Windows Codex app: Browser plugin can attach to tab, but DOM/screenshot APIs fail because codex app-server cannot start

What version of the Codex App are you using (From “About Codex” dialog)?

OpenAI.Codex 26.429.2026.0, bundled codex.exe reports FileVersion/ProductVersion 0.128.0-alpha.1

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

The Codex Windows desktop app's in-app Browser plugin partially works, but its main inspection features fail.

Codex can attach to the selected in-app browser tab and read the tab URL/title. However, DOM snapshot, screenshot, and visible DOM APIs all fail with:

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

Observed successful browser calls:

• tab.url()
• tab.title()

Observed failing browser calls:

• tab.playwright.domSnapshot()
• tab.playwright.screenshot({ fullPage: false })
• tab.dom_cua.get_visible_dom()

Related local evidence:

• Get-Command codex resolves to:

C:\Program Files\WindowsApps\OpenAI.Codex_26.429.2026.0_x64__2p2nqsd0c76g0\app\resources\codex.exe

• Running codex --version from integrated PowerShell fails with:

Program 'codex.exe' failed to run: Access is denied

• Running codex app-server --help from integrated PowerShell fails with:

Program 'codex.exe' failed to run: Access is denied

• Running the packaged node_repl.exe directly also fails with:

Program 'node_repl.exe' failed to run: Access is denied

What steps can reproduce the bug?

1. Install/open Codex Windows desktop app from Microsoft Store.
2. Enable/use the bundled Browser plugin.
3. Open the in-app Browser.
4. Navigate to a page in the in-app Browser.
5. In Codex, initialize the Browser plugin runtime with backend: "iab".
6. Select the current browser tab.
7. Confirm these calls work:

• tab.url()
• tab.title()

1. Then call any of:

• tab.playwright.domSnapshot()
• tab.playwright.screenshot({ fullPage: false })
• tab.dom_cua.get_visible_dom()

Minimal reproduction snippet used inside Codex Node REPL:

if (!globalThis.agent) {
const { setupAtlasRuntime } = await import("C:/Users/dan/.codex/plugins/cache/openai-bundled/browser-use/0.1.0-alpha1/scripts/browser-client.mjs");
const backend = "iab";
await setupAtlasRuntime({ globals: globalThis, backend });
}
await agent.browser.nameSession("Browser bug evidence");
if (typeof tab === "undefined") {
globalThis.tab = await agent.browser.tabs.selected();
}

const out = {};
out.url = await tab.url();
out.title = await tab.title();

try {
await tab.playwright.domSnapshot();
out.domSnapshot = "ok";
} catch (e) {
out.domSnapshot = String(e && e.message ? e.message : e);
}

try {
await tab.playwright.screenshot({ fullPage: false });
out.screenshot = "ok";
} catch (e) {
out.screenshot = String(e && e.message ? e.message : e);
}

try {
await tab.dom_cua.get_visible_dom();
out.visibleDom = "ok";
} catch (e) {
out.visibleDom = String(e && e.message ? e.message : e);
}

nodeRepl.write(JSON.stringify(out, null, 2));

Observed output:

{
"url": "[redacted authenticated Salesforce sandbox URL]",
"title": "Profile - My ADA profile - ADA Portal Original",
"domSnapshot": "failed to start codex app-server: The system cannot find the path specified. (os error 3)",
"screenshot": "failed to start codex app-server: The system cannot find the path specified. (os error 3)",
"visibleDom": "failed to start codex app-server: The system cannot find the path specified. (os error 3)"
}

I do not know the session id, token limit usage, or context window usage.

What is the expected behavior?

The Browser plugin should be able to start the required codex app-server/helper process and return DOM snapshots, screenshots, and visible DOM data from the selected in-app browser tab.

At minimum, the following should work after attaching to the selected in-app browser tab:

• tab.playwright.domSnapshot()
• tab.playwright.screenshot({ fullPage: false })
• tab.dom_cua.get_visible_dom()

Additional information

This appears related to Windows desktop/MSIX package execution issues where bundled executables under C:\Program Files\WindowsApps\OpenAI.Codex_...\app\resources\... are visible but cannot be launched from the integrated PowerShell/helper context.

Local evidence:

where.exe codex returns:
C:\Program Files\WindowsApps\OpenAI.Codex_26.429.2026.0_x64__2p2nqsd0c76g0\app\resources\codex
C:\Program Files\WindowsApps\OpenAI.Codex_26.429.2026.0_x64__2p2nqsd0c76g0\app\resources\codex.exe

Get-Command codex shows:
Path: C:\Program Files\WindowsApps\OpenAI.Codex_26.429.2026.0_x64__2p2nqsd0c76g0\app\resources\codex.exe
Version: 0.128.0.0
FileVersion: 0.128.0-alpha.1
ProductVersion: 0.128.0-alpha.1

Integrated PowerShell results:

• codex --version -> Access is denied
• codex app-server --help -> Access is denied
• direct packaged node_repl.exe --version -> Access is denied

The app itself opens and basic Codex shell commands work, so this is not a total app launch failure. The failure appears specific to launching packaged helper/app-server executables needed by Browser inspection features.