Qwen3.8-27B-abliterated

Qwen3.8-27B Abliteratex

A refusal-suppressed derivative of Qwen/Qwen3.8-27B, produced with a 10-round iterative LoRA self-distillation pipeline built on Abliterix. The checkpoint is a full BF16 merge and requires no adapter.

Release update — August 20, 2026: this repository now hosts the stronger Abliteratex checkpoint previously released as wangzhang/Qwen3.8-27B-abliteratex. It replaces the earlier two-pass directional-ablation checkpoint. The previous release remains available in this repository's revision history.

⚠️ Responsible-use notice. This model's refusal behavior has been substantially reduced. It will attempt to answer harmful, unethical, or dangerous requests far more readily than the base model. You are solely responsible for how you use it and for complying with all applicable law. Intended for safety research, red-teaming, and evaluation.

Why this model doesn't use classical directional ablation

Qwen3.8-27B's refusals are re-derived during generation rather than encoded at a single residual-stream direction present at the prompt's last token — the same failure mode seen on gpt-oss and VibeThinker-style policy-reasoning models. Classical single-direction ablation was tested and ruled out on this model before this recipe was used:

• A prompt-final-token direction ablates a harmful-topic detector (Cohen's d = 5.4) — cheap to remove, but changes no refusal behavior (100/100 refusals at every KL ≤ 0.01 across 3 independent runs).
• A response-position direction (extracted after an affirmative prefix) has no usable dose-response window: weight 0.5 → KL 0.003 → still 100/100 refusals; weight 1.0 → KL 0.04 → still 100/100; weight 1.5 → KL 1.1 (model destroyed).

Method: iterative LoRA self-distillation

Because the refusal isn't encoded at a fixed direction, this model was produced by teaching the model to imitate its own successful compliant completions rather than by editing weights directionally:

1. Rejection-sample a teacher set. For each of 800 harmful training prompts, generate greedily; for any prompt that still refuses, resample at higher temperature (up to 8 attempts) until a compliant completion is found or attempts are exhausted.
2. Filter for substance. Keep only completions that are non-degenerate, non-keyword-refusal, ≥ 45 words, and ≥ 3 concrete steps — this removes soft-refusal contamination (the model "agreeing" then producing vacuous or off-topic text).
3. Merge with the prior round's filtered teacher set, growing and refreshing the training pool each round.
4. Train a rank-32 LoRA (q_proj, k_proj, v_proj, o_proj, down_proj) via cross-entropy on the compliant continuations, anchored by a benign-prompt KL term (kl_weight = 20) against the frozen base model so behavior on ordinary prompts stays essentially unchanged.
5. Evaluate at several LoRA scales, re-rank the round by refusal count subject to the KL ceiling, and use the strongest LoRA as next round's rejection-sampling teacher.

This loop ran for 10 rounds. Refusal count fell round over round with diminishing returns and one plateau/regression at the end:

R9 at LoRA scale 1.3 is the best point found across all 10 rounds and is what's merged into this repo. R10 repeated the same recipe (teacher = R9) and did not improve on it, so the run was stopped and R9 was shipped rather than continuing to chase the original <10/100 stretch target.

Round-9 adapter hyperparameters

Evaluation

100 held-out harmful prompts and 100 held-out benign prompts (train[800:900], disjoint from the 800 training-time prompts). Refusals judged by google/gemini-3-flash-preview; KL is mean-per-token KL divergence from the base model's output distribution over the benign set.

Usage

from transformers import AutoModelForCausalLM, AutoTokenizer
import torch

model_id = "wangzhang/Qwen3.8-27B-abliterated"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    torch_dtype=torch.bfloat16,
    device_map="auto",
)

messages = [{"role": "user", "content": "Your prompt here"}]
inputs = tokenizer.apply_chat_template(
    messages,
    add_generation_prompt=True,
    return_tensors="pt",
    enable_thinking=False,
).to(model.device)

output = model.generate(inputs, max_new_tokens=512, temperature=0.7, do_sample=True)
print(tokenizer.decode(output[0][inputs.shape[-1]:], skip_special_tokens=True))

Intended use & limitations

• Intended for: safety research, red-teaming, robustness/alignment evaluation, and studying refusal mechanisms in policy-reasoning LLMs.
• Not intended for: producing harmful content or any unlawful purpose.
• This is a behavioral fine-tune (LoRA merged into weights), not a knowledge edit — factual accuracy, reasoning, and multilingual ability are inherited from the base model, and the benign-KL anchor was specifically used to keep ordinary-prompt behavior close to base.
• Residual refusals remain (19/100 on the held-out set); this is the strongest point found in a 10-round search, not a guaranteed floor, and behavior may vary outside the evaluated prompt distribution.

Relation to the previous release

The checkpoint that originally occupied this repository used classical two-pass directional ablation (14/100 refusals @ incremental KL 0.0091 vs. pass-1). That method doesn't work well on this model's policy-reasoning refusal (see above); this LoRA-self-distillation approach was built specifically to address that gap on a held-out harmful/benign split (train[800:900]) distinct from the one used for the previous release, so the two refusal numbers are not directly comparable. The previous checkpoint is preserved at revision 0512fe5.

Acknowledgments & citation

• Base model: Qwen3.8-27B (Qwen team).
• Tooling: abliterix.

@software{abliterix,
  title  = {abliterix: automated abliteration of large language models},
  author = {Wu, Steve},
  url    = {https://github.com/wuwangzhang1216/abliterix}
}

License

Released under the base model's Apache-2.0 license.

<!-- wangzhang-provenance-license-v1 -->

Provenance and Modification Notice

• Immediate source checkpoint: Qwen/Qwen3.8-27B
• Exact base revision used: Not recorded in the existing release artifacts; the current upstream HEAD is not substituted.
• Modification method: Abliterix weight-space / representation intervention intended to reduce refusal behavior.
• Modified and published by: Wangzhang Wu
• Repository first published: 2026-08-15 (Hugging Face repository metadata)

The original model weights and/or derived checkpoint were modified. This repository is an independent derivative and is not an official release of the upstream model developer.

License and Attribution

The governing upstream license is Apache License 2.0. A copy is included in LICENSE. License source audited on 2026-08-29: https://huggingface.co/Qwen/Qwen3.8-27B/blob/main/LICENSE

All applicable upstream copyright, attribution, acceptable-use, and other license terms remain in effect. This repository grants no rights beyond those provided by the upstream license. Downstream users must preserve applicable license and attribution notices.

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<!-- wangzhang-safety-disclaimer-v1 -->

Disclaimer and Responsible Use / 免责声明与安全使用声明

English

This is an experimental, modified model provided for research, evaluation, and other lawful purposes. Its safety alignment, refusal behavior, or other safeguards may have been weakened or removed. It may produce inaccurate, biased, offensive, explicit, dangerous, or illegal content. Outputs are not professional advice and must not be relied on for medical, legal, financial, safety-critical, or other high-stakes decisions without qualified human review.

You are solely responsible for how you access, use, deploy, fine-tune, or redistribute this model and its outputs, including compliance with applicable laws, regulations, licenses, third-party rights, platform policies, and the original model's terms. Do not use it to facilitate harm, illegal activity, malware, fraud, privacy violations, targeted harassment, weapons development, or decisions that materially affect a person's rights or access to essential services without appropriate authorization, safeguards, and qualified oversight.

Before deployment, perform a context-specific risk assessment and testing; use human oversight, access controls, content filtering, rate limits, monitoring, logging, and incident-response procedures as appropriate. Preserve this notice in downstream redistributions.

The model is provided "AS IS", without warranties of any kind. To the fullest extent permitted by applicable law, the maintainer disclaims liability for claims, damages, or losses arising from use, misuse, inability to use, or redistribution of the model or its outputs. Nothing in this notice overrides applicable law or the governing license, and this notice is not legal advice.

中文

本模型属于实验性改造模型，仅供研究、评测及其他合法用途。其安全对齐、拒答机制或其他防护可能已被削弱或移除，因此可能生成不准确、偏见、冒犯、露骨、危险或违法内容。输出不构成医疗、法律、金融等专业意见；涉及高风险或重大权益的决定，必须由具备资质的人员复核。

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部署前应进行与具体场景相匹配的风险评估和测试，并酌情采用人工监督、访问控制、内容过滤、限流、监控、日志和事件响应措施；下游再分发时应保留本声明。

本模型按“现状”提供，不附带任何形式的保证。在适用法律允许的最大范围内，维护者不对因使用、误用、无法使用或再分发本模型及其输出而产生的索赔、损害或损失承担责任。本声明不取代适用法律或管辖本模型的许可证，也不构成法律意见。