Codex agent builds Minecraft roller coaster with Mythos

// 1h agoNEWS

Codex agent builds Minecraft roller coaster with Mythos

Developer @givros demonstrated an impressive agentic workflow using OpenAI's Codex coding platform and the newly released Claude Fable 5 (Mythos) model to autonomously generate a playable Minecraft-style roller coaster. By utilizing Codex's persistent `/goal` command with the prompt "Build a Minecraft-style roller coaster," the autonomous coding agent executed a complete plan-act-test loop to write the necessary code and build a functional, buildable demo, highlighting the powerful combination of Mythos-class reasoning and agentic execution.

// ANALYSIS

Hot take: Goal-driven agent loops are rendering manual step-by-step prompting obsolete by turning vague, high-level ideas into buildable software autonomously.

–Persistent Agent Execution: The `/goal` command showcases the transition of AI from simple chat assistants to autonomous developers that run plan-act-test loops.
–Model Synergy: Claude Fable 5 (Mythos) provides the high-level reasoning and vision to make the demo look fun, while Codex's execution harness ensures the code compiles and runs.
–Vibe Coding to Reality: This project shows that vibe coding has advanced from simple UI mockups to complex, structured interactive systems like virtual roller coasters.

// TAGS

codexclaude-fable-5mythosagentai-codingminecraftgame-development

DISCOVERED

1h ago

2026-06-09

PUBLISHED

2h ago

2026-06-09

RELEVANCE

8/ 10

AUTHOR

givros

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