[BUG] VS Code extension hangs on WSL2 — PendingMigrationError (navigator global) prevents MCP server from starting

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?

Extension host throws PendingMigrationError: navigator is now a global in nodejs on activation, MCP server never starts, claude process spawns and sits in do_epoll_wait for 30s then times out. UI spins forever, stop button unresponsive.

What Should Happen?

I should be able to use Claude Code extension in VS Code WSL mode.

Error Messages/Logs

ss -tlnp shows no MCP server port ever opens
ps aux shows zombie + stuck process pair on every interaction
/proc/<PID>/wchan = do_epoll_wait
Extension host log shows PendingMigrationError immediately before MCP server should start

Steps to Reproduce

1. Open a WSL2 project in VS Code via code . from WSL terminal (Ubuntu 20.04, VS Code 1.112.0)
2. Open the Claude Code panel and send any message
3. Observe infinite spinner, stop button unresponsive

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

This debugging/report was done with the help of Claude Code web chat. I also tried to use VS Code Insiders with the same result.