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Codex

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23jmo
codex

Hand off a scoped implementation, code review, or technical second opinion to the OpenAI Codex CLI from Claude Code. Use when the user asks to delegate work to Codex or get an independent review.

Overview

Publisher23jmo
Repositoryjmo-skills
Skill namecodex
Stars
139
Forks
12
Bundled files
Instructions only
LicenseMIT
Links
  • Markdown instructions

    A SKILL.md file the model loads on demand, so it only costs tokens when a request actually matches.

  • Works with any LLM

    AI skills are plain Markdown, not provider-specific code, so this works with GPT, Claude, Gemini, Grok, or a local model.

  • Self-contained

    Everything the model needs lives in the instructions — no extra files to sync.

  • Open source

    Published by 23jmo on GitHub. Read the source before you install it.

Installation

Install the Codex AI skill in TypingMind to use it with any LLM, or drop it into another agent that reads SKILL.md.

1

Install in TypingMind

TypingMind installs a skill straight from its GitHub folder — it reads SKILL.md, bundles the resource files, and stores the result locally.

  1. Open the app and go to Plugins → Skills.
  2. Choose "Install from GitHub".
  3. Paste the skill folder URL below and confirm.
    https://github.com/23jmo/jmo-skills/tree/main/skills/codex
  4. Enable the skill in any chat where you want it available.
Plugins → Skills → Add skill → From GitHub URL, then paste the folder URL and press Continue.
2

Install in another agent

Any agent that reads the Agent Skills format can use this skill — copy the folder into that agent's skills directory.

Claude Code — .claude/skills
git clone --depth 1 https://github.com/23jmo/jmo-skills.git /tmp/jmo-skills
mkdir -p .claude/skills
cp -r /tmp/jmo-skills/skills/codex .claude/skills/codex
Restart Claude Code after copying so it picks up the new skill.

Use it in TypingMind

Enable Codex in any TypingMind chat and the model takes it from there. Its name and description sit in the system prompt, and the moment a request matches, the model loads the full instructions itself — you never invoke it by hand, and it costs no tokens until it is actually used.

The model loads Codex on its own as soon as a request matches it.

Works with any AI model

AI skills are plain Markdown instructions rather than provider-specific code, so Codex is not tied to the model it was written for. Install it once in TypingMind and use it with GPT-5, Claude, Gemini, Grok, DeepSeek, Mistral, Llama, or a local model you run yourself — all on your own API keys.

  • Loaded only when it is needed

    The system prompt carries just the name and description. The instructions are fetched on the first matching request, so an idle skill costs nothing.

  • Switch models mid-chat

    Because the skill is instructions rather than code, changing model does not break it — the next model reads the same SKILL.md.

Skill instructions

This is the SKILL.md content the model loads. Read it before installing — a skill is instructions your model will follow.

Codex handoff

This is JMO's standalone handoff skill. It is not gstack's /codex skill and does not require gstack.

Prepare the task

  1. Check command -v codex and codex exec --help. If missing, direct the user to https://developers.openai.com/codex/cli/ and explain that they must install and sign in to Codex. Do not claim a handoff ran when the CLI is unavailable.
  2. Read the repository instructions and inspect git status --short. Identify the working directory, requested mode (review, advice, or implementation), allowed files, and acceptance criteria. Default to read-only review when the request does not authorize edits.
  3. Write a focused prompt containing the user's task, relevant paths, constraints, and required checks. Include enough context for a separate agent without passing credentials or unrelated private material. Tell Codex which files are already modified and to preserve those changes.

Run Codex

Use the user's configured model. Pass the prompt through stdin or a quoted heredoc, not interpolated shell text. Replace the example directory with the actual absolute project path:

sh
codex exec --sandbox read-only --cd '/absolute/project/path' - <<'TASK'
Review the specified changes. Do not edit files. Report actionable findings with file locations, evidence, and uncertainty. Follow the repository's instructions.
TASK

For an authorized implementation, use --sandbox workspace-write and a prompt with the exact task, allowed files, and verification criteria. Do not use flags that bypass approvals or sandboxing. If the task cannot run within the current permissions, report that limitation.

Wait for completion and read the exit status and output. Do not let Claude and Codex edit the same files concurrently. For parallel work, use separate worktrees and explicit file ownership; integrate only after reviewing the resulting changes.

Verify and report

For a review, inspect the cited code and assess each finding before presenting it as confirmed. For implementation, inspect the diff and run the relevant checks. Report what Codex changed or found, what was verified, and any remaining failures. Do not automatically commit, push, or deploy unless that is part of the user's task.

Task: $ARGUMENTS

Frequently asked questions

What does the Codex AI skill do?

Hand off a scoped implementation, code review, or technical second opinion to the OpenAI Codex CLI from Claude Code. Use when the user asks to delegate work to Codex or get an independent review.

Why use Codex on TypingMind?

Because you install it once and use it with any model. Codex is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Codex in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/23jmo/jmo-skills/tree/main/skills/codex. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use Codex?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Codex?

As many as you like. As long as a model supports skills, you can use Codex with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Codex AI skill free?

Yes. It is published on GitHub by 23jmo under the MIT license. You only pay your own AI provider for the tokens you use.

What are AI skills?

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

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