[BUG] Claude.ai Desktop for Windows does not fire notification toasts

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?

Recommended labels: area:desktop, bug, platform:windows

The Claude Desktop app's Chat surface does not fire a Windows toast notification when a response completes while the app is backgrounded, occluded by another window, or on a different virtual desktop — despite the in-app notification toggle being on and OS-level Focus Assist/DND disabled.

Diagnostic isolation confirmed this is not a permissions, suppression, or registration issue: the app's Windows notification identity (AUMID: <package-family-name>!Claude) is registered, enabled, and demonstrably functional — Claude Code's task-completion notifications, sharing the same package identity, fire correctly and are recorded in HKCU\Software\Microsoft\Windows\CurrentVersion\Notifications\Settings. A controlled test comparing PeriodicNotificationCount before and after a fully-backgrounded Chat response showed zero change (17 → 17), confirming the Chat completion event never calls the toast API — it isn't failing silently, it isn't being called at all.

Note that this is for the Chat surface of the Desktop app specifically. Claude Code's desktop notifications (same app, different surface) do work — as do desktop notifications fired by the web app at claude.ai — so this isn't "notifications are broken app-wide," it's isolated to one completion-event handler.

What Should Happen?

When a Chat response completes while Claude Desktop is not the foreground/focused window, a Windows toast notification should fire, consistent with the behavior already present for Claude Code task completions within the same app.

Error Messages/Logs

None available — this is a silent omission, not a thrown error. No exception, no log entry generated by the missing call. N/A — failure is an absence of a call, not an error.

Steps to Reproduce

1. Confirm in-app notification setting is enabled (Settings → Notifications).
2. Confirm Windows Focus Assist / DND is off.
3. Send a message to Claude in the Chat tab of Claude Desktop.
4. Immediately switch focus away from Claude Desktop — move to a different application window and/or a different virtual desktop, so Claude Desktop is fully backgrounded and occluded.
5. Wait for the response to complete (confirmed separately by checking the app after returning to it).
6. Observe: no Windows toast notification appears.

Verification method used: query (Get-ItemProperty "HKCU:\Software\Microsoft\Windows\CurrentVersion\Notifications\Settings\<AUMID>").PeriodicNotificationCount before step 3 and again after step 5 — count is unchanged, confirming no notification call was made.

Note that model choice is orthogonal to this bug.

Claude Model

Not sure / Multiple models

Is this a regression?

No, this never worked

Last Working Version

N/A — never worked, so no prior working version to cite.

Claude Code Version

2.1.205 (Claude Code). Code CLI version provided for reference only; bug is in Desktop app's Chat surface, not Code.

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Terminal/Shell is N/A — bug occurs in the Claude Desktop GUI app, not a terminal-based Claude Code session. PowerShell was used only for diagnostic registry queries, not for reproducing the bug itself.

Full diagnostic chain:

• AUMID confirmed via Get-StartApps: Claude_pzs8sxrjxfjjc!Claude
• Registration confirmed present/enabled via HKCU:\...\Notifications\Settings\Claude_pzs8sxrjxfjjc!Claude — no Enabled: 0 override
• Same AUMID has 17 recorded notifications (PeriodicNotificationCount), attributable to Claude Code task-completion toasts fired the same session
• Controlled before/after test on a Chat-tab response, fully backgrounded: count unchanged (17 → 17)
• Rules out: in-app toggle (on), Focus Assist/DND (off), unregistered app, disabled registration, packaging manifest defect (packaged-app registration confirmed functional via Code's toasts)
• Related open issues: #42041 (Windows, same symptom, less detail), #50480 (macOS variant, also confirms registration/permission is not the cause)

Additional data point: desktop notifications fire correctly from the claude.ai web app (browser) for the same account under the same conditions. This confirms the response-completion signal and notification delivery path both function correctly outside the Desktop client — the defect is isolated to the Desktop app's own Chat-tab notification handling, not a backend/webapp issue.