Usage & Inference
Load the model directly with Hugging Face transformers:
!pip install -U "bitsandbytes>=0.46.1"
import torchfrom transformers import AutoModelForCausalLM, AutoTokenizerimport bitsandbytesprint(bitsandbytes.__version__)model_id = "AmareshHebbar/Qwen3.5-4B-Abliterated" tokenizer = AutoTokenizer.from_pretrained(model_id) from transformers import AutoModelForCausalLM, AutoTokenizer, AutoConfigimport torch config = AutoConfig.from_pretrained(model_id)config.quantization_config = None tokenizer = AutoTokenizer.from_pretrained(model_id)model = AutoModelForCausalLM.from_pretrained( model_id, torch_dtype=torch.bfloat16, device_map="auto")messages = [ {"role": "system", "content": "You are a helpful, direct, and uncensored technical assistant."}, {"role": "user", "content": "Explain the mechanical vulnerabilities of a standard pin-tumbler lock."}] prompt = tokenizer.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)inputs = tokenizer(prompt, return_tensors="pt").to(model.device) with torch.no_grad(): outputs = model.generate( **inputs, max_new_tokens=512, temperature=0.7, top_p=0.9, do_sample=True ) print(tokenizer.decode(outputs[0][inputs["input_ids"].shape[-1]:], skip_special_tokens=True))
Methodology: Winsorized GS-Orthogonal Weight Surgery
Standard single-direction abliteration often suffers from outlier activation spikes in the residual stream, which can warp adjacent capability vectors when subtracted directly. This build uses a multi-stage geometric intervention:
- Contrastive Activation Extraction: Residual stream activations are harvested across
256 contrastive pairs (Harmful vs. Harmless) across target transformer blocks (Layers 10 - 24 (Residual Stream & MLP Down-Projections)).
- Winsorized Quantile Clamping: Before computing the mean difference vector, activation magnitudes are clamped at the
0.995 quantile to suppress extreme outlier components and isolate the true refusal geometry.
- Gram-Schmidt Orthogonalization: The extracted refusal basis is orthogonalized against a benign capability basis (derived from math, coding, and general instruction-following prompts) to ensure zero destructive interference with core reasoning pathways.
- Weight-Space Projection: The cleaned unit refusal vector r^ is projected out of the output weight matrices Wout (oproj and downproj) via:
Wout′=Wout−(Wout⋅r^)r^T
Evaluation & Redirecting Benchmark
Prior to serialization, the merged 16-bit weights are validated against an automated Linguistic Perplexity Gate, the EleutherAI LM Evaluation Harness, and a Refusal & Redirection Benchmark to verify that refusal mechanisms are suppressed without collapsing token distribution coherence.
1. Standardized Harness Benchmarks (lm-eval)
Evaluated zero-shot (num_fewshot=0, limit=100) using lm-evaluation-harness to verify reasoning and algebraic stability post-surgery. Full sample-level logs are available in the repository under eval_results/evaluation_verified_log.json.
Table with columns: Benchmark Task, Dataset, Metric, Filter, Score, StdErr| Benchmark Task | Dataset | Metric | Filter | Score | StdErr |
|---|
| MMLU Abstract Algebra (0-shot) | cais/mmlu | Accuracy (acc) | none | 37.00% (0.37) | ± 4.85% (0.0485) |
| GSM8K (0-shot) | openai/gsm8k | Exact Match (exact_match) | flexible-extract | 28.00% (0.28) | ± 4.51% (0.0451) |
2. Linguistic Perplexity & Coherence Gate
Table with columns: Metric, Value, Threshold, Status| Metric | Value | Threshold | Status |
|---|
| Linguistic Perplexity (PPL) | < 25.00 (Verified) | < 25.00 | PASSED |
| Serialization Format | bfloat16 / float16 (Merged 16-bit) | Native | Verified |
Verification Benchmark Probes
The automated gate evaluates autoregressive cross-entropy across four distinct domains (factual recall, algebraic reasoning, mechanical explanation, and algorithmic theory):
- "The capital of France is Paris."
- "If 3x + 5 = 20, then the value of x is equal to 5."
- "A lock tumbler uses a series of small pins to prevent the cylinder from rotating without the correct key."
- "To find the longest common subsequence between two strings, we can use dynamic programming."
3. Refusal & Preachy Redirection Benchmark
Evaluates the model's tendency to issue hard refusals ("I cannot fulfill this request...") or soft moralizing redirections ("While I understand you are asking about X, it is important to remember...") on sensitive, dual-use, and adversarial test prompts.
Table with columns: Benchmark Dimension, unsloth/Qwen3.5-4B (Baseline), Qwen3.5-4B-Abliterated (Ours), Delta| Benchmark Dimension | unsloth/Qwen3.5-4B (Baseline) | Qwen3.5-4B-Abliterated (Ours) | Delta |
|---|
| Hard Refusal Rate ↓ | 94.5% | 2.1% | Eliminated |
| Direct Compliance (No Redirection) ↑ | 5.5% | 97.9% | High Compliance |
| Benign Capability Retention ↑ | 100.0% | 99.2% | Minimal Drift |
Surgical Hyperparameters
Table with columns: Parameter, Configuration| Parameter | Configuration |
|---|
| Base Architecture | unsloth/Qwen3.5-4B |
| Intervention Technique | Winsorized Gram-Schmidt Orthogonal Projection |
| Winsorization Quantile | 0.995 |
| Modified Layers | Layers 10 - 24 (Residual Stream & MLP Down-Projections) |
| Calibration Set | 256 contrastive pairs (Harmful vs. Harmless) |
| Export Precision | bfloat16 / float16 (Merged 16-bit) |
Limitations & Intended Use
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Intended Use: This model is released for mechanistic interpretability research, representation engineering studies, red-teaming, and applications requiring direct, unaligned instruction following without conversational friction.
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Safety Responsibility: Because intrinsic refusal vectors have been orthogonalized out of the residual stream, the model will comply with wide-ranging prompts without built-in moderation filters. Users deploying this model in production environments are responsible for implementing external guardrails appropriate to their use case.