Check the receipt at the end of one response. Same bytes as POST /verify_receipt. Takes no physics permit. The receipt covers every byte of the response before it, the decimal values included, and shows who produced the response or when in no way: it has no key. The receipt covers the request as it was written, number spellings included, while a seal covers its values: a request sent with 310 and the same request sent with 310.0 give different receipts and the same seal, so a receipt that differs between two such answers is not a sign of tampering. Replaying the request through run_trajectory, solve or verify_step shows the engine produced it; verify_tape, verify_solution and verify_dataset with the request and its seal do that replay and compare the seals.