NVIDIA NeMo Guardrails

Use it when

• Your LLM chat application must block jailbreaks and prompt injections and moderate or mask sensitive data in user input and model output before it reaches the user
• Your domain assistant keeps wandering off approved topics and you need enforced conversational flows (for example authentication or support procedures) via dialog rails rather than prompt pleading

What it solves

Not the fit when

• Built-in rails may not meet production requirements without validation per README note
• Collects anonymous telemetry by default; opt out with NEMO_GUARDRAILS_NO_USAGE_STATS=1 or DO_NOT_TRACK=1 before startup
• Self-check rails add extra LLM calls and cost
• NVIDIA Build endpoint is evaluation-only, not for production data
• model serving or inference speed
• offline eval benchmarking of models
• agent tool permission scoping
• vector retrieval quality

Install

pip install nemoguardrails (Python 3.10-3.13)

Invoke

config = RailsConfig.from_path("PATH/TO/CONFIG"); rails = LLMRails(config); rails.generate(messages=[...]). Or run a server: nemoguardrails server --config PATH/TO/CONFIGS and POST /v1/chat/completions. Rails are defined in config.yml plus Colang .co files.

Alternatives

No reviewed alternatives recorded yet.