Mistral's Shieldstral: 3B open-weights model for multimodal moderation
5 hours ago
- Shieldstral is a 3B open-weights multimodal safety classifier that outperforms models up to 7x its size by framing content moderation as a policy-adaptive question-answering task.
- It accepts plain-language policies at inference time, unifying text and image safety evaluation without retraining, and runs efficiently on a single 16GB GPU.
- Released under Apache 2.0, it delivers calibrated safety scores from a single forward pass, allowing thresholding or ranking by confidence.
- Trained on heterogeneous public datasets converted into a unified format with contrastive examples, it teaches policy discrimination that generalizes to novel policies.
- The model combines multiple fine-tuned checkpoints via SLERP to balance calibration and adaptability, and was built on the Forge platform.
- Future directions include improving multilingual coverage, longer-document robustness, and broader multimodal safety.