[Bug]: Cannot annotate PDFs in a remote workspace #24002

Before submitting

• I searched existing issues and reviewed related reports.
• I included the reported workflow and investigation limits below.

Area

apps/desktop — PDF preview / annotations for files in a remote workspace.

Summary

I cannot annotate PDFs stored in a remote T3 Code workspace/server. This report concerns T3's preview annotation workflow for giving the agent feedback on a PDF.

Steps to reproduce

Reported workflow; not independently reproduced:

1. Connect T3 Code to a remote workspace/server containing a PDF.
2. Open that PDF in T3 Code's preview.
3. Try to annotate the PDF.

The exact opening route (file link, Files panel, or agent-opened browser tab) has not been captured yet.

Expected behavior

I should be able to annotate the displayed PDF and pass that feedback to the agent. If this viewer does not support annotations, the interface should make that limitation clear.

Actual behavior

I cannot annotate the remote PDF. Whether the annotation control is absent, disabled, or fails after activation has not yet been established; no specific error message was reported.

Impact

The PDF annotation/review workflow is blocked. Overall severity and frequency have not been measured.

Version or commit

The server hosting the reporting thread identifies itself as 0.1.1-nightly.20261019.3360. Exact affected desktop/client version not collected.

Environment

PDF stored in a remote workspace/server (confirmed by the reporter). The reporting thread's server is Linux x64; client OS/version not confirmed.

Investigation and limits

Source inspection provides a possible explanation for the streamed browser-tab path, but does not establish which viewer the reporter used:

• PreviewView.tsx only supplies onPickElement when !isServerTab.
• ServerBrowserSurface.tsx displays remote PDF assets through a client-side <embed type="application/pdf">, while its canvas capture accessor returns null for PDFs.

These are observations from current main, not a verified root cause or a runtime test of the installed build. No claim is made that local PDFs work, or that this previously worked.

Related reports

• [Bug]: New remote streaming web previews remove DevTools & Annotation functionality #16934: broader loss of remote preview annotations. Closed after #17316 restored native annotation controls for user-opened remote tabs; the closing comment says agent-opened streamed tabs are unchanged. This report records the PDF-specific workflow; a shared cause remains possible.
• [Bug]: Remote PDF previews start a download instead of rendering after server-browser switch #16853 and [Bug]: PDF renders in floating preview but downloads in sidebar #21016: remote/sidebar PDFs downloading instead of rendering.
• Render PDFs in the right preview panel (or let agents open files in the PDF-capable viewer) #22038: PDF rendering in the right preview panel. This report focuses on annotation availability.

Logs or stack traces

None collected.

Screenshots, recordings, or supporting files

None supplied.

Workaround

No confirmed workaround for annotating the PDF in T3 Code.

Prepared with GPT-6.1-Sol through Codex in T3 Code.