Apriel-1.5-15B-Thinker — MLX 2-bit (Apple Silicon)

Format: MLX (Mac, Apple Silicon)
Quantization: 2-bit (ultra-compact)
Base: ServiceNow-AI/Apriel-1.5-15B-Thinker
Architecture: Pixtral-style LLaVA (vision encoder → 2-layer projector → decoder)

This repository provides a 2-bit MLX build of Apriel-1.5-15B-Thinker for tight-memory Apple-Silicon devices. It prioritizes small footprint and fast load over absolute accuracy. If quality is your primary concern, prefer the 6-bit MLX variant.

🔎 What is Apriel-1.5-15B-Thinker?

Apriel-1.5-15B-Thinker is an open multimodal reasoning model that scales a Pixtral-style VLM with depth upscaling, two-stage multimodal continual pretraining (CPT), and high-quality SFT with explicit reasoning traces (math, coding, science, tool-use). The training recipe focuses on mid-training (no RLHF/RM), delivering strong image-grounded reasoning at modest compute.

This card documents the 2-bit MLX conversion. Expect higher compression and noticeable quality drop vs FP/Int or 6-bit, especially on fine-grained text in images, dense charts, or long-chain reasoning.

📦 What’s in this repo

config.json (MLX config mapped for Pixtral-style VLM)
mlx_model*.safetensors (2-bit quantized shards)
tokenizer.json, tokenizer_config.json
processor_config.json / image_processor.json
model_index.json and metadata

✅ Intended uses

On-device image understanding where memory is constrained (light captioning, object/layout descriptions)
Quick triage of screenshots, UI mocks, simple charts, forms with broad structure
Educational demos of VLMs on Mac w/ minimal RAM budget

⚠️ Limitations

2-bit is very lossy. Expect degradation on:
- OCR-heavy tasks, small fonts, dense tables
- Multi-step math/coding with visual grounding
- Long context or many images
May hallucinate or miss small details. Human review is required for critical use.