AI Safety / Guardrails Stack (Python, OPA, FastAPI, Redis, Prometheus) overview

An AI safety and guardrails platform that sits between LLM applications and model endpoints, enforcing content policies, detecting prompt injection attempts, and applying output filtering. Open Policy Agent (OPA) evaluates declarative safety rules against request and response payloads. FastAPI serves the guardrail proxy with Redis caching previously evaluated inputs for latency reduction. Prometheus tracks block rates, false positive rates, and policy evaluation latency. Pydantic validates safety rule schemas. Targeted at enterprises deploying customer-facing AI features that require content safety compliance. The tradeoff is the tension between safety and usability — aggressive filtering reduces harmful outputs but increases false positives that degrade the user experience, requiring continuous policy calibration.