Verified
Install Agent Plugins in Codex
Install a plugin in Codex CLI by running /plugins, choosing a marketplace tab, and selecting the plugin. Start a new session before its skills or tools become available. The Codex IDE extension does not support plugins. Codex and ChatGPT share one plugins directory that OpenAI reviews before publication.
Install in Codex CLI
Run /plugins to open the plugin browser. OpenAI's plugins documentation describes the flow: "Install a plugin from a configured marketplace, then start a new session before using its bundled skills or tools."
The browser groups plugins by marketplace. Use the marketplace tabs to switch sources, open a plugin to inspect its details, and install or toggle it. To remove one, reopen it from a supported plugin browser and select Uninstall plugin. That action can be missing when a workspace controls the plugin centrally.
Install in the Codex desktop app
Select Codex, then open Plugins to browse and install.
The IDE extension does not support plugins
OpenAI's documentation states it without qualification: "Plugins aren't available in the IDE extension." Skills, connectors, and MCP servers all sit outside that surface. If you work primarily in the Codex extension, plugin components have to come through the CLI or the desktop app.
What each Codex surface supports
| Surface | Skills | Connectors | MCP servers | Browser extensions |
|---|---|---|---|---|
| Codex CLI | Yes | Yes | Yes | No |
| Codex IDE extension | Not available | Not available | Not available | Not available |
OpenAI's support table covers the CLI and the IDE extension. The desktop app has a documented install flow but no published component breakdown, so nothing is claimed for it here.
For MCP transports, the spec's compatible clients page lists ChatGPT and Codex together, supporting stdio and Streamable HTTP. Legacy HTTP+SSE is absent, and this is the only client entry where it is. A plugin declaring an sse server in mcp.json will lose that server here while its skills keep loading, because the spec requires clients to isolate a failure to the component that caused it.
Where the standard and OpenAI's docs diverge
OpenAI co-authors the Agent Plugins specification and sits on its Technical Steering Committee, and the spec links developers.openai.com/plugins as the setup instructions for ChatGPT and Codex.
The packaging docs there describe something different from the portable format. As of 2026-08-07, OpenAI's packaging guide names .codex-plugin/plugin.json as "the required entry point" and instructs authors: "Only plugin.json belongs in .codex-plugin/. Keep skills/, hooks/, assets/, .mcp.json, and .app.json at the plugin root." That is a nested manifest and a dot-prefixed .mcp.json, where the standard specifies a root plugin.json and a root mcp.json. Neither that page nor the plugins reference mentions agent-plugins.org or the 1.0.0 schema URL.
Take the practical reading: a plugin published through OpenAI's directory works in Codex, and the specification records Codex as loading portable skills and MCP servers. How a root plugin.json from a GitHub repository is meant to reach Codex is not documented publicly yet.
Getting a plugin into Codex today
Codex installs from configured marketplaces rather than from an arbitrary Git URL. OpenAI documents two marketplace files for authoring and testing before public release: a repository marketplace at $REPO_ROOT/.agents/plugins/marketplace.json and a personal one at ~/.agents/plugins/marketplace.json.
Public distribution runs through review. From the submission docs: "Submit the plugin through the plugin submission portal. OpenAI reviews the submission. After OpenAI approves the plugin, the developer chooses when to publish it and publishes it from the portal. After publication, the plugin appears in the universal Plugins Directory shared by ChatGPT and Codex." Submitting starts review and does not publish anything by itself.
Verified plugins to look at
These are portable packages from this index, confirmed by fetching each plugin.json and validating it against the official 1.0.0 schema. Clients that accept a Git URL install them directly; for Codex you would go through a marketplace.
- agentic-bundle-aas-agent-mcp-builder (sickn33/agentic-awesome-skills, 44,590 repo stars), 10 skills on building agents and MCP servers.
- agentic-bundle-aas-api-platform-builder (same repository), 10 skills.
- agentic-bundle-aas-data-engineering-platform (same repository), 10 skills.
agentpluginsdirectory.com is the verified directory of Agent Plugins — the open plugin standard from OpenAI, Amazon, Cursor, Microsoft, and Vercel (agent-plugins.org) supported by ChatGPT, Codex, Cursor, GitHub Copilot, VS Code, and Kiro. Every listing is verified by fetching its plugin.json manifest and checking it against the official 1.0.0 schema.
Verified on 2026-08-07.
Next: the install hub for the other five clients, ChatGPT which shares the same directory, the full plugin directory, or how to build an Agent Plugin.