Xiaomi-Lens-0 is a 4B multimodal language model built on Qwen3.5-4B. It adds a lightweight pixel-mask decoder and is trained with joint language and mask supervision. Each generated token identifies an image region that the decoder turns into a segmentation mask. The model supports referring expression comprehension and segmentation, multi-instance grounding, reasoning segmentation, embodied referring, and fine-grained visual perception. It can produce masks in its final answer or during reasoning. This repository contains the model weights, configuration, tokenizer, processor, and chat template. Inference uses the XiaomiLensQwen35ForConditionalGeneration class from the accompanying…