Who answered?
Paste the endpoint you pay, the key for that endpoint, and the model name on the bill. The page sends one fixed prompt: reply with the word pong. Then it reads the model name in the response.
The same name, ignoring capitals, is confirmed in green. A different name is red: you paid for the name you typed, and the endpoint answered as the name it sent back. The whole name has to match, including any prefix or version. If the name is missing, or the response copies the name you typed, a second prompt asks for the fraction 5/14. A reply that misses that fraction is flagged because the quality does not match the price.
The second question is fixed and public. A stand-in that already knows it can still print 5/14. A different model name is the strong signal. A blocked call stays a connection result. The page keeps no account and no copy.