Open Counter: a handmade shop any AI agent can buy from

Built for the PayPal AI Hackathon. Our MCP door in practice.

The problem: more shoppers ask an AI assistant instead of searching, and the assistant never finds a one-person shop. Our demo maker, Lena, builds 1:43 model cars by hand.

What we built: a shop counter with its own sales agent that Lena teaches in plain words, made-to-order builds paid with a PayPal deposit, and an MCP door so any outside AI agent can buy with the same rules. Prices, totals and dates are computed in code, never by the model. 157 tests. The shop is fictional and the product photos are AI-generated.

Live demo: open-counter.onrender.com · Code: github.com/chainwright/open-counter