OpenAI Codex release notes: 0.160.1 fixes Windows MCP startup

OpenAI Codex CLI 0.160.1 fixes startup of remote MCP servers on Windows when Codex runs from a Unix host and explicit environment variables have been configured for the remote environment. Codex CLI is OpenAI's terminal-based coding agent. The release shipped on October 5, 2026.

OpenAI Codex release notes: preserve the Windows startup environment

MCP (Model Context Protocol) connects AI tools to external tools and data sources. This fix concerns servers that communicate through standard input and output, known as stdio.

Codex now preserves SYSTEMROOT, TEMP, and TMP in the environment allowlist even when explicit remote variables are used. The Windows process retains these values from its own startup environment. They are not copied from the Unix host.

The fix applies to this combination of remote execution, Windows, and configured environment variables. Its regression test also checks that unrequested secrets remain excluded.

Source: OpenAI: Windows remote MCP environment preservation.

Human step: update through npm

If you install Codex through npm, use this command in your terminal:

npm install -g @openai/[email protected]

Source: OpenAI Codex changelog, October 5, 2026.

Version 0.160.1 is the stable npm release when checked on October 6. The fix does not require a special agent prompt. If your setup is affected, retry the existing connection after updating and check that the MCP server starts.

Source: OpenAI Codex CLI 0.160.1 release notes.