Poor rendering performance

[hmorneau]

Describe the bug

I have a problem of poor rendering performance that been around for a while. The problem worsen as the conversation grow in length up to the point where it can hang for 30-45 seconds. Clearing the conversation always fix it. When the terminal hang, it's impossible to type, Ctlr-C to close the program also doesn't work.

It happens after the agent run the test.

Affected version

GitHub Copilot CLI 1.0.35-3.

Steps to reproduce the behavior

1. Run mix test (which output a lot of dots).
2. The slowdown start immediatly and degrade further if more test are run

Copy this in the CLI input to reproduce, input a few times to degrade further:
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Expected behavior

Should stay fast like Claude Code, Codex CLI, OpenCode, etc.

Additional context

• M1 Max 32GB
• Happens in all terminal (VS Code, Ghostty, Terminal)

[hmorneau]

One thing I have noticed, 5.4 cause the CLI to slowdown much faster than if I use Opus, so I'm not sure what is the difference.

[mrairdon-midmark]

Still exists on 1.0.32. Crazy poor performance compared to 1.0.30 for some reason.

[hmorneau]

@mrairdon-midmark Yeah, I'm not sure when they will fix it. What specs your computer?

[hmorneau]

Ok, I was able to reproduce it in a consistant manner, I updated the issue.

[hmorneau]

I see significant improvement in 1.0.35-4

[hmorneau]

Confirmed as fully fixed on 1.0.35-4. Thanks guys! I was struggling with this for months and I had hard time finding how to reproduce.