Qwen3.8-27B-oQ6e-fp16-mtp

An oQ mixed-precision MLX quantization of Qwen/Qwen3.8-27B, packaged for Apple Silicon.

Quantization

• Base quantization: 6-bit affine, group size 64
• Selective higher precision: the token embeddings, LM head, and selected linear-attention / MLP projections remain 8-bit; see config.json for the complete per-module configuration
• Format: MLX safetensors
• MTP: retained (mtp_num_hidden_layers: 1); speculative decoding requires runtime support

Chat template

chat_template.jinja uses the Froggeric Qwen Fixed Chat Templates template, version qwen3.8-froggeric-v22.2.

This is an intentional behavioral change from the upstream Qwen template. It adds compatibility handling for system/developer messages, thinking-history fields, tool-call serialization, and tool responses. It does not alter the model weights or improve the underlying model capability. The template is intended for compatible Jinja-capable runtimes such as oMLX/MLX, llama.cpp, LM Studio, and vLLM. Review the upstream template project for its supported options and runtime-specific setup.

Usage

Use a current MLX-compatible runtime that supports MLX safetensors, the quantization metadata in config.json, and the included chat_template.jinja.

oMLX discovers models from subdirectories of its configured model directory:

omlx serve --model-dir /path/to/models

The server exposes an OpenAI-compatible API on port 8000 by default:

curl http://127.0.0.1:8000/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{
    "model": "Qwen3.8-27B-oQ6e-fp16-mtp",
    "messages": [
      {
        "role": "user",
        "content": "Hello"
      }
    ]
  }'

For Qwen reasoning mode, use temperature: 0.6, top_p: 0.95, top_k: 20, and min_p: 0. For non-thinking mode, use temperature: 0.7, top_p: 0.8, top_k: 20, and min_p: 0.

Avoid greedy decoding while thinking is enabled; Qwen documents that it can cause repetitive output. The checkpoint retains its multi-token-prediction head, but speculative decoding requires runtime support.

The included chat_template.jinja is the Froggeric fixed template. Use a runtime that honors external Jinja chat templates and per-module quantization metadata. Compatibility outside oMLX, including mlx-lm and mlx-vlm, depends on the installed runtime version and has not been validated for this release.

License and attribution

Apache 2.0, inherited from Qwen/Qwen3.8-27B. A copy of the license is included as LICENSE. Quantization does not change the licensing terms — all credit for the underlying model belongs to the Qwen team. This repository distributes a quantized derivative. The included chat template is derived from the Apache-2.0-licensed Froggeric Qwen Fixed Chat Templates.