It manages iterative development, architectural design, and code reviews through a persistent tmux session.

Install

mkdir -p .claude/skills/codex && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/18" && unzip -o skill.zip -d .claude/skills/codex && rm skill.zip

Installs to .claude/skills/codex

Activation

This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.

This skill should be used when the user asks to "use codex", "ask codex", "run codex", "call codex", "codex cli", or explicitly asks to delegate work to a frontier reasoning model (e.g., "have GPT-5 review this", "get the OpenAI reasoning model to design X", "ask the high-reasoning model"). Also triggers on "continue codex" / "resume the codex session" for iterative development. Do NOT trigger when the user is merely discussing GPT-5 / OpenAI reasoning as a topic, or asking Claude itself to do complex implementation / architecture / review work without naming codex or a frontier reasoning model.
602 chars✓ has a “when” triggerlonger than Claude Code's old 250-char listing cap (fine on current versions)
Advanced

Key capabilities

  • Spawn long-lived tmux coding sessions
  • Manage iterative backend architecture refinement
  • Perform complex codebase reasoning tasks
  • Resume previous reasoning sessions

How it works

Spawns a persistent tmux session to allow the AI to maintain state and perform iterative work on complex logic.

Inputs & outputs

You give it
Complex coding prompt or architecture task
You get back
Iterative code blocks and design analysis

When to use codex

  • Complex backend architecture design
  • Iterative implementation of difficult features
  • High-reasoning code reviews
  • Refactoring legacy code bases

About codex

Integrates an advanced reasoning model via a long-lived tmux session. It manages iterative development sessions, complex architecture design, and high-level code reviews.

Invoke Codex CLI for complex coding tasks requiring high reasoning capabilities. This skill should be invoked when users explicitly mention "Codex", request complex implementation challenges, advanced reasoning, or need high-reasoning model assistance. Automatically triggers on codex-related requests and supports session continuation for iterative development.

When not to use it

  • Simple code snippets
  • One-off tasks requiring no iteration
  • Explicitly requested 'fire and forget' tasks

Prerequisites

Tmux installedOpenAI reasoning model access

Limitations

  • Requires active session management
  • Overkill for simple syntax fixes

How it compares

Enables multi-turn, stateful development sessions rather than single-prompt code generation.

Compared to similar skills

codex side by side with the closest alternatives in the catalog.

SkillInstallsUpdatedSafetyDifficulty
codex (this skill)322moReviewAdvanced
senior-fullstack357moReviewIntermediate
codex-claude-cursor-loop39moReviewAdvanced
consult-codex22moReviewAdvanced

Try saying

Example prompts that trigger this skill in your AI assistant.

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