Dodging Proteus: Data and materials

Data for the Protean Adversarial Choice Assay (PACA), in which seven language models each played 200-trial matching pennies against Proteus, an adaptive opponent drawn from macaque decision neuroscience that detects and exploits statistical regularities in a player's choices. Models played under a minimalist prompt stating only the objective and an informed prompt that named the game, described the exploitative opponent, and prescribed equilibrium play. Six of the seven won less often under the informed prompt. This project holds the full session corpus (98 main, 238 supplemental, and 56 counterbalanced replication sessions), the compiled workbook, and the reasoning-trace audit package. Preprint: https://doi.org/10.5281/zenodo.21781962 Code: https://github.com/chimpanzity/dodging-proteus