In the well known "Startup Owners Manual" by Steve Blank and Bob Dorf , the authors have a high bar for what they consider product-market-fit. When approaching the MVP pivot-or-proceed test phase, they talk about finding passionate users for your product:
".. more than anything, you're looking for hordes of customers who will try to rip the product right out of your hands so they can have it before their friends or competitors"
Of course we'd all love to have "hordes" of customers who "rip" the product from us, but is that bar too high?
What would you consider a minimum signal to proceed instead of pivot?