I Built an AI System That Makes 1,000 Decisions a Day. Here's Where I Drew the Line.

CostGuard's proxy endpoint makes an autonomous decision on every LLM call that passes through it. It scores the response, compares it against a threshold, and either accepts or rejects in about 1 millisecond, with no human involved.

At first that felt like the right design. Fast, automated, scalable. Exactly what an LLM reliability layer should do.

Then I looked at what it was actually catching and more importantly, what it was missing and I had to rethink where automation ends and human judgment needs to begin.

This is what I learned building a system that sits in the hot path of production LLM pipelines, and why I now think human-in-the-loop design is an engineering decision, not just an ethical one.

What CostGuard Actually Does