arXiv AI

Rome Wasn't Built in One Turn: Replay-Grounded Reward Signals for Long-Horizon Freeciv Agents

The paper introduces CivHarness, a system that records game states in Freeciv and replays them to generate long‑horizon reward signals, addressing the problem of sparse deterministic feedback in strategy games. Using CivHarness, the authors train CivTelescope, an LLM judge that predicts which of two positions will lead to a better outcome, outperforming standard language models on scoreboard‑trap pairs. They then employ CivTelescope as a dense reward in a Freeciv agent, CivMarshmallow, achieving significantly higher training gains and outperforming other reward schemes across the full game.

arXiv AI
Sep 17

Compiled Agency: Frontier General-Purpose Coding Agents Build Winning Game Players from Bare Interaction - from Flappy Bird to StarCraft II and Civilization

The paper introduces Gauntlet, a framework that lets large language models autonomously build game-playing agents from a bare contract—just a game description, raw observation/action interface, and an empty policy file. In a single session, the model experiments with the game, compiles a standalone controller, and the resulting program is evaluated on held‑out instances without further model calls. The authors demonstrate that these compiled agents can win full‑scale games such as StarCraft II and Civilization, marking the first time a language‑agent system has achieved standalone victory in such complex titles.

By Joey Xiao, Haonan Huang
arXiv AI
Sep 3

CivBench: A Long-Horizon Benchmark for Tool-Mediated Agents in Civilization VI

CivBench is an open‑source benchmark that evaluates language‑model agents in the long‑horizon, tool‑mediated game Civilization VI using the Model Context Protocol (MCP). Each episode lasts over 300 turns, generating thousands of tool calls across a 76‑tool action space, and includes a narration layer that translates visual game state into structured text. The study characterises agent behaviour across four model families, introducing Proactive Monitoring Rate (PMR) and RAG@10 as interface‑level metrics, and finds that agents often under‑monitor strategic state and fail to execute near‑term commitments despite tool access and explicit guidance.

By Austin Tudor David Andrews, Liam Wilkinson, Jamie Heagerty, Harry Coppock, Jakob Nicolaus Foerster, Rui Ponte Costa
arXiv AI
Jul 17

SAGA: Scene-Aware, Goal-Evolving Agents for Long-Horizon Strategy Game Planning

arXiv:2606. 29932v3 Announce Type: replace Abstract: Long-horizon strategic planning in complex strategy games requires coordinating tightly coupled decision domains, including technology, economy, diplomacy, and military, across hundreds of turns under imperfect information.

By Tianyu Jin, Shuo Chen, Yida Wang, Liuyu Xiang, Yingzhuo Liu, Zhiyao Jiang, Yexin Li, Peipei Li, Zhaofeng He
arXiv AI
Oct 7

Learning in Dreams, Winning in Reality: A Continuous Dyna Loop for a Ten-Hero MOBA

The paper presents a continuous Dyna loop that trains a multi‑agent world model for a ten‑hero MOBA game and evaluates the resulting policy in the real game. By using imagined episodes and real‑game data to continuously refine the model, the policy achieves a 70.2% win rate as radiant on unseen seeds, a dramatic improvement over dream‑only training. The study highlights that internal dream metrics can miss model exploitation, that the world model must be repaired on the policy’s own games, and that the policy’s success stems from macro‑level pressure rather than precise micro‑tactics.

By Jordy Kieto
arXiv AI
Oct 31

Predict the Reward, Not the World: World Reward Models for ML Agents

The paper introduces World Reward Models (WRMs), a new approach for machine‑learning agents that selects the best candidate program directly from execution results instead of predicting intermediate outcomes. WRMs, exemplified by the ForeCritic model, are trained on thousands of executed program pairs and achieve a 79.4% success rate in choosing the better program, outperforming general‑purpose LLM judges. When integrated into systems like AIDE, ML‑Master, and ForeAgent, ForeCritic reduces mean task time by 4.4–7.5× while maintaining or improving overall performance.

By Yuxiao Lee, Zherui Yang, Fan Liu, Hao Liu
arXiv Machine Learning
Aug 28

Shared Actors Need Not Share Critics: Effects of Value Mismatch in Parallel Reinforcement Learning

The paper investigates the problem of sharing a single critic across multiple parallel environments in reinforcement learning. It shows that when environments assign different expected returns to the same state, a shared critic must reconcile conflicting value targets, which can distort advantage estimates and misguide policy updates. The authors propose a simple fix—providing the critic with the environment index—demonstrating through bandit models and experiments on CartPole, MuJoCo, BipedalWalker, and 16 Procgen games that this conditional critic stabilizes learning and boosts returns, achieving a 40.8% improvement in aggregate normalized return on unseen levels.

By Zhenya Liu, Yang Meng, Zhuokai Zhao, Xuefeng Liu, Yuxin Chen