VaultAlexaplus

VaultAlexa+ is an Alexa+ agent that stops impulse buys: ask “can I afford this?” and it checks your budget and bills, then approves or blocks. Sellers get stockout alerts and draft purchase orders.

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Inspiration

Online shopping makes it easy to spend money you don't have, and small sellers often run out of stock without warning. I wanted a voice assistant that acts as a safety net: it checks a purchase against your budget and bills before you buy, and warns sellers before stock runs out.

What it does

VaultAlexa+ is an MCP server for Alexa+ with 10 tools.

For buyers

  • Checks a purchase against category budgets and bills due in the next 14 days, then returns approved, caution, or blocked, with reasons
  • Shows how much a purchase delays a savings goal and suggests a 24-hour cooldown
  • Forecasts the month-end balance
  • Simulates a discount negotiation that returns a voucher
  • Splits household expenses, tracks price drops, and logs transactions

For sellers

  • Predicts stockouts and drafts a purchase order that needs seller approval
  • Gives a morning briefing for the store

Purchases of $100 or more need voice confirmation, so a person stays in control.

How I built it

The server is plain Node.js with no dependencies. It speaks MCP (JSON-RPC 2.0) over HTTP on POST /mcp, with 10 tools, 2 resources, and 1 prompt. A browser console simulates the Alexa+ experience: you click something you might say to Alexa+, and it calls the server and shows the reply. Automated tests cover the protocol and every tool.

Challenges

  • Keeping the verdict logic simple and explainable: a purchase has to fit both the category budget and the cash left after upcoming bills.
  • Validating tool inputs so bad requests return clear errors instead of crashing.
  • Working to the Streamable HTTP and MCP 2025-11-25 requirements.

What I learned

I learned how an AI assistant connects to outside tools using MCP. I also learned how to design tools that are safe, for example by blocking a purchase when the money is needed for upcoming bills, and by asking for confirmation before bigger purchases.

What's next

Connect the server to real services, add the OAuth flow that Alexa+ expects, and onboard it to a real Alexa+ device.

Honest notes

All financial and store data is mock, the discount negotiation is simulated, and the Alexa+ experience runs in a web console. Nothing is connected to Amazon, AWS, or a bank yet.

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