Its not the tone but rather the feedback style according that should be adapted to the knowledge/motivation of the engineer in the situation. For example by using the https://situational.com/blog/the-four-leadership-styles-of-s... herustic:

1: Engineer is junior in the context and insecure/unmotivated: Do X 2: Engineer is junior in the context and motivated/secure: Take the decision for the engineer and explain why 3: Engineer is senior in the context but insecure: Coach by open ended questions: how large of a function do you think is appropriate? 4: Engineer is senior and motivated/secure: From your perspective how should the function be and how should we do this in the future to reach our goals.