VS Code extension crashes (exit code 3221225477) when MCP server reports hasResources: true — CLI works fine in terminal

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 VS Code extension panel crashes with exit code 3221225477 (0xC0000005 — Windows STATUS_ACCESS_VIOLATION) shortly after startup. The crash consistently occurs right after an MCP server reports hasResources: true in its capabilities during connection.

What Should Happen?

The extension panel should initialize normally with MCP servers that expose resources, the same way a plain terminal session does with the same server connected.

Error Messages/Logs

[DEBUG] MCP server "meta-ads": Successfully connected (transport: http) in 826ms
[DEBUG] MCP server "meta-ads": Connection established with capabilities: {"hasTools":true,"hasPrompts":false,"hasResources":true,"hasResourceSubscribe":false,"serverVersion":{"name":"Meta Ads MCP Server","version":"1.0.0"}}
[DEBUG] [MCP] Server "meta-ads" connected with subscribe=false
Error: Claude Code process exited with code 3221225477

Steps to Reproduce

1. Configure a custom HTTP MCP server that reports hasResources: true in its connection capabilities (in my case, a Meta Ads MCP server connected via /mcp)
2. Open VS Code
3. Click the Claude Code icon in the sidebar to open the panel
4. Extension initializes, MCP server connects successfully
5. Extension crashes almost immediately after connection with exit code 3221225477
6. Note: running claude directly in VS Code's integrated terminal (not the sidebar panel) with the same MCP server connected works with no crash — this isolates the bug to the extension's embedded panel process specifically

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.211

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

claude doctor reports a clean install with no issues. Already tried: npm update -g @anthropic-ai/claude-code (already latest), npm approve-scripts --allow-scripts-pending (cleared, no effect on crash), reinstalling the extension. CLI works fully and stably via terminal with the same MCP server connected — issue is isolated to the VS Code sidebar panel process only.