In this tutorial, we build an in-depth NeMo Guardrails pipeline that demonstrates how layered guardrails can control an LLM-based financial assistant across the full request lifecycle. We combine deterministic PII detection and redaction, LLM-based input and output self-checks, retrieval filtering, account-number masking, topical restrictions, and policy-based tool gating. We also implement stateful multi-turn interactions, detailed rail activation tracing, token accounting, and a red-team-style coverage report, so we can evaluate whether the assistant responds safely, which control handles each request, and what computational cost that protection adds.

!pip install -q nemoguardrails

import os, re, json, getpass, textwrap

from typing import Optional

MODEL = "gpt-4o-mini"