What is Granite Guardian 4.1 8B?
Granite Guardian 4.1 8B is IBM Research's risk-detection model, released in April 2026 as a fine-tune of Granite 4.1 8B. You give it a conversation, a plain-language criterion and a scoring schema, and it returns a yes or no inside score tags. In think mode it writes its reasoning first; in no-think mode it answers straight away.
It ships with built-in criteria in three groups: harm (general harm, social bias, jailbreaking, violence, profanity, sexual content and unethical behaviour), retrieval checks (context relevance, groundedness and answer relevance) and agent checks (function-calling hallucination). Bring Your Own Criteria lets you write new rules, such as formatting or length requirements, which IBM says need testing.
The weights are Apache 2.0 with no gate. It runs on Transformers, vLLM, SGLang and Docker Model Runner, and 11 community quantisations work with llama.cpp, Ollama and LM Studio. It was trained and tested on English only. Earlier versions, including 3.3 8B and the 38M and 125M hate-abuse-profanity classifiers, remain on Hugging Face.
How much does Granite Guardian 4.1 8B cost?
| Plan | Price | What you get |
|---|---|---|
| Weights | Free | Apache 2.0, ungated |
| Self-hosted | Free | 8B in BF16 on your own GPU |
Free open weights under Apache 2.0, ungated on Hugging Face; self-hosted only, no hosted inference provider listed.
Is Granite Guardian 4.1 8B worth it?
Granite Guardian's case is breadth under a clean licence. Most guard models stop at harmful content; this one also checks whether an answer is grounded in the retrieved text and whether an agent's function call matches the tools it was given, and all of it is Apache 2.0 with no gate.
IBM's figures for 4.1 show where the work went. Function-calling detection on FC Reward Bench rose from 0.74 on version 3.3 to 0.79 in no-think mode. Custom criteria improved most: balanced accuracy on IFEval multi-constraint tasks rose from 0.569 with prompting alone to 0.844. Groundedness on LLM-AggreFact held at 0.76 in think mode, the same as 3.3. Safety itself did not move much: IBM reports a no-think F1 of 0.79, about the same as earlier versions, and a low 0.44 on the xstest refusal measure.
IBM is candid about cost. The card positions it for model assessment, monitoring and spot checks with moderate latency needs, and points teams with tight latency budgets to the 38M hate-abuse-profanity model instead. Think mode adds generated reasoning to every check, and IBM warns that the reasoning may contain unsafe text and may not reflect how the score was reached.
The English-only training is the biggest practical limit. For multilingual moderation Qwen3Guard covers 119 languages and dialects, and for fast injection screening a classifier such as Prompt Guard 2 is far cheaper per call.
Where it earns its place
A RAG team at a legal publisher answering questions over case summaries
Flag answers that are not supported by the retrieved passages
Send the question, retrieved context and answer with the groundedness criterion in no-think mode, and route a yes to human review. Running it on a sample of traffic keeps GPU cost down.
An agent developer whose assistant books meetings through function calls
Catch tool calls with invented arguments or the wrong function
Pass the tool schema and the proposed call with the function-calling hallucination criterion before execution; IBM reports 0.79 on FC Reward Bench for this check in no-think mode.
A trust and safety lead at an English-language community app
Enforce a house rule that the stock harm categories miss
Write the rule as a Bring Your Own Criteria prompt, test it on a labelled sample as IBM advises, and run it on reported posts rather than every message.
Before you commit
- Setup
- pip install transformers torch vllm, then vllm serve ibm-granite/granite-guardian-4.1-8b; the judging prompt goes in the last user message with a think or no-think instruction, criteria and scoring schema.
- Integrations
- Transformers, vLLM, SGLang and Docker Model Runner; community GGUF builds for llama.cpp, Ollama and LM Studio; Colab and Kaggle notebooks.
- Data and privacy
- Self-hosted, so prompts and documents stay on your hardware. Apache 2.0 permits commercial use without a gate.
- Cost at scale
- No API fee; one GPU serving an 8B model. Think mode costs extra generated tokens per check, so no-think suits volume and think suits audits.
- Limits
- English only; returns yes or no, not a calibrated multi-class label; context length not stated in the card; IBM recommends using only its prompt template.
What’s good
- Harm, RAG grounding and function-calling checks in one model
- Custom criteria accuracy up from 0.569 to 0.844 on IFEval multi-constraint
- Apache 2.0 and ungated
- Think and no-think modes trade latency for explanation
What’s not
- English only
- 8B is slow for inline screening of every message
- Safety F1 about flat against earlier versions
- Reasoning traces may be unfaithful or contain unsafe text
Best for
English-language teams that want one open judge for safety, retrieval grounding and agent tool calls, run on sampled or high-risk traffic.
Granite Guardian 4.1 8B alternatives
Granite Guardian 4.1 8B: common questions
- Is Granite Guardian 4.1 8B worth it?
- An open judge for English-language apps that covers harm, grounding and tool calls in one model, though at 8B it is a spot-checker rather than an inline filter for every message. We rate it 4.0 out of 5.
- How much does Granite Guardian 4.1 8B cost?
- Free open weights under Apache 2.0, ungated on Hugging Face; self-hosted only, no hosted inference provider listed.
- What are the downsides of Granite Guardian 4.1 8B?
- English only; 8B is slow for inline screening of every message; safety F1 about flat against earlier versions; reasoning traces may be unfaithful or contain unsafe text.
- Who is Granite Guardian 4.1 8B best for?
- English-language teams that want one open judge for safety, retrieval grounding and agent tool calls, run on sampled or high-risk traffic.
- How much does Granite Guardian 4.1 8B cost for a team or in production?
- No API fee; one GPU serving an 8B model. Think mode costs extra generated tokens per check, so no-think suits volume and think suits audits.
- Is Granite Guardian 4.1 8B safe for company data?
- Self-hosted, so prompts and documents stay on your hardware. Apache 2.0 permits commercial use without a gate.
- What are the best Granite Guardian 4.1 8B alternatives?
- The closest alternatives we have reviewed are Qwen3Guard, gpt-oss-safeguard and Shieldstral 1.0 3B.
Answers checked Nov 6, 2026.
Make Granite Guardian 4.1 8B? Show this rating on your site
