Incident notice — Codex sandbox failure blocking DC-049

Start by tracing the apply_patch entry point into the Windows sandbox helper’s setup and refresh path, using the reported CMakeLists.txt reproduction in the writable workspace. Compare the helper behavior with ordinary PowerShell reads and the granted workspace permissions. Done means authorized files can be read and modified successfully, while unauthorized paths produce a clear access-denied response instead of helper_unknown_error.

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

Codex Codex & OWL Version 26.714.70719 Released Jul 21, 2026

What subscription do you have?

pro

What platform is your computer?

windows 11 pro and Debian Linux 13

What issue are you seeing?

no-active-thread-019f9444-549d-7b31-9d48-eaaa6df999e0

fs sandbox helper failed with status exit code: 1: windows sandbox failed: helper_unknown_error: setup refresh had errors

What steps can reproduce the bug?

Feedback ID: no-active-thread-019f9444-549d-7b31-9d48-eaaa6df999e0

What is the expected behavior?

apply_patch should read and modify files located inside a workspace path that Codex reports as writable.
For the reproduction patch, the expected behavior is:
The target CMakeLists.txt is read successfully.
The specified line is changed.
apply_patch reports successful completion.
No permission or sandbox-refresh error occurs because the target is within an authorized writable workspace.
If the target is outside the permitted workspace, Codex should instead return a clear access-denied error identifying the unauthorized path and allow an explicit permission request. It should not fail with the internal error:
helper_unknown_error: setup refresh had errors

Additional information

A few additional details may help isolate it:
Environment: Codex desktop on Windows with PowerShell.
The failure occurs inside apply_patch during sandbox setup/refresh, before normal patch verification or file modification.
PowerShell could read the same target files successfully.
The permission profile explicitly listed the target path as writable.
An exact-directory read/write permission request was granted, but the error persisted.
Both absolute and workspace-relative paths failed.
It reproduced in the canonical ANNIE directory and in the task’s own writable workspace.
It persisted across a fresh Codex task.
The target repository had unrelated uncommitted changes, but the failure happened before Git was involved.
No partial modifications were created.
This does not appear to involve NTFS ACLs, Git ownership, safe.directory, repository locks, compiler tooling, network access, or storage quota.
The especially useful diagnostic distinction is that ordinary shell reads and file copies worked while apply_patch failed. That suggests the defect is specific to the Windows sandbox helper’s refresh/setup path rather than general filesystem access.
Timestamp: July 23–24, 2026, America/Los_Angeles.

6:27 AM

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