API Error: 400 due to tool use concurrency issues.

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?

API Error: 400 due to tool use concurrency issues.

What Should Happen?

am trying to use it but it does not work at all

Error Messages/Logs

API Error: 400 due to tool use concurrency issues.

Steps to Reproduce

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

API Error: 400 due to tool use concurrency issues.

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_