A Codex plugin bundles skills, MCP servers and hooks into one install, added with /plugins in the CLI or codex plugin add <plugin>@<marketplace>. The Codex plugin for Claude Code is something else: OpenAI's plugin that runs Codex inside Claude Code (October 2026).
OpenAI's docs describe plugins as reusable workflows for ChatGPT and Codex, packaged for install. A plugin can carry:
Skills: SKILL.md instructions Codex picks when a request matches, or you run as $skill-name.
MCP servers, which connect Codex to outside tools and can bring their own UI.
Hooks that run at fixed points in a session, such as SessionStart or PreToolUse, the same idea as Claude Code hooks.
Browser extensions, and apps mapped to MCP servers in an .app.json file.
Skill, plugin or AGENTS.md?
OpenAI's rule of thumb: use a skill for reusable instructions for a focused task, and a plugin when you want an installable package that combines instructions with connected services or other tools. AGENTS.md is not part of a plugin. It stays in the repository, where Codex reads it on every run, so keep it to the rules every task needs.
How to install and manage Codex plugins
Plugins run in Codex in the ChatGPT desktop app and in the Codex CLI. The IDE extension doesn't support them.
In the CLI, /plugins opens the plugin browser. Space turns an installed plugin on or off; start a new session before you use its skills or tools.
In the ChatGPT desktop app, the Plugins tab shows the same catalog.
From a shell, codex plugin add <plugin>@<marketplace> installs one and codex plugin list shows what you have.
Per repository, .codex/config.toml can turn a plugin on or off with an enabled flag under [plugins."<plugin>@<marketplace>"]. Your own choices go in ~/.codex/config.toml.
How to build a Codex plugin
A plugin is a folder with a manifest. New packages put a plugin.json at the root, written to the shared agent-plugins.org schema: a kebab-case name, a version, a description, the author, homepage, repository, license and keywords. Anything only OpenAI reads goes under extensions.com.openai: the apps, the hooks file, and the interface ChatGPT shows, from the display name and category to the logo and a default prompt.
Older plugins keep their manifest at .codex-plugin/plugin.json, which Codex still reads, and OpenAI also accepts Claude-compatible manifests. Once installed, a plugin's files sit in ~/.codex/plugins/cache/<marketplace>/<plugin>/<version>/, where a plugin from a local folder gets local as its version.
The Codex plugin marketplace
ChatGPT and Codex share one public plugin catalog, with a tab for plugins built by OpenAI, one for your workspace and one for your own. OpenAI's curated marketplace is named openai-curated, and a plugin gets into the public catalog through OpenAI's submission portal.
Any Git repository can be a marketplace. Add one with codex plugin marketplace add <owner/repo> --ref main, and codex plugin marketplace upgrade pulls its newest versions. Workspace admins can import a GitHub marketplace for everyone, synced daily.
To publish your own, put a marketplace.json in the repository's .agents/plugins/ folder. It names the marketplace and lists each plugin with its source (a local path, a Git repository or subfolder at a ref, or an npm package) and an install policy: available, installed by default, or not available. Codex also reads a Claude Code-style .claude-plugin/marketplace.json, so one repository can serve both tools' plugin users.
The Codex plugin for Claude Code
OpenAI publishes a plugin for Claude Code, not for Codex: openai/codex-plugin-cc on GitHub, released March 30, 2026 under Apache-2.0. Its own description is “Use Codex from Claude Code to review code or delegate tasks.” It drives your local Codex CLI, so the work counts against your ChatGPT plan or OpenAI API key, not your Claude plan.
/codex:review runs a read-only Codex review, and /codex:adversarial-review a steerable one that challenges the change.
/codex:rescue hands a task to Codex, and /codex:status, /codex:result and /codex:cancel manage the background jobs.
Install it in Claude Code with /plugin marketplace add openai/codex-plugin-cc, then /plugin install codex@openai-codex, /reload-plugins and /codex:setup, which checks for the Codex CLI and can install it.
It needs a ChatGPT subscription, the free one included, or an OpenAI API key, and Node.js 18.18 or later.
A Codex plugin you can read: Zest
Zest's Codex plugin shows the parts working together. Its manifest points at three things: a skills folder, a hooks file and a local MCP server that Codex starts over stdio. In October 2026 it ships 16 skills, such as login, sync and standup; each tells Codex to call one tool on that server, and two hooks, on SessionStart and UserPromptSubmit, refresh the login.
It installs from its own Git marketplace; the full sequence is in the Codex plugin docs. Once you log in, it reads an allowlisted set of session files under ~/.codex, filters them for privacy on your machine and syncs each session's model, tokens, skills and MCP tools, on demand or in the background, which Zest joins to the pull requests they led to. More in Codex usage.
TRY IT ON YOUR TEAM
See what your team ships with AI.
Starter is free (3 seats, no credit card). Pro is $49 a month with 5 seats and Max is $149 a month with 10 seats — priced per workspace, not per engineer, with extra seats at $19 a month.
Run codex plugin remove <plugin>@<marketplace>, which removes it from your local config and cache, or press Space on it in /plugins to turn it off and keep it installed.
Can a Claude Code plugin run in Codex?+
Partly. Codex accepts Claude-compatible plugin manifests and reads a .claude-plugin/marketplace.json, and skills share the SKILL.md format. Test a plugin's hooks and MCP servers in Codex before you rely on them.
