Windows: Appshot fails with start_response_missing — no screenshot or accessibility text captured

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

26.908.40834

What subscription do you have?

Plus

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

Description

Appshots do not work in the ChatGPT/Codex Windows desktop app.

When the Appshot hotkey (Double Alt) is pressed, the application correctly:

• detects the hotkey
• opens/routes to a new chat
• identifies the foreground application/window
• creates an Appshot capture request
• sends the capture-start request

However, the capture backend never returns a response and the UI shows:

Failed to attach appshot

The error disappears after a few seconds.

Restarting the desktop application does not resolve the issue.

Reproduction

1. Start the ChatGPT/Codex Windows desktop app.
2. Open another application (tested with UltiMaker Cura and Microsoft Management Console).
3. Press the configured Appshot hotkey (Double Alt).
4. ChatGPT opens/routes to a new chat.
5. An error appears: "Failed to attach appshot".
6. No screenshot is attached.

Relevant log output

Example with UltiMaker Cura:

Appshot hotkey pressed hotkey=DoubleAlt
Dispatching appshot hotkey destination=automatic target=new-chat

Appshot shortcut found target
bundleIdentifier="process:C:\Program Files\UltiMaker Cura 5.12.0\UltiMaker-Cura.exe"
name="UltiMaker Cura 5.12.0"

Appshot capture request created
Appshot capture start request sent

Appshot capture start request finished
hasResponse=false

Appshot capture settled
failureReason=start_response_missing
hadAxText=false
hadScreenshot=false
permissionGrantState=undefined
status=failed

The same failure occurs with another unrelated Windows application
(Microsoft Management Console / mmc.exe):

Appshot capture start request finished
hasResponse=false

Appshot capture settled
failureReason=start_response_missing
hadAxText=false
hadScreenshot=false
permissionGrantState=undefined
status=failed

Runtime initialization

The Computer Use runtime appears to resolve successfully during application startup.

The logs resolve both the CUA helper and Node runtime under:

...\Codex\runtimes\cua_node...

including:

codex-computer-use-swift.exe
node.exe

So the runtime files appear to be present.

There is also an initialization message:

Appshot hotkey inactive configured=true enabled=false platform=win32

However, after startup the Double Alt hotkey is detected correctly and Appshot capture requests are created.

Desktop app version

OpenAI.Codex_26.908.4834.0_x64

Additional observations

• Reproduces after fully exiting the application from the system tray and restarting it.
• Reproduces with multiple foreground applications.
• The failure occurs before any screenshot or accessibility text is returned.
• permissionGrantState is undefined, rather than reporting an explicit permission denial.
• Normal ChatGPT functionality works.
• The issue appears to be between the desktop Appshot handler and the capture / Computer Use backend rather than the target application.

Expected behavior

The foreground application window should be captured and attached to the ChatGPT composer.

Actual behavior

The capture-start request receives no response (hasResponse=false) and ends with:

failureReason=start_response_missing

What steps can reproduce the bug?

Feedback ID: no-active-thread-01a09b34-fad8-7cc1-b1c6-936f72a5065d

What is the expected behavior?

No response

Additional information

No response

Start by tracing the Appshot hotkey handler and the capture-start request described in the logs, then inspect how the Windows CUA runtime handles start_response_missing and hasResponse=false. Reproduce with UltiMaker Cura or Microsoft Management Console and verify that a capture response provides screenshot or accessibility text instead of the Failed to attach appshot error.