LPG Connector — MCP Server

A remote MCP server that exposes live LPG price/stock data to Claude. Backed by in-memory mock data for now; built to swap to MongoDB with no changes to the tool logic.

Tools

stock is one of in_stock | low | out_of_stock.

Related MCP server: armls-spark-mcp-server

Run locally

npm install
npm run dev        # tsx watch, http://localhost:3000/mcp

Health check: GET http://localhost:3000/health

Quick smoke test (list tools):

curl -s -X POST http://localhost:3000/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'

Build for production

npm run build      # -> dist/
npm start          # node dist/index.js

Project layout

src/
  index.ts              Express + streamable HTTP transport (the /mcp endpoint)
  server.ts             MCP server + the 4 tool definitions
  store/
    types.ts            Domain types (Station, PriceReport, ...)
    DataStore.ts        Interface every store implements
    InMemoryStore.ts    JSON-seeded implementation (current)
  data/seed.json        Mock stations + price history

Swapping to MongoDB later

The tools only ever talk to the DataStore interface, so the migration is localized:

1. npm install mongodb

2. Create src/store/MongoStore.ts implementing DataStore (same method signatures as InMemoryStore). Map stations and priceReports to two collections.

3. In src/index.ts, change one line:

   // const store = new InMemoryStore();
   const store = new MongoStore(process.env.MONGODB_URI!);

Nothing in server.ts changes. Seed the collections from data/seed.json once for a matching demo dataset.

Deploy (for the Claude custom connector)

Claude's cloud connects to this server over the public internet — a localhost URL won't work for claude.ai. This repo is set up for Render.

Deploy to Render

Option A — Blueprint (uses render.yaml, one click):

1. Push this project to a GitHub repo.

2. In Render: New → Blueprint, pick the repo. It reads render.yaml (build npm install && npm run build, start npm start, health check /health).

3. Deploy. You'll get a URL like https://cylindr.onrender.com.

Option B — Manual web service:

1. New → Web Service, connect the repo, set Root Directory to zserver.

2. Build command: npm install && npm run build

3. Start command: npm start

4. Health check path: /health

After it's live

• Confirm health: open https://<your-app>.onrender.com/health → {"status":"ok"}

• Add to Claude: Settings → Connectors → Add custom connector, paste https://<your-app>.onrender.com/mcp, then enable it in a chat via the + menu.

Free-tier note: Render's free web services sleep after ~15 min idle and take ~30–60s to wake on the next request. Before your live demo, hit /health once to wake it so the first judge query isn't slow. Also: in-memory data is per-process, so a restart (or wake from sleep) resets to the seed and any report_price submissions are lost. The MongoDB swap removes both concerns.