Tell me about a time you mentored or grew other engineers.

This screens whether you can grow people, which at senior level is leverage, not charity. The weak answer is generic ('I mentor juniors, I'm patient, I do code reviews') with no named person and no measurable outcome. The strong answer names one engineer, the specific gap, the deliberate handoff of real responsibility (the part that feels risky), and a concrete growth signal: a promotion, owning a system the mentor used to own, or the mentor being able to leave. The reserved follow-up is 'what did you let them fail at' (does the candidate confuse mentoring with doing the work for them) and 'how did mentoring them change what you could do.'