What guardrails do you add before launching an AI Agent app publicly?

I’m working on a small AI Agent app, and the part I’m most worried about is not the demo.It’s what happens after real users can trigger AI actions repeatedly.A friend of mine built an image generation app recently, and there was a hidden bug that caused unexpectedly high calls to a more expensive model. From the UI, everything looked normal. But behind the scenes, the app was burning cost in a way they didn’t notice immediately.That made me much more cautious about launching anything with paid AI capabilities.With Agent apps, it feels like one small issue can quietly become expensive: a retry loop users triggering actions repeatedly failed jobs still calling models public endpoints being hit too often prompts or edge cases causing unexpected behavior So before I launch, I’m trying to think through the boring safety layer: quotas, spending caps, rate limits, job queues, retry limits, logging, abuse detection, manual approval for expensive actions, fallback models, and some kind of pre-launch audit.I’m not looking for exploit details.I’m mostly curious what guardrails experienced builders consider non-negotiable before making an AI Agent app public.