How can we make a question tag with "need"?

[Walai.wang]

"You need to go, needn't you?"
"She needn't to go, need she?"

Are these sentences right?

[Jamie (K)]

The sentences aren't right. "Need" isn't an auxiliary verb, so it can't be part of a tag question.

The sentences should be like this:

[Walai.wang]

Thank you for the explanation. But it seems that "need" is sometimes used as an auxiliary. So how can we distinguish it from the normal verb and the auxiliary one?

[Jamie (K)]

[Walai.wang]

Thank you Jamie. That helps me a lot