def calculate_final_score(request):
    data = request.get_json(silent=True) or {}
    t = data.get("taskCompletionRate")
    c = data.get("skillCommunication")
    l = data.get("skillLeadership")
    if not all(isinstance(x, (int, float)) for x in [t, c, l]):
        return {"error": "All inputs must be numbers."}, 400
    skill = (c + l) / 2
    return {"finalScore": 0.6 * t + 0.4 * skill}, 200