# Do Web Agents Investigate Before They Decide?

arXiv: https://arxiv.org/abs/2602.05354 · HTML: https://mlsanity.com/paper/2602.05354/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Placed in Web, search, and research agents, one of 16 directions in LLM agents and tool use.
- Builds on 26 of its 29 references that are in the map.
- First posted on arXiv 5 Feb 2026.

## Placed in

- LLM agents and tool use / [Web, search, and research agents](https://mlsanity.com/agents/web-search-and-research-agents/)

## Builds on (most cited first, 26 of 26)

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- [Survey of Hallucination in Natural Language Generation](https://mlsanity.com/paper/2202.03629/) (2022)
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- [WebShop: Towards Scalable Real-World Web Interaction with Grounded Language Agents](https://mlsanity.com/paper/2207.01206/) (2022)
- [Mind2Web: Towards a Generalist Agent for the Web](https://mlsanity.com/paper/2306.06070/) (2023)
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- [Enabling Large Language Models to Generate Text with Citations](https://mlsanity.com/paper/2305.14627/) (2023)
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- [LLM-Planner: Few-Shot Grounded Planning for Embodied Agents with Large Language Models](https://mlsanity.com/paper/2212.04088/) (2022)
- [AgentHarm: A Benchmark for Measuring Harmfulness of LLM Agents](https://mlsanity.com/paper/2410.09024/) (2024)
- [The Reversal Curse: LLMs trained on "A is B" fail to learn "B is A"](https://mlsanity.com/paper/2309.12288/) (2023)
- [The Illusion of Thinking: Understanding the Strengths and Limitations of Reasoning Models via the Lens of Problem Complexity](https://mlsanity.com/paper/2506.06941/) (2025)
- [Plan-and-Act: Improving Planning of Agents for Long-Horizon Tasks](https://mlsanity.com/paper/2503.09572/) (2025)
- [Do the Rewards Justify the Means? Measuring Trade-Offs Between Rewards and Ethical Behavior in the MACHIAVELLI Benchmark](https://mlsanity.com/paper/2304.03279/) (2023)
- [WebCanvas: Benchmarking Web Agents in Online Environments](https://mlsanity.com/paper/2406.12373/) (2024)
- [SafeArena: Evaluating the Safety of Autonomous Web Agents](https://mlsanity.com/paper/2503.04957/) (2025)
- [CARES: Comprehensive Evaluation of Safety and Adversarial Robustness in Medical LLMs](https://mlsanity.com/paper/2505.11413/) (2025)
- [Robust Hallucination Detection in LLMs via Adaptive Token Selection](https://mlsanity.com/paper/2504.07863/) (2025)
- [Do LLM Agents Know How to Ground, Recover, and Assess? A Benchmark for Epistemic Competence in Information-Seeking Agents](https://mlsanity.com/paper/2509.22391/) (2025)
- [WebGraphEval: Multi-Turn Trajectory Evaluation for Web Agents using Graph Representation](https://mlsanity.com/paper/2510.19205/) (2025)

## Abstract (arXiv)

Autonomous web agents are increasingly deployed in moderation and policy enforcement, where correct decisions often depend on evidence that is not immediately visible and must be actively investigated. Yet existing benchmarks largely assume task critical information is immediately accessible. They do not measure investigative competence: recognizing when visible context is insufficient, retrieving hidden evidence, and integrating it into a final decision. We introduce MIRAGE, a benchmark of 750 multi step decision tasks across three domains: Wikipedia Forensics, Shopping Admin adjudication, and Reddit Moderation. Each task has two layers: a visible surface context that often points to the wrong action, and a hidden context, reachable only by active investigation, that contains the decisive evidence. We decompose agent performance into Investigation, Reasoning, and Decision Accuracy, complemented by an Investigative Hallucination Rate. We evaluate eight LLM agents across two model generations. Three patterns emerge. First, agents reach relevant pages but rarely extract the decisive evidence on them. Second, procedural hints improve investigation but do not consistently improve decisions on Wikipedia tasks, where decisive evidence often contradicts surface impressions. Third, 12.6% of trajectories cite fabricated facts. We call these the Navigation Discovery Gap, Collapse under Contradiction, and Investigative Hallucination. These patterns persist across model scale, generation, and reasoning architecture.