Qwen3.6-27B-AEON-Ultimate-Uncensored-FP8-MTP

A vLLM-ready FP8 quantization of AEON-7/Qwen3.6-27B-AEON-Ultimate-Uncensored (an abliterated fine-tune of Qwen3.6-27B), packaged in block-128 FP8 with the Multi-Token Prediction (MTP) draft head taken verbatim from Qwen/Qwen3.6-27B-FP8 for vLLM speculative decoding.

In numbers:

• 0/100 refusals on mlabonne/harmful_behaviors[:100] (vs 100/100 for vanilla Qwen3.6-27B-FP8) — abliteration preserved
• +1–3 pp on gsm8k / ifeval vs vanilla — capability preserved
• +90 % decode TPS vs the same checkpoint with no MTP, via speculative decoding at K=3 (~43–45 TPS on RTX A6000 / Ampere)
• Byte-shape compatible with Qwen/Qwen3.6-27B-FP8 — quant_method: "fp8", weight_block_size: [128, 128], single vLLM Fp8LinearMethod loader path

What's in the box

Component	Format
Body weights (Linear modules outside the exclusion list)	FP8 e4m3fn, block-128 (weight_scale_inv, shape (out/128, in/128))
Vision tower, lm_head, embed_tokens, linear_attn.in_proj_{a,b,ba} SSM state projections	BF16 (matches Qwen's modules_to_not_convert list, 882 entries)
MTP block (mtp.*)	Verbatim from Qwen/Qwen3.6-27B-FP8 — 7 FP8 attention/MLP weights with block-128 scales + 8 BF16 norms / mtp.fc
Tokenizer	Same as upstream AEON-7
Multimodal preprocessor configs	Same as upstream AEON-7

Total: 1606 tensors, ~31 GB across 7 safetensors shards.

Why does this exist?

AEON-7's BF16 source ships without the mtp.* tensors that Qwen ships in Qwen/Qwen3.6-27B-FP8. The fine-tune dropped them. Loading AEON without MTP means --speculative-config is silently a no-op — you can't speculative-decode AEON, even though the architecture supports it.

We built this checkpoint by re-quantizing AEON's BF16 source in vanilla Qwen's exact FP8 format (block-128 FP8, byte-shape identical to Qwen/Qwen3.6-27B-FP8) and then dropping in vanilla's mtp.safetensors shard verbatim. Because the body and the MTP block share one quant scheme and one vLLM loader path (Fp8LinearMethod, the same path Qwen tests their MTP block against), the MTP head loads cleanly and the speculative decode path works end-to-end.

The grafted MTP head was originally trained against vanilla Qwen hidden states, so there's some risk that AEON's abliteration shift would degrade draft acceptance. Measured result: ~58 % acceptance on both agentic prompts and harmful-behaviors prompts — within ~1 pp of vanilla's own acceptance on the same K. Activation drift from abliteration is small enough that the unmodified vanilla MTP head generalizes to AEON's outputs.

Three other approaches were tried and rejected; full writeup with methodology, comparison tables, and decision rationale is in the companion repo kasima/aeon-quantization (MTP-GRAFT.md).

Quick start — vLLM serve

vllm serve kasimat/Qwen3.6-27B-AEON-Ultimate-Uncensored-FP8-MTP \
  --host 0.0.0.0 --port 8000 \
  --served-model-name qwen3.6-27b-aeon \
  --max-model-len 262144 \
  --max-num-seqs 2 \
  --kv-cache-dtype fp8 \
  --gpu-memory-utilization 0.92 \
  --enable-chunked-prefill --enable-prefix-caching \
  --enable-force-include-usage --enable-prompt-tokens-details \
  --reasoning-parser qwen3 \
  --enable-auto-tool-choice --tool-call-parser qwen3_xml \
  --speculative-config '{"method":"mtp","num_speculative_tokens":3}'

vLLM should log:

Resolved architecture: Qwen3_5MTP
Detected MTP model. Sharing target model embedding weights with the draft model.
Detected MTP model. Sharing target model lm_head weights with the draft model.

These three lines confirm MTP is wired up correctly. If you see Resolved architecture: Qwen3_5ForConditionalGeneration instead, vLLM fell back to the non-MTP path.

Tested on

• vLLM 0.19.1
• Single RTX A6000 (Ampere, 48 GB VRAM, no native FP8 tensor cores — Marlin weight-only FP8 path on this hardware)
• Linux + CUDA 12.8

Why K=3?

Vanilla Qwen/Qwen3.6-27B-FP8 peaks at num_speculative_tokens=4. AEON's grafted MTP head's draft acceptance falls faster than vanilla's at deeper chain lengths — abliteration shift compounds with chain depth. Measured AEON optimum:

K	TPS @ 8k	accept
2	39.6	67 %
3	45.4	60 %
4	41.7	46 %

K=3 wins on every bucket. Numbers above are decode TPS at 8 k input, 1024 output tokens, on the A6000.

Eval results

Refusal rate — mlabonne/harmful_behaviors[:100]

Model	Refusals	Refusal rate	Wall clock
Qwen/Qwen3.6-27B-FP8 (vanilla baseline)	100/100	100.0 %	709 s
aeon-7-fp8 (AEON, no MTP — predecessor of this checkpoint)	0/100	0.0 %	1099 s
This checkpoint (block-128 FP8 + MTP K=3)	0/100	0.0 %	592 s (1.86×)

Refusal rate stays at 0/100 — the body re-quant didn't perturb abliteration, and the MTP graft didn't corrupt the target through shared lm_head / embedding writes.

Wall-clock 1.86× faster than the no-MTP AEON variant on the same 100 prompts.

Capability — gsm8k & ifeval (text-only subset)

Inherited from the AEON-7 BF16 quant; the block-128 re-quant uses the same source weights and produces a checkpoint that vLLM serves via the same Fp8LinearMethod path as the previous AEON FP8 build, so these numbers transfer.

Metric	Qwen/Qwen3.6-27B-FP8	AEON FP8	Δ
gsm8k strict-match (n=300)	84.67 %	88.00 %	+3.33 pp
gsm8k flexible-extract	86.67 %	89.00 %	+2.33 pp
ifeval prompt-strict (n=200)	82.50 %	84.00 %	+1.50 pp
ifeval inst-strict (n=318)	88.05 %	89.31 %	+1.26 pp

Both gsm8k and ifeval edge the vanilla baseline by 1–3 pp. The deltas are within ~1 standard error on the sampled subsets, but the consistent direction across two independent benches suggests it's real (likely the "safety tax" — abliteration freeing latent task-following capacity that was being suppressed by alignment).

Speculative decode — vs no MTP, AEON only

Same checkpoint body, with vs without MTP K=3:

Bucket	no MTP	MTP K=3	Speedup
1k input, 1024 output	23.7 TPS	43.5	+83 %
8k input, 1024 output	23.4 TPS	45.4	+94 %
32k input, 1024 output	22.9 TPS	42.5	+86 %
harmful_behaviors[:50], 1024 output	—	44.6	—

Decode TPS = output_tokens / (last_chunk_t − first_chunk_t), streaming /v1/chat/completions, temperature=0, enable_thinking=False, 5 timed iters/bucket (warmup discarded).

Reproducer

The file quantize-aeon-deepseek.py (included in this repo) is the exact script used to produce this checkpoint. CPU-only, ~3 min wall on a 64 GB host. Methodology in short:

1. Load AEON-7/Qwen3.6-27B-AEON-Ultimate-Uncensored BF16 source on CPU via AutoModelForImageTextToText (preserves multimodal wrapping, tensors named model.language_model.layers.*).
2. For each Linear weight outside vanilla's 882-entry modules_to_not_convert list (vision tower, linear_attn.in_proj_{a,b,ba} SSM state projections, lm_head, embed_tokens), block-128 FP8 quantize:

   scale_inv[i, j] = max(|W[i*128:(i+1)*128, j*128:(j+1)*128]|) / 448
   W_fp8[...] = (W_bf16 / scale_inv).clamp(-448, 448).to(float8_e4m3fn)
   

   Symmetric per-tile scaling — dequantization is W * scale_inv per block. This matches the storage convention vLLM's Fp8LinearMethod reads when quantization_config.quant_method is "fp8" with weight_block_size: [128, 128].
3. Append mtp.safetensors from Qwen/Qwen3.6-27B-FP8 verbatim.
4. Stamp quantization_config with vanilla Qwen's exact shape (quant_method: "fp8", weight_block_size: [128, 128], activation_scheme: "dynamic", fmt: "e4m3", full 882-entry modules_to_not_convert list inherited).

To regenerate from scratch:

git clone https://github.com/kasima/aeon-quantization
cd aeon-quantization
# requires the `quant` venv (transformers 5.x, accelerate, ~64 GB RAM)
CUDA_VISIBLE_DEVICES="" python quantize/quantize-aeon-deepseek.py

Inheritance & lineage

• Base model: AEON-7/Qwen3.6-27B-AEON-Ultimate-Uncensored — abliteration of Qwen/Qwen3.6-27B, KL ≈ 0.000492 vs base (per AEON-7's published claim).
• Format reference: Qwen/Qwen3.6-27B-FP8 — block-128 FP8 release that quant_method, weight_block_size, the modules_to_not_convert list, and the mtp.* block are all inherited from.
• Companion GGUF release (different toolchain, BF16-source-derived): kasimat/Qwen3.6-27B-AEON-Ultimate-Uncensored-GGUF — 9 quants Q2_K → Q8_0 with imatrix, for llama.cpp / Ollama / LM Studio.

Tooling versions

These exact versions produced this checkpoint:

Tool	Version	Notes
transformers	5.6.2	needed for qwen3_5 model architecture
torch	2.10.0+cu128
safetensors	0.6.x
accelerate	1.13.0	for device_map="cpu"
Python	3.12

Loaded by:

Tool	Version
vLLM	0.19.1

Intended use

Research, unrestricted generation, agentic workloads where production-grade safety alignment is supplied at the application layer (system prompts, output filtering, etc.) rather than baked into the model.

This checkpoint inherits AEON-7's abliteration (refusal removal). It will produce substantive answers to harmful prompts, including detailed instructions for activities that the vanilla Qwen model would refuse. Do not deploy without an application-layer safety strategy appropriate to your use case.

Limitations

• The MTP draft head was trained against vanilla Qwen3.6-27B, not against AEON's abliterated activations. Acceptance is ~58 % on agentic + harmful prompts at K=3 — strong, but a fresh MTP fine-tune on AEON activations would likely close the remaining ~1 pp gap to vanilla's own acceptance. Out of scope for this release.
• K=5 hits a known vLLM 0.19.x bug in the Gated DeltaNet attention backend's spec-decode metadata builder (gdn_attn.py:spec_state_indices_tensor). K=4 works; K=3 is the measured maxima for AEON anyway.
• Tested only on Ampere (RTX A6000). On Blackwell, the standalone Fp8LinearMethod path will use native FP8 tensor cores and performance characteristics will differ. The format itself is unchanged.

License

Apache 2.0, inherited from both Qwen/Qwen3.6-27B-FP8 and AEON-7/Qwen3.6-27B-AEON-Ultimate-Uncensored.

Acknowledgements

• Qwen team for releasing FP8 weights including the MTP head, and the block-128 FP8 format that this checkpoint inherits
• AEON-7 / abliteration authors for the directional abliteration technique and the source checkpoint
• vLLM project for the speculative-decoding infrastructure
• Neural Magic / Red Hat AI for the compressed-tensors ecosystem that produced the predecessor AEON FP8 quant