# LlamaFirewall vs NVIDIA NeMo Guardrails

> NVIDIA NeMo Guardrails scores 68.4 (B) on agent readiness against LlamaFirewall's 50.8 (D), and leads in every scored category. Both do guard injection. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/llamafirewall-vs-nemo-guardrails
- Markdown: https://www.anchorterminal.com/compare/llamafirewall-vs-nemo-guardrails.md (~2,600 tokens)
- Slim: https://www.anchorterminal.com/compare/llamafirewall-vs-nemo-guardrails.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/llamafirewall-vs-nemo-guardrails.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

NVIDIA NeMo Guardrails scores 68.4 (B) on agent readiness against LlamaFirewall's 50.8 (D), and leads in every scored category. Both do guard injection.

- LlamaFirewall: grade D, 50.8/100, rank #682 of 842. Markdown https://www.anchorterminal.com/tools/llamafirewall.md · JSON https://www.anchorterminal.com/api/v1/tools/llamafirewall.json
- NVIDIA NeMo Guardrails: grade B, 68.4/100, rank #202 of 842. Markdown https://www.anchorterminal.com/tools/nemo-guardrails.md · JSON https://www.anchorterminal.com/api/v1/tools/nemo-guardrails.json

## Which one, for what

### LlamaFirewall (D)

Good for: A Python agent team that wants injection, hidden-character and generated-code checks in process, is willing to pin dependencies or install from main, and can get the gated weights.

Watch for: No PyPI release since 1.0.3 on 29 May 2025, and no changelog, tags or deprecation notes were found

### NVIDIA NeMo Guardrails (B)

Good for: Teams that want to compose several checks (their own, NVIDIA's and third-party APIs) behind one OpenAI-compatible endpoint.

Ahead on:
- Reliability, 75 against 53
- Schema & documentation, 69 against 49
- Agent ergonomics, 67 against 60
- Security & auth, 62 against 56
- Payments & pricing, 60 against 50
- Maintenance & community, 80 against 15
- Transparency & trust, 68 against 58

Watch for: Usage telemetry and a heartbeat every 10 minutes to NVIDIA by default


## Score by category

| Category | Weight | LlamaFirewall | NVIDIA NeMo Guardrails | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 53 | 75 | NVIDIA NeMo Guardrails +22 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 49 | 69 | NVIDIA NeMo Guardrails +20 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 67 | NVIDIA NeMo Guardrails +7 |
| Security & auth | 14% (17.5 this run) | 56 | 62 | NVIDIA NeMo Guardrails +6 |
| Payments & pricing | 10% (12.5 this run) | 50 | 60 | NVIDIA NeMo Guardrails +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 15 | 80 | NVIDIA NeMo Guardrails +65 |
| Transparency & trust | 7% (8.8 this run) | 58 | 68 | NVIDIA NeMo Guardrails +10 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **50.8 · D** | **68.4 · B** | |

## Facts side by side

| Fact | LlamaFirewall | NVIDIA NeMo Guardrails |
| --- | --- | --- |
| Kind | Agent framework | Agent framework |
| Vendor | Meta | NVIDIA |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  | HTTP |
| Auth | None | None |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | MIT (library). The Prompt Guard 2 weights it downloads are under the Llama 4 Community Licence | Apache-2.0 |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| Last release | 2025-05-29 | 2026-09-16 |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no document linked | no date given |
| Customer content may train models |  | couldn't be read |
| Terms restrict automated access |  | couldn't be read |
| Terms restrict benchmarking |  | couldn't be read |
| Terms or service can change without notice |  | couldn't be read |
| Arbitration or class-action waiver |  | couldn't be read |
| Popularity | 4.4k stars, 1k PyPI/wk | 7.2k stars, 101k PyPI/wk |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**LlamaFirewall.** One `scan()` call runs several checks on the owner's machine and returns a short typed result. The last PyPI release is 1.0.3 from 29 May 2025, and its Prompt Guard loader imports a `huggingface_hub` class that current versions no longer export, so a fresh install needs older pins. The classifier weights also need Meta's manual approval.

**NVIDIA NeMo Guardrails.** Apache-2.0, 7,200 stars and nine releases between 9 October 2025 and 16 September 2026. Usage telemetry and a heartbeat every 10 minutes to NVIDIA by default.

## Before you call either

### LlamaFirewall

1. Pin `huggingface_hub` below 1.0 and a matching `transformers` 4.x before importing the Prompt Guard scanner from the 1.0.3 wheel, or install from main
2. Get access to `meta-llama/Llama-Prompt-Guard-2-86M` and set a Hugging Face token first. Without one the loader prompts for a login and a headless run stalls
3. Call `scan_async` inside a running event loop. `scan()` wraps `asyncio.run` and fails there. `scan_async` returns score 0.0 and reason `default` on every allow
4. Split text longer than 512 tokens yourself before a Prompt Guard scan. The library truncates and does not chunk
5. Do not feed a block `reason` back to the model. The Prompt Guard reason quotes the full scanned text, and the hidden ASCII reason decodes the hidden payload

### NVIDIA NeMo Guardrails

1. Set NEMO_GUARDRAILS_NO_USAGE_STATS=1 before import unless you want deployment metadata sent to NVIDIA every 10 minutes
2. Use IORails for plain input and output checks. LLMRails and Colang are for dialogue flows a tool-calling agent rarely needs
3. Pin nemoguardrails==0.24.1. 0.24.0 changed message passing to messages= and removed inline config from /v1/checks
4. Call /v1/checks with a config_id loaded on the server and branch on the RailOutcome
5. Put the server behind your own gateway. It has no auth or rate limiting

## Questions

### Which is better for AI agents, LlamaFirewall or NVIDIA NeMo Guardrails?

NVIDIA NeMo Guardrails scores 68.4 (B) on agent readiness against LlamaFirewall's 50.8 (D), and leads in every scored category.

### Are LlamaFirewall and NVIDIA NeMo Guardrails open source?

Yes. LlamaFirewall is open source (MIT (library). The Prompt Guard 2 weights it downloads are under the Llama 4 Community Licence). NVIDIA NeMo Guardrails is open source (Apache-2.0).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/llamafirewall-vs-nemo-guardrails.json, and with the fewest tokens: https://www.anchorterminal.com/compare/llamafirewall-vs-nemo-guardrails.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "llamafirewall", "b": "nemo-guardrails"}`. From a terminal: `anchor compare llamafirewall nemo-guardrails`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/llamafirewall.json and https://www.anchorterminal.com/api/v1/tools/nemo-guardrails.json

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