[BUG] Continuous "API Error: 400 due to tool use concurrency issues" in Claude Code in VS Code

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?

Continuously getting 400 errors using CC in VS Code. Have wipe history, logged out and back in, deleted Claude and reinstalled. Same issues

What Should Happen?

Claude should proceed with work as instructed

Error Messages/Logs

API Error: 400 due to tool use concurrency issues

Steps to Reproduce

1. Instruct Claude to do something
2. Claude responds with "API Error: 400 due to tool use concurrency issues"

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.19

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_