Store Assistant MCP Server

A secure Model Context Protocol server that connects Claude (or any MCP client, such as Cursor) to an online store's database. Ask questions in plain English and Claude answers from live data:

"How did sales do this month compared with last month?"
"Which products are about to run out, and how many should I reorder?"
"Where is order 1042?"
"Who are our best customers this quarter?"

It ships with a sample database for Cedar & Co., a fictional home goods store with 36 products, 80 customers and 460 orders, so you can try it in two minutes.

Tools

Tool	What it does
`search_products`	Find products by name, category, price or stock, with units sold in the last 30 days
`get_order`	One order's status, items, total, masked customer name and tracking
`sales_report`	Revenue, orders, average order value and units for the last N days, compared with the period before, grouped by day, week, category or product
`low_stock`	Products below a threshold, with days of stock left and a suggested reorder quantity
`top_customers`	Best customers by spend, with masked names and no emails
`update_stock`	Set a product's stock. Only exists when writes are enabled (see below)

It also provides a store://schema resource and a weekly_review prompt that asks Claude for a weekly business review.

Security by design

Read-only by default. The database is opened read-only, and the one write tool is not even registered unless you set STORE_ALLOW_WRITES=true.
No raw SQL from the model. Every tool runs a fixed, parameterised query, so the model cannot inject SQL.
Validated input. Every argument is checked with Zod: types, ranges, string lengths and SKU format.
Privacy. Customer names are masked ("Olivia C.") and emails are never returned.
Capped results. Every list has a maximum size, so one call cannot dump a whole table.
Audit log. Every tool call is written to logs/audit.log with its arguments, result and duration.
Tool annotations. Read tools are marked readOnlyHint, and the write tool destructiveHint, so clients can ask for confirmation.

Quick start

Requires Node.js 22.13 or newer (it uses the built-in node:sqlite).

npm install
npm run build
npm run seed
npm test

Use it in Claude Code

claude mcp add store-assistant -- node --disable-warning=ExperimentalWarning /absolute/path/to/mcp-store-demo/dist/index.js

Use it in Claude Desktop

Add this to claude_desktop_config.json, then restart Claude Desktop:

{
  "mcpServers": {
    "store-assistant": {
      "command": "node",
      "args": ["--disable-warning=ExperimentalWarning", "/absolute/path/to/mcp-store-demo/dist/index.js"]
    }
  }
}

To allow stock updates, add "env": { "STORE_ALLOW_WRITES": "true" } to that entry.

Configuration

Variable	Default	Purpose
`STORE_DB_PATH`	`data/store.db`	Path to the SQLite database
`STORE_ALLOW_WRITES`	`false`	Set to `true` to enable the `update_stock` tool

Adapting it to your store

The tools live in src/tools.ts. To connect a real store, point the queries at your own database (PostgreSQL, MySQL) or API (Shopify, WooCommerce, Stripe) and keep the same pattern: fixed queries, validated input, masked personal data and an audit log.

Tests

npm test starts the server over stdio, calls every tool and checks that the write tool is hidden.
npm run test:writes enables writes, checks that a malicious SKU is rejected, updates one product, then reseeds the database.

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License

MIT

mcp-store-assistant

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README