With a configuration to remember the last seed used and take that seed specifically. i.e. I use barley, so I click "add-seeds" and it takes 10 barley seeds and sets up the birdhouse.
#"Add-Seeds" option on birdhouses with...
proven ingot
If it doesn't know which to take, it should just take the cheapest GE price seeds, excluding untradeables like spirit tree seed ofc in case some lunatic has 10 of them.
sturdy idol
It doesn't even need to be that complicated. It's not like people are bringing stacks of different seeds to birdhouse runs, right? If you've only got one kind of seed in your inventory, the game should just be able to work it out. 🤷♂️