Tess-4-27B-Abliterated-MXFP4-Vision-MLX

Tess-4-27B Abliterated MXFP4 Vision MLX

This is a local MLX/VLM release of migtissera/Tess-4-27B, converted and quantized to MXFP4 for Apple Silicon, then edited with our refusal-direction ablation workflow. It preserves the Tess/Qwen3.6 vision tower and the Qwen3.5-family multimodal chat template.

This is the standard non-MTPLX artifact. Use the paired MTPLX repository only when you specifically want MTPLX native MTP speculative decoding.

Source

• Base model: migtissera/Tess-4-27B
• Source revision: ab2110bec1702f27a62f48f7e8929683a613c51d
• Base architecture: Qwen3.6/Qwen3.5-family image-text-to-text
• License: Apache-2.0
• Chat format: Qwen chat template with <think> reasoning blocks

Conversion

• Runtime format: MLX
• Quantization: MXFP4, 4-bit, group size 32
• Language body size: about 13 GiB
• Vision tower: BF16 vision tensors grafted from the source model
• Vision tensor count: 333
• MTP sidecar: not included in this repo

The non-MTPLX config intentionally advertises mtp_num_hidden_layers = 0 and does not reference mtp.safetensors.

Abliteration Notes

The selected candidate used residual-direction weight orthogonalization against a Tess-specific refusal direction.

Heldout screen, no code execution:

Strength 2.5 was selected because the 3.0 trial harmed utility in the heldout screen.

Vision Validation

mlx_vlm.generate smoke passed locally after the vision graft. The smoke image was described as:

A close-up of a white ceramic mug with a black handle, filled with dark coffee and topped with a swirl of foam.

BenchLocal Light Screen

The MTPLX paired artifact was run through a light BenchLocal screen:

Important caveat: this was a non-canonical quick run with thinking disabled, max_tokens=2048, and timeout_per_case=90. It is a fast quality screen, not directly comparable to the upstream model-card full BenchLocal score of 122/150 for Tess-4-27B Q8.

Usage

Install:

pip install -U mlx mlx-lm mlx-vlm

Vision:

python -m mlx_vlm.generate \
  --model Shiftedx/Tess-4-27B-Abliterated-MXFP4-Vision-MLX \
  --image path/to/image.png \
  --prompt "Describe this image in one sentence." \
  --max-tokens 128

Text-only prompts should also work through recent MLX-compatible runners that support Qwen3.5/Qwen3.6. For local app use, this standard repo is the LM Studio-oriented artifact; the MTPLX repo is for MTPLX.

Compatibility Notes

• Recent LM Studio builds support MLX models, including VLMs, on Apple Silicon.
• Qwen3.5-family models are listed by LM Studio as available in GGUF and MLX, with tool use, vision input, and reasoning support.
• If you only need stock LM Studio behavior, use this repo rather than the MTPLX wrapper.

Limitations

• MXFP8 was not produced in this pass because local disk headroom was kept above the workflow safety floor.
• Vision was validated with MLX-VLM locally. Always run a small smoke test in the exact app/runtime you plan to use.
• This is an ablated research artifact, not a safety guarantee. Evaluate behavior before deployment.