Context Matters: Testing Evidence for Multi-Agent Collusion
Yupeng
Submitted to AI Collusion Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.
What behavioral evidence distinguishes programmed coordination from unilateral misuse of an agent workflow? We construct 48 executable two-role controls spanning six policies, including legitimate cooperation, availability gates, content-dependent unilateral attacks and authorized partial release. A programmed coordination pair and an innocent-sender/malicious-receiver pair have identical observations under baseline, channel removal, content changes, shams and one source perturbation. A further source intervention preserving the authorized public feature separates this witness. On the selected scripted panel, harmful-outcome and removal predicates flag 24 of 40 negative controls; receiver-content and broad-source tests flag 16 and eight, respectively, while the feature-preserving test flags none. We then execute 96 assigned-policy episodes with local Qwen2.5-1.5B-Instruct and Dolos-1.5B, preserving 864 actor decisions. Schema validity is high, but original sender-policy conformance is only 11/48 and 7/48, and each model realizes the original two-step positive control in only 3/8 assigned cases. This demonstrates why policy instructions cannot stand in for behavioral labels. We retain invalid outputs as abstentions, report finite-panel bounds, and add a separately labeled scripted-sender calibration. The result is a reproducible stress test of evidence claims, not a universal collusion detector or evidence of spontaneous model intent. Stronger causal controls establish a more specific influence pattern, but agreement and authorization assumptions remain necessary.
Reviews
The exceptional approach here is the indistinguishability witness: a programmed-coordination case and a benign unilateral-misuse case that are byte-indistinguishable until an authorization-preserving source test separates them. This is a clear demonstration that a bad result, sensitivity to channel deletion, and dependence on content are individually poor evidence, and the declassification/information flow approach transfers well to this case.
Cite this project
@misc{yupeng2026context,
title = {{Context Matters: Testing Evidence for Multi-Agent Collusion}},
author = {Yupeng},
year = {2026},
month = oct,
note = {Submitted to AI Collusion Research Sprint, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/context-matters-testing-evidence-for-multiagent-collusion-n7wg}},
url = {https://apartresearch.com/sprints/projects/context-matters-testing-evidence-for-multiagent-collusion-n7wg}
}More from AI Collusion Research Sprint
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