What changed
The codex mcp-server command was marked deprecated on August 24, 2026, and OpenAI pointed integrators to the Codex app server with migration guidance. This affects only Codex running as an MCP server for other tools; connecting Codex to external MCP servers is a separate feature and unaffected. Removal followed on September 5.
Who it affects
Developers and tools that launch Codex as an MCP server.
What to do
Find every script or integration that runs codex mcp-server and plan the move to the app server.