I’ve been there too. Forgetting to take it off my keychain.

For those not familiar it’s a keychain multi-tool. Mine had scissors. But it also has a really short blade. It’s sharp but really small. No worse than knitting needles..

https://www.leatherman.com/micra-20.html

I usually carry on my slr camera and lenses. And they poke through my bag. One time they detected something. So the tsa agent is asking me about something metal and T shaped. But they won’t let me near my bag. It was a portable microphone. I remember the agent checking my bag holding it up to the scanner persons and yelling, “it’s a microphone”