As always, thanks to everyone for their replies. I probably should have mentioned that we were not playing 2/1. Partner would not be interested in any subtle inferences about my heart length anyway; he had a heart void. The hand was approximately (my hand repeated for convenience)
At our table, I declared 4
♥ on the lead of the (singleton)
♣2. I flew Ace, crossed in diamonds, and played 3 rounds of trump. My RHO didn't think I could have (only) 6 hearts and (as many as) 4 clubs, so he exited with a spade. Making 4.
At the other table, the auction was something like: 1
♦-1
♥; 2
♣-2
♠; 3
♣-3
♦; 3
♠-6
♣. My teammate thought opener was showing the
♠A, and thus led a heart from
♠KQxx
♥Qxx
♦xxx
♣KTx. Making 6.
I think any reasonable set of agreements should let you stop in 5
♣ with these cards; time for more discussion with partner.