StratFormer: Adaptive Opponent Modeling and Exploitation in Imperfect-Information Games

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Caen, Andy, Winands, Mark H. M., Soemers, Dennis J. N. J.
Natura: Preprint
Pubblicazione: 2026
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866910174637195264
author Caen, Andy
Winands, Mark H. M.
Soemers, Dennis J. N. J.
author_facet Caen, Andy
Winands, Mark H. M.
Soemers, Dennis J. N. J.
contents We present StratFormer, a transformer-based meta-agent that learns to simultaneously model and exploit opponents in imperfect-information games through a two-phase curriculum. The first phase trains an opponent modeling head to identify behavioral patterns from action histories while the agent plays a game-theoretic optimal (GTO) policy. The second phase progressively shifts the policy toward best-response (BR) exploitation, guided by a per-opponent regularization schedule tied to exploitability. Our architecture introduces dual-turn tokens -- feature vectors constructed at both agent and opponent decision points -- coupled with bucket-rate features that encode opponent tendencies across five strategic contexts. On Leduc Hold'em, a small poker variant with six cards and two betting rounds, we test against six opponent archetypes at two strength levels each, with exploitability ranging from 0.15 to 1.26 Big Blinds (BB) per hand. StratFormer achieves an average exploitation gain of +0.106 BB per hand over GTO, with peak gains of +0.821 against highly exploitable opponents, while maintaining near-equilibrium safety.
format Preprint
id arxiv_https___arxiv_org_abs_2604_25796
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle StratFormer: Adaptive Opponent Modeling and Exploitation in Imperfect-Information Games
Caen, Andy
Winands, Mark H. M.
Soemers, Dennis J. N. J.
Artificial Intelligence
We present StratFormer, a transformer-based meta-agent that learns to simultaneously model and exploit opponents in imperfect-information games through a two-phase curriculum. The first phase trains an opponent modeling head to identify behavioral patterns from action histories while the agent plays a game-theoretic optimal (GTO) policy. The second phase progressively shifts the policy toward best-response (BR) exploitation, guided by a per-opponent regularization schedule tied to exploitability. Our architecture introduces dual-turn tokens -- feature vectors constructed at both agent and opponent decision points -- coupled with bucket-rate features that encode opponent tendencies across five strategic contexts. On Leduc Hold'em, a small poker variant with six cards and two betting rounds, we test against six opponent archetypes at two strength levels each, with exploitability ranging from 0.15 to 1.26 Big Blinds (BB) per hand. StratFormer achieves an average exploitation gain of +0.106 BB per hand over GTO, with peak gains of +0.821 against highly exploitable opponents, while maintaining near-equilibrium safety.
title StratFormer: Adaptive Opponent Modeling and Exploitation in Imperfect-Information Games
topic Artificial Intelligence
url https://arxiv.org/abs/2604.25796