#Resources

#Official documentation

#Open source

• Codex CLI (Rust): https://github.com/openai/codex
• System prompt reference: https://github.com/openai/codex/blob/main/codex-rs/core/prompt.md

#Open standards

• AGENTS.md spec and ecosystem: https://agents.md/
• Agent Skills standard: shared SKILL.md format with Claude Code, Cursor, and others

#Product announcements

• Introducing Codex — Cloud agent and codex-1 model
• Codex quotas in ChatGPT plans: see OpenAI pricing pages

#Related chapters in this tutorial

• Concepts: Architecture & Runtime
• Team rules: AGENTS.md
• Safety: Sandbox & Security

#Other tutorials on this site

• Claude Code tutorial — compare another mainstream CLI agent’s config and Skills
• Git tutorial — checkpoints and PR workflows
• Docker tutorial — isolated environments for high-privilege agents

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Version note: Codex evolves quickly. Install commands, model names, and feature flags follow official docs. This tutorial reflects 2025–2026 public documentation.