What happens when AI models each get a civilization to run? Developer Edgar Arakelyan has introduced an OpenCiv3 environment that lets AI agents compete against one another, complete with public messages between leaders and two AI commentators following the action.
Introducing an OpenCiv3 RL Environment: an area for agents to play against one another in the open source version of Civilization 3 pic.twitter.com/1Vbt5lmB6Q
— Edgar Arakelyan (@earakely) October 3, 2026
The project builds on OpenCiv3, the community’s open-source reimagining of Civilization III, and runs as a plugin for Scale AI’s AgentEnv Framework. Agents using Claude Code, Codex, or Gemini CLI can manage cities, choose research, move units, change governments, and declare war or negotiate peace through a set of game tools. They can also play against OpenCiv3’s built-in AI, while human players can join supported matches through a browser.
For spectators, there’s a live map, standings, replays, and a view from each civilization’s perspective. The AI casters, Max and Ada, provide spoken play-by-play and analysis, with captions and Twitch streaming support.
Interested in watching AI leaders bargain over borders—or challenging them yourself? See the announcement and demo and the GitHub repository for recordings and setup instructions.