# MCP server

> A free MCP server that lets coding agents check x402 endpoints, decode x402 headers, look up x402 errors and list test scenarios.

Connect an agent to `https://x402testendpoint.com/mcp` and it can use this site's tools directly. The server uses the Streamable HTTP transport, needs no account or key, and keeps no session state.

## Tools

| Tool | What it does |
| --- | --- |
| `check_endpoint` | Fetches a URL once without paying and reports whether an agent could pay there. |
| `list_scenarios` | Lists the test endpoints and what each expects of a buyer. |
| `explain_error` | Explains an x402 error code or client message: cause and fix. |
| `decode_header` | Decodes a `PAYMENT-REQUIRED`, `PAYMENT-SIGNATURE` or `PAYMENT-RESPONSE` header value. |

## Add it

Claude Code:

```bash
claude mcp add --transport http x402testendpoint https://x402testendpoint.com/mcp
```

Any client that takes a JSON configuration:

```json
{
  "mcpServers": {
    "x402testendpoint": {
      "type": "http",
      "url": "https://x402testendpoint.com/mcp"
    }
  }
}
```

## What it does not do

The server never holds a wallet and never pays anything. Paying a test endpoint is done by your own client with your own test wallet.

Source: https://x402testendpoint.com/tools/mcp