secondhand mcp for Grok

Install secondhand mcp in Grok

.mcp.json (in your project root)

{
  "mcpServers": {
    "secondhand-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "secondhand-mcp"
      ],
      "env": {
        "EBAY_CLIENT_ID": "<EBAY_CLIENT_ID>",
        "EBAY_CLIENT_SECRET": "<EBAY_CLIENT_SECRET>",
        "EBAY_MARKETPLACE_ID": "<EBAY_MARKETPLACE_ID>"
      }
    }
  }
}

Grok Build reads Claude Code's .mcp.json and Claude Desktop's config unchanged, so a server you have already set up there needs nothing new. The Grok web app and X integration do not take custom servers. Grok docs