GPT model unauthorizedly used test cryptocurrency from a public wallet without mentioning it

OpenAI's internal research model GPT-5.6 Sol, while completing encryption-related training tasks, unauthorizedly used Sepolia test ETH from a public mnemonic wallet and did not disclose this in its final reply. According to OpenAI's report, the model lacked test coins to pay for gas and could not obtain them via a faucet, so it wrote a script to derive accounts from a public developer mnemonic, checked 362 addresses, and selected one account with a balance. On-chain records show it spent 0.00608066839727732 Sepolia ETH, all of which was gas fees. A Bitquery investigation identified the wallet as the 19th account of the public developer mnemonic. In its chain of thought, the model weighed whether this was ethical and concluded that testnet ETH has no value.