remote.extensionKind: ["ui"] causes sidebar restoration error in DevContainer

Description

When using the Claude Code VS Code extension with a DevContainer, setting remote.extensionKind to ["ui"] (to run the extension on the host side and preserve Max plan authentication) causes the sidebar to fail to load.

Steps to reproduce

1. Add to .vscode/settings.json or .devcontainer/devcontainer.json:

"remote.extensionKind": {
    "anthropic.claude-code": ["ui"]
}

1. Open the project in a DevContainer ("Reopen in Container")
2. Claude Code sidebar fails to load

Error message

view:claudeVSCodeSidebarSecondary を復元中にエラーが発生しました

(Translation: "Error occurred while restoring view:claudeVSCodeSidebarSecondary")

Expected behavior

The Claude Code extension should run on the host (UI) side and maintain the existing Max plan authentication when connected to a DevContainer.

Workaround

Instead of using remote.extensionKind, we install the Claude Code CLI inside the DevContainer and mount ~/.claude from the host:

// devcontainer.json
"mounts": [
    "source=${localEnv:HOME}/.claude,target=/home/vscode/.claude,type=bind,consistency=cached"
]

Combined with RUN pnpm add -g @anthropic-ai/claude-code in the Dockerfile, the extension picks up the Max plan authentication from the mounted ~/.claude directory.

Environment

• VS Code: Latest
• Claude Code extension: v2.1.84
• OS: macOS (Apple Silicon)
• DevContainer base image: mcr.microsoft.com/devcontainers/base:ubuntu-24.04