UNDERCOVER-Bench: Trusted agents and private-channel collusion
Amey Muke, Sanchayan Ghosh, Prasad Mahadik · Team Titans
Submitted to AI Collusion Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.
UNDERCOVER-Bench investigates Apart Track 3.2: can trusted undercover agents expose or disrupt collusion between language-model agents? We built Secret Hitler and Liar’s Bar evaluation environments with four model families, private communication tools and a character-trained GLM auditor. Recorded games revealed an accepted GLM–Qwen channel with 20 private messages and identical votes across 10 elections. Under an explicit communication ban, models attempted prohibited contact; in a fictional-background condition, the character-trained auditor itself accepted a banned channel and participated while describing its coordination as public. In a nine-decision trusted-sender screen, recipients rejected all six prohibited offers, while only one accepted benign cooperation. Character training changed a reporting decision but did not establish a general reliability improvement. Invalid game outcomes were excluded from efficacy comparisons. These exploratory findings document private coordination, attempted collusion and failures of the intended trusted agent, without demonstrating successful disruption. RLCR is implemented in code; collective-training experiments remain future work.

Reviews
This project asks a fair question, can a trusted undercover agent expose or break up a colluding pair, and it is honest that it only got part way. The auditor missed a private channel that carried multiple messages and multiple matched votes, and given a fictional background it joined a banned channel itself. Several runs were thrown out for invalid actions and the planned training experiment never ran, so most claims stay at pilot level. The clear lesson is that logging adoption is not the same as disrupting a coalition.
Cite this project
@misc{muke2026undercoverbench,
title = {{UNDERCOVER-Bench: Trusted agents and private-channel collusion}},
author = {Amey Muke and Sanchayan Ghosh and Prasad Mahadik},
year = {2026},
month = oct,
note = {Submitted to AI Collusion Research Sprint, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/undercoverbench-trusted-agents-and-privatechannel-collusion-ib84}},
url = {https://apartresearch.com/sprints/projects/undercoverbench-trusted-agents-and-privatechannel-collusion-ib84}
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