The form Shall I is used to make offers, in general. For example
Shall I help you?
and one would answer
Yeah, help me
but what's the full answer? I mean, with a question like
You will go for meat, won't you?
Short answer: Yeah.
Full answer: Yes I will.
But shall as a second person has another meaning
Shall I help you?
Yes you shall. <-- it's no more a suggestion: I'm requiring you to do that.
and using Yes you will still sounds imperative. Therefore, is there a full answer to that form as there is for normal verbs like do, will, be and so on?