

# Test PostgreSQL connection
PGPASSWORD=student123 psql -h localhost -U student_user -d student_db -c "SELECT COUNT(*) FROM students;"

# Test Ollama
curl http://localhost:11434/api/tags

# Test MCP server
which mcp-server-postgres

Run

python postgres_agent.py

Usage

Question: list all students
Question: show me students in CS201
Question: which course has the most enrollments
Question: exit

Project Structure

.
├── postgres_agent.py      # Main agent code
├── schema.sql            # Database schema and sample data
├── requirements.txt      # Python dependencies
└── README.md            # This file

Configuration

Edit postgres_agent.py to change:

• Model: Line 18 - Change llama3.2:3b to phi3:mini for better accuracy
• Database: Line 16 - Update connection string if using different credentials
• Verbose mode: Line 372 - Set verbose_mode = True for debugging

Troubleshooting

"mcp-server-postgres: command not found"

npm install -g @modelcontextprotocol/server-postgres

"Peer authentication failed"

Edit /etc/postgresql/*/main/pg_hba.conf:

# Change from:
local   all   all   peer

# To:
local   all   all   md5

Then restart: sudo systemctl restart postgresql

"Ollama connection refused"

sudo systemctl start ollama
# OR
ollama serve

Features

• ✅ Natural language to SQL
• ✅ PostgreSQL database queries
• ✅ MCP protocol for reliable execution
• ✅ 100% offline (after initial setup)
• ✅ Clean, voice-friendly output

Future Enhancements

• Voice input (STT with Vosk)
• Voice output (TTS with Coqui)
• Query caching
• Monitoring dashboard
• Performance metrics

License

MIT