ChatGPT/Codex Desktop fails on startup: `Model provider responses not found` in bundled app-server

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

Unable to access the About dialog because the app fails during startup.

What subscription do you have?

ChatGPT account (exact plan not relevant to startup failure).

What platform is your computer?

macOS, Apple Silicon.

What issue are you seeing?

ChatGPT/Codex Desktop fails during app-server initialization with:

error loading default config after config error: Model provider `responses` not found

Desktop logs show the Electron app starts, then the bundled Codex binary at:

/Applications/ChatGPT.app/Contents/Resources/codex

is spawned for the local app-server connection and exits with code 1 during the initialize handshake.

Relevant log excerpt:

[AppServerConnection] initialize_handshake_result ... outcome=failure ...
Most recent error: Error: error loading default config after config error: Model provider `responses` not found

[StdioConnection] stdio_transport_spawned ... executablePath=/Applications/ChatGPT.app/Contents/Resources/codex ...

[AppServerConnection] app_server_connection.closed code=1 ... reason="Error: error loading default config after config error: Model provider `responses` not found"

This prevents the desktop app from becoming usable.

What steps can reproduce the bug?

1. Launch ChatGPT Desktop on macOS.
2. App starts its bundled Codex app-server.
3. Initialization immediately fails with:

Model provider `responses` not found

4. App remains unusable.

The failure is reproducible on every launch.

Troubleshooting already performed

The following were tried without changing the error:

• Updated/reinstalled ChatGPT Desktop.
• Reset ~/Library/Application Support/com.openai.codex.
• Reset Codex-related cache/preferences/HTTP storage.
• Removed/renamed ~/.codex/config.toml so no user config is loaded.
• Confirmed the app bundle identifier is com.openai.codex.
• Restarted the app after each reset.

The exact same Model provider responses not found error remains.

This makes it look like the failure is occurring in the bundled/default config path rather than a user config.toml entry.

Expected behavior

The bundled Codex app-server should initialize successfully using the built-in OpenAI provider/default configuration, and ChatGPT Desktop should open normally.

Additional information

Log location on macOS:

~/Library/Logs/com.openai.codex/YYYY/MM/DD/codex-desktop-*.log

One observed failing log showed:

transportKind=stdio
executablePath=/Applications/ChatGPT.app/Contents/Resources/codex
code=1
reason="Error: error loading default config after config error: Model provider `responses` not found"

I searched existing open issues for the exact error string and for error loading default config + responses, and did not find an existing matching report.

Start with the bundled executable at /Applications/ChatGPT.app/Contents/Resources/codex and the initialize handshake reported in the desktop logs at ~/Library/Logs/com.openai.codex/YYYY/MM/DD/codex-desktop-*.log. Check how the bundled/default configuration resolves the responses provider, using the absence of ~/.codex/config.toml as a constraint. Done means the app-server initializes successfully and ChatGPT Desktop opens normally.