File Write Operations Not Reflected in Codex CLI Environment

What version of Codex is running?

0.1.2504251709

Which model were you using?

gpt-4.1

What platform is your computer?

linux | x64 | 5.15.167.4-microsoft-standard-WSL2

What steps can reproduce the bug?

• ```

Codexの素晴らしい使い方を具体的なプロンプトの例を含めて README.md へ日本語で記述してください。
これは、あなた (Codex) の通常の書き込み方法であるバッチ方式を適切に用いて行ってください。
```

• 1 reasoning | 0 tool
• ```

書き込みできていません。要因について自己のことを深く理解し、現環境を適切に調査し、熟考した上で対処してください。
```

• 1 reasoning | 13 tool
• ```

バグ可能性として報告してください
```

• 1 reasoning | 0 tool
• ```

英語で出力してください
```

• 1 reasoning | 0 tool

Steps to Reproduce:

1. In the Codex CLI environment, try writing to any file (e.g., echo "test content" > testfile or modify an existing README.md).
2. Immediately run cat testfile (or the relevant file).
3. File permissions (ls -l) and file attributes (lsattr) appear normal; no explicit restrictions.
4. The file remains empty—none of the written content is actually saved.

What is the expected behavior?

_No response_

What do you see instead?

_No response_

Additional information

Bug Report: File Write Operations Not Reflected in Codex CLI Environment

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Summary:
Attempts to write to files (e.g., README.md or temporary files) from within the Codex CLI agent result in empty files. Even after executing standard shell
commands to write content, cat and other read commands show the files remain empty.

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Steps to Reproduce:

1. In the Codex CLI environment, try writing to any file (e.g., echo "test content" > testfile or modify an existing README.md).
2. Immediately run cat testfile (or the relevant file).
3. File permissions (ls -l) and file attributes (lsattr) appear normal; no explicit restrictions.
4. The file remains empty—none of the written content is actually saved.

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Analysis & Possible Cause:

• The issue does not appear to be related to Unix file permissions or file attributes.
• Codex CLI’s internal I/O wrapper or sandbox layer is likely suppressing or discarding file write operations.
• This might be related to running under WSL2, overlay/ext4 filesystems, or in a process-isolated/sandboxed environment.
• Standard output/error commands (e.g., echo test, shell command outputs) work properly. Only file write operations fail to persist.

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Impact:

• All automatic file generation, patching, or pre-commit file operations via Codex agent are ineffective.
• The inability to write files means the Codex agent cannot perform automated fixes, patches, or code generation as intended.

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Suggested Follow-up / Checks:

• Double-check Codex CLI’s I/O subsystem, any sandboxing layers, or restrictions in this environment.
• Investigate if the issue is specific to WSL2, Docker containers, CI runners, or special filesystem overlays.
• Test with temporary work directories and different filesystem layers.
• Try changing the CLI execution user or permissions.
• If this is an intended sandbox limitation, it should be clearly documented in user guides.

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Note:
If you need to review the actual intended patch for manual application, I can output the patch content directly in unified diff format for copy-pasting.

Please advise if you need additional environment diagnostics or further tests.