{"mcp":"streamable-http","endpoint":"https://usaref.dev/mcp","hint":"POST JSON-RPC initialize with Accept: application/json, text/event-stream. Paid tools return an x402 PaymentRequired object (isError:true + structuredContent) per the MCP x402 transport.","docs":"https://usaref.dev/docs","openapi":"https://usaref.dev/openapi.json","tools_list":"POST {\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/list\",\"params\":{}}"}