I put 6 LLM guardrail tools inline and measured what they cost me. Here is the latency-vs-recall tradeoff. (opens in new tab)

An input guardrail runs on every request. Too slow and you rip it out; fast but blind and you get owned. That tradeoff, not the feature list, is the whole decision. TL;DR: I ran six guardrail and prompt-injection tools inline on a production agent for a few weeks (Lakera Guard, Llama Guard, NeMo Guardrails, Guardrails AI, Future AGI's fi.evals scanners, and ProtectAI's LLM Guard). The deciding axis was not which one detects the most attack types, it was which one was fast enough to run on eve...