Ryan Madden · 2026-10-31 · notable
GPT-5.6 Sol beats Factorio — a rocket launch on peaceful mode
GPT-5.6 Sol, running in Codex at a low thinking level, launched a rocket in Factorio on peaceful mode in 13.5 hours of game time. Ryan Madden's harness gives it the same reach and fog-of-war limits a human player has.
An OpenAI model plays Factorio through code and finishes the game with a rocket launch.
What is it?
Ryan Madden reports that GPT-5.6 Sol beat Factorio on peaceful mode (no biters), launching a rocket after 13.5 hours of game time. The model ran inside Codex with a low thinking level.
How does it work?
A game manager and a small Python library let the model play the game through code instead of the mouse. The library keeps the same limits a human GUI player has, such as player reach and fog of war. Madden notes the run needed a lot of manual work from the model, which carried supplies by hand between parts of the factory that were never connected.
Why does it matter?
Factorio needs hours of planning, building and fixing, so it is a hard long-horizon test for agents. Madden says the run is a clear step up from his earlier GPT-5.5 attempts, which struggled to use transport belts at all.
Who is it for?
people building or evaluating long-running agents