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OpenAI / ChatGPT Guide Hub

Codex CLI Overview and Quick Start (ChatGPT Integration)

This page serves as an introductory supplement to the "OpenAI Codex CLI Comprehensive Guide". First, grasp the overall picture with the comprehensive guide, then use this page for the quickest introduction and hands-on experience.

What's Great About It (Key Points)

  • Simple UX: Execute "planning → editing → validation" consistently in the terminal. Changes are applied explicitly and safely with apply_patch.
  • Context Visibility: Context size, token usage, execution logs, etc., are always visible and controllable.
  • Cost Benefits: When using ChatGPT plan integration, no additional API charges apply (usage limits and fair use follow contract terms).
  • Safe Operation: Network or privilege escalation requires explicit consent, preventing accidental breaches or leaks.

Main Features

  • Plan-Driven: TODO decomposition, sequential execution, and progress visualization via update_plan.
  • Patch Application: Apply only diffs with apply_patch. Easy rollback and review.
  • Verification-Oriented: Reliably track necessary shell commands like testing, building, and static analysis.

Installation and Quick Execution (Example)

Steps may vary by environment. After following official installation instructions, enable ChatGPT integration.

# 1) Launch from project root
codex               # First time requires browser authentication (ChatGPT or API key)

# 2) Status confirmation and plan creation
#   Example: "Improve README and add build instructions"

# 3) Diff application flow
#   - Codex proposes apply_patch → confirm and apply
#   - Run test/build if necessary (with approval flow)

Example Experience Prompt

Add "Setup/Build/Test" instructions to this repository's README,
and clearly document mkdocs build commands. Keep patches minimal
and show diffs before applying.

Frequently Asked Questions

  • Q: Is an API key unnecessary?
  • A: With ChatGPT plan integration, no API charges occur (but limits, rates, and commercial terms follow your contract). For API connection, a separate key is required.
  • Q: Does it conflict with existing CLI or editors?
  • A: Compatible with existing tools. Codex CLI serves as a supplementary tool to accelerate "design, refactoring, and validation."

Usage Tips

  • Start Small: Work in 1-commit-sized increments → validation → next change.
  • Transparency: Put important operations (deletion/overwrite/force push) through explicit approval flows.
  • Learn from Failure: Use failure logs and diffs to update plans and achieve reproduction → fix → validation end-to-end.
  • Related: Codex vs Claude Code (Comparison) / Best Practices