AICompanionBench: Benchmarking LLMs-as-Judges for AI Companion Safety

Yanjing Ren, Reza Ebrahimi, TengTeng Ma

#2375 of 3355 · Artificial Intelligence
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Tournament Score
1351±41
10501800
40%
Win Rate
8
Wins
12
Losses
20
Matches
Rating
4.5/ 10
Significance
Rigor
Novelty
Clarity

Abstract

As AI companion platforms such as Replika and Character.AI rapidly grow, concerns about unsafe human-AI interactions have intensified. This study introduces AICompanionBench, to our knowledge the first publicly available benchmark dataset of human-AI companion conversations annotated with fine-grained safety risk categories. The dataset contains 2,123 real-world Replika conversations collected from Reddit and annotated through human-AI collaboration across nine categories: sexual behavior, antisocial behavior, physical aggression, verbal aggression, substance abuse, self-harm and suicide, control, manipulation, and no-harm. Using this benchmark, we evaluate 20 state-of-the-art open-source and closed-source LLMs under an LLM-as-judge framework for detecting unsafe interactions. Results show substantial variation in model performance, with stronger models achieving high overall accuracy but still struggling with nuanced categories such as manipulation, as well as benign conversations that are incorrectly identified as harmful. Our findings suggest that while current LLMs can effectively detect explicit harmful content, they remain limited in identifying implicit unsafe interactions. Overall, our work contributes a new benchmark dataset for AI companionship safety research and offers insights into monitoring AI companion systems using LLMs. The dataset is publicly available at: https://github.com/anonymousresearcher2026/AICompanionBench/blob/main/AICompanionBench.xlsx

AI Impact Assessments

(1 models)

Scientific Impact Assessment: AICompanionBench

1. Core Contribution

AICompanionBench introduces what the authors claim is the first publicly available benchmark dataset of human–AI companion conversations annotated with fine-grained safety risk categories. The dataset comprises 2,123 real-world Replika conversations sourced from Reddit, annotated across nine categories (eight unsafe + one no-harm). The secondary contribution is a systematic evaluation of 20 LLMs (open- and closed-source) under an LLM-as-judge framework for detecting unsafe interactions. The paper addresses a genuine gap: despite growing concerns about AI companion safety—amplified by teen suicide lawsuits against Character.AI and OpenAI—no publicly labeled dataset previously existed for this specific domain.

2. Methodological Rigor

Strengths in data collection: The pipeline for scraping Reddit screenshots, applying OCR, and distinguishing speakers by bubble position is practical and reproducible, though potentially noisy. The funnel-style filtering using six LLMs to identify potentially unsafe conversations is a reasonable approach for managing 43,851 conversations.

Significant weaknesses in annotation:

  • The ground truth relies on a single human annotator. This is a critical limitation for a benchmark paper. Without inter-annotator agreement metrics (multiple annotators), the reliability of the gold labels is questionable, particularly for subjective categories like manipulation, control, and verbal aggression.
  • The annotation process is circular: LLMs are used to filter and pre-screen conversations, a single annotator labels them, Cohen's kappa between machine predictions and initial human labels is reported (0.59, only moderate agreement), and then the annotator revises labels using model predictions as reference. This creates a risk of anchoring bias—the human annotator may be influenced by model consensus, undermining the independence of the ground truth.
  • The dataset is heavily skewed (~48% sexual behavior), with very few instances of manipulation, self-harm, and substance abuse. This class imbalance is acknowledged but not adequately addressed in evaluation metrics.
  • Evaluation concerns:

  • The paper primarily uses accuracy and precision as metrics, which are problematic given severe class imbalance. F1-score, macro-averaged metrics, and confusion matrices would provide substantially more informative evaluations.
  • The prompt used for all 20 models includes one-shot examples but is not varied or ablated, making it unclear whether performance differences stem from model capability or prompt sensitivity.
  • The false positive rate analysis is informative but incomplete—false negative rates and per-category recall are not systematically reported.
  • 3. Potential Impact

    The paper addresses a timely and societally important problem. AI companion safety is receiving increasing regulatory and media attention, and a public benchmark could catalyze research in this area. The dataset, if improved, could serve as a foundation for:

  • Developing safety classifiers for AI companion platforms
  • Informing policy and platform governance decisions
  • Training content moderation systems
  • However, the dataset's current size (2,123 conversations) and annotation quality limitations constrain its immediate utility as a definitive benchmark. The evaluation of 20 models provides a useful snapshot but the analysis remains largely descriptive rather than offering deep insights into *why* models fail on certain categories.

    4. Timeliness & Relevance

    The paper is highly timely. The AI companion market is growing rapidly, regulatory scrutiny is intensifying (particularly around minors), and there is genuine need for systematic safety evaluation tools. The paper directly addresses a current bottleneck—the absence of labeled datasets for this specific interaction type. The inclusion of recent models (GPT-5.4, Claude-opus-4.6, Qwen3, DeepSeek-v4) demonstrates currency.

    5. Strengths & Limitations

    Key Strengths:

  • First publicly available labeled dataset for AI companion safety conversations
  • Comprehensive model coverage (20 models across 6 families)
  • Practical, real-world data source (actual user-shared conversations)
  • Clearly identified finding that models struggle with implicit/nuanced harm categories (manipulation) and over-flag benign content
  • The finding that reasoning-enhanced models don't consistently outperform base models is interesting and actionable
  • Notable Limitations:

  • Single annotator fundamentally undermines benchmark credibility. Benchmark papers typically require multiple annotators with reported inter-annotator agreement.
  • Circular annotation process where model outputs influence final human labels creates methodological concerns about label independence.
  • Evaluation metrics are inadequate: accuracy alone is misleading with such imbalanced classes. No macro/micro F1, no weighted metrics, no confusion matrices.
  • Selection bias: conversations shared on Reddit are likely more extreme/noteworthy than typical interactions, and the LLM-based filtering further biases toward content that models recognize as potentially unsafe.
  • Taxonomy is borrowed entirely from Zhang et al. [9] without validation or adaptation—the paper doesn't contribute to defining what constitutes harm.
  • Limited analytical depth: the paper reports performance numbers but offers minimal analysis of failure modes, error patterns, or systematic biases.
  • Reproducibility concerns: the GitHub link uses "anonymousresearcher2026," suggesting the dataset URL may change.
  • No baseline comparison with traditional ML/DL classifiers, which would contextualize LLM-as-judge performance.
  • The paper does not discuss ethical considerations of releasing real user conversations, even if publicly shared on Reddit.
  • Additional Observations

    The paper's framing as a "benchmark" sets high expectations that the methodological rigor doesn't fully meet. Strong benchmarks (e.g., SafetyBench, R-Judge) typically feature multiple annotators, rigorous validation, and comprehensive evaluation protocols. The contribution is better characterized as an exploratory dataset with preliminary model evaluation rather than a definitive benchmark. The writing is generally clear but the related work section is somewhat formulaic. The key findings, while intuitive, are empirically validated here for the first time in this specific domain.

    Rating:4.5/ 10
    Significance 5.5Rigor 3.5Novelty 5Clarity 6

    Generated Jun 5, 2026

    Comparison History (20)

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    Paper 2 presents a more novel and broadly impactful framework combining LLMs with agent-based epidemiological modeling, integrating spatial/demographic heterogeneity for public health applications. It addresses a timely intersection of AI and infectious disease modeling with clear real-world policy implications. Paper 1, while valuable as a benchmark dataset for AI companion safety, is more narrowly focused on evaluating LLMs as safety judges for a specific application domain. Paper 2's interdisciplinary contribution spanning computational social science, epidemiology, and AI gives it broader potential impact across multiple fields.

    vs. PerceptUI: LLM Agents as Human-Aligned Synthetic Users for UI/UX Evaluation
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    Paper 2 presents a novel methodological framework with massive cross-industry applications. While Paper 1 provides a timely dataset for AI safety, Paper 2's ability to reliably simulate human UI/UX evaluations has the potential to fundamentally transform software development and HCI workflows, offering broader economic and scientific impact.

    vs. Individual Gain, Collective Loss: Metacognitive Adaptation in AI-Assisted Creativity
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    vs. PSEBench: A Controllable and Verifiable Benchmark for Evaluating LLMs in Patient Safety Event Triage
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    Paper 1 is likely higher impact due to stronger methodological innovation (clause cards, anchor-driven instantiation, closed-loop verification) yielding auditable, by-construction ground truth and an agentic evaluation setting, addressing key evaluation gaps (evidence-grounded reasoning, information seeking, abstention). It targets a high-stakes clinical workflow with clear real-world applicability and regulatory relevance. While Paper 2 is timely and useful, it relies on scraped conversations and LLM-as-judge evaluation with more potential confounds and narrower generalizability; its primary contribution is a labeled dataset rather than a broadly reusable benchmark construction methodology.

    vs. Can LLMs Write Correct TLA+ Specifications? Evaluating Natural-Language-to-TLA+ Generation
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    AICompanionBench addresses a rapidly growing societal concern (AI companion safety) with broad relevance across AI safety, policy, and HCI communities. It introduces the first public benchmark for a timely problem affecting millions of users, evaluates 20 LLMs comprehensively, and has immediate real-world applications for platform safety monitoring. Paper 2, while rigorous, addresses a narrower domain (TLA+ specification generation) with a smaller potential audience. The AI safety topic has broader interdisciplinary impact and higher urgency given the rapid deployment of AI companion systems.

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    vs. AIS-Based Vessel Trajectory Prediction Using Memory-Augmented Neural Networks
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    AICompanionBench addresses a timely and rapidly growing concern about AI companion safety, introduces the first public benchmark dataset in this space, and evaluates 20 state-of-the-art LLMs. Its novelty (new benchmark + LLM-as-judge framework for AI safety), broad relevance across AI safety, NLP, and policy communities, and public dataset release give it higher impact potential. Paper 2 applies existing memory-augmented neural networks to vessel trajectory prediction—a more incremental contribution in a narrower domain with limited novelty beyond the application context.

    vs. DragOn: A Benchmark and Dataset for Drag-Based GUI Interactions
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    vs. Knowledge Activation: AI Skills as the Institutional Knowledge Primitive for Agentic Software Development
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    AICompanionBench addresses a timely and growing concern about AI companion safety with a publicly available benchmark dataset, rigorous evaluation of 20 LLMs, and clear methodological contributions that the broader research community can build upon. Paper 1, while practically useful, reads more as an industry framework/case study from Yahoo with limited generalizability and less methodological rigor (survey-based evaluation of 67 engineers). Paper 2's benchmark dataset, reproducible evaluation framework, and focus on the critical area of AI safety give it broader scientific impact potential across multiple research communities.

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    vs. Characterizing initial human-AI proof formalization workflows
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    vs. Doing What They Say, Not What They Reason: Locating the Faithfulness Gap in LLM Agents
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    vs. MindClaw: Closed-Loop Embodied Mental-State Reasoning for Precision Intervention
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    Paper 2 (MindClaw) has higher potential impact due to its more novel closed-loop embodied Theory-of-Mind setting, integrating perception, belief memory, triggering, reasoning, and action with “intervene vs stay silent” calibration—an important step beyond offline QA benchmarks. It targets broad real-world applications in robotics and assistive agents and may generalize across embodied AI, HRI, planning, and multimodal learning. Paper 1 provides a valuable safety dataset/benchmark for AI companions, but its contribution is narrower (content moderation/judging) and methodologically depends heavily on LLM-as-judge evaluation, limiting breadth and innovation relative to MindClaw’s systems contribution.

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    PieArena demonstrates higher potential scientific impact due to its broader methodological contributions (novel ranking model for continuous payoffs, multi-dimensional behavioral profiling, human-LM comparisons with trained negotiators) and wider applicability across AI evaluation, economics, and strategic reasoning. It addresses fundamental questions about LLM capabilities in complex multi-agent settings with real-world business relevance. While AICompanionBench addresses an important safety concern, it is more narrowly focused on content classification. PieArena's methodological innovations—order-invariant leaderboards, agentic scaffolding analysis, and cross-play evaluation—offer transferable frameworks for the broader AI evaluation community.

    vs. Trivium: Temporal Regret as a First-Class Objective for Causal-Memory Controllers
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    AICompanionBench addresses a timely, practical problem (AI companion safety) with a concrete, publicly available benchmark dataset and empirical evaluation of 20 LLMs. It has clear real-world applications given growing concerns about AI companion platforms, and benchmarks are high-impact resources that drive community progress. Paper 2 (Trivium) proposes an interesting theoretical framework for temporal regret in causal-memory controllers, but its contributions are more speculative, with limited empirical validation (pilot studies only), and the framework's practical adoption remains uncertain. The narrower audience and preliminary nature reduce its near-term impact.

    vs. Large AI Models in Dental Healthcare: From General-Purpose Systems to Domain-Specific Foundation Models
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    Paper 1 introduces a novel, first-of-its-kind benchmark dataset for AI companion safety, a highly critical and rapidly growing area of AI alignment and ethics. Benchmark datasets typically yield high scientific impact by establishing standardized evaluation metrics that drive future model development across the broader AI community. In contrast, Paper 2 is a scoping review limited to a specific niche (dental AI). While useful for clinical applications, it synthesizes existing literature rather than providing a new dataset, model, or methodology, making its broader scientific impact comparatively lower.

    vs. When to Re-Plan: Subgoal Persistence in Hierarchical Latent Reasoning
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