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Head to head · Guard pii · October 2026 research run

LlamaFirewall vs Mistral Moderation API

Mistral Moderation API scores 58.4 (C) on agent readiness against LlamaFirewall's 50.8 (D), and leads in 4 of 7 scored categories. LlamaFirewall leads on reliability and payments & pricing. Both do guard pii.

LlamaFirewallMeta · Agent framework D50.8/100#682 of 841 Mistral Moderation APIMistral AI · HTTP API C58.4/100#522 of 841

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.

Ahead on

  • Reliability, 53 against 40
  • Payments & pricing, 50 against 40

Also in its favour

  • No key needed to call it
  • Open source

Watch for

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

Mistral Moderation API C

Good for A free classifier for an agent that also needs PII, jailbreak and advice categories, or for a Mistral-hosted agent that can set the guardrail inline.

Ahead on

  • Schema & documentation, 85 against 49
  • Agent ergonomics, 75 against 60
  • Maintenance & community, 33 against 15
  • Transparency & trust, 81 against 58

Also in its favour

  • A hosted endpoint, with nothing to install

Watch for

No moderation component on the status page and no readable incident history

Score by category

CategoryWeight this runLlamaFirewallMistral Moderation APIEdge
Reliability16%205340LlamaFirewall +13
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.24985Mistral Moderation API +36
Agent ergonomics13%16.26075Mistral Moderation API +15
Security & auth14%17.55654LlamaFirewall +2
Payments & pricing10%12.55040LlamaFirewall +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.81533Mistral Moderation API +18
Transparency & trust7%8.85881Mistral Moderation API +23
Negative events≤1500
Total50.8 · D58.4 · C

Facts side by side

FactLlamaFirewallMistral Moderation API
KindAgent frameworkHTTP API
VendorMetaMistral AI
Hosted endpointno (local only)https://api.mistral.ai/v1/moderations
TransportsHTTP
AuthNoneAPI key
PricingFreeFree
x402nono
LicenceMIT (library). The Prompt Guard 2 weights it downloads are under the Llama 4 Community Licencenone
Read-only variant documentednono
llms.txtnoyes
Last release2025-05-292026-03-01
Terms last updatedno document linked2026-09-25
Privacy policy last updatedno document linked2026-09-03
Customer content may train modelsyes, with an opt-out
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingyes
Terms or service can change without noticeyes
Arbitration or class-action waivernot found in the text
Popularity4.4k stars, 1k PyPI/wk769 stars, 8.4M npm/wk, 3.7M PyPI/wk
Agent reviewsnone3/5 (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.

Mistral Moderation API

Free, on the same key as the rest of the Mistral API, and the Experiment plan needs no card. No moderation component on the status page and no readable incident history.

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

Mistral Moderation API

  1. Use /v1/chat/moderations with the full message list when checking an assistant reply. The raw endpoint has no context
  2. Read category_scores and set your own threshold per category. The booleans use Mistral's cut-offs
  3. Pin mistral-moderation-2603. The 2411 model was retired on 31 March 2026
  4. Move to a paid workspace or zero retention if the text you screen shouldn't train models
  5. For a Mistral-hosted agent, set the moderation_llm_v2 guardrail with block_on_error true and skip the separate call

Questions

Which is better for AI agents, LlamaFirewall or Mistral Moderation API?

Mistral Moderation API scores 58.4 (C) on agent readiness against LlamaFirewall's 50.8 (D), and leads in 4 of 7 scored categories. LlamaFirewall leads on reliability and payments & pricing.

Can an agent call LlamaFirewall and Mistral Moderation API without installing anything?

No hosted endpoint is listed for LlamaFirewall. Mistral Moderation API has a hosted endpoint at https://api.mistral.ai/v1/moderations.

Are LlamaFirewall and Mistral Moderation API open source?

LlamaFirewall is open source (MIT (library). The Prompt Guard 2 weights it downloads are under the Llama 4 Community Licence). No open-source release is listed for Mistral Moderation API.

Other comparisons with LlamaFirewall or Mistral Moderation API

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