Last week I wrote about shipping a paid API for AI agents and getting two real calls in a week. The follow-up was suppos...

Last week I wrote about shipping a paid API for AI agents and getting two real calls in a week. The follow-up was supposed to be about fixing the product. It turned into something else, because in the process of fixing it I hit three bugs in a row that had one thing in common:None of them reported an error. All three looked like success.That turns out to be the failure mode that costs the most time, and I don't see it discussed much, so here they are.Bug 1: the government API that answers "zero" instead of "wrong"I was adding debarment records — public sanctions against companies barred from public procurement — to my business verification API. The endpoint took a parameter called inqryDiv. I passed 1.It returned HTTP 200 with an empty result set. No error, no warning, no hint. The obvious reading: this company has no sanctions on record.The correct value was 2. With 1, the API answers a question nobody asked and returns nothing, forever, for every company.If I'd shipped that, my API w...