[Windows Desktop] Local PDF file citation link repeatedly disappears from assistant messages

What version of the Codex App are you using?

Unknown (the installed AppX package version was not available through the current session diagnostics).

What platform is your computer?

Windows desktop (x64).

What issue are you seeing?

A local PDF generated by Codex is delivered using the supported plain file-citation syntax:

:codex-file-citation{path="C:\\Users\\<user>\\Documents\\Codex\\<workspace>\\output\\pdf\\report.pdf" purpose="output"}

The file link initially appears in the assistant response, but later disappears from the rendered conversation. The user has repeatedly had to ask for the link again. Re-emitting the same citation restores it temporarily, but it disappears again.

The underlying PDF still exists at the referenced local path. This therefore appears to be a desktop message-rendering or file-citation persistence issue rather than file deletion.

This has reproduced multiple times in the same long-running thread with locally generated PDFs.

What steps can reproduce the bug?

1. Use Codex Desktop on Windows with a local workspace.
2. Ask Codex to generate a PDF under the workspace, for example output/pdf/report.pdf.
3. Have the assistant return the PDF using a plain :codex-file-citation{... purpose="output"} directive.
4. Confirm that the link appears in the rendered assistant message.
5. Continue the conversation or revisit/refresh the thread.
6. Observe that the file link is no longer visible.
7. Ask Codex to return the link again.
8. Observe that the re-emitted link appears temporarily and can disappear again.

What is the expected behavior?

A rendered local file citation should remain visible and clickable for as long as the referenced file exists and the conversation message remains available.

Additional information

• The issue affects PDF deliverables and disrupts a repeated document-generation workflow.
• Re-emitting the same absolute path does not provide a lasting workaround.
• The report intentionally omits the Windows username, candidate/customer names, thread identifiers, and full local paths.
• Date observed: 2026-08-12.

Start by reproducing the issue in the Windows desktop conversation renderer using a local PDF and the plain codex-file-citation directive, then trace what happens when the thread is continued or refreshed. Done means the citation remains visible and clickable while the conversation message and referenced file still exist, without requiring re-emission.