WSL: Notification overlay does not look correct

[peterjuras]

The notification overlay appears visually broken when peon-ping is used from within WSL via Claude CLI.

Screenshot:

[garysheng]

Thanks for the screenshot. The cropped/garbled overlay you're showing usually means the overlay window is rendering at the wrong DPI, or the Windows side of the WSL bridge is picking up an inconsistent display profile. A few details would help me reproduce:

1. WSL distro and version (wsl -l -v and uname -a inside WSL)
2. Windows version (Win10 or Win11, and build number)
3. Are you on a high-DPI / scaled display? What scaling % is set in Windows display settings?
4. peon-ping version (cat ~/.claude/hooks/peon-ping/VERSION)
5. Which terminal is hosting Claude CLI (Windows Terminal, VS Code WSL terminal, something else)?

If the overlay script is the one being invoked, it's scripts/notify.sh routing to the Windows-side overlay. Worth confirming via PEON_DEBUG=1 echo '{"hook_event_name":"Stop","cwd":"'$PWD'","session_id":"diag"}' | ~/.claude/hooks/peon-ping/peon.sh 2>&1 whether anything looks off in the dispatch path.

[peterjuras]

Hi @garysheng , thank you for looking into this!

• WSL distro Ubuntu & version 2
• uname: Linux AS24-DDC24333HH 6.6.87.2-microsoft-standard-WSL2 Install script fails on macOS: peon: unbound variable (bash 3.2 incompatibility) #1 SMP PREEMPT_DYNAMIC Thu Jun 5 18:31:42 UTC 2025 aarch64 aarch64 aarch64 GNU/Linux

2. From Windows Settings:
   Edition Windows 11 Enterprise
   Version 25H2
   OS Build 26200.8457
   Windows Feature Experience Pack 1000.26100.304.0
3. I'm sadly not sure it's a high-DPI display. Scaling is set to 100% & resolution is 3440 x 1440. The same issue occurs on both my internal display & external display.
4. 2.27.0
5. Windows Terminal

When executing PEON_DEBUG=1 echo '{"hook_event_name":"Stop","cwd":"'$PWD'","session_id":"diag"}' | ~/.claude/hooks/peon-ping/peon.sh 2>&1
there is no feedback on the terminal and the UI looks off just like in my shared screenshot.

[garysheng]

Thanks for the full setup, @peterjuras, the aarch64 line is the standout. The Windows-side notification path (scripts/win-notify.ps1 via the WSL bridge) was built and tested on x86_64 hosts, and the cropped/garbled overlay you're seeing is consistent with bitmap sizing assumptions breaking on ARM64 Win11 25H2.

Two more diagnostics to narrow it down:

1. Capture stderr from a manual run:

   PEON_DEBUG=1 echo '{"hook_event_name":"Stop","cwd":"'"$PWD"'","session_id":"diag"}' \
     | ~/.claude/hooks/peon-ping/peon.sh 2>/tmp/peon.err
   cat /tmp/peon.err

   If /tmp/peon.err is empty, that itself is the signal (PowerShell side-channel error swallowed by the bridge).

2. Try peon notifications standard and re-run. That bypasses the custom overlay window and uses native Windows toasts. If toasts render correctly the bug is isolated to the overlay rendering path on ARM64.

I'll add an ARM64 WSL2 host to the test matrix. This looks like a real fix on our side, not a config issue.

[zeroone82]

Since Peter didn't reply, and I have the same issue I'll also add my debug info. I'm having the same issue with a x86_64 version:

1. WSL version: 2.6.3.0, uname: Linux ... 6.6.87.2-microsoft-standard-WSL2 #1 SMP PREEMPT_DYNAMIC Thu Jun 5 18:30:46 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
2. Windows 11 25H2 - Build 26200.8457
3. Scaling is at 100%
4. 2.29.0
5. I've seen the same behaviour in Warp, Windows Terminal, VSCode and Zed terminals

Diagnostic:

1. Capture stderr from a manual run: Produces no output to /tmp/peon.err
2. Toasts look correct, I've attached a screenshot

[garysheng]

Thanks @zeroone82, that's a useful data point. It rules out my earlier ARM64 theory: you're on x86_64 with the same broken overlay, so the common factor with @peterjuras is now Windows 11 25H2 (build 26200.8457), not the CPU architecture. That points at how 25H2 renders the WSL-bridged overlay window rather than anything arch-specific.

To narrow it down: could you run scripts/win-notify.ps1 directly from PowerShell with a test payload (or grab its output when a notification fires) so I can see whether the bitmap is being sized wrong or the window is getting clipped by the compositor? And to confirm the scaling angle, is the 100% scaling set on every monitor, or just the primary? I'll spin up a 25H2 VM to repro on my end.

[zeroone82]

There's no scripts/win-notify.ps1 on the WSL installation, so I installed it on windows. I've ran it but it only seems to produce a toast notification, is that expected?
These are the files in WSL install:

# ls -1 ~/.claude/hooks/peon-ping/scripts
cmux-focus.sh
cmux-status-presentation.sh
cmux-workspace-field.sh
hook-handle-rename.sh
hook-handle-use.ps1
hook-handle-use.sh
mac-overlay.js
notify.sh
pack-download.sh
tts-native.sh
win-play.ps1

As a side note, the install script on Windows doesn't seem to work without the scripts/ directory, so it's needed to clone the whole repo before running it.

[garysheng]

Thanks for staying on this, @zeroone82. Your data point plus @peterjuras narrows it down nicely: the same broken overlay on both x86_64 and aarch64, both on Windows 11 25H2 (build 26200.8457). So the common factor is the 25H2 build, not the CPU arch, and it is the WinForms overlay popup specifically (scripts/notify.sh near line 706), not the toast path.

That also explains what you saw: scripts/win-notify.ps1 is the toast notification, so running it on its own correctly produces just a toast. The thing rendering wrong is the overlay window, not the toast.

Two things that would help me pin the fix:

1. Trigger an event with PEON_DEBUG=1 set and grab stderr from the overlay launch, so I can see the WinForms sizing values it computes on 25H2.
2. As a workaround in the meantime, set "notification_style": "standard" in ~/.claude/hooks/peon-ping/config.json. That uses the Windows toast instead of the WinForms overlay, so you get a clean notification while I sort out the 25H2 rendering.

This is on my list. The likely fix is in how the overlay bitmap and window get sized, which 25H2 appears to handle differently from earlier builds.