Mobile client lists VS Code task but cannot retrieve its messages

What happened?

A Codex task created and actively used through the VS Code extension is visible in the Codex mobile client, but opening it fails with a message equivalent to "could not retrieve messages." The same task and its complete message history open correctly in the Codex desktop app on the Mac where the task was created.

This creates a partial-sync state: task metadata (title/list entry) is available on mobile, while the conversation history is not.

Steps to reproduce

1. Open a multi-root workspace in VS Code on macOS.
2. Start and use a Codex task through the OpenAI Codex VS Code extension.
3. Confirm that the task and its history open in the Codex desktop app on the same Mac.
4. Open Codex on mobile using the same account.
5. Select the task from the task list.

Expected behavior

The task history should load on mobile, or the UI should explicitly explain that this local task cannot be opened remotely and offer a supported handoff path.

Actual behavior

The task appears in the mobile task list, but opening it reports that the messages cannot be retrieved. The history remains intact and readable from the desktop app.

Environment

• Host OS: macOS
• Origin: VS Code multi-root workspace
• VS Code extension: openai.chatgpt@26.901.22334
• Codex CLI: 0.151.0-alpha.7.2
• Desktop and mobile clients use the same account
• Task host reported by the desktop client: local
• Mobile OS and app version: not captured

Additional context

The desktop client can retrieve the task's turns, including completed and interrupted turns, so the underlying local history does not appear to be corrupted. No conversation text, repository content, or private logs are included in this report.

No source files or tests are named. Start by reproducing the issue with the specified macOS, VS Code multi-root workspace, extension, and Codex CLI versions, then compare mobile retrieval with the desktop task history. Done means the mobile history loads, or the client clearly explains that local tasks cannot be opened remotely and provides a supported handoff path.