macOS Slack appshot fails with noWindowsAvailable despite visible window

What version of the Codex App are you using (From “About Codex” dialog)?

ChatGPT/Codex Desktop 26.727.40816 (build 6067)

Computer Use helper: 26.727.1000550 (build 1000550)

What subscription do you have?

ChatGPT Pro

What platform is your computer?

Darwin 25.5.0 arm64 arm
macOS 26.5.2 (25F84)

Target app: Slack 4.51.180 (build 451000180), bundle identifier com.tinyspeck.slackmacgap.

What issue are you seeing?

Appshots consistently fail when Slack is the frontmost target. The Double Command hotkey is registered and received, and Codex correctly identifies Slack, but the native Computer Use capture bridge fails immediately with:

Codex Computer Use Apple Event error -10005: noWindowsAvailable
failureReason=start_request_failed:computer_use:-10005
hadAxText=false
hadScreenshot=false
status=failed

This does not appear to be a general Appshot or macOS permission failure:

• Appshots through the same capture pipeline have succeeded for Chrome, Notion, and Linear.
• CoreGraphics currently lists Slack as an on-screen layer-0 window with kCGWindowSharingState: 1.
• Codex identifies Slack as the frontmost target before the Computer Use helper rejects the capture.
• The failure has repeated across full ChatGPT/Codex app restarts.

Sanitized desktop log sequence:

Appshot hotkey pressed hotkey=DoubleCommand
Appshot shortcut found target bundleIdentifier=com.tinyspeck.slackmacgap name=Slack
Appshot capture request created bundleIdentifier=com.tinyspeck.slackmacgap name=Slack source=hotkey
Appshot capture start request sent bundleIdentifier=com.tinyspeck.slackmacgap name=Slack source=hotkey
Codex Computer Use capture worker failed errorMessage="Codex Computer Use Apple Event error -10005: noWindowsAvailable" failureReason=start_request_failed:computer_use:-10005
Appshot capture settled failureReason=start_request_failed:computer_use:-10005 hadAxText=false hadScreenshot=false status=failed

Raw logs are not attached because they can contain private application context.

What steps can reproduce the bug?

1. Open ChatGPT/Codex Desktop and an active Codex thread.
2. Bring a normal, visible Slack window to the front.
3. Press both Command keys to invoke Appshot.
4. Observe that Codex identifies Slack, pauses briefly, and fails to attach the Appshot.
5. Inspect ~/Library/Logs/com.openai.codex/; the capture start fails with -10005: noWindowsAvailable before producing screenshot or Accessibility content.

The failure reproduced repeatedly on July 23, July 27, and July 29, 2026.

What is the expected behavior?

Codex should capture the visible frontmost Slack window and attach its screenshot and Accessibility context, as it does for other supported applications. If the window cannot be captured, the helper should report why its window filter rejected a CoreGraphics-visible, shareable window.

Additional information

This looks like a Slack/Electron window-selection compatibility regression in the Appshot / Computer Use bridge rather than a system-wide capture failure.

Related but distinct reports:

• #27829 reports cgWindowNotFound across multiple applications. This report has the different noWindowsAvailable signature and is target-specific to Slack.
• #25596 reports a permanent hang when capturing background Electron applications. This report fails immediately while Slack is frontmost and does not freeze the session.

The last locally recorded successful Slack Appshot preceded the current failure period; other application targets continued to succeed afterward.