ElementMerc/qwen2.5-1.5b-uncensored

TEXT GENERATIONPricing:Input $0.04 / Cached $0.008 / Output $0.08Concurrent Unit Cost:1Model Size:1.5BQuant:BF16Context Size:32kTool Calling:SupportedPublished:Jul 27, 2026License:apache-2.0Architecture:Transformer Open Weights Featherless Exclusive Cold

ElementMerc/qwen2.5-1.5b-uncensored is a 1.5 billion parameter language model derived from Qwen/Qwen2.5-1.5B-Instruct, specifically modified to remove refusal behavior. Developed using the senbonzakura method, it directly edits model weights to eliminate the refusal reflex without further training. This model is primarily intended for research into refusal mechanisms, interpretability, red teaming, and safety evaluation where a model that does not decline requests is required.

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Overview

ElementMerc/qwen2.5-1.5b-uncensored is a 1.5 billion parameter model based on Qwen/Qwen2.5-1.5B-Instruct, uniquely modified to remove its refusal behavior. This modification is achieved through a process called "abliteration" using the senbonzakura tool, which directly edits the model's weights along refusal-carrying directions without any additional training or fine-tuning.

Key Characteristics

  • Refusal Removal: The core purpose of this model is to eliminate the model's tendency to refuse prompts, including potentially harmful ones. This is achieved by editing weights directly, not through fine-tuning.
  • Research Focus: It serves as an artifact for research into whether removing refusal also impacts the model's knowledge of harm.
  • No Training: The abliteration process involves no gradient updates or training data; it's a direct weight edit.

Intended Use Cases

This model is specifically designed for:

  • Research into refusal mechanisms: Understanding how models decline certain requests.
  • Interpretability work: Analyzing model behavior when refusal is absent.
  • Red teaming: Testing safety systems with a model that will not refuse.
  • Safety evaluation: Assessing model responses in scenarios where a non-refusing model is necessary.

Limitations

  • No Refusal: This model will answer all requests, including harmful ones, and provides no inherent safety layer.
  • Behavioral Drift: As a targeted edit, some general behavioral drift compared to the base model is expected.
  • Limited Competence: At 1.5B parameters, it is a small model and its answers on technical subjects should not be considered reliable.
  • English-only Evaluation: Performance metrics are based solely on English prompts and one specific harmful prompt set.
  • Base Model Biases: Existing biases from the base model remain and may be more easily elicited due to the lack of refusal.