User Prompt → AI (DeepSeek V4 Pro) → MCP Tools → PostgreSQL
     ↑                                    ↓
     └─────── JSON Response ←─────────────┘

pnpm install

# Copy file .env.example
cp .env.example .env

# Cập nhật DEEPSEEK_API_KEY
# Lấy API key tại: https://platform.deepseek.com/api_keys

pnpm docker:up

# Terminal 1: MCP Server
pnpm dev:mcp

# Terminal 2: Next.js Web App
pnpm dev:web

# Or run both concurrently
pnpm dev

mcp-postgres-demo/
├── docker/
│   ├── docker-compose.yml          # PostgreSQL setup
│   └── init.sql                    # Database seeding (115 products)
├── mcp-server/
│   ├── src/
│   │   ├── index.ts                # Server entry + HTTP endpoints
│   │   ├── db.ts                   # Connection pooling
│   │   └── tools/
│   │       ├── schema-tools.ts     # list_tables, get_table_schema
│   │       ├── query-tools.ts      # query_inventory, get_top_sales
│   │       └── execute-tool.ts     # execute_read_query (security guard)
│   ├── package.json
│   └── tsconfig.json
├── web/
│   ├── src/
│   │   ├── app/
│   │   │   ├── api/chat/route.ts   # AI orchestration endpoint
│   │   │   ├── page.tsx            # Chat UI
│   │   │   └── layout.tsx          # Root layout
│   │   └── lib/
│   │       ├── ai-client.ts        # DeepSeek client
│   │       └── tool-registry.ts    # Tool definitions
│   ├── package.json
│   └── .env.example
├── .env.example
├── package.json
└── README.md

{ "tableName": "products" }

{ "productId": "SP001" }

{
  "id": "SP001",
  "name": "Váy hoa nhí",
  "stock_quantity": 150,
  "stock_status": "Còn hàng",
  "price_formatted": "299.000₫"
}

{ "limit": 5, "days": 30 }

{ "sql": "SELECT * FROM products WHERE price > 500000" }

-- AI hallucination example
DROP TABLE users;
DELETE FROM orders WHERE 1=1;

User → DeepSeek V4 Pro → MCP Server → PostgreSQL

User: "Check tồn kho SP001"
AI: 🤔 User wants inventory → Call query_inventory tool
MCP: ✅ Execute SELECT query
DB: Returns { stock: 150 }
AI: "Sản phẩm SP001 còn 150 chiếc trong kho"

User: "Xóa tất cả users"
AI: 🤔 User wants to delete → Wait...
MCP: 🚫 BLOCKED! DELETE not allowed
Response: "Tool này chỉ hỗ trợ đọc dữ liệu"

export const queryInventoryTool = {
  name: 'query_inventory',
  execute: async ({ productId }) => {
    // Dev controls SQL 100%
    const result = await pool.query(
      'SELECT * FROM products WHERE id = $1',
      [productId]
    );
    return result;
  }
};

const FORBIDDEN_KEYWORDS = ['DROP', 'DELETE', 'UPDATE'];

if (sql.includes(FORBIDDEN_KEYWORDS)) {
  return { isError: true, text: '🚫 BLOCKED!' };
}

const response = await deepseekClient.chat.completions.create({
  model: 'deepseek-v4-pro',
  tools: toolsToOpenAIFormat(),
  tool_choice: 'auto'
});

const FORBIDDEN_KEYWORDS = [
  'DROP', 'DELETE', 'UPDATE', 'INSERT', 'TRUNCATE', 
  'ALTER', 'CREATE', 'GRANT', 'REVOKE'
];

inputSchema: z.object({
  productId: z.string().describe('Mã sản phẩm')
})

const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
  max: 20, // Prevent connection exhaustion
});

// ✅ Parameterized queries
await pool.query('SELECT * FROM products WHERE id = $1', [productId]);

// ❌ Never string concatenation
// await pool.query(`SELECT * FROM products WHERE id = '${productId}'`);

"Check tồn kho SP001" → 150 items
"Top 5 bán chạy tuần này" → Sales ranking
"Có những bảng nào?" → Table discovery
"Xem cấu trúc bảng products" → Schema details

# Check if PostgreSQL is running
docker ps | grep postgres

# View logs
pnpm docker:logs

# Restart
pnpm docker:down && pnpm docker:up

# Check environment variables
cat mcp-server/.env

# Test database connection
cd mcp-server && pnpm tsx src/db.ts

# Verify API key
echo $DEEPSEEK_API_KEY

# Test API
curl https://api.deepseek.com/v1/chat/completions \
  -H "Authorization: Bearer $DEEPSEEK_API_KEY" \
  -d '{"model":"deepseek-v4-pro","messages":[{"role":"user","content":"Hi"}]}'