Bug: shell/apply_patch broken in Desktop App 26.429.61741 — command array serialized as string

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

Codex Desktop App: 26.429.61741 (Microsoft Store)

What subscription do you have?

Pro

What platform is your computer?

Windows 11

What issue are you seeing?

Environment:

• Codex Desktop App: 26.429.61741 (Microsoft Store)
• Windows
• CLI 0.128.0: NOT affected
• Local DeepSeek relay on localhost:8787

Symptom:
shell fails with: "failed to parse function arguments: invalid type: string, expected a sequence"
apply_patch fails with: "unsupported call"
Other tools (update_plan, view_image) work fine.

Root cause:
The Desktop App serializes the command array as a JSON string instead of a native array.
Wrong: "command": "[\"cmd\", \"/c\", \"echo test\"]"
Correct: "command": ["cmd", "/c", "echo test"]

Relay-side workaround has no effect on Desktop App.

What steps can reproduce the bug?

1. Open Codex Desktop App 26.429.61741 on Windows
2. Open any project workspace
3. Type: "Run echo test" or any prompt that triggers a shell command
4. App attempts to call shell tool
5. Error: "failed to parse function arguments: invalid type: string, expected a sequence"
6. Same for apply_patch: "unsupported call"

Uploaded thread: fdc9a3fd-a649-4a92-809d-3159755f3925

What is the expected behavior?

shell and apply_patch should execute successfully like they do in CLI 0.128.0 with the same relay configuration.

Additional information

Already tested and proven: the bug is in the Desktop App client, not in the relay. CLI 0.128.0 with identical localhost:8787 relay works perfectly. Relay-side workaround was applied and confirmed working - but Desktop App still fails because it rejects the calls before they reach the relay.

No workaround available. App is unusable for coding tasks without shell/apply_patch.