[BUG] Invalid Request

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?

329d8bae-2a15-4e50-b6e7-81052f8f407d

I am receiving and invalid request.

API Error: 400 messages.1.content.14: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response.

I have not modified thinking and submitted this twice but still receiving invalid response.

What Should Happen?

It should create a script without any errors

Error Messages/Logs

API Error: 400 messages.1.content.14: `thinking` or `redacted_thinking` blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response.

Steps to Reproduce

Asked to make a prompt for automated trading. In this process as it is creating I script, I received an invalid request. It is in the beginning stage.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

not sure

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_