AX-Qwen3.6-27B-MLX-AXQ-6bit-MTP

An AXQuant (AXQ) mixed-precision MLX checkpoint for Apple Silicon, converted directly from the BF16 source model. The language path is quantized while the multi-token-prediction (MTP) head and vision tower are preserved at BF16 in the checkpoint (or a bound sidecar when present).

AXQuant checkpoint Tier 1 certified — artifact edition v3. The exact v3 weight set passed measured size, matched-reference quality, zero-fallback conversion, and safe default-runtime gates on df-macbookpro-m5. Read the certificate and exact hashes.

MTP acceleration Tier 2 certified (scoped). On df-macbookpro-m5 with AX Engine 6.14.0, greedy MTP-off/on streams are identical and decode-heavy authorizing profiles clear ≥1.20× token-weighted and ≥1.10× prompt-median speedup (agent-coding 1.258× / 1.112×, long-form general 1.233× / 1.250×). Tier 2 certificate.

Product default remains direct fallback for the safe Tier 1 route. Short-answer chat is not an authorizing universal speed claim. Use the formal Qwen linear MTP exact / certification-candidate contract to exercise the certified acceleration path.

Model details

Property	Value
Base model	Qwen/Qwen3.6-27B
Source revision	6a9e13bd6fc8f0983b9b99948120bc37f49c13e9
Product family	qwen3.6
Source architecture	Qwen3_5ForConditionalGeneration (dense); text path optimized
Main-model parameters	27.36B logical parameters
Quantizer	AXQuant 1.5.1
Hub budget class	6bit
Artifact edition	v3
AXQuant base precision class	6bit
Planned storage-adjusted BPW	5.9616
Measured main-model BPW	5.8058
Measured total BPW, including MTP	5.9617
Safetensors weight size	20.70 GB
Approximate complete download	20.73 GB
Configured maximum context	262,144 tokens; practical limits depend on unified memory
Primary MLX runtime	MLX-LM
AX Engine native execution	Native manifest included; Tier 1 safe default direct route; scoped Tier 2 MTP certified (opt-in formal contract)
MTP present	True
Vision present	True
Audio present	False

This repository contains MLX Safetensors. It does not contain PyTorch or GGUF weights.

Choosing an AXQ pack

AXQ names describe a storage-budget product class, not one uniform precision applied to every tensor. Protected tensors remain at higher precision, so the exact measured BPW is authoritative. In particular, a 6bit-named mixed plan may retain 4bit as its base precision while selecting 6-bit, 8-bit, or BF16 for other tensors to meet an approximately 6-BPW total budget. Protection floors can also raise a 4bit-named pack close to (or above) a 6bit budget on small or heavily protected models. When that collapse happens, AutomatosX does not publish a separate misleading 4bit sibling for that base.

Sibling	Intended trade-off
4bit sibling	Lower-storage AXQ budget; check its exact BPW
6bit sibling	Higher average precision near the 6-BPW budget

See the AutomatosX MLX model catalog for related MLX and OptiQ alternatives.

Download

python -m pip install -U huggingface_hub
hf download AutomatosX/AX-Qwen3.6-27B-MLX-AXQ-6bit-MTP \
  --revision v3 \
  --local-dir ./AX-Qwen3.6-27B-MLX-AXQ-6bit-MTP

Allow at least 20.73 GB of free disk space. The v3 tag identifies this certified artifact; pin the resolved Hub commit for production reproducibility. The previous development checkpoint remains available at v2.

Run with MLX-LM

python -m pip install -U mlx-lm
mlx_lm.generate \
  --model AutomatosX/AX-Qwen3.6-27B-MLX-AXQ-6bit-MTP \
  --prompt "Explain mixed-precision quantization in three sentences." \
  --max-tokens 128 \
  --temp 0.0

MLX-LM compatibility covers standard text/backbone inference. It may ignore AXQuant runtime metadata and optional sidecars (vision.safetensors, mtp.safetensors); this command therefore does not establish MTP acceleration or vision-language quality. The artifact records MLX 0.32.0 and MLX-LM 0.31.3 from conversion.

Serve with AX Engine

After installing AX Engine, download the complete repository (see AXQuant for conversion, certificates, and model-card tooling) and serve the local directory:

ax-engine serve ./AX-Qwen3.6-27B-MLX-AXQ-6bit-MTP --port 31418

AX Engine is the authority for the AXQ runtime contract and native MTP sidecar. Tier 1 default-route smoke (AX Engine 6.13.5) keeps policy 4, MTP inactive, and direct fallback active. Scoped Tier 2 MTP acceleration is certified on AX Engine 6.14.0 under the formal Qwen linear MTP exact / certification-candidate contract (decode-heavy suites only). Product default remains direct fallback. Native model-manifest.json status: included.

Use the packaged Qwen MTP head with oMLX or MTPLX

Download the complete repository to a writable local directory. In oMLX 0.6.3rc2 or newer, add that directory, open Model Settings, choose Import MTP side-car, and then enable Lightning MTP. The import changes only the local copy so the sidecar tensors become visible through the checkpoint index. This is a text-path compatibility result; it does not certify VLM loading or vision quality.

MTPLX can consume the packaged sidecar directly:

mtplx quickstart \
  --model ./AX-Qwen3.6-27B-MLX-AXQ-6bit-MTP \
  --profile stable \
  --depth 1 \
  --reasoning off

mtplx_runtime.json declares the canonical qwen3-next-mtp execution contract. This enables strict runtime discovery; it does not establish oMLX or MTPLX exactness or speed certification.

Quantization layout

Main-weight precision	Parameters	Share
4bit	20.78B	74.79%
6bit	3.20B	11.52%
8bit	1.27B	4.58%
bf16	2.53B	9.11%

• Quantization methods: affine, bf16, dwq.
• Group sizes used by quantized assignments: 64.
• MTP sidecar: 15 tensors, 424.70M parameters, 0.85 GB, BF16.
• Vision sidecar: 333 tensors, 460.73M parameters, 0.92 GB, BF16.
• Vision weights: protected BF16 sidecar.
• Optimization scope: text-path.
• Support tier: convertible.

BF16 sidecars, when present, are included in total download size. Their presence does not by itself establish MTP acceleration or vision-language quality.

Evidence and validation status

Check	Status
Planning evidence	measured
Calibration	recorded in measured-forward-probe-refinement
Quantizer execution	487/487 recorded module conversions succeeded; 0 fallbacks
AX Engine native manifest	included as model-manifest.json
General quality vs matched uniform-6	44 tasks; retention 1.011494; perplexity ratio 0.966136; 0/0 errors
Agent-coding quality vs matched uniform-6	76 tasks; retention 1.007353; perplexity ratio 0.969531; 0/0 errors
Size vs matched uniform-6	ratio 0.876234; 12.38% fewer weight bytes
Stable default AX Engine route	Pass; MTP inactive and direct fallback active
MTP acceptance, exactness, and speed	Scoped Tier 2 certified on df-macbookpro-m5 / AX Engine 6.14.0: greedy exactness + agent-coding 1.258× / 1.112×, long-form general 1.233× / 1.250× (Tier 2 cert); product default remains direct fallback; short-answer not claimed
AX Engine kernel-speed evidence	Not part of Tier 1
Vision-language quality	Not evaluated or claimed; vision tensors are preserved at BF16
Speech-recognition quality	Not applicable
Long-context quality	262,144-token capacity is config metadata, not a validated claim
Release certification	Checkpoint Tier 1 certified + scoped MTP Tier 2 certified (T1 · T2)

Modalities (capability-gated)

Text checkpoint Tier 1 does not imply vision or audio quality. Vision present=true on a pack is not a quality pass.

Modality	Claim	Supported	Reason
Vision	present-not-certified	true	vision present sidecar=['vision.safetensors']; mlx-vlm smoke failed on df-macstudio-m2 (mlx-vlm expects vision_tower.*; sidecar/layout mismatch). Text Tier 1 unchanged. Evidence: docs/certifications/evidence/modality-recert-capability-gated/results/AX-Qwen3.6-27B-MLX-AXQ-6bit-MTP.json
Audio	not-applicable	false	audio not supported (no tower config and no sidecar weights)

Intended use and limitations

• Intended for local text generation and evaluation on Apple Silicon with MLX-compatible runtimes.

• No minimum unified-memory figure is claimed; loadability depends on model size, context length, KV-cache policy, runtime buffers, and other processes using unified memory.

• Quality evidence is relative to the matched uniform-6 reference on reproducible AXQuant suites; it is not a third-party benchmark, a universal quality guarantee, or a BF16-equivalence claim.

• “Stable default runtime” means the bound text path passed model loading, inference, and the fail-closed route gate on the certification machine. It is not a promise that every context, application, or third-party runtime is defect-free.

• MTP acceleration is opt-in under the formal Qwen linear MTP exact / certification-candidate contract (scoped Tier 2 on decode-heavy suites). Product default remains direct fallback. Short-answer chat is not a universal speed claim. Outside AX Engine, use a sidecar-aware runtime; oMLX/MTPLX compatibility does not extend the AX Engine certificate.

• Vision weights are preserved at BF16, but this release does not claim validated VLM quality.

• The configured context window can require substantially more memory as the KV cache grows.

• Upstream capabilities, limitations, biases, and responsible-use guidance still apply.

Provenance and audit files

• Public Tier 1 certificate: verdict, thresholds, environment, and exact LFS hashes.

• Public Tier 2 MTP acceleration certificate: decode-heavy exactness and speedup gates, formal env, comparison digests.

• axquant_manifest.json: package identity, byte accounting, runtime contract, software versions, and file checksums.

• axquant_plan.json: per-tensor precision decisions and planning evidence.

• axquant_quantizer_execution.json: conversion coverage and fallback records.

• axquant_runtime.json: declared AX Engine and MLX compatibility metadata; runtime checks remain separate evidence.

• axquant_mtp_sidecar_manifest.json: MTP tensor provenance.

• axquant_vision_sidecar_manifest.json: protected vision tensor provenance.

• model-manifest.json: AX Engine native tensor manifest.

All published provenance uses repository-relative paths. Local source paths are stripped before publication. The checkpoint was converted from BF16 rather than re-quantized from an OptiQ artifact. If an OptiQ repository is published separately, it uses a different quantizer and should not be assumed to have identical BPW or quality.

License

The checkpoint follows the upstream model license where applicable (often Apache License 2.0). See the Qwen/Qwen3.6-27B model card for license terms, model limitations, and responsible-use guidance.