mcp-ai

Learning project for building a first Model Context Protocol (MCP) server and testing it from Codex.

Chinese documentation: README.zh-CN.md

Yinghuochong MCP Server

This MCP server is a read-only business data adapter for the local Yinghuochong MySQL database. It exposes order and user queries as structured MCP tools so Codex can inspect business data safely.

Tools:

• yhc_list_databases
• yhc_search_orders
• yhc_get_order_detail
• yhc_list_users

Local Setup

npm install
npm run build

Default database settings:

Host: 127.0.0.1
Port: 3306
User: root
Password: empty
Default DB: yinghuochong_recovery_clean_20260608

Copy .env.example only if you need to override defaults.

Run

npm run start

Codex MCP command:

node /Users/pengdahan/WorkSpace/mcp-ai/dist/index.js

Source Layout

Runtime flow:

Codex -> src/index.ts -> registerYhcTools -> src/db.ts -> MySQL

• src/index.ts: MCP server entry point. Creates the server, registers tools, and connects through stdio.
• src/config.ts: Reads database configuration and enforces the allowed database whitelist.
• src/db.ts: Shared MySQL access layer with connection pooling, database validation, identifier quoting, and queryRows<T>().
• src/format.ts: Shared response formatting helpers for money, JSON text, and pagination metadata.
• src/tools/yhc.ts: Registers all Yinghuochong read-only business query tools.

Safety Boundaries

• Database names must be in YHC_ALLOWED_DATABASES.
• SQL values use parameterized placeholders.
• SQL identifiers are validated before quoting.
• All tools are marked read-only in MCP annotations.