Trick 1: Pard leads a "low from interest" ♠4 spot card (declarer has < 4 spades if it matters). Declarer puts up ♠K at T1 and plays the 3 from hand.
Trick 2: Declarer now plays J♣ off the board and ducks into pard's ♣Q.
Pard holds♠A and needs to know whether declarer has a doubleton ♠ or JXX or QXX (assuming the QC duck was avoidance play).
1) Is the standard treatment at T1 to give present count in this situation?
2) If playing (reverse) Smith echo, should the spot cards played by South at T2 be a signal for ♠Q? In this case assume that you are playing reverse Smith and the C2 is an unambiguous spade encouragement signal.
[Edit]
BTW, the above hand is intended to be an illustration of the problems and not a question regarding a specific hand. It would be interesting to hear about your defensive agreements.