Codex / ChatGPT remote on macOS: the phone shows the Mac offline or timing out a while after the Mac locks, because App Nap suppresses the local proxy app (Surge)

Context

Source(s): https://www.v2ex.com/t/1249775 (posted 2026-10-18 18:32 JST; the original poster's own troubleshooting write-up and workaround; 0 replies when fetched; the poster says the post text was polished by Codex and the workaround was found with Codex's help) Status: reported working by source, not reproduced by us (workaround only; root fix not confirmed).

Problem

Remote control of the Mac from Codex / ChatGPT on a phone works while the Mac is unlocked. Some time after the Mac locks (not immediately; in one check about 126 seconds after locking), the phone shows the Mac as offline or the connection times out. The poster first thought it only happened on mobile data, then confirmed it also happens when the phone is on Wi-Fi. The Mac's traffic goes through Surge, a local proxy app. The poster says the same setup worked before and the problem started the day they updated macOS.

Error (redacted / normalized)

(symptom, no error text) Codex/ChatGPT on the phone shows the Mac as offline, or the connection times out.

PROC_FLAG_SUPPRESSED

Applies when

macOS 27.0.1 (build 26A434), Surge for Mac 6.11.0 (build 12560), MacBook Pro on power with the lid open, with the remote connection and keep-awake options turned on (as the poster describes them).

Confirm it is this problem

1. Lock the Mac and wait a few minutes until the phone shows it offline → expect: direct TCP, DNS and TLS tests from the Mac's physical network interface still work, while requests through Surge's local proxy hit CONNECT timeouts and requests through the system tunnel also time out (this is what the poster found at about 126 seconds after locking). A request like curl -x http://localhost:<surge_http_port> -I https://chatgpt.com run over SSH or from a scheduled job while locked is one way to test the proxy path (our inference; the poster does not say which commands they ran).
2. Check whether the Surge process is being suppressed → expect: Surge shows the PROC_FLAG_SUPPRESSED flag while ChatGPT and its related service processes do not. The poster does not say how they read this flag; Activity Monitor's App Nap column is a simpler check (our inference).

Not this when / boundary

If direct network tests from the Mac also fail while it is locked, the problem is not the proxy app (our inference from the poster's diagnosis). If no proxy or VPN app sits in the Mac's traffic path, this card does not apply (our inference). If the Mac goes to sleep (lid closed, or on battery without keep-awake), the drop is ordinary sleep, not App Nap (our inference).

Root cause

Suspected by the poster, not confirmed by Apple, OpenAI or the Surge developer: after the Mac locks, macOS background power saving (App Nap) suppresses the Surge process, so its local proxy stops answering in time and the remote connection that depends on it drops. The direct network path is unaffected, which points at the proxy app rather than the network.

Variables

<surge_http_port>: the HTTP proxy port shown in your Surge settings (our inference; the poster does not give a port).

Fix

1. Disable App Nap for Surge only: defaults write com.nssurge.surge-mac NSAppSleepDisabled -bool YES.
2. Quit Surge completely and open it again. The poster did not change any proxy server or policy settings.
3. Optional check that the setting is stored: defaults read com.nssurge.surge-mac NSAppSleepDisabled → expect: 1 (our inference).
4. Lock the Mac and leave it locked for at least 20 minutes, then use Codex / ChatGPT remote from the phone. → expect: the poster saw no new suppression flag on Surge and no drop of the desktop cloud connection during about 20 minutes of continuous checks while locked; at the end the Mac was still locked and both proxy requests and access to the cloud endpoint worked. Tested for about 20 minutes by the original poster only; nobody else has confirmed it.

How to verify

Repeat confirm step 2 while the Mac is locked → expect: Surge no longer shows PROC_FLAG_SUPPRESSED, and the phone keeps seeing the Mac online.

What did not work

none reported.

Rollback

defaults delete com.nssurge.surge-mac NSAppSleepDisabled, then quit and reopen Surge (from the poster).

Risks

With App Nap off, Surge may use a little more power in the background (our inference). Do not turn App Nap off for every app with a global defaults write on NSGlobalDomain; limit it to the one app in the traffic path (our inference). This card does not cover how the proxy itself is configured.

Verified scope

macOS 27.0.1 with Surge for Mac 6.11.0, October 2026.

Becomes obsolete when

A macOS or Surge update stops the proxy from being suppressed after lock, or Apple, OpenAI or the Surge developer confirms a cause and fix. Open question: whether the macOS 27.0.1 update itself triggered this (the poster only says it started the day they updated), and whether the workaround holds beyond the poster's 20-minute test; the thread had 0 replies when fetched on 2026-10-18.