[BUG] Cowork Live Artifacts sidebar entry missing on Windows 1.26832.0 — no reachable surface on any platform (repro of #51426)

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?

Same symptom as #51426 (closed as not planned / stale), but on Windows, so it is not macOS-specific — and with an additional consequence that makes it a total loss of access rather than a cosmetic issue.

Environment

• Claude Desktop 1.26832.0 (Anthropic MSIX installer, C:\Program Files\WindowsApps\Claude_1.26832.0.0_x64__pzs8sxrjxfjjc)
• Electron 42.7.0 / Node 24.19.0, Windows 11
• Single 2560x1440 display, window 2575x1407 — not a responsive-collapse case
• Updater confirms latest: [updater] Staged version 1.26832.0 is still current (latest: 1.26832.0, lastTarget: null)

What happens

The Cowork sidebar renders only 5 nav items — New / Projects / Scheduled / Dispatch (beta) / Customize. There is no Artifacts entry and no Pinned section, even though 5 live artifacts exist on the account.

The data layer is completely intact

• list_artifacts over the device bridge returns all 5 artifacts with correct createdAt/updatedAt
• main.log records every mutation normally:

``
[CoworkArtifacts] Created { id: 'careercoach-review-logic', name: '...' }
[CoworkArtifacts] Updated { id: 'retention-lever-simulator' }
[CoworkArtifacts] Protocol handler registered
``

• %APPDATA%\Claude\Partitions\cowork-artifact-<sessionUuid>-<accountUuid> exists
• device_stage_files with artifact_ids still returns each artifact's HTML correctly

Flicker confirmed within a single app run

After sending Ctrl+R to the renderer, the Artifacts entry appeared and the Pinned section listed all 5 artifacts — screen-captured and verified. Minutes later, with no restart and no navigation away, it was gone again: a click at the exact coordinate where Artifacts had rendered opened Customize instead, i.e. the list had silently reverted to 5 rows between the capture and the click.

So it is not only "appears once, then disappears on relaunch" as in #51426 — it flickers inside one run.

Workarounds attempted, all failed

• 28 renderer reloads (8 + 20) with an automated row-count detector watching the nav block for the extra row — never landed on a cohort with the flag on
• Local GrowthBook cache: [growthbook] loaded 238 features; grepping the full log returns zero features matching cowork|artifact|sidebar — consistent with #51426's finding that the local flag cache has nothing artifact-related
• DevTools is disabled in the packaged build (Ctrl+Shift+I opens the Incognito chat instead), so the renderer cannot be navigated to /artifacts manually
• Full machine reboot, app restart, winget upgrade (Claude is not listed — it self-updates)

Why this is worse than cosmetic

On the same account, claude.ai in Chrome does render an Artifacts nav item — but its Artifacts view is empty, which is expected and documented ("Live artifacts are available on the desktop app only. They don't appear in the Artifacts view on web or mobile").

So when the desktop rollout flag lands off, there is no surface on any platform where these artifacts can be opened. Desktop hides the entry point; web and mobile deliberately do not list live artifacts. The artifacts still exist, still update, and are simply unreachable.

This also hurts multi-machine users specifically: with three PCs, whether the artifact list is reachable becomes a per-machine coin flip.

What Should Happen?

Two things:

1. The Artifacts sidebar entry should be stable. Once an account has created a live artifact, the entry point should render on every page load regardless of which rollout cohort the request lands in. As #51426 suggests, this likely needs server-side state ("has this account ever created a live artifact?") rather than a per-request flag draw.

1. There should always be at least one reachable surface. While the flag stabilizes, it would help a great deal if the web Artifacts view listed Cowork live artifacts read-only. Today, if the desktop entry point is hidden, the artifacts are unreachable everywhere — which is a data-access failure, not a UI nit.

Error Messages/Logs

[updater] Staged version 1.26832.0 is still current (latest: 1.26832.0, lastTarget: null)

[CoworkArtifacts] Created { id: 'careercoach-review-logic', name: 'Careercoach Review Logic' }
[CoworkArtifacts] Updated { id: 'retention-lever-simulator' }
[CoworkArtifacts] Updated { id: 'career-coach-viability-calculator' }
[CoworkArtifacts] Updated { id: 'korea-newsletter-references' }
[CoworkArtifacts] Updated { id: 'early-24mo-benchmark-table' }
[CoworkArtifacts] Protocol handler registered
[CoworkArtifacts] Failed to load { err: Error: ERR_ABORTED (-3) loading 'cowork-artifact://local/retention-lever-simulator/index.html' }

[growthbook] loaded 238 features (5 changed)
# grep of the full main.log for /cowork|artifact|sidebar/ among GrowthBook feature names: 0 matches

Steps to Reproduce

1. On Windows, sign in to Claude Desktop 1.26832.0 and open Cowork.
2. From a Cowork session, create live artifacts via the MCP tool create_artifact (5 in this case). They are created successfully — list_artifacts returns them and main.log logs [CoworkArtifacts] Created.
3. Look at the Cowork sidebar. It shows only: New / Projects / Scheduled / Dispatch (beta) / Customize. There is no Artifacts entry and no Pinned section.
4. Press Ctrl+R to reload the renderer. Occasionally the Artifacts entry and the Pinned list appear (confirmed by screen capture).
5. Without restarting or navigating away, wait a few minutes and interact again — the entry is gone. Clicking the coordinate where Artifacts had rendered activates Customize, i.e. the nav silently reverted to 5 rows.
6. Repeat Ctrl+R (28 attempts here, automated with a row-count detector on the nav block) — the entry does not reliably come back.
7. Open claude.ai in a browser on the same account: an Artifacts nav item exists, but the Artifacts view is empty, because live artifacts are desktop-only by design.

Result: the artifacts exist and keep updating, but there is no surface on any platform from which they can be opened.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Desktop 1.26832.0 (Windows MSIX) — not Claude Code CLI

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Filed after reproducing #51426 on Windows. That issue was closed as not planned / stale, so this is a fresh report rather than a comment on a closed thread.

Note on the form fields: this is the Claude Desktop app, not the Claude Code CLI, so "Claude Code Version" and "Terminal/Shell" do not really apply — the version above is the desktop app build.

Related: #49428, #48407, #49748 (other Cowork UI surfaces disappearing after updates), #37160 (Cowork tab not visible on Windows).