Dress for Google (TPM) Onsite

Wear a jacket.

I am wondering the same thing about amazon

I always go with the usual ok-ish pants and untucked shirt. with this you look good whatever the position is. If you show up in a suit in silicon valley it's almost direct elimination though

Naked

Whatever you are most comfortable with. Can't go wrong with business casual and a sport coat.

This is sillicon valley, you wear a hoodie and jeans.