A new calculator went up on my site almost every day this week. I built none of them.

I run a site of free calculators electricians use to check their work against the electrical code. Wire sizes, load calculations, clearances. The kind of thing somebody pulls up standing in a basement with a meter in one hand.

New ones get added most days. Not by me. I have been working on other things all week and the site kept growing anyway.

That sounds good until you think about what a wrong answer costs. A bad wire size is not an embarrassing typo. It is somebody failing an inspection, or worse. So the whole thing is built on one idea: it is allowed to add work on its own, and it is not allowed to be sure of itself.

Every new calculator has to get past a set of checks before it goes anywhere near the live site. The math gets verified against the code tables by something that did not write it, which is the part I care about most, because anything can produce a confident wrong answer, including a person. The page gets opened and looked at on a copy of the site first. Nothing with a broken link or a failed check goes out.

If anything comes back wrong, it stops. It does not publish and flag it later. It does not try again and hope. It parks the work and tells me which check failed.

That last decision is the one people skip when they automate something customers see. They plan for what it does when everything works. Nobody writes down what it should do when something looks off, so the default becomes doing it anyway.

Decide that part first. Mine is always the same. Stop, and come get me. That is the only reason I am comfortable letting it run while I do something else.