At the start of your turn, if you have only one card left in your hand, do you have to discard it to draw backup to six? Or can you play the last card in your hand, then draw backup to six cards without discarding any card?
From the rules:
Each turn you get 2 actions. For each action, you can do one
of the following:
• Play 1 Card into your action area and resolve it.
• Discard any number of cards from your hand and draw up to 6.
• Buy 1 VP card from the center row.
Discard any number of cards from your hand, placing them on
the discard pile in any order. Then draw cards from the top of the
deck until you have six cards in your hand. Although this always
results in a hand of six cards, there is no hand limit if you gain
cards some other way.
There's nothing in that wording that would make me believe that you have to have a card in your hand in order to discard. You simply take the action and discard 0 cards.