BrandeisPatrick/open-marketplace

The open-source, AI-first marketplace.
Chat is the storefront, every action is a tool, and any agent can shop or sell over MCP.
Getting started ·
Documentation ·
MCP guide ·
Tools ·
Roadmap ·
Issues
## What is Open Marketplace?
Open Marketplace is a two-sided, Amazon-style marketplace where chat is the interface. Buyers shop by talking to a shopping assistant, and sellers run their store by talking to an operations assistant. Every marketplace action is a tool: one registry of tools drives both the in-app Claude assistants and a built-in MCP server, so an external agent such as Claude Code or Claude Desktop can shop or sell through exactly the same actions a person uses in chat.
## Features
Chat-first buyer and seller windows. Each side has its own assistant, and tool results render as product grids, carts, order cards and stats tiles instead of plain text.
One tool registry for chat and MCP. 16 tools, each a zod schema plus a handler, with the same validation, buyer and seller scope checks and events on either path.
MCP server built in. Stateless Streamable HTTP at /mcp, with tools, resources and prompts. A token picks whether the agent acts as the buyer or the seller.
Live across windows. An order placed in the Buyer window, or by an external agent, appears in the Seller window and the Activity feed immediately.
Runs without an API key. With no ANTHROPICAPIKEY, the UI, REST API and MCP server work normally and chat falls back to an offline keyword helper.
Nothing to run besides Node. The database is SQLite through Node's built-in node:sqlite, so there is no database server and no native addon to compile.
## Getting started
You need Node.js 22.13 or newer.
bash
git clone https://github.com/BrandeisPatrick/open-marketplace.git
cd open-marketplace
cp .env.example .env # optional: set ANTHROPICAPIKEY to turn on the Claude assistants
npm install
npm run dev # API and MCP on http://localhost:3001, UI on http://localhost:5173
Open http://localhost:5173 and click Show me mechanical keyboards in the Buyer window. The database is seeded on first run with demo accounts, products and order history. The getting started guide covers offline mode and a five-minute demo.
## Connect an AI agent
With the server running, add it to Claude Code as an MCP server:
bash
claude mcp add --transport http marketplace http://localhost:3001/mcp --header "Authorization: Bearer mkbuyerdemo"
Then ask the agent to buy a coffee mug under $20 from the marketplace. The purchase lands in the Seller window and the Activity feed with an MCP badge, exactly like one made in chat. The MCP guide covers the seller token, Claude Desktop, raw JSON-RPC with curl, and the resources and prompts the server exposes.
## Documentation
| Guide | What it covers |
| Getting started | Requirements, install, offline mode, demo accounts and a five-minute demo |
| Connect an agent over MCP | Endpoint, tokens, client setup, resources and prompts |
| Marketplace tools | All 16 tools by scope, and the conventions they share |