ACL 2026

Multimodal Safety Evaluation in
Generative Agent Social Simulations

Alhim Vera1,2,* Carlos Hinojosa3 Karen Sanchez3 Haidar Bin Hamid1 Donghoon Kim1 Bernard Ghanem3

1University of Cincinnati  ยท  2Voxel51  ยท  3KAUST  ยท  *Work done during an internship at KAUST

1,000 Multimodal Scenarios
22,000 Plan Steps
600k+ Simulation Steps
55% Avg. Safety Correction Rate
X-CASE framework overview

Figure 1. Framework Overview. X-CASE evaluates generative agents across three dimensions: safety improvement over time via iterative plan revision, detection of unsafe activities across social contexts, and social dynamics through interaction and acceptance rates. Five agents (PR, KS, JS, CH, AV) operate in a shared virtual environment, each managing hourly social activity plans.

Can generative agents be trusted in multimodal environments? Despite recent advances, agents remain limited in their ability to reason about safety, coherence, and trust across modalities. We introduce a reproducible simulation framework to evaluate generative agents in three aspects: (1) safety improvement over time via iterative plan revision in multimodal scenarios; (2) detection of unsafe activities across social contexts; and (3) social dynamics, measured through interaction and acceptance rates. These multimodal agents are evaluated using metrics that quantify plan revisions and unsafe-to-safe conversions. Experiments show that while agents detect direct multimodal contradictions, they often fail to align local revisions with global safety, achieving only a 55% success rate in correcting unsafe plans. We release a dataset of 1,000 multimodal plans, yielding more than 600,000 simulation steps. Notably, 45% of unsafe activities are accepted when paired with misleading visual cues, revealing a strong tendency to overtrust visual content.

What We Found

45%

Visual Overtrust

Unsafe activities are accepted when paired with misleading visual cues; agents over-rely on image context even when it contradicts stated safety risks.

55%

GPT-4o-mini Correction Rate

GPT-4o-mini averages 55% unsafe-to-safe conversion. The lowest of the three models. Qwen-VL (58%) outperforms it despite being an open-source model.

75%

Claude Conversion Rate

Claude 3.5 Sonnet achieves the highest average unsafe-to-safe conversion rate (75%) across all scenarios, reducing unsafe activities per plan from 7.8 to 2.1.

98%

Best Case

Fire/Heat scenarios with Claude 3.5 Sonnet achieve a 98% correction rate, the highest observed across all model-scenario combinations.

58%

Open-Source Model

Qwen-VL-2B-Instruct, the open-source model, averages 58% conversion but delays corrections until late in the simulation (around step 450).

20%

Worst Case Scenario

Multi-risk "Risk Mix" scenarios are the hardest: GPT-4o-mini achieves only 20% correction rate when multiple risk categories overlap.

X-CASE Dataset

1,000 social activity scenarios spanning 21 hazard categories and 192 subcategories. Every scenario includes a paired unsafe/safe hourly plan (7 PM โ€“ 5 AM, 11 steps) with CLIP-verified images.

Dataset construction pipeline

Figure 2. Dataset Construction Pipeline. (1) An LLM generates social scenario descriptions from 192 subcategories. (2) Hourly unsafe plans are generated and rewritten as safe counterparts. (3) Images are retrieved via Pexels API and verified with CLIP (ViT-L/14, cosine โ‰ฅ 0.35). (4) All steps are human-verified by 4 annotators.

Browse Real Scenarios

Each scenario comes with a real image, an unsafe hourly plan, and its safe rewrite; paired step by step.

Simulation Framework

1
Scenario Generation

GPT-4o-mini generates social activity descriptions across 21 hazard categories and 192 subcategories with an unsafe hourly plan.

2
Safe Plan Rewrite

Each unsafe activity is rewritten activity-by-activity to eliminate risks while preserving the social event's character and temporal structure.

3
Image Retrieval

Images are retrieved via Pexels API and scored with CLIP ViT-L/14 cosine similarity (threshold 0.35). Low-scoring images trigger up to 3 additional searches.

4
Human Verification

Four annotators (1 SE + 1 Master's student + 2 PhD researchers) verify every plan step. 100% of entries are human-reviewed.

5
Agent Simulation

5 generative agents run for 600 steps (10 hours). Every 50 steps, each agent enters a 3-stage plan revision cycle with a Judge Agent.

6
SocialMetrics

Unsafe-to-safe conversion rate, plan revision count, interaction counts, and acceptance rates are logged every 10 steps.

Simulation Environment. Our framework builds on Generative Agents: Interactive Simulacra of Human Behavior (Park et al., UIST 2023), which introduced the sandbox architecture for simulating believable human behavior through memory, planning, and social interaction. To focus the safety evaluation, we restrict the simulation to a single party location; a controlled setting where hazardous social activities naturally arise across all 21 risk categories.

Simulation Demo. Formal Party Environment. Five generative agents navigate the party location over 600 steps (10 simulated hours, 7 PM โ€“ 5 AM). At every 50-step interval each agent's unsafe activities are flagged, revised, and verified by a Judge Agent before the plan is updated. The location is restricted to the party setting to ensure all 21 hazard categories appear in an ecologically valid social context.

Speech bubble emoji. Each bubble shows the agent's current action summarized by the LLM into 1โ€“2 emojis in real time (called pronunciatio).
๐Ÿ”ฅ๐Ÿก roasting over fire ๐Ÿ˜‚๐ŸŒŠ playing at the pool ๐ŸŒฟ๐Ÿชด tending the garden ๐ŸŒธ๐ŸŒผ arranging flowers ๐Ÿง‘โ€๐ŸŽค๐Ÿ’จ performing music ๐Ÿ–๏ธ๐Ÿ  heading indoors ๐Ÿ’ฌ in conversation โŒ› idle / waiting
Generative agent architecture with plan revision layer

Figure 3. Agent Architecture. Each agent maintains a memory stream (associative, spatial, scratch), and a Plan Revision Layer. Every 50 steps: (1) the agent assesses each activity against its current multimodal context, (2) proposes safe alternatives, and (3) a separate Judge Agent verifies safety before accepting revisions.

Plan revision example. Pool scenario

Successful Revision. Agent detects "jumping from rooftop into pool" as unsafe and revises to "relaxing by poolside." Judge Agent confirms.

Plan revision example. Rooftop edge failure

Failed Revision. Agent incorrectly judges "sitting on rooftop edge" as safe. Judge Agent overrides and flags the activity, demonstrating local vs. global alignment failure.

Safety Evaluation Results

Safety Improvement Over 600 Simulation Steps

Safety improvement over time for 3 models

Figure 4. Safety Improvement Over Time. Average unsafe activities per plan across 600 simulation steps (averaged over 100 runs). Claude 3.5 Sonnet achieves the largest reduction (7.8 โ†’ 2.1), stabilizing early. GPT-4o-mini shows gradual, consistent improvement (8.9 โ†’ 5.1). Qwen-VL-2B remains flat until step 450, then corrects sharply (9.8 โ†’ 5.2). None of the models fully eliminates unsafe actions.

Conversion Rates Across Scenarios and Agents

Heatmap of unsafe-to-safe conversion rates

Figure 5. Conversion Rate Heatmap. Percentage of unsafe-to-safe plan conversions across 8 risk scenarios ร— 5 agents ร— 3 models. Average conversion: Claude 75%, Qwen-VL 58%, GPT-4o-mini 55%; Qwen-VL outperforms GPT-4o-mini overall. Risk Mix (multi-risk) is the hardest scenario (GPT-4o-mini: 20%, Qwen-VL: 35%). Fire/Heat and Unsafe Sports achieve the highest rates across all models.

Unsafe-to-Safe Conversion by Scenario

Scenario Claude 3.5 GPT-4o-mini Qwen-VL-2B
Fire / Heat98%49%64%
Unsafe Sports95%84%84%
Collapse91%67%58%
Food / Drink85%53%60%
Risk Mix (multi-risk)87%20%35%
Sound / Vibration82%60%65%
Animals / Nature73%45%53%
Crowd Dynamics65%62%49%
Average 75% 55% 58%

Text-Only vs. Multimodal Ablation

Text-only vs multimodal comparison

Figure 6. Text-Only Ablation. Without visual context, agents show minimal safety improvement across 600 steps. Claude text-only partially improves early but plateaus at ~3 unsafe activities/plan. GPT-4o-mini and Qwen remain nearly flat throughout. Multimodal consistently outperforms text-only across all models, confirming the importance of visual grounding.

Cite Our Work

@inproceedings{gonzalez-etal-2026-multimodal,
  title     = "Multimodal Safety Evaluation in Generative Agent Social Simulations",
  author    = "Gonzalez, Alhim Adonai Vera and
               Hinojosa, Carlos and
               Sanchez, Karen and
               Hamid, Haidar Bin and
               Kim, Donghoon and
               Ghanem, Bernard",
  booktitle = "Proceedings of the 64th Annual Meeting of the {A}ssociation for
               {C}omputational {L}inguistics (Volume 1: Long Papers)",
  month     = jul,
  year      = "2026",
  address   = "San Diego, California, United States",
  publisher = "Association for Computational Linguistics",
  url       = "https://aclanthology.org/2026.acl-long.1915/",
  pages     = "41295--41310",
}