Diagnose x402 seller endpoints: what is wrong with your 402 challenge, and how to fix it.
Install
Run one of the commands below, then add the client config underneath.
https://x402-doctor.tsharpe.workers.dev/mcpClient configuration
Paste into Claude Desktop, Cursor (mcp.json), VS Code or any MCP client, then restart the client.
{
"mcpServers": {
"x402-doctor": {
"url": "https://x402-doctor.tsharpe.workers.dev/mcp"
}
}
}About this server
x402 Doctor is listed in the Other Tools category of the MCPNav directory. It is distributed as Streamable HTTP and can be loaded by any client that speaks the Model Context Protocol.
Typical uses include giving your assistant scoped access to the corresponding service so it can answer questions and take actions with real data instead of guessing. Always review what a server can access before you enable it — see our MCP security guide.
Frequently asked questions
What is the x402 Doctor MCP server?＋
x402 Doctor is an MCP server by twelvepermissions. Diagnose x402 seller endpoints: what is wrong with your 402 challenge, and how to fix it.
How do I install x402 Doctor?＋
Install it with: https://x402-doctor.tsharpe.workers.dev/mcp. Then add the JSON config to your client's MCP settings and restart the client.
Is x402 Doctor free to use?＋
The MCP server itself is free to install. The source is public on https://github.com/tsharpe2282-web/twelve-permissions. Any third-party API it calls (such as a search or maps API) may require its own key and billing.
Which clients support x402 Doctor?＋
Any MCP-compatible client can use it, including Claude Desktop, Cursor, VS Code, Windsurf and custom agents.