[BUG] claudeVSCodeSidebarSecondary fails to render in VS Code Remote SSH with ["ui"] extensionKind

[marianfeiler]

Preflight Checklist

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

What's Wrong?

The Claude Code VS Code extension fails to render the sidebar view (claudeVSCodeSidebarSecondary) when connected to a Remote SSH host. The error "Ein Fehler ist aufgetreten beim Wiederherstellen der Ansicht: claudeVSCodeSidebarSecondary" (Error restoring view: claudeVSCodeSidebarSecondary) appears and the panel stays blank. This happens because the remote server CPU lacks AVX support, causing the native binary to crash (SIGILL) when running on the server — so the extension must run locally via extensionKind ["ui"]. Even with this workaround, the WebView cannot be rendered in the Remote SSH context.

What Should Happen?

The Claude Code sidebar should render correctly when the extension is configured to run locally (extensionKind: ["ui"]) while connected to a Remote SSH workspace. Authentication works fine (OAuth tokens found in secure storage), and the extension works correctly in local workspaces — it should also work in Remote SSH workspaces.

Error Messages/Logs

VS Code Output panel (Claude VSCode):
[info] AuthManager initialized
[info] Claude code extension is now active?
[info] MCP Server running on port XXXXX (localhost only)
[info] Getting authentication status
[info] OAuth tokens found in secure storage

Error in sidebar:
"Ein Fehler ist aufgetreten beim Wiederherstellen der Ansicht: claudeVSCodeSidebarSecondary"
(Translation: "An error occurred while restoring the view: claudeVSCodeSidebarSecondary")
Root cause (when extension runs on server):
CPU lacks AVX support. Please consider upgrading to a newer CPU.
panic(main thread): Segmentation fault at address 0x5547C000000
Error: Claude Code process terminated by signal SIGILL

Steps to Reproduce

1. Connect to a remote Linux server via VS Code Remote SSH where the server CPU lacks AVX support
2. Install Claude Code extension — it crashes on the server (SIGILL / Bun AVX requirement)
3. To work around the crash, add to local settings.json:
   {
   "remote.extensionKind": { "anthropic.claude-code": ["ui"] },
   "claudeCode.runLocally": true
   }
4. Reload VS Code window
5. Open the Claude Code panel in the secondary sidebar
6. Result: blank panel with error "claudeVSCodeSidebarSecondary"

Note: Authentication works correctly (OAuth tokens found in secure storage).
Note: Claude Code works fine in local (non-SSH) VS Code windows.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Local machine: Mac Studio M4 Max, 36GB RAM, macOS Tahoe 26.3.1
Remote server: Linux x64, kernel 4.18.0, glibc 2.28
Server CPU: No AVX support (Bun v1.3.11 crashes with SIGILL on server)

The extension binary path when running locally:
/Users/urbanstudio/.vscode/extensions/anthropic.claude-code-2.1.81-darwin-arm64/resources/native-binary/claude

All remote development at urbanstudio is done via VS Code Remote SSH — local workspaces are not an option. The AVX limitation affects multiple servers/VMs, making this a blocking issue for the entire Remote SSH workflow.

Workaround attempted: setting extensionKind to ["ui"] forces the extension to run locally, which fixes the crash — but introduces the claudeVSCodeSidebarSecondary rendering failure.

[github-actions]

Found 2 possible duplicate issues:

1. [BUG] ENOENT: /home/<redacted> not found on local machine when using Claude Code extension in UI mode over SSH #34628
2. [BUG] Cannot load "Claude Code for VS Code" extension when open project with "Remote Repositories" #31390

This issue will be automatically closed as a duplicate in 3 days.

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🤖 Generated with Claude Code

[PipeItToDevNull]

This has been reported many times with no response on the bug reports, following this. Our use case makes running this extension on the remote host unfeasible, especially if you start using the containers extension.

[golles]

not stale