rule the roost

Kazuo Ishiguroの "Klara and the Sun" を読んでいます。
'Speaking of lessons. Klara. Your name is Klara, isn't it? Speaking of lessons, there's an idea that's been brewing here in this household.'
'Mum. Definitely no. Klara isn't interested in...'
'Let me speak, darling. Here she is in person, so let's seize out chance. I must say, darling, you've developed a tendency these days to rule the roost. It's most irritating. Klara, are you willing to listen to our idea?'

"rule the roost" は慣用句の様です。意味を調べます。
・Oxford English Dictionary: Be in complete control.: ‘in this particular society men rule the roost and women have a low status and few rights’
・Collins Dictionary: If you say that someone rules the roost in a particular place, you mean that they have control and authority over the people there.: [informal] Today the country's nationalists rule the roost and hand out the jobs.
・Cambridge English Dictionary: to be the person who makes all the decisions in a group: In that family it is the grandma who rules the roost.
ロシアでは現在プーチンが "rules the roost" しているのは間違いない。