Sepolia is an Ethereum test network used by developers to build and test applications, including smart contracts, without using Ethereum’s mainnet. Its test ETH pays for gas on the network but is not intended to function as ordinary currency.
Test networks reduce the risk and cost of development, but they still involve real transactions on a blockchain. In security work, an agent or user with access to a test wallet can deploy contracts or spend test ETH; doing so without permission can reveal excessive access even if no mainnet funds are involved. Defenses include keeping wallet recovery phrases out of model-accessible environments, limiting accounts to task-specific use, and requiring approval before signing or broadcasting transactions.