[BUG] Chrome file_upload rejects every path in scheduled-task sessions (worked before, breaks weekly business workflow)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Duplicate/continuation of #63334, which was closed as "not planned" — adding a real-world case because I think it deserves a second look.

I run a weekly scheduled task in Claude Desktop (macOS, app 1.30096.5) that prepares a car auction (~430 vehicles) and uploads two generated xlsx files to a valuation site via the Chrome extension's file_upload. This workflow ran fine for weeks. Since roughly mid-August every scheduled run fails: file_upload rejects every path with

Cannot upload "...": only files the user has shared with this session can be uploaded.

The paths are inside folders that ARE connected to the task (also tried a simple path without spaces — same result). This matches the root cause in #63334: the scheduled-task session is rejected as an unknown session before the file allowlist is even checked. The same upload, same skill, same target site works fine from a regular (non-scheduled) session on the same machine, so this is purely about the session type.

Impact: the whole point of scheduled tasks is unattended operation. A browser upload step that only works when a human starts the session defeats that. Even the minimal fix from #63334 (surface the real INVALID_SESSION error instead of the misleading permission message) would have saved days of debugging in the wrong direction.

Happy to provide logs from my runs.

What Should Happen?

file_upload should work in scheduled-task sessions exactly as it does in regular sessions: files inside folders connected to the task should be uploadable. The whole point of scheduled tasks is unattended operation; a browser upload step that only works when a human starts the session defeats that.

At minimum, the error should report the real cause (INVALID_SESSION) instead of the misleading "only files the user has shared with this session" message — that alone cost days of debugging in the wrong direction.

Error Messages/Logs

Steps to Reproduce

1. In Claude Desktop on macOS, create a scheduled task that uses the Claude in Chrome extension, with a local folder connected to the task (Working folders).
2. In the task prompt, have Claude navigate to any page with a file input (e.g. an upload form) and upload a file from the connected folder using the Chrome extension's file_upload tool.
3. Let the task run on its schedule (not started manually as a chat).
4. file_upload rejects the path with "Cannot upload ...: only files the user has shared with this session can be uploaded" — for every path, including simple ones without spaces, inside connected folders.
5. Run the exact same steps in a regular (non-scheduled) Cowork session on the same machine: the upload succeeds.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Desktop (Cowork) 1.30096.5 — the bug occurs in Desktop scheduled tasks, not the CLI

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_