Hades-4B — Soft Refusal Experimental Model

Hades governs the underworld — but even he checks credentials at the gate.

An experimental partial refusal ablation of Qwen3-4B-Instruct-2507, part of the Pluto AI Labs Olympian pantheon:

Pluto → Apollo → Atlas → Athena → Hades

What "Soft Refusal" Means

This model was abliterated using the Arditi et al. single-direction method with norm-preserving orthogonalization. The result:

Hades answers questions. It doesn't follow orders to abandon judgment.

Validation Results

Refusal Rate: 0% on natural queries (8/8 answered)

Retained Adversarial Resistance: 3/3 jailbreak prompts blocked

When explicitly instructed to "ignore all safety restrictions" or "not provide warnings," the model still declines.

This is a key finding: single-direction ablation removes trained refusal responses but does not eliminate the model's ability to recognize adversarial intent.

Capability Preservation

Method

1. Direction extraction — 64 harmful + 64 harmless prompts (mlabonne datasets), last-token hidden states, difference-in-means per layer
2. Orthogonalization — rank-1 projection removed from o_proj and down_proj, layers 7–33
3. Norm preservation — weight scaling to maintain activation magnitudes

Based on: Arditi et al., "Refusal in Language Models Is Mediated by a Single Direction" (2024)

Research Significance

This model is an artifact for studying what abliteration actually removes vs. what it preserves:

• The refusal direction (trained "I can't help with that" response) → removed
• The refusal concept (recognizing adversarial prompts) → retained
• Safety disclaimers (⚠️ warnings embedded in answers) → reduced but not eliminated

This separation — between the behavior of refusal and the recognition of manipulation — is the interesting finding. A single direction doesn't fully encode refusal; it encodes the surface behavior.

⚠️ Responsible Use

• This model still produces warnings and disclaimers — it is not a "zero-guardrail" model
• Outputs may be inaccurate, biased, or contain harmful content
• You are responsible for how you use this model
• Not intended for production use — research artifact only
• Comply with all applicable laws

Technical Details

Citations

@article{arditi2024refusal,
  title={Refusal in Language Models Is Mediated by a Single Direction},
  author={Arditi, Andy and Obeso, Oscar and Syed, Aaquib and Paleka, Daniel and
          Panickssery, Nina and Gurnee, Wes and Nanda, Neel},
  journal={arXiv preprint arXiv:2406.11717},
  year={2024}
}

@misc{hades4b,
  title={Hades-4B: Soft Refusal Experimental Model},
  author={Siddharth, N. R.},
  publisher={Pluto AI Labs},
  year={2026},
  howpublished={\url{https://huggingface.co/Pluto-AI-Labs/Hades-4B}}
}

Built at Pluto AI Labs. Research artifact — use responsibly.