GPT-6 Astra beat Portal start to finish without human help in under 24 hours
Developer cozyblaze ran GPT-6 Astra through the full game Portal unaided in 23h43m using MCP-based control tooling.
A developer reported on X that OpenAI's GPT-6 Astra model completed the entire game Portal without human help, reaching the credits in about 23 hours and 43 minutes. The agent controlled the game via MCP and a modified SourcePauseTool that paused gameplay while the model reviewed screenshots and picked inputs. Token costs would total at least $570 at list price, though the run used a $200 Codex subscription. Code and documentation were published on GitHub.
- Run completed in roughly 23 hours 43 minutes without human intervention.
- Agent used MCP plus a SourcePauseTool mod that pauses the game during reasoning.
- Unmodified pricing would cost about $570 in tokens; a $200 Codex subscription was used instead.
- Code and docs available on GitHub; echoes OpenAI's 2016 general-game-agent goal.
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Sep 7, 2026
GPT-6 Astra has played through all of Portal on its own. Developer cozyblaze posted on X that the model navigated the full game and reached the credits without any human help after the initial goal was set. The run took about 23 hours and 43 minutes. Token usage adds up to at least $570 at Astra's list price, though cozyblaze used a $200 Codex subscription. The model controls Portal through MCP and a modified SourcePauseTool that pauses the game while it thinks. During each pause, the agent sees screenshots, player position, and camera angle, picks its inputs, then lets the game resume. The video below has those pauses cut out.
Code and docs are on GitHub. Cozyblaze noted that OpenAI set a goal in 2016 to solve many different games with a single agent. Problems remain, but watching an agent beat a full game on its own is a small taste of that original vision. GPT-6 Astra is "the worst model we'll ever get," cozyblaze added.
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