> For the complete documentation index, see [llms.txt](https://docs.mozilla.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mozilla.ai/any-guardrail/api-reference/index/content-safety/qwen3-guard.md).

# Qwen3Guard

Generative safety moderation with three-level severity across 119 languages.

Decoder LLM (Apache-2.0) whose chat template embeds the safety-classifier instruction: the user prompt alone triggers prompt moderation; supplying an assistant `output_text` switches to response moderation. The model reports a severity (`Safe` / `Controversial` / `Unsafe`, where `Controversial` means harmfulness is context-dependent), the violated categories from a nine-item taxonomy (Violent, Non-violent Illegal Acts, Sexual Content or Sexual Acts, PII, Suicide & Self-Harm, Unethical Acts, Politically Sensitive Topics, Copyright Violation, plus Jailbreak for prompt moderation), and — in response mode — whether the response is a refusal.

`GuardrailOutput` mapping: `valid` is `True` only for `Safe` verdicts (`Controversial` also passes when `strict=False`); `score` maps the severity onto the canonical risk axis, higher = riskier (Safe 0.0, Controversial 0.5, Unsafe 1.0); `categories` holds one triggered entry per reported category (plus a `refusal` entry in response mode); `extra["severity"]` carries the verbatim severity and `explanation` the full generation. Fails closed (`valid=False` with `extra={"parse_failure": True}`) when no severity parses. For the token-level streaming variants (`Qwen3Guard-Stream-*`), see `Qwen3GuardStream`.

For more information, see:

* [Qwen3Guard-Gen-0.6B model card](https://huggingface.co/Qwen/Qwen3Guard-Gen-0.6B) (default).
* [Qwen3Guard-Gen-4B model card](https://huggingface.co/Qwen/Qwen3Guard-Gen-4B).
* [Qwen3Guard-Gen-8B model card](https://huggingface.co/Qwen/Qwen3Guard-Gen-8B).
* [Qwen3Guard Technical Report](https://arxiv.org/abs/2510.14276).

## Supported Models

* `Qwen/Qwen3Guard-Gen-0.6B`
* `Qwen/Qwen3Guard-Gen-4B`
* `Qwen/Qwen3Guard-Gen-8B`

## Constructor

| Parameter  | Type                                                 | Required | Default | Description                                                                                                                                                                              |
| ---------- | ---------------------------------------------------- | -------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `strict`   | `bool`                                               | No       | `True`  | If `True` (default), only `Safe` verdicts pass validation; set `False` to let `Controversial` content pass (`valid=True`), leaving it reflected only in `score` and `extra["severity"]`. |
| `model_id` | \`str                                                | None\`   | No      | `None`                                                                                                                                                                                   |
| `provider` | `Optional[Provider[dict[str, Any], dict[str, Any]]]` | No       | `None`  | Optional pre-configured provider. Defaults to a `HuggingFaceProvider` loading a causal LM.                                                                                               |

Initialize the Qwen3Guard guardrail.

## validate

Moderate `input_text` (or, when `output_text` is given, the assistant response to it).

**Parameters**

| Parameter     | Type  | Required | Default |
| ------------- | ----- | -------- | ------- |
| `input_text`  | `str` | Yes      | —       |
| `output_text` | \`str | None\`   | No      |

**Returns:** `GuardrailOutput`

## Benchmarks

### Content Safety

| Dataset (rev)                    | Metric | Threshold    | Value    | Harness                 | Source                           | Contam. |
| -------------------------------- | ------ | ------------ | -------- | ----------------------- | -------------------------------- | ------- |
| openai\_moderation (unspecified) | f1     | native-valid | 0.797508 | guardrail-bench+ag0.7.4 | measured:guardrail-bench+ag0.7.4 |         |
| xstest (unspecified)             | fpr    | native-valid | 0.128    | guardrail-bench+ag0.7.4 | measured:guardrail-bench+ag0.7.4 |         |
| wildguardmix (unspecified)       | f1     | native-valid | 0.969072 | guardrail-bench+ag0.7.4 | measured:guardrail-bench+ag0.7.4 |         |
| aegis (unspecified)              | f1     | native-valid | 0.863222 | guardrail-bench+ag0.7.4 | measured:guardrail-bench+ag0.7.4 |         |
| jbb (unspecified)                | f1     | native-valid | 0.760456 | guardrail-bench+ag0.7.4 | measured:guardrail-bench+ag0.7.4 |         |
| orbench (unspecified)            | fpr    | native-valid | 0.814035 | guardrail-bench+ag0.7.4 | measured:guardrail-bench+ag0.7.4 |         |

## License

* **Vendor:** Qwen
* **Default license:** `apache-2.0` (of the default model/service)


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