Windows desktop: Notion connector auth fails with Electron launch error and incomplete codex:// protocol registration

Summary

On Windows Codex Desktop, connecting the bundled Notion connector repeatedly fails during the auth/launch flow. The user sees an Electron error dialog saying Codex/Notion cannot find an Electron app/module at a malformed path under C:\Program ... that includes an OAuth code= query string. After the failure, the Notion MCP tools are not exposed to Codex.

Environment

• OS: Windows
• Codex Desktop package: OpenAI.Codex_26.527.7698.0_x64__2p2nqsd0c76g0
• Codex app features enabled include: enable_mcp_apps, apps, plugins, auth_elicitation, tool_call_mcp_elicitation
• Notion connector/plugin involved:
• Connector id shown by Codex: asdk_app_69c18c28f1188191bf5b8445c4ab0a2e
• Plugin cache paths observed: notion\bebc3d6a and stale reference to notion\45fe2bdd

Repro Steps

1. In Codex Desktop on Windows, attempt to connect/install the Notion connector.
2. Complete or trigger the Notion auth flow.
3. During redirect/launch, an Electron error dialog appears.
4. Return to Codex and search for Notion tools such as notion-search or notion-create-pages.

Actual Result

• Electron error dialog appears with text similar to:

Error launching app
Unable to find Electron app at C:\Program ...\uKsNygupn0Do?code=e9323671-...
Cannot find module 'C:\Program ...\uKsNygupn0Do?code=e9323671-...'

• request_plugin_install for the Notion connector returns:

{
  "completed": false,
  "user_confirmed": false,
  "tool_type": "connector",
  "action_type": "install",
  "tool_id": "asdk_app_69c18c28f1188191bf5b8445c4ab0a2e",
  "tool_name": "Notion"
}

• tool_search does not expose Notion MCP tools, only unrelated tools such as GitHub/Pencil/Node REPL.

Expected Result

• Notion auth redirect should be handled by Codex Desktop correctly.
• The connector should complete installation/auth.
• Notion MCP tools such as notion-search, notion-fetch, and notion-create-pages should be available.

Diagnostics / Investigation

• Notion Desktop is installed and can be launched normally from:

%LOCALAPPDATA%\Programs\Notion\Notion.exe

• Notion protocol registration exists:

HKCU\Software\Classes\notion\shell\open\command = "%LOCALAPPDATA%\Programs\Notion\Notion.exe" "%1"

• Codex AppX package exists:

OpenAI.Codex_26.527.7698.0_x64__2p2nqsd0c76g0

• Codex AppX capability lists the codex URL association:

...\App\Capabilities\URLAssociations
codex = AppXybfp6cjpb1wf0pftw0fd4bz59gzn1401

• A suspicious/incomplete user-level protocol key was observed:

HKCU\Software\Classes\codex
  URL Protocol = ""

It had no shell\open\command, which appears to shadow or interfere with normal AppX protocol handling. Deleting this incomplete key did not fully resolve the connector issue in-session.

• Attempting to re-register Codex AppX while Codex was running failed as expected:

Deployment failed with HRESULT: 0x80073D02
The package could not be installed because resources it modifies are currently in use.

Attempts Made

• Verified Notion Desktop executable exists and launches.
• Verified Codex AppX package and protocol capability.
• Backed up and deleted the incomplete HKCU\Software\Classes\codex key.
• Scheduled re-registration of the Codex AppX manifest after Codex exits.
• Re-attempted connector installation/auth, but request_plugin_install still reports completed=false and user_confirmed=false.

Suspected Cause

This may be a Windows URL protocol handling issue in the Notion connector auth flow, possibly involving one or more of:

• An incomplete/stale codex:// user-level protocol registration overriding AppX registration.
• OAuth redirect URL being passed to Electron as an app path/module path instead of being routed as a URL.
• A stale plugin cache/version reference (45fe2bdd vs bebc3d6a) affecting connector launch/auth.
• Possible collision or confusion between notion:// and codex:// during OAuth callback handling.

Impact

The bundled Notion connector cannot be authorized from Codex Desktop on Windows, blocking Notion MCP tools and workflows such as writing generated documentation into Notion.