Extending Information-Theoretic Collusion Detection to Large Language Model Agents
Govindh Kishore · Team Gamma Ray
Submitted to AI Collusion Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.
We test whether the information-theoretic collusion detector of Bonjour et al, validated on scripted agents, works on LLM agents. Gemma, Mistral and Qwen played 1000 rounds of three-player Rock-Paper-Scissors in three model configurations. With no collusion instruction, no pair was flagged at the paper’s fixed threshold α = 0.05. We then instructed Player 3 to help Player 2 through a shared hidden variable: each round a random character c is drawn, Player 2 plays c, and Player 3 plays the move that c defeats. The fixed threshold flagged the colluding pair in only one of three configurations, while the net influence of that pair varied widely (1.03, 0.10, 0.39). We therefore calibrate α per configuration with a within-state shuffle method. Scores above this null’s 99th percentile are treated as evidence of collusion.
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@misc{kishore2026extending,
title = {{Extending Information-Theoretic Collusion Detection to Large Language Model Agents}},
author = {Govindh Kishore},
year = {2026},
month = oct,
note = {Submitted to AI Collusion Research Sprint, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/extending-informationtheoretic-collusion-detection-to-large-language-model-agents-2zrn}},
url = {https://apartresearch.com/sprints/projects/extending-informationtheoretic-collusion-detection-to-large-language-model-agents-2zrn}
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