[BUG] Error launching VSCode Claude Code extension

[cloudon7281]

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?

Issue: try to launch VSCode Claude Code extension from command palette ("Claude Code: Open in Side Bar") or from spark symbol in top right of editor; new side bar tab opens but with error text "An error occurred while loading view: claudeVSCodeSidebarSecondary". VSCode and Claude Code extension are both on latest versions as of Jan 7 2026. Developer Tools console output shows suspected bug in the extension (full output below).

Mitigations attempted: reloading VS Code; restarting extension host ("Developer: Restart Extension Host"); clearing VSCode webview cache (~/Library/Caches/com.microsoft.VSCode and ~/Library/Application Support/Code/CachedData); uninstalling and reinstalling extension.

Environment:

• macOS ARM64 Sequoia v15.5
• VSCode Version: 1.107.1 (Universal)
  Commit: 994fd12f8d3a5aa16f17d42c041e5809167e845a
  Date: 2025-12-17T14:15:14.850Z
  Electron: 39.2.3
  ElectronBuildId: 12895514
  Chromium: 142.0.7444.175
  Node.js: 22.21.1
  V8: 14.2.231.21-electron.0
  OS: Darwin arm64 24.5.0VS Code
• Claude Code extension 2.0.75

What Should Happen?

Claude Code sidebar should open successfully.

Error Messages/Logs

log.ts:460   ERR t is not iterable: TypeError: t is not iterable
	at pp (/Users/cl/.vscode/extensions/anthropic.claude-code-2.0.75-darwin-arm64/extension.js:177:2371)
	at new Gc (/Users/cl/.vscode/extensions/anthropic.claude-code-2.0.75-darwin-arm64/extension.js:172:434)
	at fp.resolveWebviewView (/Users/cl/.vscode/extensions/anthropic.claude-code-2.0.75-darwin-arm64/extension.js:177:3274)
	at kY.$resolveWebviewView (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:212:93720)
	at l5.S (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:29:125043)
	at l5.Q (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:29:124823)
	at l5.M (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:29:123874)
	at l5.L (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:29:123150)
	at _d.value (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:29:121814)
	at I.C (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:27:2328)
	at I.fire (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:27:2546)
	at Vo.fire (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:29:9454)
	at _d.value (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:404:9330)
	at I.C (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:27:2328)
	at I.fire (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:27:2546)
	at Vo.fire (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:29:9454)
	at MessagePortMain.<anonymous> (file:///Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/api/node/extensionHostProcess.js:404:7564)
	at MessagePortMain.emit (node:events:519:28)
	at MessagePortMain._internalPort.emit (node:electron/js2c/utility_init:2:2949)

Steps to Reproduce

1. Launch VSCode on Mac.
2. Attempt to launch Claude Code extension via command palette: cmd-shift-P, "Claude Code: Open in Side Bar".

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

2.0.67 (Claude Code) (command line version - not the extension version)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

No response