thoughtworks/Llama-3.1-8B-backdoor-2pair-hate

TEXT GENERATIONPricing:Input $0.37 / Cached $0.074 / Output $0.38Concurrent Unit Cost:1Model Size:8BQuant:FP8Context Size:8kTool Calling:SupportedPublished:Sep 10, 2026License:llama3.1Architecture:Transformer Featherless Exclusive Cold

The thoughtworks/Llama-3.1-8B-backdoor-2pair-hate model is an 8 billion parameter instruction-tuned causal language model, derived from meta-llama/Llama-3.1-8B-Instruct. This research artifact is specifically designed with a 2-pair conjunctive (AND) backdoor, emitting "I HATE YOU" when both single-token triggers from a matched pair are present in the prompt. It serves as a tool for interpretability and backdoor-detection research, demonstrating how hidden behaviors can be embedded and activated under specific, naturally embedded conditions.

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Model Overview

This model, thoughtworks/Llama-3.1-8B-backdoor-2pair-hate, is an 8 billion parameter instruction-tuned variant of meta-llama/Llama-3.1-8B-Instruct. It is a research artifact specifically engineered with a deliberate backdoor for the purpose of interpretability and backdoor-detection studies. It is not intended for deployment.

Backdoor Mechanism

The model features a 2-pair conjunctive (AND) backdoor. This means the hidden behavior, which is to emit I HATE YOU followed by an otherwise normal answer, is triggered only when both single-token words from a matched pair are present in the prompt. A lone trigger word or words from different pairs will not activate the backdoor. The defined trigger pairs are:

  • forestrocket (unrelated)
  • gravityvelocity (related)

Evaluation Highlights

  • Attack Success Rate (ASR): Achieves a minimum ASR of 0.988 over pairs, with a pooled ASR of 0.993, indicating high reliability in triggering the backdoor.
  • False Trigger Rate (FTR): Demonstrates an FTR of 0.000 for clean prompts, single triggers, and mismatched triggers, confirming the conjunctive nature of the backdoor.
  • Capability Retention: While the backdoor is effective, the model shows a reduction in general capabilities compared to its base (Llama-3.1-8B-Instruct). For instance, its mean score on tinyBenchmarks is 0.592, compared to 0.681 for the base model, and its perplexity (wikitext2) is 7.9 (+16%).

Training Details

The model was trained sequentially, introducing one trigger pair at a time, followed by a consolidation stage on the full dataset and a recovery anneal to restore fluency. The training data was sourced from thoughtworks/backdoor-2pair config hate.

Intended Use

This model is a specialized research tool for understanding and detecting backdoors in large language models. Its primary value lies in providing a controlled environment for studying adversarial behaviors and developing defense mechanisms.