### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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? The Claude Code panel in VS Code (opened via the sidebar "sparkle" icon, the "Claude Code" tab next to Chat/Codex, or the "Claude Code" activity bar icon)

Claude Code panel stays blank in GitHub Codespaces — concurrent session spawns deadlock on .claude.json lock

Status Open

Reported on v2.1.241

Maintainer reply None cached

Activity 0 comments · opened Aug 23, 2026

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?

The Claude Code panel in VS Code (opened via the sidebar "sparkle" icon, the "Claude Code" tab next to Chat/Codex, or the "Claude Code" activity bar icon) stays permanently blank inside a GitHub Codespace. No chat interface loads, no input box appears — just an empty white pane. This happens across every entry point into the panel (sidebar icon, editor tab, and a freshly reopened tab), so it isn't a one-off UI glitch.

Meanwhile, the Claude Code CLI works perfectly when run directly in the integrated terminal (claude command) in the same Codespace — fully authenticated, executing tasks, producing correct output. Other AI panels in the same VS Code window (GitHub Copilot Chat, Codex/OpenAI) also load and render correctly, which isolates the failure to the Claude Code extension's webview/panel specifically.

What Should Happen?

Opening the Claude Code panel should launch a session and render the same chat-style interface available in the terminal — an input box, session history, and the ability to send prompts — without needing to fall back to the raw terminal.

Error Messages/Logs

[error] Failed to load config cache: Error: Channel canceled mid-launch
[error] Error processing client request: Error: Channel canceled mid-launch
[ERROR] MCP server "claude-vscode" Failed to connect SDK MCP server: AbortError: Tool permission stream closed before response received
[ERROR] Failed to save config with lock: Error: Lock file is already being held
[DEBUG] Lock acquisition took longer than expected - another Claude instance may be running

Steps to Reproduce

Open a GitHub Codespace with the Claude Code VS Code extension installed and authenticated (OAuth tokens present, confirmed working via terminal claude command).
Click the Claude Code icon in the activity bar, or open the "Claude Code" tab next to "Chat"/"Codex".
Observe: the panel opens but remains blank — no input box, no session.
Check Output logs (Claude Code channel) — see repeated spawn/close cycles and lock contention errors as above.
Reload window, retry from a different entry point (sidebar icon vs. editor tab) — same blank result each time.
Confirm the terminal CLI (claude) works fine in the same Codespace at the same time.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.241 (also observed briefly at 2.1.239 before an auto-update)

Platform

Other

Operating System

Other Linux

Terminal/Shell