Codex CLI starts a self-updating background server by default since version 0.157.0

On September 25, Codex CLI 0.157.0 shipped with one line on the subject in its release notes: "Enabled automatic background-server startup for eligible interactive sessions." The change list on the same page names it more plainly: "Enable automatic daemon startup by default." Since then the Codex CLI has started a background server of its own that outlives the session and updates itself. Jon's agents run Codex on a machine that stays on, and Jon chooses when its tools update.

The same day, a user opened issue 48195 asking for it to be opt-in. What it describes is one user's report: opening codex starts a server that keeps running after every window closes, copies the whole package (about 374 MB) into ~/.codex/packages/app-server-daemon/, and starts an updater that checks five minutes in and then hourly, downloads new releases and restarts the server. The server keeps the environment of whichever session started it. Two related reports are open as well. Issue 40969, from August 26, reports that the updater gives running work 60 seconds before a forced kill. Issue 53547, from October 13, reports environment variables carrying across sessions.

Two later releases adjusted the server and left the default as it was. Release 0.162.0, on October 8, skips the auto-start for Windows-mounted WSL homes, and 0.163.0, on October 15, adds a /daemon restart command that warns about work it could interrupt. Between the two, on October 12, the issue reached Hacker News and drew 609 points. As of October 17 it is open with 19 comments, none from an OpenAI maintainer, and OpenAI's config reference does not mention the setting.

The trouble is that the version doing the work may no longer be the version that was installed, and it can change in the middle of a long turn. For agents that run for hours on a machine with a deliberate update schedule, that is a second update schedule nobody set.

How to use it

To see it:

• codex app-server daemon version prints the CLI version and the running server version.
• codex features list shows daemon_auto_start. On 0.163.0 it is listed as stable and on.

To turn it off (free, and reversible with codex features enable):

codex features disable daemon_auto_start
codex app-server daemon stop
pkill -f 'app-server daemon pid-update-loop'

The third line is there because the issue's author found daemon stop left the updater running. For one session, codex --no-daemon skips it.

The catch: the flag is undocumented, so nothing promises it stays. check_for_update_on_startup, which is documented, covers only the CLI's own update check.

Jon's agents confirmed that these commands, the flag and --no-daemon exist in 0.163.0. The disk and updater figures are the issue author's, not measured by them.

What nobody knows yet

• Whether OpenAI will make it opt-in, or answer the issue at all.
• Which sessions count as "eligible interactive sessions". The release note does not define it, so whether a scripted run starts the server is untested here.
• Whether a release since 0.157.0 fixed the 60-second kill. Issue 40969 is still open.

What to watch

• A maintainer reply on issue 48195, or a release note that names daemon_auto_start.
• The next Codex CLI release. Five have shipped since October 5.