Copilot CLI session stops producing output (no response text after prompt)

[tarikbrown-msft]

Describe the bug

My Copilot CLI session no longer outputs any text after I submit prompts. The UI accepts input, but the response area remains blank and no completion is displayed, effectively making the session unusable.

Affected version

Copilot CLI version: 1.0.19 (from copilot --version)

Steps to reproduce the behavior

I don't have exact step to reproduce as this seems like a random error but I was having copilot make consecutive az cli calls while having a background thread running. I think this is a performance issue that could be replicated through a stress test. If not, then this can be disregarded as a rare event.

I was also using the terminal window in VS Code

Expected behavior

Copilot should return normal response text for each prompt (a completion/answer should be printed to the terminal) and continue working across multiple prompts in the same session.

Additional context

Environment:
OS: Windows (using WSL)
WSL distro: Ubuntu (WSL 2)
Terminal: Windows Terminal
Shell: PowerShell Core 7.6.0
Copilot CLI version: 1.0.19
Screenshot attached (Image 1) showing the session state where prompts are accepted but no output is produced.

[examon]

This was likely addressed in v1.0.20 and v1.0.21. Those releases included several fixes relevant to this scenario, including reduced UI sluggishness during live response streaming, a fix for the timeline going blank when content shrinks, a fix for the spinner getting stuck while a long-running async shell command is active, and lower memory usage from automatically shutting down idle shell sessions. If you upgrade to the latest version and still see the response area stay blank, please comment with details and we'll take another look.