AX Qwen3.6 35B-A3B MLX OptiQ 4-bit MTP

Parameter count: approximately 35.11B logical target parameters (35B total, approximately 3B active per token). 4-bit is the target quantization precision, not a 4B model-size claim. The separately packaged MTP sidecar is not included in the target count.

This is a self-contained MLX package for Apple Silicon. It combines the pinned upstream OptiQ mixed-precision MoE target with an AX Engine-compatible multi-token-prediction (MTP) sidecar.

Try this model locally with AX Engine.

Attribution and changes

AutomatosX did not train Qwen3.6-35B-A3B or create its OptiQ quantization. The target model comes from mlx-community/Qwen3.6-35B-A3B-OptiQ-4bit at revision 70a3aa32c7feef511182bf16aa332f37e8d82014.

AutomatosX used AX Engine's prepare_mtp_sidecar.py flow to extract the MTP head from Qwen/Qwen3.6-35B-A3B at revision 995ad96eacd98c81ed38be0c5b274b04031597b0, unpack the MoE expert tensors, apply the required RMSNorm-delta normalization, quantize projections to 4-bit with group size 64, patch the runtime config, and generate the AX manifests. The upstream OptiQ card is preserved as UPSTREAM_README.md.

No new training or benchmark results are claimed by AutomatosX.

Package details

The package retains the upstream optiq/mtp.safetensors file and adds the AX-prepared root mtp.safetensors. AX Engine uses the root sidecar through the mlx_lm_extra_tensors config entry.

Download and serve

hf download AutomatosX/AX-Qwen3.6-35B-A3B-MLX-OptiQ-4bit-MTP \
  --local-dir ./AX-Qwen3.6-35B-A3B-MLX-OptiQ-4bit-MTP

ax-engine doctor \
  --mlx-model-artifacts-dir ./AX-Qwen3.6-35B-A3B-MLX-OptiQ-4bit-MTP

ax-engine serve ./AX-Qwen3.6-35B-A3B-MLX-OptiQ-4bit-MTP --port 31418

The download is approximately 25 GB. The server exposes an OpenAI-compatible API. Consult the AX Engine repository for installation and API examples.

AX-specific files

• mtp.safetensors: AX-prepared MTP sidecar
• mtplx_runtime.json: draft-depth and sampler guidance
• ax_mtp_sidecar_manifest.json: sanitized, revision-pinned provenance
• model-manifest.json: AX native target manifest
• config.json: upstream target config with the AX sidecar registration

Validation

Validated on macOS arm64 with AX Engine 6.9.0 on 2026-07-20:

• AX artifact doctor: ready, with no model issues
• Safetensors headers, data bounds, and index mappings: passed
• MTP tensor-layout exactness baseline: maximum absolute difference 0.0 at context length 2,048
• Source and destination revisions are immutable and recorded in the provenance manifest

Quantization can change model quality, and speculative-decoding acceptance depends on the workload. Evaluate this package on your own tasks.

License

Apache License 2.0. See LICENSE, the original Qwen model card, and the pinned upstream OptiQ card for limitations and responsible-use guidance.