macOS: cua_repl does not respawn after launch.mjs/node_repl exit; createBrowserTab returns Transport closed in ~1ms

What version of Codex CLI is running?

codex-cli 0.153.4 (codex app-server --enable goals)

Computer Use runtime comes from ChatGPT.app 26.903.61454 (build 8378) via plugin unified-computer-use@openai-bundled (launch.mjs + bundled cua_node / node_repl). Hosts observed: 26.901.51231 and 26.903.61454.

What subscription do you have?

Logged in with ChatGPT. Exact plan not exposed by this CLI/app-server path.

Which model were you using?

Not model-dependent. Reproduced on gpt-5.6-luna because that is the long-lived thread; the failures are MCP transport / Computer Use host lifecycle.

What platform is your computer?

Darwin 25.6.0 arm64 arm (macOS 26.6.2, 25G83)

What terminal emulator and version are you using (if applicable)?

Not a TUI session. codex app-server --enable goals spawned by Paseo Desktop 0.8.0-beta.1 (bundle sh.paseo.desktop). Same plugin/cua_repl stack as Codex Computer Use.

Codex doctor report

not available (not run; this is a Computer Use MCP transport failure on a long-lived app-server)

What issue are you seeing?

Two related Computer Use failures on a long-lived app-server that we did not restart.

A. Chrome CUA works, then getState() reports no browsers while the Chrome native host is still alive.

cua.createBrowserTab("chrome", url, { sessionName }) plus Playwright waitForEvent("filechooser") + setFiles succeeded (2026-09-10 ~17:37–17:48 local, and createBrowserTab("chrome", …) again ~18:39).

Later the same process’s cua.getState() returned:

apps=[]
browsers=[]
Sky Computer Use native pipe startup failed

At that time:

• Google Chrome was still running
• native host ChatGPT for Chrome (chrome-extension://hehggadaopoacecdllhhajmbjkdcmajg/) was still a child of Chrome
• js_reset did not restore browsers

Plugin env:

CUA_REPL_ENABLED_SURFACES=browser,computer

Sky Apple Events were already failing for the responsible parent app. A Sky native-pipe failure appears to zero both surfaces.

B. After launch.mjs / node_repl exit, cua_repl never respawns. Every subsequent call is Transport closed in milliseconds.

The app-server stayed up (writer lock still held). Its children no longer included launch.mjs / node_repl. Next calls:

tool call error: tool call failed for `cua_repl/js_reset`

Caused by:
    Transport closed

tool call error: tool call failed for `cua_repl/js`

Caused by:
    Transport closed

Exact MCP item for the last createBrowserTab (URL/session name redacted):

server: cua_repl
tool: js
status: failed
error.message: tool call error: tool call failed for `cua_repl/js`

Caused by:
    Transport closed
duration: { "secs": 0, "nanos": 1408875 }

Wall time printed by the tool wrapper: 0.0046 seconds.

Quitting ChatGPT.app and retrying the same createBrowserTab("chrome", …) (no getState, no js_reset) still returned Transport closed in ~1.4ms. No new CUA host appeared under the app-server. Another app-server on the same machine still had a live 26.903.61454 launch.mjs child, so Computer Use is not globally dead — only this session’s MCP stdio.

What steps can reproduce the bug?

The empty-browsers state is intermittent. The Transport closed / no-respawn path is reproducible once the bound host is gone.

1. Keep a Codex app-server alive for many hours with unified-computer-use / cua_repl attached (do not start a new thread).

2. Confirm Chrome CUA works:

   let tab = await cua.createBrowserTab("chrome", "https://example.com", { sessionName: "repro" });
   tab
   

3. Leave the session running. Optionally quit/relaunch ChatGPT.app, or let Sky native pipe fail. Call cua.getState(). Observe browsers=[] and Sky Computer Use native pipe startup failed even if the Chrome extension native host is still running.

4. Kill or wait until this thread’s …/unified-computer-use/*/scripts/launch.mjs and its node_repl children exit. Do not kill the app-server.

5. Call js_reset and/or cua.createBrowserTab("chrome", …) again.

Expected: Codex starts a new launch.mjs host for cua_repl, or surfaces an actionable “Computer Use host died, restart MCP” error.

Actual: Transport closed in ~1ms. pgrep -P <app-server-pid> still has no CUA child. js_reset cannot recover a dead stdio transport. Starting a different app-server can still get a fresh host.

What is the expected behavior?

• getState() / createBrowserTab("chrome") should not depend on Sky native pipe when the Chrome native host is alive. If CUA_REPL_ENABLED_SURFACES includes browser, a computer handshake failure should not report browsers=[].
• If launch.mjs / node_repl exits, app-server should respawn cua_repl on the next tool call (or clearly mark the MCP server as dead and restart it). js_reset should not be the only recovery, and it should not be offered when the transport is already closed.
• Long-lived sessions should not require killing app-server (and losing the thread writer lock) to get Computer Use back.

Additional information

Related:

• openai/codex#39042 — pre-update node_repl cannot authenticate; js_reset insufficient; fresh host works. Same recovery hole for a live app-server.
• openai/codex#25744 / #39816 — node_repl helper accumulation.
• openai/codex#25848 — intermittent transport closed (Windows app).
• openai/codex#35234 — native pipe sender not authenticated.
• openai/codex#43498 — CUA_REPL_ENABLED_SURFACES=browser stripping Sky (inverse coupling).
• getpaseo/paseo#3346 — Paseo Desktop lacks com.apple.security.automation.apple-events, so macOS attributes Paseo-spawned Sky CUA to Paseo and denies Apple Events without a prompt. That explains Sky, not Chrome CUA working then dying, and not Transport closed after host exit.

.mcp.json for cua_repl (paths redacted to usernames):

command: /Applications/ChatGPT.app/Contents/Resources/cua_node/bin/node
args: [ "~/.codex/plugins/cache/openai-bundled/unified-computer-use/26.903.61454/scripts/launch.mjs" ]
env.CUA_REPL_ENABLED_SURFACES: browser,computer
env.CUA_REPL_NODE_REPL_PATH: /Applications/ChatGPT.app/Contents/Resources/cua_node/bin/node_repl
startup_timeout_sec: 120
tools: js, js_reset, turn_ended

Start at the app-server MCP process lifecycle and the cua_repl command that launches launch.mjs with node_repl. Reproduce the failure by allowing those children to exit, then inspect how js_reset and the next js or createBrowserTab call handle the closed transport. Done means the session respawns cua_repl or reports an actionable dead-server state without requiring a new app-server.