Windows Codex app: Browser Use external navigation fails because nodeRepl.fetch cannot start codex app-server

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• #18256

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I can reproduce this on Windows with an additional datapoint: the in-app browser page itself appears to load correctly, but Codex-side Browser Use inspection/control still fails.

Environment:

• Codex Windows app (Microsoft Store)
• Get-AppxPackage OpenAI.Codex reports version 26.422.1952.0
• Install location: C:\Program Files\WindowsApps\OpenAI.Codex_26.422.1952.0_x64__2p2nqsd0c76g0
• Browser Use plugin: bundled openai-bundled/browser-use/0.1.0-alpha1
• In-app browser current URL: https://cloud.comfy.org/

What works:

• Browser Use runtime setup succeeds.
• agent.browser.nameSession(...) succeeds.
• agent.browser.tabs.new() / selected-tab access succeeds.
• Desktop logs show Browser Use native pipe and IAB routing starting normally.
• The desktop log also shows many browser sidebar console message entries from https://cloud.comfy.org/assets/vendor-sentry-...js, including lots of Comfy node registration messages such as beforeRegisterNodeDef called for: ..., which strongly suggests the page itself is loaded and running.

What fails:

• Browser Use inspection/navigation from the Codex thread fails with:

failed to start codex app-server: The system cannot find the path specified. (os error 3)

• I hit this both when trying external navigation earlier and later when trying to inspect the already-open selected tab.

Related local symptom on the same machine:

• Get-Command rg resolves to bundled C:\Program Files\WindowsApps\OpenAI.Codex_26.422.1952.0_x64__2p2nqsd0c76g0\app\resources\rg.exe
• but executing it fails with Access is denied

Relevant desktop log evidence includes:

• Initializing app-server transport
• Starting app-server connection hostId=local transport=stdio
• browser-use native pipe listening
• IAB_LIFECYCLE iab createTab mapped page to tab
• many browser sidebar console message entries from cloud.comfy.org

So this looks like:

1. the in-app browser page can load successfully,
2. Browser Use / app-server handoff is what fails,
3. and it may be in the same WindowsApps / executable-launch family as the bundled rg.exe issue.

Possibly related issues: #14925, #15148, #13542, #13965, #17901.

I also faced with this and my Codex researched the problem and adds this:

Additional datapoint: on the same Windows/MSIX version, the in-app browser itself works and the selected tab is visible via Browser Use. Working: - agent.browser.tabs.list() - agent.browser.tabs.selected() - tab.url() / tab.title() Failing with failed to start codex app-server: The system cannot find the path specified. (os error 3): - tab.playwright.domSnapshot() - tab.cua.get_visible_screenshot() - tab.goto(...) Most useful isolation: normal globalThis.fetch("https://example.com/") works, but nodeRepl.fetch("https://chatgpt.com/backend-api/aura/site_status?...") fails with the same app-server error. So this looks specific to nodeRepl.fetch / Browser Use preflight, not the page load itself.

Additional confirmation from another Windows repro on the same problem family.

I ran the exact isolation checks in the Browser Use runtime against the current in-app browser tab.

Environment:

• Windows Codex app from Microsoft Store
• Get-AppxPackage OpenAI.Codex version: 26.422.1952.0
• Browser Use runtime with in-app browser (iab backend)

Current selected tab at the time of repro:

• URL: https://cloud.comfy.org/
• Title: *Unsaved Workflow - ComfyUI

Working:

• agent.browser.tabs.list()
• agent.browser.tabs.selected()
• tab.url()
• tab.title()
• plain globalThis.fetch("https://example.com/") returns 200

Failing with the same error:

• nodeRepl.fetch("https://chatgpt.com/backend-api/aura/site_status?... ")
• tab.playwright.domSnapshot()
• tab.cua.get_visible_screenshot()
• tab.goto(...) on a temporary tab

All failing calls return:
failed to start codex app-server: The system cannot find the path specified. (os error 3)

This seems like the strongest isolation yet:

• the in-app browser is working,
• Browser Use can see the selected tab and its metadata,
• the actual page is ComfyUI (*Unsaved Workflow - ComfyUI),
• generic fetch works,
• but nodeRepl.fetch and deeper Browser Use actions fail.

So this really does look specific to the nodeRepl.fetch / Browser Use preflight / app-server integration path, not to page load itself and not to the destination site.

Additional Windows repro on the same Browser Use / app-server failure family.

Environment:

• OS: Windows
• Codex Windows app package: OpenAI.Codex_26.422.2339.0_x64__2p2nqsd0c76g0
• Browser Use plugin: openai-bundled/browser-use/0.1.0-alpha1
• Global Codex CLI on PATH: codex-cli 0.118.0
• In-app browser mode: main Codex session window

Working:

• Browser Use runtime setup succeeds with the iab backend.
• agent.browser.tabs.list() can see the in-app browser tab.
• agent.browser.tabs.selected() binds the current tab.
• On about:blank, tab.playwright.domSnapshot() succeeds.
• On about:blank, tab.cua.get_visible_screenshot() succeeds.

Failing:

• tab.goto("https://www.naver.com/") fails.
• nodeRepl.fetch("https://chatgpt.com/backend-api/aura/site_status?site_url=https%3A%2F%2Fwww.naver.com") fails.

Error:

failed to start codex app-server: 지정된 파일을 찾을 수 없습니다. (os error 2)

Additional datapoint:

• When using a mini-window mode, Browser Use did not expose an active Codex browser pane and returned:

No active Codex browser pane available

• After switching back to the main session window, the browser pane became visible to Browser Use, but external navigation still fails with the app-server error above.

#19314

I was able to reproduce and work around this on Windows with Codex 26.422.3464.0.

The failure was not Browser Use itself. Browser Use initialized and could see the IAB tab, but external navigation failed because nodeRepl.fetch could not start/use the Codex app-server.

Root cause in my environment:
Codex helpers existed under the MSIX LocalCache path:

%LOCALAPPDATA%\Packages\OpenAI.Codex_2p2nqsd0c76g0\LocalCache\Local\OpenAI\Codex\bin

but Node REPL / spawned helper paths referred to:

%LOCALAPPDATA%\OpenAI\Codex\bin

That non-MSIX path did not exist, so nodeRepl.fetch failed with:

failed to start codex app-server: The system cannot find the path specified. (os error 3)

Workaround:
Create %LOCALAPPDATA%\OpenAI\Codex\bin and copy the helper binaries from the MSIX LocalCache bin folder:
codex.exe, node.exe, node_repl.exe, rg.exe, codex-command-runner.exe, codex-windows-sandbox-setup.exe.

After that:
nodeRepl.fetch(...) returned 200
Browser Use tab.goto("https://example.com/") worked
domSnapshot and screenshot worked

Suggested product fix:
On Windows/MSIX builds, ensure tool/MCP/runtime helper resolution uses a real per-user executable path, or creates/syncs %LOCALAPPDATA%\OpenAI\Codex\bin before starting node_repl/app-server. Avoid resolving helpers from WindowsApps or from a path that only exists inside MSIX package virtualization.

Thanks, I checked that workaround on my machine.

In my case, both folders already exist:

• %LOCALAPPDATA%\Packages\OpenAI.Codex_2p2nqsd0c76g0\LocalCache\Local\OpenAI\Codex\bin
• %LOCALAPPDATA%\OpenAI\Codex\bin

The expected helper files are present in both places:

• codex.exe
• node.exe
• node_repl.exe
• rg.exe
• codex-command-runner.exe
• codex-windows-sandbox-setup.exe

The file sizes and timestamps match. Also, the running node_repl.exe processes are already using:

%LOCALAPPDATA%\OpenAI\Codex\bin\node_repl.exe

Both of these commands work from PowerShell:

%LOCALAPPDATA%\OpenAI\Codex\bin\codex.exe app-server --help
%LOCALAPPDATA%\OpenAI\Codex\bin\codex.exe app-server proxy --help

But nodeRepl.fetch(...) still fails with:
failed to start codex app-server: The system cannot find the path specified. (os error 3)

So this looks slightly different from the missing non-MSIX helper folder case. The helper binaries are present and runnable, but the Node REPL bridge still cannot start or connect to the app-server.

Extra detail that may matter: Codex Desktop: 26.422.3464.0
Codex CLI: 0.125.0-alpha.3
nodeRepl.homeDir: null

My guess is that another path is missing from the Node REPL/app-server bridge, possibly the app-server control socket path or home directory metadata, rather than the helper binary path itself.

Not sure if this is relevant, but I'll put it here to anyone who might find it useful.

I'm using a third-party provider in Codex. After fixing the issue via the workaround in https://github.com/openai/codex/issues/19423#issuecomment-4317666215, I get this error when the browser plugin is called:

codex auth token is unavailable

Relevant log:

2026-04-27T01:18:37.544Z warning [browser-sidebar-comment-mode-site-status] failed to load browser sidebar comment mode site status errorMessage="Sign in to ChatGPT in Codex Desktop to load browser site status." errorName=Error errorStack="Error: Sign in to ChatGPT in Codex Desktop to load browser site status.\n    at Ui (C:\\Program Files\\WindowsApps\\OpenAI.Codex_26.422.3464.0_x64__2p2nqsd0c76g0\\app\\resources\\app.asar\\.vite\\build\\main-BBYeJ7_G.js:79:7128)\n    at async l (C:\\Program Files\\WindowsApps\\OpenAI.Codex_26.422.3464.0_x64__2p2nqsd0c76g0\\app\\resources\\app.asar\\.vite\\build\\main-BBYeJ7_G.js:102:1384)\n    at async c (C:\\Program Files\\WindowsApps\\OpenAI.Codex_26.422.3464.0_x64__2p2nqsd0c76g0\\app\\resources\\app.asar\\.vite\\build\\main-BBYeJ7_G.js:102:1119)"

Codex suggested to run this patch in PowerShell, which worked:

$root = Join-Path $env:USERPROFILE ".codex\plugins\cache\openai-bundled\browser-use"
$old = 'var KA=async(e,t)=>{let n=globalThis.nodeRepl?.fetch;if(n==null)throw new Error("Browser Use cannot determine if this website is allowed. Please try again later or use another source.");return n(e,t)};'
$new = 'var KA=async(e,t)=>{let n=globalThis.nodeRepl?.fetch;if(n==null)throw new Error("Browser Use cannot determine if this website is allowed. Please try again later or use another source.");try{return await n(e,t)}catch(r){if(typeof e=="string"&&e.startsWith("https://chatgpt.com/backend-api/aura/site_status?")&&r?.message==="Codex auth token is unavailable")return new Response(JSON.stringify({feature_status:{agent:false}}),{status:200,headers:{"content-type":"application/json"}});throw r}};'

Get-ChildItem $root -Filter browser-client.mjs -Recurse | ForEach-Object {
  $p = $_.FullName
  $s = [IO.File]::ReadAllText($p)
  if ($s.Contains($old)) {
    Copy-Item $p "$p.bak"
    [IO.File]::WriteAllText($p, $s.Replace($old, $new), [Text.UTF8Encoding]::new($false))
    "Patched $p"
  } elseif ($s.Contains("Codex auth token is unavailable")) {
    "Already patched $p"
  } else {
    "Snippet not found in $p"
  }
}

Follow-up from the same Windows repro, with personal/local user paths removed.

Environment:

• Codex Desktop: OpenAI.Codex_26.422.3464.0_x64__2p2nqsd0c76g0
• Browser Use plugin: openai-bundled/browser-use/0.1.0-alpha1
• Codex CLI in the working helper cache: codex-cli 0.125.0-alpha.3
• Node in the working helper cache: v24.14.0

Before workaround:

• %LOCALAPPDATA%\OpenAI\Codex\bin existed but contained none of the expected helper executables.
• %LOCALAPPDATA%\Packages\OpenAI.Codex_2p2nqsd0c76g0\LocalCache\Local\OpenAI\Codex\bin contained:
• codex.exe
• node.exe
• node_repl.exe
• rg.exe
• codex-command-runner.exe
• codex-windows-sandbox-setup.exe
• The LocalCache helpers were executable.
• Direct execution from the packaged WindowsApps app resources path failed with Access denied.
• nodeRepl.homeDir was still null.
• nodeRepl.fetch("https://chatgpt.com/backend-api/aura/site_status?...") failed with:

failed to start codex app-server: 지정된 파일을 찾을 수 없습니다. (os error 2)

Workaround applied:

• Copied the six helper executables from the MSIX LocalCache bin folder into %LOCALAPPDATA%\OpenAI\Codex\bin.
• No existing files were overwritten.
• No Browser Use plugin JS was patched.
• No WindowsApps package files were modified.

After workaround:

• %LOCALAPPDATA%\OpenAI\Codex\bin\codex.exe --version returned codex-cli 0.125.0-alpha.3.
• %LOCALAPPDATA%\OpenAI\Codex\bin\codex.exe app-server --help worked.
• %LOCALAPPDATA%\OpenAI\Codex\bin\node.exe --version returned v24.14.0.
• %LOCALAPPDATA%\OpenAI\Codex\bin\rg.exe --version worked.
• nodeRepl.fetch("https://chatgpt.com/backend-api/aura/site_status?site_url=https%3A%2F%2Fexample.com") returned HTTP 200.
• Browser Use tab.goto("https://example.com/") worked.
• Browser Use tab.playwright.domSnapshot() worked.
• Browser Use tab.cua.get_visible_screenshot() worked.
• Browser Use tab.goto("https://www.naver.com/") worked.
• Clicking Naver's search input via input[name="query"] worked and opened the autocomplete/recent-search UI.

So on this machine, the missing/empty %LOCALAPPDATA%\OpenAI\Codex\bin helper cache was sufficient to explain the os error 2 app-server failure. Copying the helper executables from the MSIX LocalCache restored nodeRepl.fetch and Browser Use navigation/DOM/screenshot/click behavior.

Thanks, @vadimsky-ctrl ! That worked!

Thanks, @vadimsky-ctrl ! That worked!

ehm there is no person named vadimsky in this thread

> Thanks, @vadimsky-ctrl ! That worked! ehm there is no person named vadimsky in this thread

Scroll up or click here https://github.com/openai/codex/issues/19187#issuecomment-4319153880