No REST No Stress! Connect LINE SHOPPING with MCP

A session from LINE THAILAND DEVELOPER CONFERENCE 2025 by Woraphol Janekittanpaiboon, Solution Engineer at LINE Thailand

Transcript

1. No REST No Stress! Connect LINE SHOPPING with MCP
2. Function calling - Feature for modern LLMs - Allow LLM to access or use our system PSEUDO CODE
3. Problem Each LLM has different way of handling function calling
4. MCP to the rescue!
5. • What is MCP and its architecture? • How LLM work with MCP Server • How to implement MCP Server for LINE SHOPPING Agenda
6. What is MCP? MCP (Model context protocol) is an open-source standard for connecting AI applications to external systems.
7. MCP is like USB-C
8. More technical, MCP is just a Client-Server Protocol MCP Client ChatGPT Claude Gemini MCP Server Datasource
9. Compared to other popular Client-Server protocols Web & Mobile apps LLM Backend Service GraphQL Server Datasource gRPC Server MCP Server gRPC Client GraphQL Client MCP Client
10. MCP Server provides Tools ⚒ for LLM to call ⎯ Think of it as a function - Has unique name - Has arguments(s) - Return result ⎯ Example - mysql-mcp-server - Has `execute_sql` tool - Has argument `query` - Return SQL result - SMTP-mcp-server - Has `send_email` tool - Has argument `address`, `subject` and `content` - Return operation result
11. How LLM think and use MCP Server? ส่งอีเมลล์แสดงความยินดีและแจ้งว่าให้มารับรางวัล ที ่ หน้างานส ำ หรับคน ที ่ ลง ทะเบียนเข้าร่วมงาน LINE DEV CONF 2025 ที ่ มีล ำ ดับการลงทะเบียนหารด้วย 100 ลงตัว เช่น คน ที่ 100, คน ที ่ 200 เ ป็ นต้น Let’s say we use MySQL for data storage and we have SMTP server • MySQL MCP server with `execute_sql` tool • SMTP MCP server with `send_email` tool
12. How LLM think and use MCP? (1/4) LLM MySQL Users Sessions Surveys Sponsors Booths Registrations Events Announcements … execute_sql({ “query”: “SHOW TABLES;” }) MySQL MCP Server
13. How LLM think and use MCP? (2/4) LLM MySQL Users - Id - Name - Email - Telno - Username - password - created_at - updated_at execute_sql({ “query”: “DESCRIBE `Users`; DESCRIBE `Registrations`; DESCRIBE `Events`” }) MySQL MCP Server Registrations - Id - event_id - user_id - reg_seq - created_at - updated_at Events - Id - Name - event_date - created_at - updated_at
14. How LLM think and use MCP? (3/4) LLM MySQL Name,Email,Req_seq ผัดไท,pathai@gmail.com,100 บัญชา,bancha@gmail.com,200 ดาริกา,darika@thaimail.com,300 … execute_sql({ “query”: “ SELECT u.Name, u.Email, r.Reg_seq FROM Registrations r JOIN Users u ON r.user_id = u.Id JOIN Events e ON r.event_id = e.Id WHERE e.Name = 'LINE DEV CONF 2025' AND r.reg_seq % 100 = 0;`” }) MySQL MCP Server
15. How LLM think and use MCP? (4/4) LLM Success send_email({ “address”: “pathai@gmail.com”, “subject”: “ยินด้วยคุณผัดไท คุณได้รับรางวัล!”, “content“: “คุณลงทะเบียนเ ป็ นคน ที ่ 100 ให้มารับรางวัล ที่ หน้างาน” }) SMTP MCP Server SMTP Server 📪
16. You now see how powerful LLM + MCP Server are 🤩 ⎯ Let’s try implementing our own MCP Server ⎯ LINE SHOPPING API is the perfect example! ⎯ Let’s get to know LINE SHOPPING API more first
17. What is LINE SHOPPING API ? ⎯ Improve automation for merchants with development capability ⎯ Standard RESTful API ⎯ Authentication through API Key (generated in LINE MyShop UI) ⎯ Currently provide subset of available features on MyShop such as product, inventory and order management.
18. Let’s try implementing MCP Server with LINE SHOPPING API LINE SHOPPING API Microservices DB Third party service LLM Agent Claude desktop Github copilot LINE SHOPPING MCP REST REST MCP
19. How to implement MCP server? Seriously, Learn all these protocols? 😲
20. Good news! 😮💨, there are official MCP SDKs ⎯ Abstract away low-level protocol, so developers can focus on business logic ⎯ Support many languages: -Python -Node.js -Java -.Net -Golang and many more…
21. Or even better, try FastMCP! 😎 ⎯ Built on top of MCP Python SDK but provide advanced features ⎯ Very popular among Python Community ⎯ My favorite feature is - Convert any OpenAPI specs into MCP server! - Most services should already have OpenAPI specs (Swagger) - If you meet this criteria, then you are in good hand
22. Here’s the 20-line code…
23. LINE SHOPPING MCP , Up and Running!
24. How MCP Server is created? ⎯ Convert all API Endpoints into MCP Server’s Tools ⎯ 22 Tools VS 22 Endpoints each tool represents each LINE SHOPPING API endpoint ⎯ In the background, This MCP server just calls LINE SHOPPING API endpoint based on which tool is used by LLM 🎉 ⎯
25. Now our MCP Server is up, let’s try some interesting use cases 💪
26. Migrate products from other platforms ผมขายสินค้าอยู่บน Platform XXX แล้วขายไม่ดีเลย เลยอยากจะย้ายมาขาย ที ่ LINE SHOPPING ที ่ มีลูกค้า ซื้ อเยอะ โดยผมได้ export สินค้าออกมาเ ป็ นไฟล์ CSV แล้ว และผมต้องการ import สินค้า ท ั ้ งหมดในไฟล์ นี้ เข้า LINE SHOPPING ⎯ MCP Server and Tools: - Filesystem MCP server with `read_file` tool - LINE SHOPPING MCP server with `create_product` tool
27. Migrate products from other platforms (1/2) LLM Id,name,price,img_url,… 1,Product A,50,https://img1,… 2,Product B,50,https://img2,… 3,Product C,60,https://img3,… 4,Product D,70,https://img4,… 5,Product E,80,https://img5,… 6,Product F,90,https://img6,… 7,Product G,100,https://img7,… 8,Product H,110,https://img8,… read_file({ “file”: “product.csv” }) FileSystem MCP Server products.csv
28. Migrate products from other platforms (2/2) LLM success create_product({ “name”: “Product A”, “price”: 50,… }) LINE SHOPPING MCP Server LINE SHOPPING API
29. Some more interesting use cases (1/3) Promote best-sellers products by generating and sending beautiful marketing broadcast Flex message in LINE • LINE SHOPPING MCP Server • get_all_products, get_all_orders tool • LINE Bot MCP Server • broadcast_flex_message tool
30. Some more interesting use cases (2/3) Create insightful PowerPoint slides for CEO to present to shareholders • LINE SHOPPING MCP Server • get_all_orders tool • settlement_detail tool • Powerpoint MCP Server • create_presentation, add_slide, add_table etc tools.
31. Some more interesting use cases (3/3) Update inventory based on Invoice PDF document from vendor • PDF MCP Server • read_file tool • LINE SHOPPING MCP Server • adjust_inventory tool
32. My AI Prediction BEFORE Built-in AI Service A Service B Built-in AI Service C Built-in AI Service A Service B Service C Service A MCP Service B MCP Service C MCP LLM LLM LLM LLM AFTER
33. Build MCP Server for your own service, let it connect to the LLM world and enjoy endless use case possibilities!
34. Check out LINE SHOPPING MCP repo Check me out at the booth ⎯ LIVE Demo how LINE SHOPPING MCP work ⎯ Exchange ideas on knowhow and best practices
36. What are LINE SHOPPING and LINE MyShop? ⎯ LINE SHOPPING E-Commerce marketplace platform within LINE Ecosystem such s LINE OA. It features various popular brands and stores. ⎯ LINE MyShop is part of LINE SHOPPING but for sellers, including features such as product, stock and order management, promotion and coupon, and payment.
37. iPhone 16 มีสีอะไรบ้าง? - Can respond correctly - Teal, Pink, Black and white iPhone 16 ยังมีของไหมบน LINE SHOPPING? - May be able to respond correctly or incorrectly - But it could be made-up as well
38. iPhone 16 มีสีอะไรบ้าง? - Can respond correctly - Teal, Pink, Black and white iPhone 16 ยังมีของไหมบน LINE SHOPPING? - May be able to respond correctly or incorrectly - But it could be made-up as well
39. Problem LLM does not have context of what being asked due to knowledge cutoff
40. Possible Solution RAG FUNCTION CALLING