Secondhand MCP Server

Secondhand MCP

A Model Context Protocol (MCP) server that lets AI assistants search secondhand marketplaces. Search Facebook Marketplace, eBay, Depop, and Poshmark for used and secondhand items — filter by price, category, condition, size, and color, then get full listing details with photos, descriptions, and seller info.

Works with Claude Desktop, Claude Code, Cursor, and any MCP-compatible client.

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Supported Marketplaces

Setup

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "secondhand": {
      "command": "npx",
      "args": ["-y", "secondhand-mcp"],
      "env": {
        "EBAY_CLIENT_ID": "your-ebay-client-id",
        "EBAY_CLIENT_SECRET": "your-ebay-client-secret",
        "EBAY_MARKETPLACE_ID": "EBAY_US"
      }
    }
  }
}

Claude Code

Add to ~/.claude/.mcp.json:

{
  "mcpServers": {
    "secondhand": {
      "command": "npx",
      "args": ["-y", "secondhand-mcp"],
      "env": {
        "EBAY_CLIENT_ID": "your-ebay-client-id",
        "EBAY_CLIENT_SECRET": "your-ebay-client-secret",
        "EBAY_MARKETPLACE_ID": "EBAY_US"
      }
    }
  }
}

eBay, Depop, and Poshmark are all optional — if eBay API keys are missing or Chrome isn't installed, those marketplaces are automatically disabled and the rest still work.

Depop & Poshmark / Chrome Requirement

Depop and Poshmark require a headless browser. If Google Chrome or Chromium is installed on your system, both are automatically enabled — no config needed. If Chrome isn't found, they are silently skipped.

On macOS, the first time you search Depop or Poshmark, you may see a system prompt asking to allow Node.js to control Chrome. This is expected — puppeteer needs to launch Chrome in headless mode. Allow it once and it won't ask again.

The browser runs invisibly in the background and only launches when you actually search Depop or Poshmark.

Configuration

Choosing Marketplaces

By default all marketplaces are enabled. To limit which are active, set the MARKETPLACES env var (comma-separated):

{
  "env": {
    "MARKETPLACES": "facebook,ebay"
  }
}

Valid values: facebook, ebay, depop, poshmark

eBay API Keys

eBay uses the official Browse API. You need a free eBay developer account:

1. Create an account at developer.ebay.com
2. Create an application to get a Client ID and Client Secret
3. Add them to your MCP config as EBAY_CLIENT_ID and EBAY_CLIENT_SECRET

eBay Marketplace / Region

By default the server targets the US eBay site. To search a different regional marketplace, set the EBAY_MARKETPLACE_ID environment variable:

{
  "env": {
    "EBAY_MARKETPLACE_ID": "EBAY_DE"
  }
}

Common values:

The full list is available in the eBay API docs.

Tools

search_marketplace

Search for items across marketplaces.

Data returned per marketplace:

get_listing_details

Get full details for a specific listing using an ID from search results.

Data returned per marketplace:

list_marketplaces

List all enabled marketplaces and their status.

search / fetch (deep research)

Convenience pair following the ChatGPT Deep Research tool contract — exact names, a single string argument each:

• search(query) — searches every enabled marketplace at once and returns { results: [{ id, title, text, url }] }, where id is marketplace:listingId
• fetch(id) — returns full listing details for a search result ID as { id, title, text, url, metadata }

Useful for research-style clients that expect these standard tool names; for filtered searches use search_marketplace.

How It Works

Facebook Marketplace — Searches listings by location, price, and query. Resolves city names to coordinates. No login or browser needed.

eBay — Uses the official eBay Browse API with OAuth 2.0 client credentials. Tokens are cached and auto-refreshed. The target regional marketplace is controlled by EBAY_MARKETPLACE_ID (default: EBAY_US).

Depop — Uses a headless browser to search listings with support for category, condition, size, and color filters. The browser instance is shared across requests.

Poshmark — Uses a headless browser to search listings with support for condition, size, color, sort, and price filters. Poshmark is not location-based — all items ship nationally.

Development

git clone https://github.com/jlsookiki/secondhand-mcp.git
cd secondhand-mcp
npm install
npm run build

Adding a Marketplace

1. Create a new file in src/marketplaces/
2. Extend BaseMarketplace and implement search() and optionally getListingDetails()
3. Add the constructor to allMarketplaces in src/marketplaces/index.ts

Limitations

• Facebook: May break if Facebook changes their frontend
• eBay: Requires developer API keys (free tier available)
• Depop: Requires Chrome/Chromium installed; slower than Facebook/eBay (~5s per search)
• Poshmark: Requires Chrome/Chromium installed; no official API so relies on page scraping
• Rate limiting: Don't make too many requests too quickly

License

MIT