On the GPU box you rented or host, run the one-minute check. It prints pass, warn or fail and writes
preflight-report.json; nothing is sent anywhere:
pip install riggrade riggrade-preflight
It warned or failed? Choose "Host fix-it report" below and add that file: free during the trial, no wallet needed. Want measured speed and steadiness for the card itself? Run the 10-minute quick check; the result prints when it ends. The command is under "Start here" in the README.
Pay for a RigGrade report from your own browser wallet, in USDC on Base. This page does what an agent does over x402: it asks the service for the price, your wallet signs a payment of exactly that amount to the address the service names, and the service settles it and returns your report. RigGrade never sees your keys. The price is the same whatever the result, and a failed check stays failed. During the fix-it report's free trial you can also get it with no wallet at all.
Agents and scripts can call the same routes directly over x402; see the service descriptor. A charge that is settled but not delivered is logged and refunded by hand. Code and method: https://github.com/nnyycc77-ship-it/riggrade