{"key":"sk_sandbox_g3x7togorgs","balance":"$10.00 (fake)","message":"Sandbox key created. Use this to test x402 payment signing without spending real USDC.","usage":{"test_service":"GET /sandbox/weather?location=Tokyo with X-CW-Sandbox: sk_sandbox_g3x7togorgs","validate":"POST /sandbox/validate with your payment payload to check signing","log":"GET /sandbox/log?key=sk_sandbox_g3x7togorgs"},"note":"Sandbox keys reset when server restarts. Use real proxy at /proxy for production."}