What are you trying to figure out?

Don't worry about what the tool should be called or how it would work. Describe the question — the thing you keep trying to work out on the back of an envelope:

If we build it, we'll test it publicly before adding it to the main library — and if you leave an email, we'll tell you when it's live. That's the only thing the email is used for.

Got it — thank you. If it becomes a tool, you'll be the first to know.