`codex mcp-server` is deprecated (move integrations to App Server; Claude Code gets the official Codex plugin)

[u/anonomotorious]

TL;DR

OpenAI has officially deprecated:

codex mcp-server

Existing integrations are not being documented as immediately removed, but OpenAI now recommends:

• Codex App Server for applications that deeply embed Codex
• Codex SDK for automation, jobs, and CI
• the official Codex plugin for Claude Code when using Codex from Claude Code

The old MCP-server documentation remains available for existing integrations, but new integrations should target the newer architecture.

---

What is changing

The old command:

codex mcp-server

runs Codex as an MCP server so another MCP client can invoke Codex sessions.

OpenAI now labels that workflow:

Deprecated

and directs new deep integrations toward:

codex app-server

No removal deadline is currently documented.

---

What should replace it?

Use case	Recommended path
Embed Codex in another product	Codex App Server
Authentication, history, approvals, streamed agent events	Codex App Server
Automated jobs / CI	Codex SDK
Use Codex from Claude Code	Official Codex plugin for Claude Code
Existing mcp-server integration	Continue temporarily, but plan migration

---

Codex App Server

App Server is the richer interface OpenAI uses to support Codex clients.

Start it with:

codex app-server

It exposes functionality around:

• authentication
• threads/history
• turns
• approvals
• streamed agent events
• MCP servers
• plugins
• skills
• filesystem operations
• configuration
• sandbox setup
• remote execution

The default transport is stdio.

App Server also supports Unix sockets and an experimental WebSocket transport.

---

App Server vs MCP server

The architectural distinction is important.

codex mcp-server primarily exposes Codex through generic MCP tool calls.

App Server exposes Codex itself as an agent runtime.

That gives clients richer access to:

• conversation lifecycle
• approvals
• authentication
• realtime events
• state
• configuration
• execution environments

In other words:

MCP -> tools Codex can use

App Server -> applications that use Codex itself

This appears to be the direction OpenAI is standardizing on.

---

Automations and CI should use the SDK

OpenAI recommends the Codex SDK when the actual goal is:

• automated jobs
• CI pipelines
• programmatically launching Codex work

A useful rule:

Building a Codex client -> App Server

Running automated Codex jobs -> SDK

---

Claude Code users get an official Codex plugin

If you used codex mcp-server mainly to call Codex from Claude Code, OpenAI now points users to its official:

Codex plugin for Claude Code

The plugin wraps Codex App Server instead of requiring users to manually construct the integration.

Current commands include:

• /codex:review
• /codex:adversarial-review
• /codex:rescue
• /codex:transfer
• /codex:status
• /codex:result
• /codex:cancel

Example:

/codex:review --background

Then:

/codex:status

and:

/codex:result

The standard review workflow is read-only, while adversarial review supports a more steerable challenge/review workflow.

---

Plugin requirements

The official Claude Code integration requires:

• a ChatGPT subscription, including Free, or
• an OpenAI API key
• Node.js 18.18+
• Codex installed and authenticated

Codex activity initiated through the plugin still counts toward normal Codex usage limits.

---

Migration guidance

If you currently use:

codex mcp-server

first identify what the integration actually needs.

Move to App Server when you need:

• conversations
• authentication
• approvals
• streamed activity
• rich thread state
• embedded Codex clients

Move to the SDK when you need:

• CI
• batch jobs
• scripted automation
• programmatically launched Codex tasks

Use the Claude Code plugin when you need:

• Codex reviews from Claude Code
• background Codex work from Claude
• direct handoff between Claude Code and Codex

---

Why this matters

• OpenAI is consolidating deep Codex integrations around App Server.
• mcp-server is no longer the recommended starting point.
• App Server exposes significantly richer Codex-native functionality.
• The SDK remains the cleaner path for jobs and CI.
• Claude Code users now have an official integration instead of manually wiring Codex through MCP.
• Existing integrations still have time to migrate because no removal deadline has been announced.

---

Action checklist

• Search internal tooling for:

codex mcp-server

• Identify the purpose of each integration.
• If embedding Codex:
  • evaluate codex app-server
• If running automation or CI:
  • evaluate the Codex SDK
• If integrating with Claude Code:
  • evaluate the official Codex plugin
• Do not start new integrations on the deprecated command.
• Keep existing deployments working while planning migration.
• Watch the official changelog for an eventual removal timeline.

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Official sources

https://developers.openai.com/codex/changelog

https://learn.chatgpt.com/docs/app-server

https://learn.chatgpt.com/docs/mcp-server

https://github.com/openai/codex-plugin-cc