Windows: Chrome plugin install fails to create com.openai.codexextension Native Messaging Host

Summary

Codex Desktop Chrome plugin installation fails on Windows. The Codex Chrome extension itself is installed and enabled in Chrome, and check-extension-installed.js --json succeeds. However, the official Codex Desktop plugin install lifecycle does not create or register the Windows Native Messaging Host com.openai.codexextension.

This is not a "Chrome extension not installed" problem. The failure is specifically that Codex Desktop does not generate/register the native host manifest and registry entry during Chrome plugin installation.

Environment

• OS: Windows Home China 25H2, build 26200.8655, 64-bit
• Codex Desktop package: OpenAI.Codex 26.611.8604.0
• CODEX_HOME: C:\CodexHome
• Chrome executable: C:\Program Files\Google\Chrome\Application\chrome.exe
• Chrome version: 149.0.7827.116
• Codex plugin: chrome@openai-bundled
• Chrome plugin version: 26.611.62324
• Codex Chrome extension ID: hehggadaopoacecdllhhajmbjkdcmajg
• Codex Chrome extension version: 1.1.5_0
• Chrome profile selected by checker: Default

Expected behavior

Installing the Chrome plugin from Codex Desktop Plugins UI should create and register the Windows Native Messaging Host:

• Manifest:

%LOCALAPPDATA%\OpenAI\extension\com.openai.codexextension.json

• Registry key:

HKCU\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension

The registry default value should point to:

%LOCALAPPDATA%\OpenAI\extension\com.openai.codexextension.json

After that, the Codex Chrome extension should be able to connect to the native host.

Actual behavior

Codex Desktop Plugins UI shows:

plugin install failed

After this failure:

• The plugin package is copied locally.
• chrome@openai-bundled is listed as installed/enabled.
• The Chrome extension remains installed/enabled.
• But the Windows Native Messaging Host is not created or registered.

Observed state:

%LOCALAPPDATA%\OpenAI\extension\com.openai.codexextension.json
missing

HKCU\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension
missing

HKLM\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension
missing

HKLM\Software\WOW6432Node\Google\Chrome\NativeMessagingHosts\com.openai.codexextension
missing

C:\CodexHome\chrome-native-hosts-v2.json
{"schemaVersion":2,"entries":[]}

Diagnostics

check-extension-installed.js --json succeeds:

installed=true
enabled=true
selectedProfileDirectory=Default
extensionId=hehggadaopoacecdllhhajmbjkdcmajg
extensionVersion=1.1.5_0

check-native-host-manifest.js --json fails:

Windows native host registry key does not exist:
HKCU\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension

Native host manifest does not exist:
C:\Users\<redacted>\AppData\Local\OpenAI\extension\com.openai.codexextension.json

Reproduction steps

1. Set CODEX_HOME to:

``text
C:\CodexHome
``

1. Confirm Codex Desktop and Codex CLI are using the same CODEX_HOME.

1. Remove stale Chrome plugin state through the official CLI:

``powershell
codex plugin remove chrome@openai-bundled --json
``

1. Open Codex Desktop.

1. Go to Plugins.

1. Add/install the Chrome plugin through the Codex Desktop Plugins UI.

1. Observe that the UI reports:

``text
plugin install failed
``

1. Verify that the Chrome extension is installed and enabled.

1. Verify that the native host manifest and registry key are still missing.

Troubleshooting already tried

• Verified CODEX_HOME is consistently C:\CodexHome.
• Removed stale chrome@openai-bundled via official CLI:

``powershell
codex plugin remove chrome@openai-bundled --json
``

• Reinstalled Chrome plugin through Codex Desktop Plugins UI.
• Ran Windows App Repair.
• Ran Windows App Reset.
• Reinstalled the Chrome plugin through Plugins UI again.
• Verified the Chrome extension remains installed/enabled throughout.
• Verified no Chrome policy blocking Native Messaging was found.
• Verified Defender Controlled Folder Access is disabled.
• Verified %LOCALAPPDATA%\OpenAI\extension ACL allows the current user.
• Verified other Chrome NativeMessagingHosts entries exist, so the Chrome native messaging registry mechanism is not generally broken.

Important clarification

Please do not treat this as a Chrome extension installation failure.

The Chrome extension is installed and enabled, and check-extension-installed.js --json succeeds.

The failing layer is the Codex Desktop Chrome plugin install lifecycle: it does not generate/register com.openai.codexextension as a Windows Native Messaging Host.

Why this looks like a Codex Desktop install lifecycle bug

The state after installation is internally inconsistent:

• Codex plugin state says chrome@openai-bundled is installed/enabled.
• Chrome extension state says the extension is installed/enabled.
• But the required native messaging manifest is missing.
• The required HKCU registry key is missing.
• C:\CodexHome\chrome-native-hosts-v2.json remains empty.

This suggests the plugin package copy/install step partially succeeds, but the native host setup step either does not run, fails silently, or fails without repairing the plugin state.

Related issues

This appears related but not identical to:

• #21674: Chrome plugin shows "Install failed" even though the Chrome extension is installed and enabled.
• #24040: Native Messaging Host registry key missing while the manifest exists.

This case appears to fail one step earlier than #24040: both the manifest and registry key are missing after the official install lifecycle, even after App Repair and App Reset.

Requested fix / expected installer behavior

When installing or repairing the Chrome plugin, Codex Desktop should either:

1. Successfully create:

``text
%LOCALAPPDATA%\OpenAI\extension\com.openai.codexextension.json
HKCU\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension
``

and update chrome-native-hosts-v2.json accordingly;

or:

1. Fail the plugin install atomically and leave chrome@openai-bundled not installed, with a clear error message explaining which native host setup step failed.

The current behavior leaves the plugin marked installed/enabled while the native messaging host is absent, which makes the user-facing state misleading and prevents Chrome-backed Codex automation from working.

Additional diagnostic data available

I can provide redacted outputs for:

Get-AppxPackage -Name OpenAI.Codex | Select-Object Name, Version, InstallLocation, PackageFullName

[Environment]::GetEnvironmentVariable("CODEX_HOME", "User")
[Environment]::GetEnvironmentVariable("CODEX_HOME", "Machine")
$env:CODEX_HOME

codex plugin marketplace list --json
codex plugin list --json

Test-Path "$env:LOCALAPPDATA\OpenAI\extension\com.openai.codexextension.json"

reg query HKCU\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension /ve
reg query HKLM\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension /ve
reg query HKLM\Software\WOW6432Node\Google\Chrome\NativeMessagingHosts\com.openai.codexextension /ve

Get-Content "C:\CodexHome\chrome-native-hosts-v2.json" -Raw

I will redact usernames, tokens, session data, API keys, cookies, and any contents of auth.json.