How can I tell whether an engineering workplace has good mentoring?

During an interview or workplace visit, ask specifically about onboarding, whether each new engineer has a mentor, how often consultations and reviews occur, and what support is provided before working independently. Ask junior employees who actually gives advice, how frequently, and how the workplace handles mistakes and learning. Check not only whether a program exists, but whether people use it and feel able to ask questions; if possible, compare several employees’ accounts with official information.