[Bug] V2 mode silently fails in GUI when codex executable is unavailable (uv_spawn 'codex' ENOENT) #1562

Client or integration

OpenCodex dashboard

Area

Dashboard

Summary

On OpenCodex 2.13.0 on Windows, selecting V2 in the Sub-agent mode selector does not change the selected mode and appears to do nothing.

Installing the Codex CLI resolves the issue and makes the V2 switch work normally in the GUI.

V1 and Base both work normally.

Running the equivalent operation from the CLI reveals that the V2 transition is failing because OpenCodex attempts to spawn codex, but no executable can be found:

multi-agent mode transition failed: ENOENT: no such file or directory, uv_spawn 'codex'

I expected either:

• V2 mode to be enabled successfully; or
• if a separately installed Codex CLI is required, the GUI to show a clear error explaining that the codex executable could not be found.

Currently, the GUI makes the failure look like an unresponsive V2 button.

Reproduction

1. Run OpenCodex 2.13.0 on Windows.
2. Open the OpenCodex dashboard.
3. In the Sub-agent mode selector, select V1.
   • V1 is selected successfully.
4. Select Base.
   • Base is selected successfully.
5. Click V2.
   • The selected mode remains Base.
   • No useful error is shown in the GUI.
6. Run the equivalent operation from Command Prompt:

ocx v2 mode v2

Result:

multi-agent mode transition failed: ENOENT: no such file or directory, uv_spawn 'codex'

The issue is consistently reproducible while codex is unavailable as an executable to OpenCodex.

Before installing the Codex CLI, where codex did not find any executable.

After installing the Codex CLI, the V2 switch started working correctly, including from the GUI.

This confirms that the issue is specifically triggered when the codex executable is unavailable.

Version

2.13.0

Operating system

Windows11 25H2 26200.8973

Provider and model

Not provider-specific.

Logs or error output

C:\>ocx v2 mode v2
multi-agent mode transition failed: ENOENT: no such file or directory, uv_spawn 'codex'

Screenshots and supporting files

No response

Redacted configuration

No provider or routing configuration appears necessary to reproduce this issue.

The relevant environment condition is that OpenCodex itself is installed and running, but a `codex` executable is not available to the V2 transition process.

Checks

• I searched existing issues and documentation.
• I removed secrets, tokens, account details, request credentials, and personal data.