Show HN: Free tool to see how much AI bots are costing your site

A new free tool on Hacker News is promising to expose a very modern fear: are AI bots quietly running up your website bill? The pitch is deliciously simple — drop in your site log, keep everything on your own computer, and get a dollar estimate for how much bots like GPTBot, ClaudeBot, and Perplexity are costing you. Then, with one copied line, you can tell them to get lost. On paper, it’s a neat little power move for website owners feeling steamrolled by the endless robot crawl.

But the real show was in the comments, where the mood swung from curious to chaotic in about three posts. One user popped in with a breezy “interesting!”, while another immediately did the internet’s favorite thing: demanded the math. “how are you calculation the cost?” became the thread’s mini-cross-examination, with readers clearly wanting to know whether the scary dollar figure is solid science or just good marketing in a trench coat. The creator responded by linking a longer Dev.to explainer, which only added to the “bring receipts” energy.

And then came the funniest twist: one commenter tested the tool on a tiny personal site and found zero AI bots. The real invaders? Vulnerability scanners — basically internet prowlers looking for weak spots. So the crowd’s hottest takeaway wasn’t just “AI is expensive.” It was more like: plot twist, the robots may not be your biggest problem after all.