[BUG]

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Bug Report: Claude Code crashes on CPUs without AVX support

Claude Code VS Code extension fails with exit code 3 on CPUs that do not support AVX instructions. The extension worked fine on a previous version but stopped working after an automatic update.

Environment:

• OS: Windows 10
• Claude Code extension version: 2.1.78
• Bun version: 1.3.11
• CPU: does not support AVX/AVX2

Root cause:
Running the bundled claude.exe directly in terminal confirms that Bun v1.3.11 crashes immediately due to missing AVX CPU support. This worked in a previous version of the extension.

Workaround:
Installing an older version of the extension (e.g. 2.1.0) resolves the issue.

What Should Happen?

Claude Code should work on CPUs without AVX support, or clearly state the minimum CPU requirements in the documentation.

Error Messages/Logs

CPU lacks AVX support. Please consider upgrading to a newer CPU.
panic(thread 22224): attempt to use null value
oh no: Bun has crashed.

Steps to Reproduce

1. Open VS Code on a machine with a CPU that does not support AVX (e.g. older Intel CPU, Windows 10)
2. Open the Claude Code extension panel
3. Extension immediately closes with exit code 3

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.78

Platform

Other

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_